Initial upload of NetEq4

This is the first public upload of the new NetEq, version 4.

It has been through extensive internal review during the course of
the project.

TEST=trybots

Review URL: https://webrtc-codereview.appspot.com/1073005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@3425 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq/neteq.gypi b/webrtc/modules/audio_coding/neteq/neteq.gypi
index 88c8260..371a6da 100644
--- a/webrtc/modules/audio_coding/neteq/neteq.gypi
+++ b/webrtc/modules/audio_coding/neteq/neteq.gypi
@@ -138,109 +138,7 @@
             'test/NetEqRTPplay.cc',
           ],
         },
-       {
-          'target_name': 'RTPencode',
-          'type': 'executable',
-          'dependencies': [
-            'NetEqTestTools',# Test helpers
-            'G711',
-            'G722',
-            'PCM16B',
-            'iLBC',
-            'iSAC',
-            'CNG',
-            '<(webrtc_root)/common_audio/common_audio.gyp:vad',
-          ],
-          'defines': [
-            # TODO: Make codec selection conditional on definitions in target NetEq
-            'CODEC_ILBC',
-            'CODEC_PCM16B',
-            'CODEC_G711',
-            'CODEC_G722',
-            'CODEC_ISAC',
-            'CODEC_PCM16B_WB',
-            'CODEC_ISAC_SWB',
-            'CODEC_ISAC_FB',
-            'CODEC_PCM16B_32KHZ',
-            'CODEC_CNGCODEC8',
-            'CODEC_CNGCODEC16',
-            'CODEC_CNGCODEC32',
-            'CODEC_ATEVENT_DECODE',
-            'CODEC_RED',
-          ],
-          'include_dirs': [
-            'interface',
-            'test',
-          ],
-          'sources': [
-            'test/RTPencode.cc',
-          ],
-        },
-        {
-          'target_name': 'RTPjitter',
-          'type': 'executable',
-          'dependencies': [
-            '<(DEPTH)/testing/gtest.gyp:gtest',
-          ],
-          'sources': [
-            'test/RTPjitter.cc',
-          ],
-        },
-        {
-          'target_name': 'RTPanalyze',
-          'type': 'executable',
-          'dependencies': [
-            'NetEqTestTools',
-            '<(DEPTH)/testing/gtest.gyp:gtest',
-          ],
-          'sources': [
-            'test/RTPanalyze.cc',
-          ],
-        },
-        {
-          'target_name': 'RTPchange',
-          'type': 'executable',
-          'dependencies': [
-            'NetEqTestTools',
-            '<(DEPTH)/testing/gtest.gyp:gtest',
-          ],
-          'sources': [
-           'test/RTPchange.cc',
-          ],
-        },
-        {
-          'target_name': 'RTPtimeshift',
-          'type': 'executable',
-          'dependencies': [
-           'NetEqTestTools',
-            '<(DEPTH)/testing/gtest.gyp:gtest',
-          ],
-          'sources': [
-            'test/RTPtimeshift.cc',
-          ],
-        },
-        {
-          'target_name': 'RTPcat',
-          'type': 'executable',
-          'dependencies': [
-            'NetEqTestTools',
-            '<(DEPTH)/testing/gtest.gyp:gtest',
-          ],
-          'sources': [
-            'test/RTPcat.cc',
-          ],
-        },
-        {
-          'target_name': 'rtp_to_text',
-          'type': 'executable',
-          'dependencies': [
-            'NetEqTestTools',
-            '<(webrtc_root)/system_wrappers/source/system_wrappers.gyp:system_wrappers',
-          ],
-          'sources': [
-            'test/rtp_to_text.cc',
-          ],
-        },
+
         {
          'target_name': 'NetEqTestTools',
           # Collection of useful functions used in other tests
diff --git a/webrtc/modules/audio_coding/neteq4/OWNERS b/webrtc/modules/audio_coding/neteq4/OWNERS
new file mode 100644
index 0000000..04941fa
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/OWNERS
@@ -0,0 +1,4 @@
+henrik.lundin@webrtc.org
+tina.legrand@webrtc.org
+turajs@webrtc.org
+minyue@webrtc.org
diff --git a/webrtc/modules/audio_coding/neteq4/accelerate.cc b/webrtc/modules/audio_coding/neteq4/accelerate.cc
new file mode 100644
index 0000000..3ea2e80
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/accelerate.cc
@@ -0,0 +1,81 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/accelerate.h"
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+
+namespace webrtc {
+
+Accelerate::ReturnCodes Accelerate::Process(
+    const int16_t* input,
+    int input_length,
+    AudioMultiVector<int16_t>* output,
+    int16_t* length_change_samples) {
+  // Input length must be (almost) 30 ms.
+  static const int k15ms = 120;  // 15 ms = 120 samples at 8 kHz sample rate.
+  if (num_channels_ == 0 ||
+      input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_) {
+    // Length of input data too short to do accelerate. Simply move all data
+    // from input to output.
+    output->PushBackInterleaved(input, input_length);
+    return kError;
+  }
+  return TimeStretch::Process(input, input_length, output,
+                              length_change_samples);
+}
+
+void Accelerate::SetParametersForPassiveSpeech(int /*len*/,
+                                               int16_t* best_correlation,
+                                               int* /*peak_index*/) const {
+  // When the signal does not contain any active speech, the correlation does
+  // not matter. Simply set it to zero.
+  *best_correlation = 0;
+}
+
+Accelerate::ReturnCodes Accelerate::CheckCriteriaAndStretch(
+    const int16_t* input, int input_length, size_t peak_index,
+    int16_t best_correlation, bool active_speech,
+    AudioMultiVector<int16_t>* output) const {
+  // Check for strong correlation or passive speech.
+  if ((best_correlation > kCorrelationThreshold) || !active_speech) {
+    // Do accelerate operation by overlap add.
+
+    // Pre-calculate common multiplication with |fs_mult_|.
+    // 120 corresponds to 15 ms.
+    size_t fs_mult_120 = fs_mult_ * 120;
+
+    assert(fs_mult_120 >= peak_index);  // Should be handled in Process().
+    // Copy first part; 0 to 15 ms.
+    output->PushBackInterleaved(input, fs_mult_120 * num_channels_);
+    // Copy the |peak_index| starting at 15 ms to |temp_vector|.
+    AudioMultiVector<int16_t> temp_vector(num_channels_);
+    temp_vector.PushBackInterleaved(&input[fs_mult_120 * num_channels_],
+                                    peak_index * num_channels_);
+    // Cross-fade |temp_vector| onto the end of |output|.
+    output->CrossFade(temp_vector, peak_index);
+    // Copy the last unmodified part, 15 ms + pitch period until the end.
+    output->PushBackInterleaved(
+        &input[(fs_mult_120 + peak_index) * num_channels_],
+        input_length - (fs_mult_120 + peak_index) * num_channels_);
+
+    if (active_speech) {
+      return kSuccess;
+    } else {
+      return kSuccessLowEnergy;
+    }
+  } else {
+    // Accelerate not allowed. Simply move all data from decoded to outData.
+    output->PushBackInterleaved(input, input_length);
+    return kNoStretch;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/accelerate.h b/webrtc/modules/audio_coding/neteq4/accelerate.h
new file mode 100644
index 0000000..856a01f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/accelerate.h
@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_ACCELERATE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_ACCELERATE_H_
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/time_stretch.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+
+// This class implements the Accelerate operation. Most of the work is done
+// in the base class TimeStretch, which is shared with the PreemptiveExpand
+// operation. In the Accelerate class, the operations that are specific to
+// Accelerate are implemented.
+class Accelerate : public TimeStretch {
+ public:
+  Accelerate(int sample_rate_hz, size_t num_channels,
+             const BackgroundNoise& background_noise)
+      : TimeStretch(sample_rate_hz, num_channels, background_noise) {
+  }
+
+  virtual ~Accelerate() {}
+
+  // This method performs the actual Accelerate operation. The samples are
+  // read from |input|, of length |input_length| elements, and are written to
+  // |output|. The number of samples removed through time-stretching is
+  // is provided in the output |length_change_samples|. The method returns
+  // the outcome of the operation as an enumerator value.
+  ReturnCodes Process(const int16_t* input,
+                      int input_length,
+                      AudioMultiVector<int16_t>* output,
+                      int16_t* length_change_samples);
+
+ protected:
+  // Sets the parameters |best_correlation| and |peak_index| to suitable
+  // values when the signal contains no active speech.
+  virtual void SetParametersForPassiveSpeech(int len,
+                                             int16_t* best_correlation,
+                                             int* peak_index) const;
+
+  // Checks the criteria for performing the time-stretching operation and,
+  // if possible, performs the time-stretching.
+  virtual ReturnCodes CheckCriteriaAndStretch(
+      const int16_t* input, int input_length, size_t peak_index,
+      int16_t best_correlation, bool active_speech,
+      AudioMultiVector<int16_t>* output) const;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Accelerate);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_ACCELERATE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/audio_decoder.cc b/webrtc/modules/audio_coding/neteq4/audio_decoder.cc
new file mode 100644
index 0000000..3e9b464
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_decoder.cc
@@ -0,0 +1,206 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_decoder_impl.h"
+
+namespace webrtc {
+
+bool AudioDecoder::CodecSupported(NetEqDecoder codec_type) {
+  switch (codec_type) {
+    case kDecoderPCMu:
+    case kDecoderPCMa:
+    case kDecoderPCMu_2ch:
+    case kDecoderPCMa_2ch:
+#ifdef WEBRTC_CODEC_ILBC
+    case kDecoderILBC:
+#endif
+#if defined(WEBRTC_CODEC_ISACFX) || defined(WEBRTC_CODEC_ISAC)
+    case kDecoderISAC:
+#endif
+#ifdef WEBRTC_CODEC_ISAC
+    case kDecoderISACswb:
+#endif
+#ifdef WEBRTC_CODEC_PCM16
+    case kDecoderPCM16B:
+    case kDecoderPCM16Bwb:
+    case kDecoderPCM16Bswb32kHz:
+    case kDecoderPCM16Bswb48kHz:
+    case kDecoderPCM16B_2ch:
+    case kDecoderPCM16Bwb_2ch:
+    case kDecoderPCM16Bswb32kHz_2ch:
+    case kDecoderPCM16Bswb48kHz_2ch:
+    case kDecoderPCM16B_5ch:
+#endif
+#ifdef WEBRTC_CODEC_G722
+    case kDecoderG722:
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+    case kDecoderOpus:
+    case kDecoderOpus_2ch:
+#endif
+    case kDecoderRED:
+    case kDecoderAVT:
+    case kDecoderCNGnb:
+    case kDecoderCNGwb:
+    case kDecoderCNGswb32kHz:
+    case kDecoderCNGswb48kHz:
+    case kDecoderArbitrary: {
+      return true;
+    }
+    default: {
+      return false;
+    }
+  }
+}
+
+int AudioDecoder::CodecSampleRateHz(NetEqDecoder codec_type) {
+  switch (codec_type) {
+    case kDecoderPCMu:
+    case kDecoderPCMa:
+    case kDecoderPCMu_2ch:
+    case kDecoderPCMa_2ch:
+#ifdef WEBRTC_CODEC_ILBC
+    case kDecoderILBC:
+#endif
+#ifdef WEBRTC_CODEC_PCM16
+    case kDecoderPCM16B:
+    case kDecoderPCM16B_2ch:
+    case kDecoderPCM16B_5ch:
+#endif
+    case kDecoderCNGnb: {
+      return 8000;
+    }
+#if defined(WEBRTC_CODEC_ISACFX) || defined(WEBRTC_CODEC_ISAC)
+    case kDecoderISAC:
+#endif
+#ifdef WEBRTC_CODEC_PCM16
+    case kDecoderPCM16Bwb:
+    case kDecoderPCM16Bwb_2ch:
+#endif
+#ifdef WEBRTC_CODEC_G722
+    case kDecoderG722:
+#endif
+    case kDecoderCNGwb: {
+      return 16000;
+    }
+#ifdef WEBRTC_CODEC_ISAC
+    case kDecoderISACswb:
+#endif
+#ifdef WEBRTC_CODEC_PCM16
+    case kDecoderPCM16Bswb32kHz:
+    case kDecoderPCM16Bswb32kHz_2ch:
+#endif
+    case kDecoderCNGswb32kHz: {
+      return 32000;
+    }
+#ifdef WEBRTC_CODEC_PCM16
+    case kDecoderPCM16Bswb48kHz:
+    case kDecoderPCM16Bswb48kHz_2ch: {
+      return 48000;
+    }
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+    case kDecoderOpus:
+    case kDecoderOpus_2ch: {
+      return 32000;
+    }
+#endif
+    case kDecoderCNGswb48kHz: {
+      // TODO(tlegrand): Remove limitation once ACM has full 48 kHz support.
+      return 32000;
+    }
+    default: {
+      return -1;  // Undefined sample rate.
+    }
+  }
+}
+
+AudioDecoder* AudioDecoder::CreateAudioDecoder(NetEqDecoder codec_type) {
+  if (!CodecSupported(codec_type)) {
+    return NULL;
+  }
+  switch (codec_type) {
+    case kDecoderPCMu:
+      return new AudioDecoderPcmU;
+    case kDecoderPCMa:
+      return new AudioDecoderPcmA;
+    case kDecoderPCMu_2ch:
+      return new AudioDecoderPcmUMultiCh(2);
+    case kDecoderPCMa_2ch:
+      return new AudioDecoderPcmAMultiCh(2);
+#ifdef WEBRTC_CODEC_ILBC
+    case kDecoderILBC:
+      return new AudioDecoderIlbc;
+#endif
+#if defined(WEBRTC_CODEC_ISACFX)
+    case kDecoderISAC:
+      return new AudioDecoderIsacFix;
+#elif defined(WEBRTC_CODEC_ISAC)
+    case kDecoderISAC:
+      return new AudioDecoderIsac;
+#endif
+#ifdef WEBRTC_CODEC_ISAC
+    case kDecoderISACswb:
+      return new AudioDecoderIsacSwb;
+#endif
+#ifdef WEBRTC_CODEC_PCM16
+    case kDecoderPCM16B:
+    case kDecoderPCM16Bwb:
+    case kDecoderPCM16Bswb32kHz:
+    case kDecoderPCM16Bswb48kHz:
+      return new AudioDecoderPcm16B(codec_type);
+    case kDecoderPCM16B_2ch:
+    case kDecoderPCM16Bwb_2ch:
+    case kDecoderPCM16Bswb32kHz_2ch:
+    case kDecoderPCM16Bswb48kHz_2ch:
+    case kDecoderPCM16B_5ch:
+      return new AudioDecoderPcm16BMultiCh(codec_type);
+#endif
+#ifdef WEBRTC_CODEC_G722
+    case kDecoderG722:
+      return new AudioDecoderG722;
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+    case kDecoderOpus:
+    case kDecoderOpus_2ch:
+      return new AudioDecoderOpus(codec_type);
+#endif
+    case kDecoderCNGnb:
+    case kDecoderCNGwb:
+    case kDecoderCNGswb32kHz:
+    case kDecoderCNGswb48kHz:
+      return new AudioDecoderCng(codec_type);
+    case kDecoderRED:
+    case kDecoderAVT:
+    case kDecoderArbitrary:
+    default: {
+      return NULL;
+    }
+  }
+}
+
+AudioDecoder::SpeechType AudioDecoder::ConvertSpeechType(int16_t type) {
+  switch (type) {
+    case 0:  // TODO(hlundin): Both iSAC and Opus return 0 for speech.
+    case 1:
+      return kSpeech;
+    case 2:
+      return kComfortNoise;
+    default:
+      assert(false);
+      return kSpeech;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/audio_decoder_impl.cc b/webrtc/modules/audio_coding/neteq4/audio_decoder_impl.cc
new file mode 100644
index 0000000..75455d6
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_decoder_impl.cc
@@ -0,0 +1,347 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/audio_decoder_impl.h"
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/codecs/cng/include/webrtc_cng.h"
+#include "webrtc/modules/audio_coding/codecs/g711/include/g711_interface.h"
+#ifdef WEBRTC_CODEC_G722
+#include "webrtc/modules/audio_coding/codecs/g722/include/g722_interface.h"
+#endif
+#ifdef WEBRTC_CODEC_ILBC
+#include "webrtc/modules/audio_coding/codecs/ilbc/interface/ilbc.h"
+#endif
+#ifdef WEBRTC_CODEC_ISACFX
+#include "webrtc/modules/audio_coding/codecs/isac/fix/interface/isacfix.h"
+#endif
+#ifdef WEBRTC_CODEC_ISAC
+#include "webrtc/modules/audio_coding/codecs/isac/main/interface/isac.h"
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+#include "webrtc/modules/audio_coding/codecs/opus/interface/opus_interface.h"
+#endif
+#ifdef WEBRTC_CODEC_PCM16
+#include "webrtc/modules/audio_coding/codecs/pcm16b/include/pcm16b.h"
+#endif
+
+namespace webrtc {
+
+// PCMu
+int AudioDecoderPcmU::Decode(const uint8_t* encoded, size_t encoded_len,
+                              int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcG711_DecodeU(
+      state_, reinterpret_cast<int16_t*>(const_cast<uint8_t*>(encoded)),
+      static_cast<int16_t>(encoded_len), decoded, &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderPcmU::PacketDuration(const uint8_t* encoded,
+                                     size_t encoded_len) {
+  return encoded_len / channels_;  // One encoded byte per sample per channel.
+}
+
+// PCMa
+int AudioDecoderPcmA::Decode(const uint8_t* encoded, size_t encoded_len,
+                              int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcG711_DecodeA(
+      state_, reinterpret_cast<int16_t*>(const_cast<uint8_t*>(encoded)),
+      static_cast<int16_t>(encoded_len), decoded, &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderPcmA::PacketDuration(const uint8_t* encoded,
+                                     size_t encoded_len) {
+  return encoded_len / channels_;  // One encoded byte per sample per channel.
+}
+
+// PCM16B
+#ifdef WEBRTC_CODEC_PCM16
+AudioDecoderPcm16B::AudioDecoderPcm16B(enum NetEqDecoder type)
+    : AudioDecoder(type) {
+  assert(type == kDecoderPCM16B ||
+         type == kDecoderPCM16Bwb ||
+         type == kDecoderPCM16Bswb32kHz ||
+         type == kDecoderPCM16Bswb48kHz);
+}
+
+int AudioDecoderPcm16B::Decode(const uint8_t* encoded, size_t encoded_len,
+                               int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcPcm16b_DecodeW16(
+      state_, reinterpret_cast<int16_t*>(const_cast<uint8_t*>(encoded)),
+      static_cast<int16_t>(encoded_len), decoded, &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderPcm16B::PacketDuration(const uint8_t* encoded,
+                                       size_t encoded_len) {
+  // Two encoded byte per sample per channel.
+  return encoded_len / (2 * channels_);
+}
+
+AudioDecoderPcm16BMultiCh::AudioDecoderPcm16BMultiCh(
+    enum NetEqDecoder type)
+    : AudioDecoderPcm16B(kDecoderPCM16B) {  // This will be changed below.
+  codec_type_ = type;  // Changing to actual type here.
+  switch (codec_type_) {
+    case kDecoderPCM16B_2ch:
+    case kDecoderPCM16Bwb_2ch:
+    case kDecoderPCM16Bswb32kHz_2ch:
+    case kDecoderPCM16Bswb48kHz_2ch:
+      channels_ = 2;
+      break;
+    case kDecoderPCM16B_5ch:
+      channels_ = 5;
+      break;
+    default:
+      assert(false);
+  }
+}
+#endif
+
+// iLBC
+#ifdef WEBRTC_CODEC_ILBC
+AudioDecoderIlbc::AudioDecoderIlbc() : AudioDecoder(kDecoderILBC) {
+  WebRtcIlbcfix_DecoderCreate(reinterpret_cast<iLBC_decinst_t**>(&state_));
+}
+
+AudioDecoderIlbc::~AudioDecoderIlbc() {
+  WebRtcIlbcfix_DecoderFree(static_cast<iLBC_decinst_t*>(state_));
+}
+
+int AudioDecoderIlbc::Decode(const uint8_t* encoded, size_t encoded_len,
+                             int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcIlbcfix_Decode(static_cast<iLBC_decinst_t*>(state_),
+                                     reinterpret_cast<const int16_t*>(encoded),
+                                     static_cast<int16_t>(encoded_len), decoded,
+                                     &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderIlbc::DecodePlc(int num_frames, int16_t* decoded) {
+  return WebRtcIlbcfix_NetEqPlc(static_cast<iLBC_decinst_t*>(state_),
+                                decoded, num_frames);
+}
+
+int AudioDecoderIlbc::Init() {
+  return WebRtcIlbcfix_Decoderinit30Ms(static_cast<iLBC_decinst_t*>(state_));
+}
+#endif
+
+// iSAC float
+#ifdef WEBRTC_CODEC_ISAC
+AudioDecoderIsac::AudioDecoderIsac() : AudioDecoder(kDecoderISAC) {
+  WebRtcIsac_Create(reinterpret_cast<ISACStruct**>(&state_));
+  WebRtcIsac_SetDecSampRate(static_cast<ISACStruct*>(state_), 16000);
+}
+
+AudioDecoderIsac::~AudioDecoderIsac() {
+  WebRtcIsac_Free(static_cast<ISACStruct*>(state_));
+}
+
+int AudioDecoderIsac::Decode(const uint8_t* encoded, size_t encoded_len,
+                             int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcIsac_Decode(static_cast<ISACStruct*>(state_),
+                                  reinterpret_cast<const uint16_t*>(encoded),
+                                  static_cast<int16_t>(encoded_len), decoded,
+                                  &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderIsac::DecodeRedundant(const uint8_t* encoded,
+                                      size_t encoded_len, int16_t* decoded,
+                                      SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcIsac_DecodeRcu(static_cast<ISACStruct*>(state_),
+                                     reinterpret_cast<const uint16_t*>(encoded),
+                                     static_cast<int16_t>(encoded_len), decoded,
+                                     &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderIsac::DecodePlc(int num_frames, int16_t* decoded) {
+  return WebRtcIsac_DecodePlc(static_cast<ISACStruct*>(state_),
+                                 decoded, num_frames);
+}
+
+int AudioDecoderIsac::Init() {
+  return WebRtcIsac_DecoderInit(static_cast<ISACStruct*>(state_));
+}
+
+int AudioDecoderIsac::IncomingPacket(const uint8_t* payload,
+                                     size_t payload_len,
+                                     uint16_t rtp_sequence_number,
+                                     uint32_t rtp_timestamp,
+                                     uint32_t arrival_timestamp) {
+  return WebRtcIsac_UpdateBwEstimate(static_cast<ISACStruct*>(state_),
+                                     reinterpret_cast<const uint16_t*>(payload),
+                                     payload_len,
+                                     rtp_sequence_number,
+                                     rtp_timestamp,
+                                     arrival_timestamp);
+}
+
+int AudioDecoderIsac::ErrorCode() {
+  return WebRtcIsac_GetErrorCode(static_cast<ISACStruct*>(state_));
+}
+
+// iSAC SWB
+AudioDecoderIsacSwb::AudioDecoderIsacSwb() : AudioDecoderIsac() {
+  codec_type_ = kDecoderISACswb;
+  WebRtcIsac_SetDecSampRate(static_cast<ISACStruct*>(state_), 32000);
+}
+#endif
+
+// iSAC fix
+#ifdef WEBRTC_CODEC_ISACFX
+AudioDecoderIsacFix::AudioDecoderIsacFix() : AudioDecoder(kDecoderISAC) {
+  WebRtcIsacfix_Create(reinterpret_cast<ISACFIX_MainStruct**>(&state_));
+}
+
+AudioDecoderIsacFix::~AudioDecoderIsacFix() {
+  WebRtcIsacfix_Free(static_cast<ISACFIX_MainStruct*>(state_));
+}
+
+int AudioDecoderIsacFix::Decode(const uint8_t* encoded, size_t encoded_len,
+                                int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcIsacfix_Decode(static_cast<ISACFIX_MainStruct*>(state_),
+                                     reinterpret_cast<const uint16_t*>(encoded),
+                                     static_cast<int16_t>(encoded_len), decoded,
+                                     &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderIsacFix::Init() {
+  return WebRtcIsacfix_DecoderInit(static_cast<ISACFIX_MainStruct*>(state_));
+}
+
+int AudioDecoderIsacFix::IncomingPacket(const uint8_t* payload,
+                                        size_t payload_len,
+                                        uint16_t rtp_sequence_number,
+                                        uint32_t rtp_timestamp,
+                                        uint32_t arrival_timestamp) {
+  return WebRtcIsacfix_UpdateBwEstimate(
+      static_cast<ISACFIX_MainStruct*>(state_),
+      reinterpret_cast<const uint16_t*>(payload), payload_len,
+      rtp_sequence_number, rtp_timestamp, arrival_timestamp);
+}
+
+int AudioDecoderIsacFix::ErrorCode() {
+  return WebRtcIsacfix_GetErrorCode(static_cast<ISACFIX_MainStruct*>(state_));
+}
+#endif
+
+// G.722
+#ifdef WEBRTC_CODEC_G722
+AudioDecoderG722::AudioDecoderG722() : AudioDecoder(kDecoderG722) {
+  WebRtcG722_CreateDecoder(reinterpret_cast<G722DecInst**>(&state_));
+}
+
+AudioDecoderG722::~AudioDecoderG722() {
+  WebRtcG722_FreeDecoder(static_cast<G722DecInst*>(state_));
+}
+
+int AudioDecoderG722::Decode(const uint8_t* encoded, size_t encoded_len,
+                             int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  int16_t ret = WebRtcG722_Decode(
+      static_cast<G722DecInst*>(state_),
+      const_cast<int16_t*>(reinterpret_cast<const int16_t*>(encoded)),
+      static_cast<int16_t>(encoded_len), decoded, &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderG722::Init() {
+  return WebRtcG722_DecoderInit(static_cast<G722DecInst*>(state_));
+}
+
+int AudioDecoderG722::PacketDuration(const uint8_t* encoded,
+                                     size_t encoded_len) {
+  // 1/2 encoded byte per sample per channel.
+  return 2 * encoded_len / channels_;
+}
+#endif
+
+// Opus
+#ifdef WEBRTC_CODEC_OPUS
+AudioDecoderOpus::AudioDecoderOpus(enum NetEqDecoder type)
+    : AudioDecoder(type) {
+  if (type == kDecoderOpus_2ch) {
+    channels_ = 2;
+  } else {
+    channels_ = 1;
+  }
+  WebRtcOpus_DecoderCreate(reinterpret_cast<OpusDecInst**>(&state_), channels_);
+}
+
+AudioDecoderOpus::~AudioDecoderOpus() {
+  WebRtcOpus_DecoderFree(static_cast<OpusDecInst*>(state_));
+}
+
+int AudioDecoderOpus::Decode(const uint8_t* encoded, size_t encoded_len,
+                             int16_t* decoded, SpeechType* speech_type) {
+  int16_t temp_type;
+  assert(channels_ == 1);
+  // TODO(hlundin): Allow 2 channels when WebRtcOpus_Decode provides both
+  // channels interleaved.
+  int16_t ret = WebRtcOpus_Decode(
+      static_cast<OpusDecInst*>(state_),
+      const_cast<int16_t*>(reinterpret_cast<const int16_t*>(encoded)),
+      static_cast<int16_t>(encoded_len), decoded, &temp_type);
+  *speech_type = ConvertSpeechType(temp_type);
+  return ret;
+}
+
+int AudioDecoderOpus::Init() {
+  return WebRtcOpus_DecoderInit(static_cast<OpusDecInst*>(state_));
+}
+
+int AudioDecoderOpus::PacketDuration(const uint8_t* encoded,
+                                     size_t encoded_len) {
+  return WebRtcOpus_DurationEst(static_cast<OpusDecInst*>(state_),
+                                encoded, encoded_len);
+}
+#endif
+
+AudioDecoderCng::AudioDecoderCng(enum NetEqDecoder type)
+    : AudioDecoder(type) {
+  assert(type == kDecoderCNGnb || type == kDecoderCNGwb ||
+         kDecoderCNGswb32kHz || type == kDecoderCNGswb48kHz);
+  WebRtcCng_CreateDec(reinterpret_cast<CNG_dec_inst**>(&state_));
+  assert(state_);
+}
+
+AudioDecoderCng::~AudioDecoderCng() {
+  if (state_) {
+    WebRtcCng_FreeDec(static_cast<CNG_dec_inst*>(state_));
+  }
+}
+
+int AudioDecoderCng::Init() {
+  assert(state_);
+  return WebRtcCng_InitDec(static_cast<CNG_dec_inst*>(state_));
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/audio_decoder_impl.h b/webrtc/modules/audio_coding/neteq4/audio_decoder_impl.h
new file mode 100644
index 0000000..1776a39
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_decoder_impl.h
@@ -0,0 +1,223 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_DECODER_IMPL_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_DECODER_IMPL_H_
+
+#include <assert.h>
+
+#ifndef AUDIO_DECODER_UNITTEST
+// If this is compiled as a part of the audio_deoder_unittest, the codec
+// selection is made in the gypi file instead of in engine_configurations.h.
+#include "webrtc/engine_configurations.h"
+#endif
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+class AudioDecoderPcmU : public AudioDecoder {
+ public:
+  AudioDecoderPcmU() : AudioDecoder(kDecoderPCMu) {}
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual int Init() { return 0; }
+  virtual int PacketDuration(const uint8_t* encoded, size_t encoded_len);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcmU);
+};
+
+class AudioDecoderPcmA : public AudioDecoder {
+ public:
+  AudioDecoderPcmA() : AudioDecoder(kDecoderPCMa) {}
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual int Init() { return 0; }
+  virtual int PacketDuration(const uint8_t* encoded, size_t encoded_len);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcmA);
+};
+
+class AudioDecoderPcmUMultiCh : public AudioDecoderPcmU {
+ public:
+  explicit AudioDecoderPcmUMultiCh(size_t channels) : AudioDecoderPcmU() {
+    assert(channels > 0);
+    channels_ = channels;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcmUMultiCh);
+};
+
+class AudioDecoderPcmAMultiCh : public AudioDecoderPcmA {
+ public:
+  explicit AudioDecoderPcmAMultiCh(size_t channels) : AudioDecoderPcmA() {
+    assert(channels > 0);
+    channels_ = channels;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcmAMultiCh);
+};
+
+#ifdef WEBRTC_CODEC_PCM16
+// This class handles all four types (i.e., sample rates) of PCM16B codecs.
+// The type is specified in the constructor parameter |type|.
+class AudioDecoderPcm16B : public AudioDecoder {
+ public:
+  explicit AudioDecoderPcm16B(enum NetEqDecoder type);
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual int Init() { return 0; }
+  virtual int PacketDuration(const uint8_t* encoded, size_t encoded_len);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcm16B);
+};
+
+// This class handles all four types (i.e., sample rates) of PCM16B codecs.
+// The type is specified in the constructor parameter |type|, and the number
+// of channels is derived from the type.
+class AudioDecoderPcm16BMultiCh : public AudioDecoderPcm16B {
+ public:
+  explicit AudioDecoderPcm16BMultiCh(enum NetEqDecoder type);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderPcm16BMultiCh);
+};
+#endif
+
+#ifdef WEBRTC_CODEC_ILBC
+class AudioDecoderIlbc : public AudioDecoder {
+ public:
+  AudioDecoderIlbc();
+  virtual ~AudioDecoderIlbc();
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual bool HasDecodePlc() const { return true; }
+  virtual int DecodePlc(int num_frames, int16_t* decoded);
+  virtual int Init();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderIlbc);
+};
+#endif
+
+#ifdef WEBRTC_CODEC_ISAC
+class AudioDecoderIsac : public AudioDecoder {
+ public:
+  AudioDecoderIsac();
+  virtual ~AudioDecoderIsac();
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual int DecodeRedundant(const uint8_t* encoded, size_t encoded_len,
+                              int16_t* decoded, SpeechType* speech_type);
+  virtual bool HasDecodePlc() const { return true; }
+  virtual int DecodePlc(int num_frames, int16_t* decoded);
+  virtual int Init();
+  virtual int IncomingPacket(const uint8_t* payload,
+                             size_t payload_len,
+                             uint16_t rtp_sequence_number,
+                             uint32_t rtp_timestamp,
+                             uint32_t arrival_timestamp);
+  virtual int ErrorCode();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderIsac);
+};
+
+class AudioDecoderIsacSwb : public AudioDecoderIsac {
+ public:
+  AudioDecoderIsacSwb();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderIsacSwb);
+};
+#endif
+
+#ifdef WEBRTC_CODEC_ISACFX
+class AudioDecoderIsacFix : public AudioDecoder {
+ public:
+  AudioDecoderIsacFix();
+  virtual ~AudioDecoderIsacFix();
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual int Init();
+  virtual int IncomingPacket(const uint8_t* payload,
+                             size_t payload_len,
+                             uint16_t rtp_sequence_number,
+                             uint32_t rtp_timestamp,
+                             uint32_t arrival_timestamp);
+  virtual int ErrorCode();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderIsacFix);
+};
+#endif
+
+#ifdef WEBRTC_CODEC_G722
+class AudioDecoderG722 : public AudioDecoder {
+ public:
+  AudioDecoderG722();
+  virtual ~AudioDecoderG722();
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual bool HasDecodePlc() const { return false; }
+  virtual int Init();
+  virtual int PacketDuration(const uint8_t* encoded, size_t encoded_len);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderG722);
+};
+#endif
+
+#ifdef WEBRTC_CODEC_OPUS
+class AudioDecoderOpus : public AudioDecoder {
+ public:
+  explicit AudioDecoderOpus(enum NetEqDecoder type);
+  virtual ~AudioDecoderOpus();
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type);
+  virtual int Init();
+  virtual int PacketDuration(const uint8_t* encoded, size_t encoded_len);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderOpus);
+};
+#endif
+
+// AudioDecoderCng is a special type of AudioDecoder. It inherits from
+// AudioDecoder just to fit in the DecoderDatabase. None of the class methods
+// should be used, except constructor, destructor, and accessors.
+// TODO(hlundin): Consider the possibility to create a super-class to
+// AudioDecoder that is stored in DecoderDatabase. Then AudioDecoder and a
+// specific CngDecoder class could both inherit from that class.
+class AudioDecoderCng : public AudioDecoder {
+ public:
+  explicit AudioDecoderCng(enum NetEqDecoder type);
+  virtual ~AudioDecoderCng();
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type) { return -1; }
+  virtual int Init();
+  virtual int IncomingPacket(const uint8_t* payload,
+                             size_t payload_len,
+                             uint16_t rtp_sequence_number,
+                             uint32_t rtp_timestamp,
+                             uint32_t arrival_timestamp) { return -1; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoderCng);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_DECODER_IMPL_H_
diff --git a/webrtc/modules/audio_coding/neteq4/audio_decoder_unittest.cc b/webrtc/modules/audio_coding/neteq4/audio_decoder_unittest.cc
new file mode 100644
index 0000000..8236c54
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_decoder_unittest.cc
@@ -0,0 +1,647 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/audio_decoder_impl.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "webrtc/common_audio/resampler/include/resampler.h"
+#include "webrtc/modules/audio_coding/codecs/g711/include/g711_interface.h"
+#include "webrtc/modules/audio_coding/codecs/g722/include/g722_interface.h"
+#include "webrtc/modules/audio_coding/codecs/ilbc/interface/ilbc.h"
+#include "webrtc/modules/audio_coding/codecs/isac/fix/interface/isacfix.h"
+#include "webrtc/modules/audio_coding/codecs/isac/main/interface/isac.h"
+#include "webrtc/modules/audio_coding/codecs/opus/interface/opus_interface.h"
+#include "webrtc/modules/audio_coding/codecs/pcm16b/include/pcm16b.h"
+#include "webrtc/system_wrappers/interface/data_log.h"
+#include "webrtc/test/testsupport/fileutils.h"
+
+namespace webrtc {
+
+class AudioDecoderTest : public ::testing::Test {
+ protected:
+  AudioDecoderTest()
+    : input_fp_(NULL),
+      input_(NULL),
+      encoded_(NULL),
+      decoded_(NULL),
+      frame_size_(0),
+      data_length_(0),
+      encoded_bytes_(0),
+      decoder_(NULL) {
+    input_file_ = webrtc::test::ProjectRootPath() +
+        "resources/audio_coding/testfile32kHz.pcm";
+  }
+
+  virtual ~AudioDecoderTest() {}
+
+  virtual void SetUp() {
+    // Create arrays.
+    ASSERT_GT(data_length_, 0u) << "The test must set data_length_ > 0";
+    input_ = new int16_t[data_length_];
+    encoded_ = new uint8_t[data_length_ * 2];
+    decoded_ = new int16_t[data_length_];
+    // Open input file.
+    input_fp_ = fopen(input_file_.c_str(), "rb");
+    ASSERT_TRUE(input_fp_ != NULL) << "Failed to open file " << input_file_;
+    // Read data to |input_|.
+    ASSERT_EQ(data_length_,
+              fread(input_, sizeof(int16_t), data_length_, input_fp_)) <<
+                  "Could not read enough data from file";
+    // Logging to view input and output in Matlab.
+    // Use 'gyp -Denable_data_logging=1' to enable logging.
+    DataLog::CreateLog();
+    DataLog::AddTable("CodecTest");
+    DataLog::AddColumn("CodecTest", "input", 1);
+    DataLog::AddColumn("CodecTest", "output", 1);
+  }
+
+  virtual void TearDown() {
+    delete decoder_;
+    decoder_ = NULL;
+    // Close input file.
+    fclose(input_fp_);
+    // Delete arrays.
+    delete [] input_;
+    input_ = NULL;
+    delete [] encoded_;
+    encoded_ = NULL;
+    delete [] decoded_;
+    decoded_ = NULL;
+    // Close log.
+    DataLog::ReturnLog();
+  }
+
+  virtual void InitEncoder() { }
+
+  // This method must be implemented for all tests derived from this class.
+  virtual int EncodeFrame(const int16_t* input, size_t input_len,
+                          uint8_t* output) = 0;
+
+  // Encodes and decodes audio. The absolute difference between the input and
+  // output is compared vs |tolerance|, and the mean-squared error is compared
+  // with |mse|. The encoded stream should contain |expected_bytes|.
+  void EncodeDecodeTest(size_t expected_bytes, int tolerance, double mse,
+                        int delay = 0) {
+    ASSERT_GE(tolerance, 0) << "Test must define a tolerance >= 0";
+    size_t processed_samples = 0u;
+    encoded_bytes_ = 0u;
+    InitEncoder();
+    EXPECT_EQ(0, decoder_->Init());
+    while (processed_samples + frame_size_ <= data_length_) {
+      size_t enc_len = EncodeFrame(&input_[processed_samples], frame_size_,
+                                   &encoded_[encoded_bytes_]);
+      AudioDecoder::SpeechType speech_type;
+      size_t dec_len = decoder_->Decode(&encoded_[encoded_bytes_], enc_len,
+                                        &decoded_[processed_samples],
+                                        &speech_type);
+      EXPECT_EQ(frame_size_, dec_len);
+      encoded_bytes_ += enc_len;
+      processed_samples += frame_size_;
+    }
+    EXPECT_EQ(expected_bytes, encoded_bytes_);
+    CompareInputOutput(processed_samples, tolerance, delay);
+    EXPECT_LE(MseInputOutput(processed_samples, delay), mse);
+  }
+
+  // The absolute difference between the input and output is compared vs
+  // |tolerance|. The parameter |delay| is used to correct for codec delays.
+  void CompareInputOutput(size_t num_samples, int tolerance, int delay) const {
+    assert(num_samples <= data_length_);
+    for (unsigned int n = 0; n < num_samples - delay; ++n) {
+      ASSERT_NEAR(input_[n], decoded_[n + delay], tolerance) <<
+          "Exit test on first diff; n = " << n;
+      DataLog::InsertCell("CodecTest", "input", input_[n]);
+      DataLog::InsertCell("CodecTest", "output", decoded_[n]);
+      DataLog::NextRow("CodecTest");
+    }
+  }
+
+  // Calculates mean-squared error between input and output. The parameter
+  // |delay| is used to correct for codec delays.
+  double MseInputOutput(size_t num_samples, int delay) const {
+    assert(num_samples <= data_length_);
+    if (num_samples == 0) return 0.0;
+
+    double squared_sum = 0.0;
+    for (unsigned int n = 0; n < num_samples - delay; ++n) {
+      squared_sum += (input_[n] - decoded_[n + delay]) *
+          (input_[n] - decoded_[n + delay]);
+    }
+    return squared_sum / (num_samples - delay);
+  }
+
+  // Encodes a payload and decodes it twice with decoder re-init before each
+  // decode. Verifies that the decoded result is the same.
+  void ReInitTest() {
+    uint8_t* encoded = encoded_;
+    uint8_t* encoded_copy = encoded_ + 2 * frame_size_;
+    int16_t* output1 = decoded_;
+    int16_t* output2 = decoded_ + frame_size_;
+    InitEncoder();
+    size_t enc_len = EncodeFrame(input_, frame_size_, encoded);
+    // Copy payload since iSAC fix destroys it during decode.
+    // Issue: http://code.google.com/p/webrtc/issues/detail?id=845.
+    // TODO(hlundin): Remove if the iSAC bug gets fixed.
+    memcpy(encoded_copy, encoded, enc_len);
+    AudioDecoder::SpeechType speech_type1, speech_type2;
+    EXPECT_EQ(0, decoder_->Init());
+    size_t dec_len = decoder_->Decode(encoded, enc_len, output1, &speech_type1);
+    EXPECT_EQ(frame_size_, dec_len);
+    // Re-init decoder and decode again.
+    EXPECT_EQ(0, decoder_->Init());
+    dec_len = decoder_->Decode(encoded_copy, enc_len, output2, &speech_type2);
+    EXPECT_EQ(frame_size_, dec_len);
+    for (unsigned int n = 0; n < frame_size_; ++n) {
+      ASSERT_EQ(output1[n], output2[n]) << "Exit test on first diff; n = " << n;
+    }
+    EXPECT_EQ(speech_type1, speech_type2);
+  }
+
+  // Call DecodePlc and verify that the correct number of samples is produced.
+  void DecodePlcTest() {
+    InitEncoder();
+    size_t enc_len = EncodeFrame(input_, frame_size_, encoded_);
+    AudioDecoder::SpeechType speech_type;
+    EXPECT_EQ(0, decoder_->Init());
+    size_t dec_len =
+        decoder_->Decode(encoded_, enc_len, decoded_, &speech_type);
+    EXPECT_EQ(frame_size_, dec_len);
+    // Call DecodePlc and verify that we get one frame of data.
+    // (Overwrite the output from the above Decode call, but that does not
+    // matter.)
+    dec_len = decoder_->DecodePlc(1, decoded_);
+    EXPECT_EQ(frame_size_, dec_len);
+  }
+
+  std::string input_file_;
+  FILE* input_fp_;
+  int16_t* input_;
+  uint8_t* encoded_;
+  int16_t* decoded_;
+  size_t frame_size_;
+  size_t data_length_;
+  size_t encoded_bytes_;
+  AudioDecoder* decoder_;
+};
+
+class AudioDecoderPcmUTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderPcmUTest() : AudioDecoderTest() {
+    frame_size_ = 160;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderPcmU;
+    assert(decoder_);
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    int enc_len_bytes =
+        WebRtcG711_EncodeU(NULL, const_cast<int16_t*>(input), input_len_samples,
+                           reinterpret_cast<int16_t*>(output));
+    EXPECT_EQ(input_len_samples, static_cast<size_t>(enc_len_bytes));
+    return enc_len_bytes;
+  }
+};
+
+class AudioDecoderPcmATest : public AudioDecoderTest {
+ protected:
+  AudioDecoderPcmATest() : AudioDecoderTest() {
+    frame_size_ = 160;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderPcmA;
+    assert(decoder_);
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    int enc_len_bytes =
+        WebRtcG711_EncodeA(NULL, const_cast<int16_t*>(input), input_len_samples,
+                           reinterpret_cast<int16_t*>(output));
+    EXPECT_EQ(input_len_samples, static_cast<size_t>(enc_len_bytes));
+    return enc_len_bytes;
+  }
+};
+
+class AudioDecoderPcm16BTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderPcm16BTest() : AudioDecoderTest() {
+    frame_size_ = 160;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderPcm16B(kDecoderPCM16B);
+    assert(decoder_);
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    int enc_len_bytes = WebRtcPcm16b_EncodeW16(
+        const_cast<int16_t*>(input), input_len_samples,
+        reinterpret_cast<int16_t*>(output));
+    EXPECT_EQ(2 * input_len_samples, static_cast<size_t>(enc_len_bytes));
+    return enc_len_bytes;
+  }
+};
+
+class AudioDecoderIlbcTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderIlbcTest() : AudioDecoderTest() {
+    frame_size_ = 240;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderIlbc;
+    assert(decoder_);
+    assert(WebRtcIlbcfix_EncoderCreate(&encoder_) == 0);
+  }
+
+  ~AudioDecoderIlbcTest() {
+    WebRtcIlbcfix_EncoderFree(encoder_);
+  }
+
+  virtual void InitEncoder() {
+    ASSERT_EQ(0, WebRtcIlbcfix_EncoderInit(encoder_, 30));  // 30 ms.
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    int enc_len_bytes =
+        WebRtcIlbcfix_Encode(encoder_, input, input_len_samples,
+                             reinterpret_cast<int16_t*>(output));
+    EXPECT_EQ(50, enc_len_bytes);
+    return enc_len_bytes;
+  }
+
+  // Overload the default test since iLBC's function WebRtcIlbcfix_NetEqPlc does
+  // not return any data. It simply resets a few states and returns 0.
+  void DecodePlcTest() {
+    InitEncoder();
+    size_t enc_len = EncodeFrame(input_, frame_size_, encoded_);
+    AudioDecoder::SpeechType speech_type;
+    EXPECT_EQ(0, decoder_->Init());
+    size_t dec_len =
+        decoder_->Decode(encoded_, enc_len, decoded_, &speech_type);
+    EXPECT_EQ(frame_size_, dec_len);
+    // Simply call DecodePlc and verify that we get 0 as return value.
+    EXPECT_EQ(0, decoder_->DecodePlc(1, decoded_));
+  }
+
+  iLBC_encinst_t* encoder_;
+};
+
+class AudioDecoderIsacFloatTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderIsacFloatTest() : AudioDecoderTest() {
+    input_size_ = 160;
+    frame_size_ = 480;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderIsac;
+    assert(decoder_);
+    assert(WebRtcIsac_Create(&encoder_) == 0);
+    assert(WebRtcIsac_SetEncSampRate(encoder_, 16000) == 0);
+  }
+
+  ~AudioDecoderIsacFloatTest() {
+    WebRtcIsac_Free(encoder_);
+  }
+
+  virtual void InitEncoder() {
+    ASSERT_EQ(0, WebRtcIsac_EncoderInit(encoder_, 1));  // Fixed mode.
+    ASSERT_EQ(0, WebRtcIsac_Control(encoder_, 32000, 30));  // 32 kbps, 30 ms.
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    // Insert 3 * 10 ms. Expect non-zero output on third call.
+    EXPECT_EQ(0, WebRtcIsac_Encode(encoder_, input,
+                                   reinterpret_cast<int16_t*>(output)));
+    input += input_size_;
+    EXPECT_EQ(0, WebRtcIsac_Encode(encoder_, input,
+                                   reinterpret_cast<int16_t*>(output)));
+    input += input_size_;
+    int enc_len_bytes =
+        WebRtcIsac_Encode(encoder_, input, reinterpret_cast<int16_t*>(output));
+    EXPECT_GT(enc_len_bytes, 0);
+    return enc_len_bytes;
+  }
+
+  ISACStruct* encoder_;
+  int input_size_;
+};
+
+class AudioDecoderIsacSwbTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderIsacSwbTest() : AudioDecoderTest() {
+    input_size_ = 320;
+    frame_size_ = 960;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderIsacSwb;
+    assert(decoder_);
+    assert(WebRtcIsac_Create(&encoder_) == 0);
+    assert(WebRtcIsac_SetEncSampRate(encoder_, 32000) == 0);
+  }
+
+  ~AudioDecoderIsacSwbTest() {
+    WebRtcIsac_Free(encoder_);
+  }
+
+  virtual void InitEncoder() {
+    ASSERT_EQ(0, WebRtcIsac_EncoderInit(encoder_, 1));  // Fixed mode.
+    ASSERT_EQ(0, WebRtcIsac_Control(encoder_, 32000, 30));  // 32 kbps, 30 ms.
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    // Insert 3 * 10 ms. Expect non-zero output on third call.
+    EXPECT_EQ(0, WebRtcIsac_Encode(encoder_, input,
+                                   reinterpret_cast<int16_t*>(output)));
+    input += input_size_;
+    EXPECT_EQ(0, WebRtcIsac_Encode(encoder_, input,
+                                   reinterpret_cast<int16_t*>(output)));
+    input += input_size_;
+    int enc_len_bytes =
+        WebRtcIsac_Encode(encoder_, input, reinterpret_cast<int16_t*>(output));
+    EXPECT_GT(enc_len_bytes, 0);
+    return enc_len_bytes;
+  }
+
+  ISACStruct* encoder_;
+  int input_size_;
+};
+
+class AudioDecoderIsacFixTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderIsacFixTest() : AudioDecoderTest() {
+    input_size_ = 160;
+    frame_size_ = 480;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderIsacFix;
+    assert(decoder_);
+    assert(WebRtcIsacfix_Create(&encoder_) == 0);
+  }
+
+  ~AudioDecoderIsacFixTest() {
+    WebRtcIsacfix_Free(encoder_);
+  }
+
+  virtual void InitEncoder() {
+    ASSERT_EQ(0, WebRtcIsacfix_EncoderInit(encoder_, 1));  // Fixed mode.
+    ASSERT_EQ(0,
+              WebRtcIsacfix_Control(encoder_, 32000, 30));  // 32 kbps, 30 ms.
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    // Insert 3 * 10 ms. Expect non-zero output on third call.
+    EXPECT_EQ(0, WebRtcIsacfix_Encode(encoder_, input,
+                                      reinterpret_cast<int16_t*>(output)));
+    input += input_size_;
+    EXPECT_EQ(0, WebRtcIsacfix_Encode(encoder_, input,
+                                      reinterpret_cast<int16_t*>(output)));
+    input += input_size_;
+    int enc_len_bytes = WebRtcIsacfix_Encode(
+        encoder_, input, reinterpret_cast<int16_t*>(output));
+    EXPECT_GT(enc_len_bytes, 0);
+    return enc_len_bytes;
+  }
+
+  ISACFIX_MainStruct* encoder_;
+  int input_size_;
+};
+
+class AudioDecoderG722Test : public AudioDecoderTest {
+ protected:
+  AudioDecoderG722Test() : AudioDecoderTest() {
+    frame_size_ = 160;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderG722;
+    assert(decoder_);
+    assert(WebRtcG722_CreateEncoder(&encoder_) == 0);
+  }
+
+  ~AudioDecoderG722Test() {
+    WebRtcG722_FreeEncoder(encoder_);
+  }
+
+  virtual void InitEncoder() {
+    ASSERT_EQ(0, WebRtcG722_EncoderInit(encoder_));
+  }
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    int enc_len_bytes =
+        WebRtcG722_Encode(encoder_, const_cast<int16_t*>(input),
+                          input_len_samples,
+                          reinterpret_cast<int16_t*>(output));
+    EXPECT_EQ(80, enc_len_bytes);
+    return enc_len_bytes;
+  }
+
+  G722EncInst* encoder_;
+};
+
+class AudioDecoderOpusTest : public AudioDecoderTest {
+ protected:
+  AudioDecoderOpusTest() : AudioDecoderTest() {
+    frame_size_ = 320;
+    data_length_ = 10 * frame_size_;
+    decoder_ = new AudioDecoderOpus(kDecoderOpus);
+    assert(decoder_);
+    assert(WebRtcOpus_EncoderCreate(&encoder_, 1) == 0);
+  }
+
+  ~AudioDecoderOpusTest() {
+    WebRtcOpus_EncoderFree(encoder_);
+  }
+
+  virtual void InitEncoder() {}
+
+  virtual int EncodeFrame(const int16_t* input, size_t input_len_samples,
+                          uint8_t* output) {
+    // Upsample from 32 to 48 kHz.
+    Resampler rs;
+    rs.Reset(32000, 48000, kResamplerSynchronous);
+    const int max_resamp_len_samples = input_len_samples * 3 / 2;
+    int16_t* resamp_input = new int16_t[max_resamp_len_samples];
+    int resamp_len_samples;
+    EXPECT_EQ(0, rs.Push(input, input_len_samples, resamp_input,
+                         max_resamp_len_samples, resamp_len_samples));
+    EXPECT_EQ(max_resamp_len_samples, resamp_len_samples);
+    int enc_len_bytes =
+        WebRtcOpus_Encode(encoder_, resamp_input,
+                          resamp_len_samples, data_length_, output);
+    EXPECT_GT(enc_len_bytes, 0);
+    delete [] resamp_input;
+    return enc_len_bytes;
+  }
+
+  OpusEncInst* encoder_;
+};
+
+TEST_F(AudioDecoderPcmUTest, EncodeDecode) {
+  int tolerance = 251;
+  double mse = 1734.0;
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCMu));
+  EncodeDecodeTest(data_length_, tolerance, mse);
+  ReInitTest();
+  EXPECT_FALSE(decoder_->HasDecodePlc());
+}
+
+TEST_F(AudioDecoderPcmATest, EncodeDecode) {
+  int tolerance = 308;
+  double mse = 1931.0;
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCMa));
+  EncodeDecodeTest(data_length_, tolerance, mse);
+  ReInitTest();
+  EXPECT_FALSE(decoder_->HasDecodePlc());
+}
+
+TEST_F(AudioDecoderPcm16BTest, EncodeDecode) {
+  int tolerance = 0;
+  double mse = 0.0;
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16B));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bwb));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bswb32kHz));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bswb48kHz));
+  EncodeDecodeTest(2 * data_length_, tolerance, mse);
+  ReInitTest();
+  EXPECT_FALSE(decoder_->HasDecodePlc());
+}
+
+TEST_F(AudioDecoderIlbcTest, EncodeDecode) {
+  int tolerance = 6808;
+  double mse = 2.13e6;
+  int delay = 80;  // Delay from input to output.
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderILBC));
+  EncodeDecodeTest(500, tolerance, mse, delay);
+  ReInitTest();
+  EXPECT_TRUE(decoder_->HasDecodePlc());
+  DecodePlcTest();
+}
+
+TEST_F(AudioDecoderIsacFloatTest, EncodeDecode) {
+  int tolerance = 3399;
+  double mse = 434951.0;
+  int delay = 48;  // Delay from input to output.
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderISAC));
+  EncodeDecodeTest(883, tolerance, mse, delay);
+  ReInitTest();
+  EXPECT_TRUE(decoder_->HasDecodePlc());
+  DecodePlcTest();
+}
+
+TEST_F(AudioDecoderIsacSwbTest, EncodeDecode) {
+  int tolerance = 19757;
+  double mse = 8.18e6;
+  int delay = 160;  // Delay from input to output.
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderISACswb));
+  EncodeDecodeTest(853, tolerance, mse, delay);
+  ReInitTest();
+  EXPECT_TRUE(decoder_->HasDecodePlc());
+  DecodePlcTest();
+}
+
+TEST_F(AudioDecoderIsacFixTest, EncodeDecode) {
+  int tolerance = 11034;
+  double mse = 3.46e6;
+  int delay = 54;  // Delay from input to output.
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderISAC));
+  EncodeDecodeTest(735, tolerance, mse, delay);
+  ReInitTest();
+  EXPECT_FALSE(decoder_->HasDecodePlc());
+}
+
+TEST_F(AudioDecoderG722Test, EncodeDecode) {
+  int tolerance = 6176;
+  double mse = 238630.0;
+  int delay = 22;  // Delay from input to output.
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderG722));
+  EncodeDecodeTest(data_length_ / 2, tolerance, mse, delay);
+  ReInitTest();
+  EXPECT_FALSE(decoder_->HasDecodePlc());
+}
+
+TEST_F(AudioDecoderOpusTest, EncodeDecode) {
+  int tolerance = 6176;
+  double mse = 238630.0;
+  int delay = 22;  // Delay from input to output.
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderOpus));
+  EncodeDecodeTest(731, tolerance, mse, delay);
+  ReInitTest();
+  EXPECT_FALSE(decoder_->HasDecodePlc());
+}
+
+TEST(AudioDecoder, CodecSampleRateHz) {
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCMu));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCMa));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCMu_2ch));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCMa_2ch));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderILBC));
+  EXPECT_EQ(16000, AudioDecoder::CodecSampleRateHz(kDecoderISAC));
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderISACswb));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16B));
+  EXPECT_EQ(16000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16Bwb));
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16Bswb32kHz));
+  EXPECT_EQ(48000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16Bswb48kHz));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16B_2ch));
+  EXPECT_EQ(16000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16Bwb_2ch));
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16Bswb32kHz_2ch));
+  EXPECT_EQ(48000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16Bswb48kHz_2ch));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderPCM16B_5ch));
+  EXPECT_EQ(16000, AudioDecoder::CodecSampleRateHz(kDecoderG722));
+  EXPECT_EQ(-1, AudioDecoder::CodecSampleRateHz(kDecoderG722_2ch));
+  EXPECT_EQ(-1, AudioDecoder::CodecSampleRateHz(kDecoderRED));
+  EXPECT_EQ(-1, AudioDecoder::CodecSampleRateHz(kDecoderAVT));
+  EXPECT_EQ(8000, AudioDecoder::CodecSampleRateHz(kDecoderCNGnb));
+  EXPECT_EQ(16000, AudioDecoder::CodecSampleRateHz(kDecoderCNGwb));
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderCNGswb32kHz));
+  // TODO(tlegrand): Change 32000 to 48000 below once ACM has 48 kHz support.
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderCNGswb48kHz));
+  EXPECT_EQ(-1, AudioDecoder::CodecSampleRateHz(kDecoderArbitrary));
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderOpus));
+  EXPECT_EQ(32000, AudioDecoder::CodecSampleRateHz(kDecoderOpus_2ch));
+  EXPECT_EQ(-1, AudioDecoder::CodecSampleRateHz(kDecoderCELT_32));
+  EXPECT_EQ(-1, AudioDecoder::CodecSampleRateHz(kDecoderCELT_32_2ch));
+}
+
+TEST(AudioDecoder, CodecSupported) {
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCMu));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCMa));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCMu_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCMa_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderILBC));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderISAC));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderISACswb));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16B));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bwb));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bswb32kHz));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bswb48kHz));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16B_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bwb_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bswb32kHz_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16Bswb48kHz_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderPCM16B_5ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderG722));
+  EXPECT_FALSE(AudioDecoder::CodecSupported(kDecoderG722_2ch));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderRED));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderAVT));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderCNGnb));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderCNGwb));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderCNGswb32kHz));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderCNGswb48kHz));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderArbitrary));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderOpus));
+  EXPECT_TRUE(AudioDecoder::CodecSupported(kDecoderOpus_2ch));
+  EXPECT_FALSE(AudioDecoder::CodecSupported(kDecoderCELT_32));
+  EXPECT_FALSE(AudioDecoder::CodecSupported(kDecoderCELT_32_2ch));
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/audio_multi_vector.cc b/webrtc/modules/audio_coding/neteq4/audio_multi_vector.cc
new file mode 100644
index 0000000..53fd1f4
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_multi_vector.cc
@@ -0,0 +1,228 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+
+#include <assert.h>
+
+#include <algorithm>
+
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+template<typename T>
+AudioMultiVector<T>::AudioMultiVector(size_t N) {
+  assert(N > 0);
+  if (N < 1) N = 1;
+  for (size_t n = 0; n < N; ++n) {
+    channels_.push_back(new AudioVector<T>);
+  }
+}
+
+template<typename T>
+AudioMultiVector<T>::AudioMultiVector(size_t N, size_t initial_size) {
+  assert(N > 0);
+  if (N < 1) N = 1;
+  for (size_t n = 0; n < N; ++n) {
+    channels_.push_back(new AudioVector<T>(initial_size));
+  }
+}
+
+template<typename T>
+AudioMultiVector<T>::~AudioMultiVector() {
+  typename std::vector<AudioVector<T>*>::iterator it = channels_.begin();
+  while (it != channels_.end()) {
+    delete (*it);
+    ++it;
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::Clear() {
+  for (size_t i = 0; i < Channels(); ++i) {
+    channels_[i]->Clear();
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::Zeros(size_t length) {
+  for (size_t i = 0; i < Channels(); ++i) {
+    channels_[i]->Clear();
+    channels_[i]->Extend(length);
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::CopyFrom(AudioMultiVector<T>* copy_to) const {
+  if (copy_to) {
+    for (size_t i = 0; i < Channels(); ++i) {
+      channels_[i]->CopyFrom(&(*copy_to)[i]);
+    }
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::PushBackInterleaved(const T* append_this,
+                                              size_t length) {
+  assert(length % Channels() == 0);
+  size_t length_per_channel = length / Channels();
+  T* temp_array = new T[length_per_channel];  // Intermediate storage.
+  for (size_t channel = 0; channel < Channels(); ++channel) {
+    // Copy elements to |temp_array|.
+    // Set |source_ptr| to first element of this channel.
+    const T* source_ptr = &append_this[channel];
+    for (size_t i = 0; i < length_per_channel; ++i) {
+      temp_array[i] = *source_ptr;
+      source_ptr += Channels();  // Jump to next element of this channel.
+    }
+    channels_[channel]->PushBack(temp_array, length_per_channel);
+  }
+  delete [] temp_array;
+}
+
+template<typename T>
+void AudioMultiVector<T>::PushBack(const AudioMultiVector<T>& append_this) {
+  assert(Channels() == append_this.Channels());
+  if (Channels() == append_this.Channels()) {
+    for (size_t i = 0; i < Channels(); ++i) {
+      channels_[i]->PushBack(append_this[i]);
+    }
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::PushBackFromIndex(
+    const AudioMultiVector<T>& append_this,
+    size_t index) {
+  assert(index < append_this.Size());
+  index = std::min(index, append_this.Size() - 1);
+  size_t length = append_this.Size() - index;
+  assert(Channels() == append_this.Channels());
+  if (Channels() == append_this.Channels()) {
+    for (size_t i = 0; i < Channels(); ++i) {
+      channels_[i]->PushBack(&append_this[i][index], length);
+    }
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::PopFront(size_t length) {
+  for (size_t i = 0; i < Channels(); ++i) {
+    channels_[i]->PopFront(length);
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::PopBack(size_t length) {
+  for (size_t i = 0; i < Channels(); ++i) {
+    channels_[i]->PopBack(length);
+  }
+}
+
+template<typename T>
+size_t AudioMultiVector<T>::ReadInterleaved(size_t length,
+                                            T* destination) const {
+  return ReadInterleavedFromIndex(0, length, destination);
+}
+
+template<typename T>
+size_t AudioMultiVector<T>::ReadInterleavedFromIndex(size_t start_index,
+                                                     size_t length,
+                                                     T* destination) const {
+  if (!destination) {
+    return 0;
+  }
+  size_t index = 0;  // Number of elements written to |destination| so far.
+  assert(start_index <= Size());
+  start_index = std::min(start_index, Size());
+  if (length + start_index > Size()) {
+    length = Size() - start_index;
+  }
+  for (size_t i = 0; i < length; ++i) {
+    for (size_t channel = 0; channel < Channels(); ++channel) {
+      destination[index] = (*this)[channel][i + start_index];
+      ++index;
+    }
+  }
+  return index;
+}
+
+template<typename T>
+size_t AudioMultiVector<T>::ReadInterleavedFromEnd(size_t length,
+                                                   T* destination) const {
+  length = std::min(length, Size());  // Cannot read more than Size() elements.
+  return ReadInterleavedFromIndex(Size() - length, length, destination);
+}
+
+template<typename T>
+void AudioMultiVector<T>::OverwriteAt(const AudioMultiVector<T>& insert_this,
+                                      size_t length,
+                                      size_t position) {
+  assert(Channels() == insert_this.Channels());
+  // Cap |length| at the length of |insert_this|.
+  assert(length <= insert_this.Size());
+  length = std::min(length, insert_this.Size());
+  if (Channels() == insert_this.Channels()) {
+    for (size_t i = 0; i < Channels(); ++i) {
+      channels_[i]->OverwriteAt(&insert_this[i][0], length, position);
+    }
+  }
+}
+
+template<typename T>
+void AudioMultiVector<T>::CrossFade(const AudioMultiVector<T>& append_this,
+                                    size_t fade_length) {
+  assert(Channels() == append_this.Channels());
+  if (Channels() == append_this.Channels()) {
+    for (size_t i = 0; i < Channels(); ++i) {
+      channels_[i]->CrossFade(append_this[i], fade_length);
+    }
+  }
+}
+
+template<typename T>
+size_t AudioMultiVector<T>::Size() const {
+  assert(channels_[0]);
+  return channels_[0]->Size();
+}
+
+template<typename T>
+void AudioMultiVector<T>::AssertSize(size_t required_size) {
+  if (Size() < required_size) {
+    size_t extend_length = required_size - Size();
+    for (size_t channel = 0; channel < Channels(); ++channel) {
+      channels_[channel]->Extend(extend_length);
+    }
+  }
+}
+
+template<typename T>
+bool AudioMultiVector<T>::Empty() const {
+  assert(channels_[0]);
+  return channels_[0]->Empty();
+}
+
+template<typename T>
+const AudioVector<T>& AudioMultiVector<T>::operator[](size_t index) const {
+  return *(channels_[index]);
+}
+
+template<typename T>
+AudioVector<T>& AudioMultiVector<T>::operator[](size_t index) {
+  return *(channels_[index]);
+}
+
+// Instantiate the template for a few types.
+template class AudioMultiVector<int16_t>;
+template class AudioMultiVector<int32_t>;
+template class AudioMultiVector<double>;
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/audio_multi_vector.h b/webrtc/modules/audio_coding/neteq4/audio_multi_vector.h
new file mode 100644
index 0000000..5f933d9
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_multi_vector.h
@@ -0,0 +1,132 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_MULTI_VECTOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_MULTI_VECTOR_H_
+
+#include <cstring>  // Access to size_t.
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+
+namespace webrtc {
+
+template <typename T>
+class AudioMultiVector {
+ public:
+  // Creates an empty AudioMultiVector with |N| audio channels. |N| must be
+  // larger than 0.
+  explicit AudioMultiVector(size_t N);
+
+  // Creates an AudioMultiVector with |N| audio channels, each channel having
+  // an initial size. |N| must be larger than 0.
+  AudioMultiVector(size_t N, size_t initial_size);
+
+  virtual ~AudioMultiVector();
+
+  // Deletes all values and make the vector empty.
+  virtual void Clear();
+
+  // Clears the vector and inserts |length| zeros into each channel.
+  virtual void Zeros(size_t length);
+
+  // Copies all values from this vector to |copy_to|. Any contents in |copy_to|
+  // are deleted. After the operation is done, |copy_to| will be an exact
+  // replica of this object. The source and the destination must have the same
+  // number of channels.
+  virtual void CopyFrom(AudioMultiVector<T>* copy_to) const;
+
+  // Appends the contents of array |append_this| to the end of this
+  // object. The array is assumed to be channel-interleaved. |length| must be
+  // an even multiple of this object's number of channels.
+  // The length of this object is increased with the |length| divided by the
+  // number of channels.
+  virtual void PushBackInterleaved(const T* append_this, size_t length);
+
+  // Appends the contents of AudioMultiVector |append_this| to this object. The
+  // length of this object is increased with the length of |append_this|.
+  virtual void PushBack(const AudioMultiVector<T>& append_this);
+
+  // Appends the contents of AudioMultiVector |append_this| to this object,
+  // taken from |index| up until the end of |append_this|. The length of this
+  // object is increased.
+  virtual void PushBackFromIndex(const AudioMultiVector<T>& append_this,
+                                 size_t index);
+
+  // Removes |length| elements from the beginning of this object, from each
+  // channel.
+  virtual void PopFront(size_t length);
+
+  // Removes |length| elements from the end of this object, from each
+  // channel.
+  virtual void PopBack(size_t length);
+
+  // Reads |length| samples from each channel and writes them interleaved to
+  // |destination|. The total number of elements written to |destination| is
+  // returned, i.e., |length| * number of channels. If the AudioMultiVector
+  // contains less than |length| samples per channel, this is reflected in the
+  // return value.
+  virtual size_t ReadInterleaved(size_t length, T* destination) const;
+
+  // Like ReadInterleaved() above, but reads from |start_index| instead of from
+  // the beginning.
+  virtual size_t ReadInterleavedFromIndex(size_t start_index,
+                                          size_t length,
+                                          T* destination) const;
+
+  // Like ReadInterleaved() above, but reads from the end instead of from
+  // the beginning.
+  virtual size_t ReadInterleavedFromEnd(size_t length,
+                                        T* destination) const;
+
+  // Overwrites each channel in this AudioMultiVector with values taken from
+  // |insert_this|. The values are taken from the beginning of |insert_this| and
+  // are inserted starting at |position|. |length| values are written into each
+  // channel. If |length| and |position| are selected such that the new data
+  // extends beyond the end of the current AudioVector, the vector is extended
+  // to accommodate the new data. |length| is limited to the length of
+  // |insert_this|.
+  virtual void OverwriteAt(const AudioMultiVector<T>& insert_this,
+                           size_t length,
+                           size_t position);
+
+  // Appends |append_this| to the end of the current vector. Lets the two
+  // vectors overlap by |fade_length| samples (per channel), and cross-fade
+  // linearly in this region.
+  virtual void CrossFade(const AudioMultiVector<T>& append_this,
+                         size_t fade_length);
+
+  // Returns the number of channels.
+  virtual size_t Channels() const { return channels_.size(); }
+
+  // Returns the number of elements per channel in this AudioMultiVector.
+  virtual size_t Size() const;
+
+  // Verify that each channel can hold at least |required_size| elements. If
+  // not, extend accordingly.
+  virtual void AssertSize(size_t required_size);
+
+  virtual bool Empty() const;
+
+  // Accesses and modifies a channel (i.e., an AudioVector object) of this
+  // AudioMultiVector.
+  const AudioVector<T>& operator[](size_t index) const;
+  AudioVector<T>& operator[](size_t index);
+
+ protected:
+  std::vector<AudioVector<T>*> channels_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioMultiVector);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_MULTI_VECTOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/audio_multi_vector_unittest.cc b/webrtc/modules/audio_coding/neteq4/audio_multi_vector_unittest.cc
new file mode 100644
index 0000000..33f538b
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_multi_vector_unittest.cc
@@ -0,0 +1,304 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// This is a value-parameterized test. The test cases are instantiated with
+// different values for the test parameter, which is used to determine the
+// number of channels in the AudioMultiBuffer. Note that it is not possible
+// to combine typed testing with value-parameterized testing, and since the
+// tests for AudioVector already covers a number of different type parameters,
+// this test focuses on testing different number of channels, and keeping the
+// value type constant.
+class AudioMultiVectorTest : public ::testing::TestWithParam<size_t> {
+ protected:
+  typedef int16_t T;  // Use this value type for all tests.
+
+  AudioMultiVectorTest()
+      : num_channels_(GetParam()),  // Get the test parameter.
+        interleaved_length_(num_channels_ * kLength) {
+    array_interleaved_ = new T[num_channels_ * kLength];
+  }
+
+  ~AudioMultiVectorTest() {
+    delete [] array_interleaved_;
+  }
+
+  virtual void SetUp() {
+    // Populate test arrays.
+    for (size_t i = 0; i < kLength; ++i) {
+      array_[i] = static_cast<T>(i);
+    }
+    T* ptr = array_interleaved_;
+    // Write 100, 101, 102, ... for first channel.
+    // Write 200, 201, 202, ... for second channel.
+    // And so on.
+    for (size_t i = 0; i < kLength; ++i) {
+      for (size_t j = 1; j <= num_channels_; ++j) {
+        *ptr = j * 100 + i;
+        ++ptr;
+      }
+    }
+  }
+
+  enum {
+    kLength = 10
+  };
+
+  const size_t num_channels_;
+  size_t interleaved_length_;
+  T array_[kLength];
+  T* array_interleaved_;
+};
+
+// Create and destroy AudioMultiVector objects, both empty and with a predefined
+// length.
+TEST_P(AudioMultiVectorTest, CreateAndDestroy) {
+  AudioMultiVector<T> vec1(num_channels_);
+  EXPECT_TRUE(vec1.Empty());
+  EXPECT_EQ(num_channels_, vec1.Channels());
+  EXPECT_EQ(0u, vec1.Size());
+
+  size_t initial_size = 17;
+  AudioMultiVector<T> vec2(num_channels_, initial_size);
+  EXPECT_FALSE(vec2.Empty());
+  EXPECT_EQ(num_channels_, vec2.Channels());
+  EXPECT_EQ(initial_size, vec2.Size());
+}
+
+// Test the subscript operator [] for getting and setting.
+TEST_P(AudioMultiVectorTest, SubscriptOperator) {
+  AudioMultiVector<T> vec(num_channels_, kLength);
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    for (size_t i = 0; i < kLength; ++i) {
+      vec[channel][i] = static_cast<T>(i);
+      // Make sure to use the const version.
+      const AudioVector<T>& audio_vec = vec[channel];
+      EXPECT_EQ(static_cast<T>(i), audio_vec[i]);
+    }
+  }
+}
+
+// Test the PushBackInterleaved method and the CopyFrom method. The Clear
+// method is also invoked.
+TEST_P(AudioMultiVectorTest, PushBackInterleavedAndCopy) {
+  AudioMultiVector<T> vec(num_channels_);
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  AudioMultiVector<T> vec_copy(num_channels_);
+  vec.CopyFrom(&vec_copy);  // Copy from |vec| to |vec_copy|.
+  ASSERT_EQ(num_channels_, vec.Channels());
+  ASSERT_EQ(kLength, vec.Size());
+  ASSERT_EQ(num_channels_, vec_copy.Channels());
+  ASSERT_EQ(kLength, vec_copy.Size());
+  for (size_t channel = 0; channel < vec.Channels(); ++channel) {
+    for (size_t i = 0; i < kLength; ++i) {
+      EXPECT_EQ(static_cast<T>((channel + 1) * 100 + i), vec[channel][i]);
+      EXPECT_EQ(vec[channel][i], vec_copy[channel][i]);
+    }
+  }
+
+  // Clear |vec| and verify that it is empty.
+  vec.Clear();
+  EXPECT_TRUE(vec.Empty());
+
+  // Now copy the empty vector and verify that the copy becomes empty too.
+  vec.CopyFrom(&vec_copy);
+  EXPECT_TRUE(vec_copy.Empty());
+}
+
+// Try to copy to a NULL pointer. Nothing should happen.
+TEST_P(AudioMultiVectorTest, CopyToNull) {
+  AudioMultiVector<T> vec(num_channels_);
+  AudioMultiVector<T>* vec_copy = NULL;
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  vec.CopyFrom(vec_copy);
+}
+
+// Test the PushBack method with another AudioMultiVector as input argument.
+TEST_P(AudioMultiVectorTest, PushBackVector) {
+  AudioMultiVector<T> vec1(num_channels_, kLength);
+  AudioMultiVector<T> vec2(num_channels_, kLength);
+  // Set the first vector to [0, 1, ..., kLength - 1] + 100 * channel_number.
+  // Set the second vector to [kLength, kLength + 1, ..., 2 * kLength - 1]  +
+  // 100 * channel_number.
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    for (size_t i = 0; i < kLength; ++i) {
+      vec1[channel][i] = static_cast<T>(i + 100 * channel);
+      vec2[channel][i] = static_cast<T>(i + 100 * channel + kLength);
+    }
+  }
+  // Append vec2 to the back of vec1.
+  vec1.PushBack(vec2);
+  ASSERT_EQ(2u * kLength, vec1.Size());
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    for (size_t i = 0; i < 2 * kLength; ++i) {
+      EXPECT_EQ(static_cast<T>(i + 100 * channel), vec1[channel][i]);
+    }
+  }
+}
+
+// Test the PushBackFromIndex method.
+TEST_P(AudioMultiVectorTest, PushBackFromIndex) {
+  AudioMultiVector<T> vec1(num_channels_);
+  vec1.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  AudioMultiVector<T> vec2(num_channels_);
+
+  // Append vec1 to the back of vec2 (which is empty). Read vec1 from the second
+  // last element.
+  vec2.PushBackFromIndex(vec1, kLength - 2);
+  ASSERT_EQ(2u, vec2.Size());
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    for (size_t i = 0; i < 2; ++i) {
+      EXPECT_EQ(array_interleaved_[channel + num_channels_ * (kLength - 2 + i)],
+                vec2[channel][i]);
+    }
+  }
+}
+
+// Starts with pushing some values to the vector, then test the Zeros method.
+TEST_P(AudioMultiVectorTest, Zeros) {
+  AudioMultiVector<T> vec(num_channels_);
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  vec.Zeros(2 * kLength);
+  ASSERT_EQ(num_channels_, vec.Channels());
+  ASSERT_EQ(2u * kLength, vec.Size());
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    for (size_t i = 0; i < 2 * kLength; ++i) {
+      EXPECT_EQ(0, vec[channel][i]);
+    }
+  }
+}
+
+// Test the ReadInterleaved method
+TEST_P(AudioMultiVectorTest, ReadInterleaved) {
+  AudioMultiVector<T> vec(num_channels_);
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  T* output = new T[interleaved_length_];
+  // Read 5 samples.
+  size_t read_samples = 5;
+  EXPECT_EQ(num_channels_ * read_samples,
+            vec.ReadInterleaved(read_samples, output));
+  EXPECT_EQ(0, memcmp(array_interleaved_, output, read_samples * sizeof(T)));
+
+  // Read too many samples. Expect to get all samples from the vector.
+  EXPECT_EQ(interleaved_length_,
+            vec.ReadInterleaved(kLength + 1, output));
+  EXPECT_EQ(0, memcmp(array_interleaved_, output, read_samples * sizeof(T)));
+
+  delete [] output;
+}
+
+// Try to read to a NULL pointer. Expected to return 0.
+TEST_P(AudioMultiVectorTest, ReadInterleavedToNull) {
+  AudioMultiVector<T> vec(num_channels_);
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  T* output = NULL;
+  // Read 5 samples.
+  size_t read_samples = 5;
+  EXPECT_EQ(0u, vec.ReadInterleaved(read_samples, output));
+}
+
+// Test the PopFront method.
+TEST_P(AudioMultiVectorTest, PopFront) {
+  AudioMultiVector<T> vec(num_channels_);
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  vec.PopFront(1);  // Remove one element from each channel.
+  ASSERT_EQ(kLength - 1u, vec.Size());
+  // Let |ptr| point to the second element of the first channel in the
+  // interleaved array.
+  T* ptr = &array_interleaved_[num_channels_];
+  for (size_t i = 0; i < kLength - 1; ++i) {
+    for (size_t channel = 0; channel < num_channels_; ++channel) {
+      EXPECT_EQ(*ptr, vec[channel][i]);
+      ++ptr;
+    }
+  }
+  vec.PopFront(kLength);  // Remove more elements than vector size.
+  EXPECT_EQ(0u, vec.Size());
+}
+
+// Test the PopBack method.
+TEST_P(AudioMultiVectorTest, PopBack) {
+  AudioMultiVector<T> vec(num_channels_);
+  vec.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  vec.PopBack(1);  // Remove one element from each channel.
+  ASSERT_EQ(kLength - 1u, vec.Size());
+  // Let |ptr| point to the first element of the first channel in the
+  // interleaved array.
+  T* ptr = array_interleaved_;
+  for (size_t i = 0; i < kLength - 1; ++i) {
+    for (size_t channel = 0; channel < num_channels_; ++channel) {
+      EXPECT_EQ(*ptr, vec[channel][i]);
+      ++ptr;
+    }
+  }
+  vec.PopBack(kLength);  // Remove more elements than vector size.
+  EXPECT_EQ(0u, vec.Size());
+}
+
+// Test the AssertSize method.
+TEST_P(AudioMultiVectorTest, AssertSize) {
+  AudioMultiVector<T> vec(num_channels_, kLength);
+  EXPECT_EQ(kLength, vec.Size());
+  // Start with asserting with smaller sizes than already allocated.
+  vec.AssertSize(0);
+  vec.AssertSize(kLength - 1);
+  // Nothing should have changed.
+  EXPECT_EQ(kLength, vec.Size());
+  // Assert with one element longer than already allocated.
+  vec.AssertSize(kLength + 1);
+  // Expect vector to have grown.
+  EXPECT_EQ(kLength + 1u, vec.Size());
+  // Also check the individual AudioVectors.
+  for (size_t channel = 0; channel < vec.Channels(); ++channel) {
+    EXPECT_EQ(kLength + 1u, vec[channel].Size());
+  }
+}
+
+// Test the PushBack method with another AudioMultiVector as input argument.
+TEST_P(AudioMultiVectorTest, OverwriteAt) {
+  AudioMultiVector<T> vec1(num_channels_);
+  vec1.PushBackInterleaved(array_interleaved_, interleaved_length_);
+  AudioMultiVector<T> vec2(num_channels_);
+  vec2.Zeros(3);  // 3 zeros in each channel.
+  // Overwrite vec2 at position 5.
+  vec1.OverwriteAt(vec2, 3, 5);
+  // Verify result.
+  ASSERT_EQ(kLength, vec1.Size());  // Length remains the same.
+  T* ptr = array_interleaved_;
+  for (size_t i = 0; i < kLength - 1; ++i) {
+    for (size_t channel = 0; channel < num_channels_; ++channel) {
+      if (i >= 5 && i <= 7) {
+        // Elements 5, 6, 7 should have been replaced with zeros.
+        EXPECT_EQ(0, vec1[channel][i]);
+      } else {
+        EXPECT_EQ(*ptr, vec1[channel][i]);
+      }
+      ++ptr;
+    }
+  }
+}
+
+INSTANTIATE_TEST_CASE_P(TestNumChannels,
+                        AudioMultiVectorTest,
+                        ::testing::Values(static_cast<size_t>(1),
+                                          static_cast<size_t>(2),
+                                          static_cast<size_t>(5)));
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/audio_vector.cc b/webrtc/modules/audio_coding/neteq4/audio_vector.cc
new file mode 100644
index 0000000..402e075
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_vector.cc
@@ -0,0 +1,202 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/audio_vector.h"
+
+#include <assert.h>
+
+#include <algorithm>
+
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+template<typename T>
+void AudioVector<T>::Clear() {
+  vector_.clear();
+}
+
+template<typename T>
+void AudioVector<T>::CopyFrom(AudioVector<T>* copy_to) const {
+  if (copy_to) {
+    copy_to->vector_.assign(vector_.begin(), vector_.end());
+  }
+}
+
+template<typename T>
+void AudioVector<T>::PushFront(const AudioVector<T>& prepend_this) {
+  vector_.insert(vector_.begin(), prepend_this.vector_.begin(),
+                 prepend_this.vector_.end());
+}
+
+template<typename T>
+void AudioVector<T>::PushFront(const T* prepend_this, size_t length) {
+  // Same operation as InsertAt beginning.
+  InsertAt(prepend_this, length, 0);
+}
+
+template<typename T>
+void AudioVector<T>::PushBack(const AudioVector<T>& append_this) {
+  vector_.reserve(vector_.size() + append_this.Size());
+  for (size_t i = 0; i < append_this.Size(); ++i) {
+    vector_.push_back(append_this[i]);
+  }
+}
+
+template<typename T>
+void AudioVector<T>::PushBack(const T* append_this, size_t length) {
+  vector_.reserve(vector_.size() + length);
+  for (size_t i = 0; i < length; ++i) {
+    vector_.push_back(append_this[i]);
+  }
+}
+
+template<typename T>
+void AudioVector<T>::PopFront(size_t length) {
+  if (length >= vector_.size()) {
+    // Remove all elements.
+    vector_.clear();
+  } else {
+    typename std::vector<T>::iterator end_range = vector_.begin();
+    end_range += length;
+    // Erase all elements in range vector_.begin() and |end_range| (not
+    // including |end_range|).
+    vector_.erase(vector_.begin(), end_range);
+  }
+}
+
+template<typename T>
+void AudioVector<T>::PopBack(size_t length) {
+  // Make sure that new_size is never negative (which causes wrap-around).
+  size_t new_size = vector_.size() - std::min(length, vector_.size());
+  vector_.resize(new_size);
+}
+
+template<typename T>
+void AudioVector<T>::Extend(size_t extra_length) {
+  vector_.insert(vector_.end(), extra_length, 0);
+}
+
+template<typename T>
+void AudioVector<T>::InsertAt(const T* insert_this,
+                              size_t length,
+                              size_t position) {
+  typename std::vector<T>::iterator insert_position = vector_.begin();
+  // Cap the position at the current vector length, to be sure the iterator
+  // does not extend beyond the end of the vector.
+  position = std::min(vector_.size(), position);
+  insert_position += position;
+  // First, insert zeros at the position. This makes the vector longer (and
+  // invalidates the iterator |insert_position|.
+  vector_.insert(insert_position, length, 0);
+  // Write the new values into the vector.
+  for (size_t i = 0; i < length; ++i) {
+    vector_[position + i] = insert_this[i];
+  }
+}
+
+template<typename T>
+void AudioVector<T>::InsertZerosAt(size_t length,
+                                   size_t position) {
+  typename std::vector<T>::iterator insert_position = vector_.begin();
+  // Cap the position at the current vector length, to be sure the iterator
+  // does not extend beyond the end of the vector.
+  position = std::min(vector_.size(), position);
+  insert_position += position;
+  // Insert zeros at the position. This makes the vector longer (and
+  // invalidates the iterator |insert_position|.
+  vector_.insert(insert_position, length, 0);
+}
+
+template<typename T>
+void AudioVector<T>::OverwriteAt(const T* insert_this,
+                                 size_t length,
+                                 size_t position) {
+  // Cap the insert position at the current vector length.
+  position = std::min(vector_.size(), position);
+  // Extend the vector if needed. (It is valid to overwrite beyond the current
+  // end of the vector.)
+  if (position + length > vector_.size()) {
+    Extend(position + length - vector_.size());
+  }
+  for (size_t i = 0; i < length; ++i) {
+    vector_[position + i] = insert_this[i];
+  }
+}
+
+template<typename T>
+void AudioVector<T>::CrossFade(const AudioVector<T>& append_this,
+                               size_t fade_length) {
+  // Fade length cannot be longer than the current vector or |append_this|.
+  assert(fade_length <= Size());
+  assert(fade_length <= append_this.Size());
+  fade_length = std::min(fade_length, Size());
+  fade_length = std::min(fade_length, append_this.Size());
+  size_t position = Size() - fade_length;
+  // Cross fade the overlapping regions.
+  // |alpha| is the mixing factor in Q14.
+  // TODO(hlundin): Consider skipping +1 in the denominator to produce a
+  // smoother cross-fade, in particular at the end of the fade.
+  int alpha_step = 16384 / (fade_length + 1);
+  int alpha = 16384;
+  for (size_t i = 0; i < fade_length; ++i) {
+    alpha -= alpha_step;
+    vector_[position + i] = (alpha * vector_[position + i] +
+        (16384 - alpha) * append_this[i] + 8192) >> 14;
+  }
+  assert(alpha >= 0);  // Verify that the slope was correct.
+  // Append what is left of |append_this|.
+  PushBack(&append_this[fade_length], append_this.Size() - fade_length);
+}
+
+// Template specialization for double. The only difference is in the calculation
+// of the cross-faded value, where we divide by 16384 instead of shifting with
+// 14 steps, and also not adding 8192 before scaling.
+template<>
+void AudioVector<double>::CrossFade(const AudioVector<double>& append_this,
+                                    size_t fade_length) {
+  // Fade length cannot be longer than the current vector or |append_this|.
+  assert(fade_length <= Size());
+  assert(fade_length <= append_this.Size());
+  fade_length = std::min(fade_length, Size());
+  fade_length = std::min(fade_length, append_this.Size());
+  size_t position = Size() - fade_length;
+  // Cross fade the overlapping regions.
+  // |alpha| is the mixing factor in Q14.
+  // TODO(hlundin): Consider skipping +1 in the denominator to produce a
+  // smoother cross-fade, in particular at the end of the fade.
+  int alpha_step = 16384 / (fade_length + 1);
+  int alpha = 16384;
+  for (size_t i = 0; i < fade_length; ++i) {
+    alpha -= alpha_step;
+    vector_[position + i] = (alpha * vector_[position + i] +
+        (16384 - alpha) * append_this[i]) / 16384;
+  }
+  assert(alpha >= 0);  // Verify that the slope was correct.
+  // Append what is left of |append_this|.
+  PushBack(&append_this[fade_length], append_this.Size() - fade_length);
+}
+
+template<typename T>
+const T& AudioVector<T>::operator[](size_t index) const {
+  return vector_[index];
+}
+
+template<typename T>
+T& AudioVector<T>::operator[](size_t index) {
+  return vector_[index];
+}
+
+// Instantiate the template for a few types.
+template class AudioVector<int16_t>;
+template class AudioVector<int32_t>;
+template class AudioVector<double>;
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/audio_vector.h b/webrtc/modules/audio_coding/neteq4/audio_vector.h
new file mode 100644
index 0000000..6081cd8
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_vector.h
@@ -0,0 +1,105 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_VECTOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_VECTOR_H_
+
+#include <cstring>  // Access to size_t.
+#include <vector>
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+
+namespace webrtc {
+
+template <typename T>
+class AudioVector {
+ public:
+  // Creates an empty AudioVector.
+  AudioVector() {}
+
+  // Creates an AudioVector with an initial size.
+  explicit AudioVector(size_t initial_size)
+      : vector_(initial_size, 0) {}
+
+  virtual ~AudioVector() {}
+
+  // Deletes all values and make the vector empty.
+  virtual void Clear();
+
+  // Copies all values from this vector to |copy_to|. Any contents in |copy_to|
+  // are deleted before the copy operation. After the operation is done,
+  // |copy_to| will be an exact replica of this object.
+  virtual void CopyFrom(AudioVector<T>* copy_to) const;
+
+  // Prepends the contents of AudioVector |prepend_this| to this object. The
+  // length of this object is increased with the length of |prepend_this|.
+  virtual void PushFront(const AudioVector<T>& prepend_this);
+
+  // Same as above, but with an array |prepend_this| with |length| elements as
+  // source.
+  virtual void PushFront(const T* prepend_this, size_t length);
+
+  // Same as PushFront but will append to the end of this object.
+  virtual void PushBack(const AudioVector<T>& append_this);
+
+  // Same as PushFront but will append to the end of this object.
+  virtual void PushBack(const T* append_this, size_t length);
+
+  // Removes |length| elements from the beginning of this object.
+  virtual void PopFront(size_t length);
+
+  // Removes |length| elements from the end of this object.
+  virtual void PopBack(size_t length);
+
+  // Extends this object with |extra_length| elements at the end. The new
+  // elements are initialized to zero.
+  virtual void Extend(size_t extra_length);
+
+  // Inserts |length| elements taken from the array |insert_this| and insert
+  // them at |position|. The length of the AudioVector is increased by |length|.
+  // |position| = 0 means that the new values are prepended to the vector.
+  // |position| = Size() means that the new values are appended to the vector.
+  virtual void InsertAt(const T* insert_this, size_t length, size_t position);
+
+  // Like InsertAt, but inserts |length| zero elements at |position|.
+  virtual void InsertZerosAt(size_t length, size_t position);
+
+  // Overwrites |length| elements of this AudioVector with values taken from the
+  // array |insert_this|, starting at |position|. The definition of |position|
+  // is the same as for InsertAt(). If |length| and |position| are selected
+  // such that the new data extends beyond the end of the current AudioVector,
+  // the vector is extended to accommodate the new data.
+  virtual void OverwriteAt(const T* insert_this,
+                           size_t length,
+                           size_t position);
+
+  // Appends |append_this| to the end of the current vector. Lets the two
+  // vectors overlap by |fade_length| samples, and cross-fade linearly in this
+  // region.
+  virtual void CrossFade(const AudioVector<T>& append_this, size_t fade_length);
+
+  // Returns the number of elements in this AudioVector.
+  virtual size_t Size() const { return vector_.size(); }
+
+  // Returns true if this AudioVector is empty.
+  virtual bool Empty() const { return vector_.empty(); }
+
+  // Accesses and modifies an element of AudioVector.
+  const T& operator[](size_t index) const;
+  T& operator[](size_t index);
+
+ private:
+  std::vector<T> vector_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioVector);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_AUDIO_VECTOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/audio_vector_unittest.cc b/webrtc/modules/audio_coding/neteq4/audio_vector_unittest.cc
new file mode 100644
index 0000000..366f9be
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/audio_vector_unittest.cc
@@ -0,0 +1,408 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/audio_vector.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// The tests in this file are so called typed tests (see e.g.,
+// http://code.google.com/p/googletest/wiki/AdvancedGuide#Typed_Tests).
+// This means that the tests are written with the typename T as an unknown
+// template type. The tests are then instantiated for a few types; int16_t,
+// int32_t and double in this case. Each test is then run once for each of these
+// types.
+// A few special tricks are needed. For instance, the member variable |array_|
+// in the test fixture must be accessed using this->array_ in the tests. Also,
+// the enumerator value kLength must be accessed with TestFixture::kLength.
+template<typename T>
+class AudioVectorTest : public ::testing::Test {
+ protected:
+  virtual void SetUp() {
+    // Populate test array.
+    for (size_t i = 0; i < kLength; ++i) {
+      array_[i] = static_cast<T>(i);
+    }
+  }
+
+  enum {
+    kLength = 10
+  };
+
+  T array_[kLength];
+};
+
+// Instantiate typed tests with int16_t, int32_t, and double.
+typedef ::testing::Types<int16_t, int32_t, double> MyTypes;
+TYPED_TEST_CASE(AudioVectorTest, MyTypes);
+
+// Create and destroy AudioVector objects, both empty and with a predefined
+// length.
+TYPED_TEST(AudioVectorTest, CreateAndDestroy) {
+  AudioVector<TypeParam> vec1;
+  EXPECT_TRUE(vec1.Empty());
+  EXPECT_EQ(0u, vec1.Size());
+
+  size_t initial_size = 17;
+  AudioVector<TypeParam> vec2(initial_size);
+  EXPECT_FALSE(vec2.Empty());
+  EXPECT_EQ(initial_size, vec2.Size());
+}
+
+// Test the subscript operator [] for getting and setting.
+TYPED_TEST(AudioVectorTest, SubscriptOperator) {
+  AudioVector<TypeParam> vec(TestFixture::kLength);
+  for (size_t i = 0; i < TestFixture::kLength; ++i) {
+    vec[i] = static_cast<TypeParam>(i);
+    const TypeParam& value = vec[i];  // Make sure to use the const version.
+    EXPECT_EQ(static_cast<TypeParam>(i), value);
+  }
+}
+
+// Test the PushBack method and the CopyFrom method. The Clear method is also
+// invoked.
+TYPED_TEST(AudioVectorTest, PushBackAndCopy) {
+  AudioVector<TypeParam> vec;
+  AudioVector<TypeParam> vec_copy;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  vec.CopyFrom(&vec_copy);  // Copy from |vec| to |vec_copy|.
+  ASSERT_EQ(TestFixture::kLength, vec.Size());
+  ASSERT_EQ(TestFixture::kLength, vec_copy.Size());
+  for (size_t i = 0; i < TestFixture::kLength; ++i) {
+    EXPECT_EQ(this->array_[i], vec[i]);
+    EXPECT_EQ(this->array_[i], vec_copy[i]);
+  }
+
+  // Clear |vec| and verify that it is empty.
+  vec.Clear();
+  EXPECT_TRUE(vec.Empty());
+
+  // Now copy the empty vector and verify that the copy becomes empty too.
+  vec.CopyFrom(&vec_copy);
+  EXPECT_TRUE(vec_copy.Empty());
+}
+
+// Try to copy to a NULL pointer. Nothing should happen.
+TYPED_TEST(AudioVectorTest, CopyToNull) {
+  AudioVector<TypeParam> vec;
+  AudioVector<TypeParam>* vec_copy = NULL;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  vec.CopyFrom(vec_copy);
+}
+
+// Test the PushBack method with another AudioVector as input argument.
+TYPED_TEST(AudioVectorTest, PushBackVector) {
+  static const size_t kLength = 10;
+  AudioVector<TypeParam> vec1(kLength);
+  AudioVector<TypeParam> vec2(kLength);
+  // Set the first vector to [0, 1, ..., kLength - 1].
+  // Set the second vector to [kLength, kLength + 1, ..., 2 * kLength - 1].
+  for (size_t i = 0; i < kLength; ++i) {
+    vec1[i] = static_cast<TypeParam>(i);
+    vec2[i] = static_cast<TypeParam>(i + kLength);
+  }
+  // Append vec2 to the back of vec1.
+  vec1.PushBack(vec2);
+  ASSERT_EQ(2 * kLength, vec1.Size());
+  for (size_t i = 0; i < 2 * kLength; ++i) {
+    EXPECT_EQ(static_cast<TypeParam>(i), vec1[i]);
+  }
+}
+
+// Test the PushFront method.
+TYPED_TEST(AudioVectorTest, PushFront) {
+  AudioVector<TypeParam> vec;
+  vec.PushFront(this->array_, TestFixture::kLength);
+  ASSERT_EQ(TestFixture::kLength, vec.Size());
+  for (size_t i = 0; i < TestFixture::kLength; ++i) {
+    EXPECT_EQ(this->array_[i], vec[i]);
+  }
+}
+
+// Test the PushFront method with another AudioVector as input argument.
+TYPED_TEST(AudioVectorTest, PushFrontVector) {
+  static const size_t kLength = 10;
+  AudioVector<TypeParam> vec1(kLength);
+  AudioVector<TypeParam> vec2(kLength);
+  // Set the first vector to [0, 1, ..., kLength - 1].
+  // Set the second vector to [kLength, kLength + 1, ..., 2 * kLength - 1].
+  for (size_t i = 0; i < kLength; ++i) {
+    vec1[i] = static_cast<TypeParam>(i);
+    vec2[i] = static_cast<TypeParam>(i + kLength);
+  }
+  // Prepend vec1 to the front of vec2.
+  vec2.PushFront(vec1);
+  ASSERT_EQ(2 * kLength, vec2.Size());
+  for (size_t i = 0; i < 2 * kLength; ++i) {
+    EXPECT_EQ(static_cast<TypeParam>(i), vec2[i]);
+  }
+}
+
+// Test the PopFront method.
+TYPED_TEST(AudioVectorTest, PopFront) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  vec.PopFront(1);  // Remove one element.
+  EXPECT_EQ(TestFixture::kLength - 1u, vec.Size());
+  for (size_t i = 0; i < TestFixture::kLength - 1; ++i) {
+    EXPECT_EQ(static_cast<TypeParam>(i + 1), vec[i]);
+  }
+  vec.PopFront(TestFixture::kLength);  // Remove more elements than vector size.
+  EXPECT_EQ(0u, vec.Size());
+}
+
+// Test the PopBack method.
+TYPED_TEST(AudioVectorTest, PopBack) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  vec.PopBack(1);  // Remove one element.
+  EXPECT_EQ(TestFixture::kLength - 1u, vec.Size());
+  for (size_t i = 0; i < TestFixture::kLength - 1; ++i) {
+    EXPECT_EQ(static_cast<TypeParam>(i), vec[i]);
+  }
+  vec.PopBack(TestFixture::kLength);  // Remove more elements than vector size.
+  EXPECT_EQ(0u, vec.Size());
+}
+
+// Test the Extend method.
+TYPED_TEST(AudioVectorTest, Extend) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  vec.Extend(5);  // Extend with 5 elements, which should all be zeros.
+  ASSERT_EQ(TestFixture::kLength + 5u, vec.Size());
+  // Verify that all are zero.
+  for (int i = TestFixture::kLength; i < TestFixture::kLength + 5; ++i) {
+    EXPECT_EQ(0, vec[i]);
+  }
+}
+
+// Test the InsertAt method with an insert position in the middle of the vector.
+TYPED_TEST(AudioVectorTest, InsertAt) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  TypeParam new_array[kNewLength];
+  // Set array elements to {100, 101, 102, ... }.
+  for (int i = 0; i < kNewLength; ++i) {
+    new_array[i] = 100 + i;
+  }
+  int insert_position = 5;
+  vec.InsertAt(new_array, kNewLength, insert_position);
+  // Verify that the vector looks as follows:
+  // {0, 1, ..., |insert_position| - 1, 100, 101, ..., 100 + kNewLength - 1,
+  //  |insert_position|, |insert_position| + 1, ..., kLength - 1}.
+  int pos = 0;
+  for (int i = 0; i < insert_position; ++i) {
+    EXPECT_EQ(this->array_[i], vec[pos]);
+    ++pos;
+  }
+  for (int i = 0; i < kNewLength; ++i) {
+    EXPECT_EQ(new_array[i], vec[pos]);
+    ++pos;
+  }
+  for (int i = insert_position; i < TestFixture::kLength; ++i) {
+    EXPECT_EQ(this->array_[i], vec[pos]);
+    ++pos;
+  }
+}
+
+// Test the InsertZerosAt method with an insert position in the middle of the
+// vector. Use the InsertAt method as reference.
+TYPED_TEST(AudioVectorTest, InsertZerosAt) {
+  AudioVector<TypeParam> vec;
+  AudioVector<TypeParam> vec_ref;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  vec_ref.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  int insert_position = 5;
+  vec.InsertZerosAt(kNewLength, insert_position);
+  TypeParam new_array[kNewLength] = {0};  // All zero elements.
+  vec_ref.InsertAt(new_array, kNewLength, insert_position);
+  // Verify that the vectors are identical.
+  ASSERT_EQ(vec_ref.Size(), vec.Size());
+  for (size_t i = 0; i < vec.Size(); ++i) {
+    EXPECT_EQ(vec_ref[i], vec[i]);
+  }
+}
+
+// Test the InsertAt method with an insert position at the start of the vector.
+TYPED_TEST(AudioVectorTest, InsertAtBeginning) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  TypeParam new_array[kNewLength];
+  // Set array elements to {100, 101, 102, ... }.
+  for (int i = 0; i < kNewLength; ++i) {
+    new_array[i] = 100 + i;
+  }
+  int insert_position = 0;
+  vec.InsertAt(new_array, kNewLength, insert_position);
+  // Verify that the vector looks as follows:
+  // {100, 101, ..., 100 + kNewLength - 1,
+  //  0, 1, ..., kLength - 1}.
+  int pos = 0;
+  for (int i = 0; i < kNewLength; ++i) {
+    EXPECT_EQ(new_array[i], vec[pos]);
+    ++pos;
+  }
+  for (int i = insert_position; i < TestFixture::kLength; ++i) {
+    EXPECT_EQ(this->array_[i], vec[pos]);
+    ++pos;
+  }
+}
+
+// Test the InsertAt method with an insert position at the end of the vector.
+TYPED_TEST(AudioVectorTest, InsertAtEnd) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  TypeParam new_array[kNewLength];
+  // Set array elements to {100, 101, 102, ... }.
+  for (int i = 0; i < kNewLength; ++i) {
+    new_array[i] = 100 + i;
+  }
+  int insert_position = TestFixture::kLength;
+  vec.InsertAt(new_array, kNewLength, insert_position);
+  // Verify that the vector looks as follows:
+  // {0, 1, ..., kLength - 1, 100, 101, ..., 100 + kNewLength - 1 }.
+  int pos = 0;
+  for (int i = 0; i < TestFixture::kLength; ++i) {
+    EXPECT_EQ(this->array_[i], vec[pos]);
+    ++pos;
+  }
+  for (int i = 0; i < kNewLength; ++i) {
+    EXPECT_EQ(new_array[i], vec[pos]);
+    ++pos;
+  }
+}
+
+// Test the InsertAt method with an insert position beyond the end of the
+// vector. Verify that a position beyond the end of the vector does not lead to
+// an error. The expected outcome is the same as if the vector end was used as
+// input position. That is, the input position should be capped at the maximum
+// allowed value.
+TYPED_TEST(AudioVectorTest, InsertBeyondEnd) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  TypeParam new_array[kNewLength];
+  // Set array elements to {100, 101, 102, ... }.
+  for (int i = 0; i < kNewLength; ++i) {
+    new_array[i] = 100 + i;
+  }
+  int insert_position = TestFixture::kLength + 10;  // Too large.
+  vec.InsertAt(new_array, kNewLength, insert_position);
+  // Verify that the vector looks as follows:
+  // {0, 1, ..., kLength - 1, 100, 101, ..., 100 + kNewLength - 1 }.
+  int pos = 0;
+  for (int i = 0; i < TestFixture::kLength; ++i) {
+    EXPECT_EQ(this->array_[i], vec[pos]);
+    ++pos;
+  }
+  for (int i = 0; i < kNewLength; ++i) {
+    EXPECT_EQ(new_array[i], vec[pos]);
+    ++pos;
+  }
+}
+
+// Test the OverwriteAt method with a position such that all of the new values
+// fit within the old vector.
+TYPED_TEST(AudioVectorTest, OverwriteAt) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  TypeParam new_array[kNewLength];
+  // Set array elements to {100, 101, 102, ... }.
+  for (int i = 0; i < kNewLength; ++i) {
+    new_array[i] = 100 + i;
+  }
+  int insert_position = 2;
+  vec.OverwriteAt(new_array, kNewLength, insert_position);
+  // Verify that the vector looks as follows:
+  // {0, ..., |insert_position| - 1, 100, 101, ..., 100 + kNewLength - 1,
+  //  |insert_position|, |insert_position| + 1, ..., kLength - 1}.
+  int pos = 0;
+  for (pos = 0; pos < insert_position; ++pos) {
+    EXPECT_EQ(this->array_[pos], vec[pos]);
+  }
+  for (int i = 0; i < kNewLength; ++i) {
+    EXPECT_EQ(new_array[i], vec[pos]);
+    ++pos;
+  }
+  for (; pos < TestFixture::kLength; ++pos) {
+    EXPECT_EQ(this->array_[pos], vec[pos]);
+  }
+}
+
+// Test the OverwriteAt method with a position such that some of the new values
+// extend beyond the end of the current vector. This is valid, and the vector is
+// expected to expand to accommodate the new values.
+TYPED_TEST(AudioVectorTest, OverwriteBeyondEnd) {
+  AudioVector<TypeParam> vec;
+  vec.PushBack(this->array_, TestFixture::kLength);
+  static const int kNewLength = 5;
+  TypeParam new_array[kNewLength];
+  // Set array elements to {100, 101, 102, ... }.
+  for (int i = 0; i < kNewLength; ++i) {
+    new_array[i] = 100 + i;
+  }
+  int insert_position = TestFixture::kLength - 2;
+  vec.OverwriteAt(new_array, kNewLength, insert_position);
+  ASSERT_EQ(TestFixture::kLength - 2u + kNewLength, vec.Size());
+  // Verify that the vector looks as follows:
+  // {0, ..., |insert_position| - 1, 100, 101, ..., 100 + kNewLength - 1,
+  //  |insert_position|, |insert_position| + 1, ..., kLength - 1}.
+  int pos = 0;
+  for (pos = 0; pos < insert_position; ++pos) {
+    EXPECT_EQ(this->array_[pos], vec[pos]);
+  }
+  for (int i = 0; i < kNewLength; ++i) {
+    EXPECT_EQ(new_array[i], vec[pos]);
+    ++pos;
+  }
+  // Verify that we checked to the end of |vec|.
+  EXPECT_EQ(vec.Size(), static_cast<size_t>(pos));
+}
+
+TYPED_TEST(AudioVectorTest, CrossFade) {
+  static const size_t kLength = 100;
+  static const size_t kFadeLength = 10;
+  AudioVector<TypeParam> vec1(kLength);
+  AudioVector<TypeParam> vec2(kLength);
+  // Set all vector elements to 0 in |vec1| and 100 in |vec2|.
+  for (size_t i = 0; i < kLength; ++i) {
+    vec1[i] = 0;
+    vec2[i] = 100;
+  }
+  vec1.CrossFade(vec2, kFadeLength);
+  ASSERT_EQ(2 * kLength - kFadeLength, vec1.Size());
+  // First part untouched.
+  for (size_t i = 0; i < kLength - kFadeLength; ++i) {
+    EXPECT_EQ(0, vec1[i]);
+  }
+  // Check mixing zone.
+  for (size_t i = 0 ; i < kFadeLength; ++i) {
+    EXPECT_NEAR((i + 1) * 100 / (kFadeLength + 1),
+                vec1[kLength - kFadeLength + i], 1);
+  }
+  // Second part untouched.
+  for (size_t i = kLength; i < vec1.Size(); ++i) {
+    EXPECT_EQ(100, vec1[i]);
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/background_noise.cc b/webrtc/modules/audio_coding/neteq4/background_noise.cc
new file mode 100644
index 0000000..7b0e828
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/background_noise.cc
@@ -0,0 +1,251 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+
+#include <assert.h>
+
+#include <algorithm>  // min, max
+#include <cstring>  // memcpy
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/post_decode_vad.h"
+
+namespace webrtc {
+
+void BackgroundNoise::Reset() {
+  initialized_ = false;
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    channel_parameters_[channel].Reset();
+  }
+  // Keep _bgnMode as it is.
+}
+
+void BackgroundNoise::Update(const AudioMultiVector<int16_t>& input,
+                             const PostDecodeVad& vad) {
+  if (vad.running() && vad.active_speech()) {
+    // Do not update the background noise parameters if we know that the signal
+    // is active speech.
+    return;
+  }
+
+  int32_t auto_correlation[kMaxLpcOrder + 1];
+  int16_t fiter_output[kMaxLpcOrder + kResidualLength];
+  int16_t reflection_coefficients[kMaxLpcOrder];
+  int16_t lpc_coefficients[kMaxLpcOrder + 1];
+
+  for (size_t channel_ix = 0; channel_ix < num_channels_; ++channel_ix) {
+    ChannelParameters& parameters = channel_parameters_[channel_ix];
+    int16_t temp_signal_array[kVecLen + kMaxLpcOrder] = {0};
+    int16_t* temp_signal = &temp_signal_array[kMaxLpcOrder];
+    memcpy(temp_signal,
+           &input[channel_ix][input.Size() - kVecLen],
+           sizeof(int16_t) * kVecLen);
+
+    int32_t sample_energy = CalculateAutoCorrelation(temp_signal, kVecLen,
+                                                     auto_correlation);
+
+    if ((!vad.running() &&
+        sample_energy < parameters.energy_update_threshold) ||
+        (vad.running() && !vad.active_speech())) {
+      // Generate LPC coefficients.
+      if (auto_correlation[0] > 0) {
+        // Regardless of whether the filter is actually updated or not,
+        // update energy threshold levels, since we have in fact observed
+        // a low energy signal.
+        if (sample_energy < parameters.energy_update_threshold) {
+          // Never go under 1.0 in average sample energy.
+          parameters.energy_update_threshold = std::max(sample_energy, 1);
+          parameters.low_energy_update_threshold = 0;
+        }
+
+        // Only update BGN if filter is stable, i.e., if return value from
+        // Levinson-Durbin function is 1.
+        if (WebRtcSpl_LevinsonDurbin(auto_correlation, lpc_coefficients,
+                                     reflection_coefficients,
+                                     kMaxLpcOrder) != 1) {
+          return;
+        }
+      } else {
+        // Center value in auto-correlation is not positive. Do not update.
+        return;
+      }
+
+      // Generate the CNG gain factor by looking at the energy of the residual.
+      WebRtcSpl_FilterMAFastQ12(temp_signal + kVecLen - kResidualLength,
+                                fiter_output, lpc_coefficients,
+                                kMaxLpcOrder + 1, kResidualLength);
+      int32_t residual_energy = WebRtcSpl_DotProductWithScale(fiter_output,
+                                                              fiter_output,
+                                                              kResidualLength,
+                                                              0);
+
+      // Check spectral flatness.
+      // Comparing the residual variance with the input signal variance tells
+      // if the spectrum is flat or not.
+      // If 20 * residual_energy >= sample_energy << 6, the spectrum is flat
+      // enough.  Also ensure that the energy is non-zero.
+      if ((residual_energy * 20 >= (sample_energy << 6)) &&
+          (sample_energy > 0)) {
+        // Spectrum is flat enough; save filter parameters.
+        // |temp_signal| + |kVecLen| - |kMaxLpcOrder| points at the first of the
+        // |kMaxLpcOrder| samples in the residual signal, which will form the
+        // filter state for the next noise generation.
+        SaveParameters(channel_ix, lpc_coefficients,
+                       temp_signal + kVecLen - kMaxLpcOrder, sample_energy,
+                       residual_energy);
+      }
+    } else {
+      // Will only happen if post-decode VAD is disabled and |sample_energy| is
+      // not low enough. Increase the threshold for update so that it increases
+      // by a factor 4 in 4 seconds.
+      IncrementEnergyThreshold(channel_ix, sample_energy);
+    }
+  }
+  return;
+}
+
+int32_t BackgroundNoise::Energy(size_t channel) const {
+  assert(channel < num_channels_);
+  return channel_parameters_[channel].energy;
+}
+
+void BackgroundNoise::SetMuteFactor(size_t channel, int16_t value) {
+  assert(channel < num_channels_);
+  channel_parameters_[channel].mute_factor = value;
+}
+
+int16_t BackgroundNoise::MuteFactor(size_t channel) const {
+  assert(channel < num_channels_);
+  return channel_parameters_[channel].mute_factor;
+}
+
+const int16_t* BackgroundNoise::Filter(size_t channel) const {
+  assert(channel < num_channels_);
+  return channel_parameters_[channel].filter;
+}
+
+const int16_t* BackgroundNoise::FilterState(size_t channel) const {
+  assert(channel < num_channels_);
+  return channel_parameters_[channel].filter_state;
+}
+
+void BackgroundNoise::SetFilterState(size_t channel, const int16_t* input,
+                                     size_t length) {
+  assert(channel < num_channels_);
+  length = std::min(length, static_cast<size_t>(kMaxLpcOrder));
+  memcpy(channel_parameters_[channel].filter_state, input,
+         length * sizeof(int16_t));
+}
+
+int16_t BackgroundNoise::Scale(size_t channel) const {
+  assert(channel < num_channels_);
+  return channel_parameters_[channel].scale;
+}
+int16_t BackgroundNoise::ScaleShift(size_t channel) const {
+  assert(channel < num_channels_);
+  return channel_parameters_[channel].scale_shift;
+}
+
+int32_t BackgroundNoise::CalculateAutoCorrelation(
+    const int16_t* signal, size_t length, int32_t* auto_correlation) const {
+  int16_t signal_max = WebRtcSpl_MaxAbsValueW16(signal, length);
+  int correlation_scale = kLogVecLen -
+      WebRtcSpl_NormW32(signal_max * signal_max);
+  correlation_scale = std::max(0, correlation_scale);
+
+  static const int kCorrelationStep = -1;
+  WebRtcSpl_CrossCorrelation(auto_correlation, signal, signal,
+                             length, kMaxLpcOrder + 1, correlation_scale,
+                             kCorrelationStep);
+
+  // Number of shifts to normalize energy to energy/sample.
+  int energy_sample_shift = kLogVecLen - correlation_scale;
+  return auto_correlation[0] >> energy_sample_shift;
+}
+
+void BackgroundNoise::IncrementEnergyThreshold(size_t channel,
+                                               int32_t sample_energy) {
+  // TODO(hlundin): Simplify the below threshold update. What this code
+  // does is simply "threshold += (increment * threshold) >> 16", but due
+  // to the limited-width operations, it is not exactly the same. The
+  // difference should be inaudible, but bit-exactness would not be
+  // maintained.
+  assert(channel < num_channels_);
+  ChannelParameters& parameters = channel_parameters_[channel];
+  int32_t temp_energy =
+      WEBRTC_SPL_MUL_16_16_RSFT(kThresholdIncrement,
+                                parameters.low_energy_update_threshold, 16);
+  temp_energy += kThresholdIncrement *
+      (parameters.energy_update_threshold & 0xFF);
+  temp_energy += (kThresholdIncrement *
+      ((parameters.energy_update_threshold>>8) & 0xFF)) << 8;
+  parameters.low_energy_update_threshold += temp_energy;
+
+  parameters.energy_update_threshold += kThresholdIncrement *
+      (parameters.energy_update_threshold>>16);
+  parameters.energy_update_threshold +=
+      parameters.low_energy_update_threshold >> 16;
+  parameters.low_energy_update_threshold =
+      parameters.low_energy_update_threshold & 0x0FFFF;
+
+  // Update maximum energy.
+  // Decrease by a factor 1/1024 each time.
+  parameters.max_energy = parameters.max_energy -
+      (parameters.max_energy >> 10);
+  if (sample_energy > parameters.max_energy) {
+    parameters.max_energy = sample_energy;
+  }
+
+  // Set |energy_update_threshold| to no less than 60 dB lower than
+  // |max_energy_|. Adding 524288 assures proper rounding.
+  int32_t energy_update_threshold = (parameters.max_energy + 524288) >> 20;
+  if (energy_update_threshold > parameters.energy_update_threshold) {
+    parameters.energy_update_threshold = energy_update_threshold;
+  }
+}
+
+void BackgroundNoise::SaveParameters(size_t channel,
+                                     const int16_t* lpc_coefficients,
+                                     const int16_t* filter_state,
+                                     int32_t sample_energy,
+                                     int32_t residual_energy) {
+  assert(channel < num_channels_);
+  ChannelParameters& parameters = channel_parameters_[channel];
+  memcpy(parameters.filter, lpc_coefficients,
+         (kMaxLpcOrder+1) * sizeof(int16_t));
+  memcpy(parameters.filter_state, filter_state,
+         kMaxLpcOrder * sizeof(int16_t));
+  // Save energy level and update energy threshold levels.
+  // Never get under 1.0 in average sample energy.
+  parameters.energy = std::max(sample_energy, 1);
+  parameters.energy_update_threshold = parameters.energy;
+  parameters.low_energy_update_threshold = 0;
+
+  // Normalize residual_energy to 29 or 30 bits before sqrt.
+  int norm_shift = WebRtcSpl_NormW32(residual_energy) - 1;
+  if (norm_shift & 0x1) {
+    norm_shift -= 1;  // Even number of shifts required.
+  }
+  assert(norm_shift >= 0);  // Should always be positive.
+  residual_energy = residual_energy << norm_shift;
+
+  // Calculate scale and shift factor.
+  parameters.scale = WebRtcSpl_SqrtFloor(residual_energy);
+  // Add 13 to the |scale_shift_|, since the random numbers table is in
+  // Q13.
+  // TODO(hlundin): Move the "13" to where the |scale_shift_| is used?
+  parameters.scale_shift = 13 + ((kLogResidualLength + norm_shift) / 2);
+
+  initialized_ = true;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/background_noise.h b/webrtc/modules/audio_coding/neteq4/background_noise.h
new file mode 100644
index 0000000..0ee95e0
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/background_noise.h
@@ -0,0 +1,145 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_BACKGROUND_NOISE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_BACKGROUND_NOISE_H_
+
+#include <cstring>  // size_t
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class PostDecodeVad;
+
+// This class handles estimation of background noise parameters.
+class BackgroundNoise {
+ public:
+  enum BackgroundNoiseMode {
+      kBgnOn,    // Default behavior with eternal noise.
+      kBgnFade,  // Noise fades to zero after some time.
+      kBgnOff    // Background noise is always zero.
+  };
+
+  // TODO(hlundin): For 48 kHz support, increase kMaxLpcOrder to 10.
+  // Will work anyway, but probably sound a little worse.
+  static const int kMaxLpcOrder = 8;  // 32000 / 8000 + 4.
+
+  explicit BackgroundNoise(size_t num_channels)
+      : num_channels_(num_channels),
+        channel_parameters_(new ChannelParameters[num_channels_]),
+        mode_(kBgnOn) {
+    Reset();
+  }
+
+  virtual ~BackgroundNoise() {
+  }
+
+  void Reset();
+
+  // Updates the parameter estimates based on the signal currently in the
+  // |sync_buffer|, and on the latest decision in |vad| if it is running.
+  void Update(const AudioMultiVector<int16_t>& sync_buffer,
+              const PostDecodeVad& vad);
+
+  // Returns |energy_| for |channel|.
+  int32_t Energy(size_t channel) const;
+
+  // Sets the value of |mute_factor_| for |channel| to |value|.
+  void SetMuteFactor(size_t channel, int16_t value);
+
+  // Returns |mute_factor_| for |channel|.
+  int16_t MuteFactor(size_t channel) const;
+
+  // Returns a pointer to |filter_| for |channel|.
+  const int16_t* Filter(size_t channel) const;
+
+  // Returns a pointer to |filter_state_| for |channel|.
+  const int16_t* FilterState(size_t channel) const;
+
+  // Copies |length| elements from |input| to the filter state. Will not copy
+  // more than |kMaxLpcOrder| elements.
+  void SetFilterState(size_t channel, const int16_t* input, size_t length);
+
+  // Returns |scale_| for |channel|.
+  int16_t Scale(size_t channel) const;
+
+  // Returns |scale_shift_| for |channel|.
+  int16_t ScaleShift(size_t channel) const;
+
+  // Accessors.
+  bool initialized() const { return initialized_; }
+  BackgroundNoiseMode mode() const { return mode_; }
+
+ private:
+  static const int kThresholdIncrement = 229;  // 0.0035 in Q16.
+  static const int kVecLen = 256;
+  static const int kLogVecLen = 8;  // log2(kVecLen).
+  static const int kResidualLength = 64;
+  static const int kLogResidualLength = 6;  // log2(kResidualLength)
+
+  struct ChannelParameters {
+    // Constructor.
+    ChannelParameters() {
+      Reset();
+    }
+
+    void Reset() {
+      energy = 2500;
+      max_energy = 0;
+      energy_update_threshold = 500000;
+      low_energy_update_threshold = 0;
+      memset(filter_state, 0, sizeof(filter_state));
+      memset(filter, 0, sizeof(filter));
+      filter[0] = 4096;
+      mute_factor = 0,
+      scale = 20000;
+      scale_shift = 24;
+    }
+
+    int32_t energy;
+    int32_t max_energy;
+    int32_t energy_update_threshold;
+    int32_t low_energy_update_threshold;
+    int16_t filter_state[kMaxLpcOrder];
+    int16_t filter[kMaxLpcOrder + 1];
+    int16_t mute_factor;
+    int16_t scale;
+    int16_t scale_shift;
+  };
+
+  int32_t CalculateAutoCorrelation(const int16_t* signal,
+                                   size_t length,
+                                   int32_t* auto_correlation) const;
+
+  // Increments the energy threshold by a factor 1 + |kThresholdIncrement|.
+  void IncrementEnergyThreshold(size_t channel, int32_t sample_energy);
+
+  // Updates the filter parameters.
+  void SaveParameters(size_t channel,
+                      const int16_t* lpc_coefficients,
+                      const int16_t* filter_state,
+                      int32_t sample_energy,
+                      int32_t residual_energy);
+
+  size_t num_channels_;
+  scoped_array<ChannelParameters> channel_parameters_;
+  bool initialized_;
+  BackgroundNoiseMode mode_;
+
+  DISALLOW_COPY_AND_ASSIGN(BackgroundNoise);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_BACKGROUND_NOISE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/background_noise_unittest.cc b/webrtc/modules/audio_coding/neteq4/background_noise_unittest.cc
new file mode 100644
index 0000000..eb7b9fa
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/background_noise_unittest.cc
@@ -0,0 +1,26 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for BackgroundNoise class.
+
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+
+#include "gtest/gtest.h"
+
+namespace webrtc {
+
+TEST(BackgroundNoise, CreateAndDestroy) {
+  size_t channels = 1;
+  BackgroundNoise bgn(channels);
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/buffer_level_filter.cc b/webrtc/modules/audio_coding/neteq4/buffer_level_filter.cc
new file mode 100644
index 0000000..70b4931
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/buffer_level_filter.cc
@@ -0,0 +1,60 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+
+#include <algorithm>  // Provide access to std::max.
+
+namespace webrtc {
+
+BufferLevelFilter::BufferLevelFilter() {
+  Reset();
+}
+
+void BufferLevelFilter::Reset() {
+  filtered_current_level_ = 0;
+  level_factor_ = 253;
+}
+
+void BufferLevelFilter::Update(int buffer_size_packets,
+                               int time_stretched_samples,
+                               int packet_len_samples) {
+  // Filter:
+  // |filtered_current_level_| = |level_factor_| * |filtered_current_level_| +
+  //                            (1 - |level_factor_|) * |buffer_size_packets|
+  // |level_factor_| and |filtered_current_level_| are in Q8.
+  // |buffer_size_packets| is in Q0.
+  filtered_current_level_ = ((level_factor_ * filtered_current_level_) >> 8) +
+      ((256 - level_factor_) * buffer_size_packets);
+
+  // Account for time-scale operations (accelerate and pre-emptive expand).
+  if (time_stretched_samples && packet_len_samples > 0) {
+    // Time-scaling has been performed since last filter update. Subtract the
+    // value of |time_stretched_samples| from |filtered_current_level_| after
+    // converting |time_stretched_samples| from samples to packets in Q8.
+    // Make sure that the filtered value remains non-negative.
+    filtered_current_level_ = std::max(0,
+        filtered_current_level_ -
+        (time_stretched_samples << 8) / packet_len_samples);
+  }
+}
+
+void BufferLevelFilter::SetTargetBufferLevel(int target_buffer_level) {
+  if (target_buffer_level <= 1) {
+    level_factor_ = 251;
+  } else if (target_buffer_level <= 3) {
+    level_factor_ = 252;
+  } else if (target_buffer_level <= 7) {
+    level_factor_ = 253;
+  } else {
+    level_factor_ = 254;
+  }
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/buffer_level_filter.h b/webrtc/modules/audio_coding/neteq4/buffer_level_filter.h
new file mode 100644
index 0000000..282ab7a
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/buffer_level_filter.h
@@ -0,0 +1,47 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_BUFFER_LEVEL_FILTER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_BUFFER_LEVEL_FILTER_H_
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+
+namespace webrtc {
+
+class BufferLevelFilter {
+ public:
+  BufferLevelFilter();
+  virtual ~BufferLevelFilter() {}
+  virtual void Reset();
+
+  // Updates the filter. Current buffer size is |buffer_size_packets| (Q0).
+  // If |time_stretched_samples| is non-zero, the value is converted to the
+  // corresponding number of packets, and is subtracted from the filtered
+  // value (thus bypassing the filter operation). |packet_len_samples| is the
+  // number of audio samples carried in each incoming packet.
+  virtual void Update(int buffer_size_packets, int time_stretched_samples,
+                      int packet_len_samples);
+
+  // Set the current target buffer level (obtained from
+  // DelayManager::base_target_level()). Used to select the appropriate
+  // filter coefficient.
+  virtual void SetTargetBufferLevel(int target_buffer_level);
+
+  virtual int filtered_current_level() const { return filtered_current_level_; }
+
+ private:
+  int level_factor_;  // Filter factor for the buffer level filter in Q8.
+  int filtered_current_level_;  // Filtered current buffer level in Q8.
+
+  DISALLOW_COPY_AND_ASSIGN(BufferLevelFilter);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_BUFFER_LEVEL_FILTER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/buffer_level_filter_unittest.cc b/webrtc/modules/audio_coding/neteq4/buffer_level_filter_unittest.cc
new file mode 100644
index 0000000..febdb83
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/buffer_level_filter_unittest.cc
@@ -0,0 +1,162 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for BufferLevelFilter class.
+
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+
+#include <cmath>  // Access to pow function.
+
+#include "gtest/gtest.h"
+
+namespace webrtc {
+
+TEST(BufferLevelFilter, CreateAndDestroy) {
+  BufferLevelFilter* filter = new BufferLevelFilter();
+  EXPECT_EQ(0, filter->filtered_current_level());
+  delete filter;
+}
+
+TEST(BufferLevelFilter, ConvergenceTest) {
+  BufferLevelFilter filter;
+  for (int times = 10; times <= 50; times += 10) {
+    for (int value = 100; value <= 200; value += 10) {
+      filter.Reset();
+      filter.SetTargetBufferLevel(1);  // Makes filter coefficient 251/256.
+      std::ostringstream ss;
+      ss << "times = " << times << ", value = " << value;
+      SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+      for (int i = 0; i < times; ++i) {
+        filter.Update(value, 0 /* time_stretched_samples */,
+                      160 /* packet_len_samples */);
+      }
+      // Expect the filtered value to be (theoretically)
+      // (1 - (251/256) ^ |times|) * |value|.
+      double expected_value_double =
+          (1 - pow(251.0 / 256.0, times)) * value;
+      int expected_value = static_cast<int>(expected_value_double);
+      // filtered_current_level() returns the value in Q8.
+      // The actual value may differ slightly from the expected value due to
+      // intermediate-stage rounding errors in the filter implementation.
+      // This is why we have to use EXPECT_NEAR with a tolerance of +/-1.
+      EXPECT_NEAR(expected_value, filter.filtered_current_level() >> 8, 1);
+    }
+  }
+}
+
+// Verify that target buffer level impacts on the filter convergence.
+TEST(BufferLevelFilter, FilterFactor) {
+  BufferLevelFilter filter;
+  // Update 10 times with value 100.
+  const int kTimes = 10;
+  const int kValue = 100;
+
+  filter.SetTargetBufferLevel(3);  // Makes filter coefficient 252/256.
+  for (int i = 0; i < kTimes; ++i) {
+    filter.Update(kValue, 0 /* time_stretched_samples */,
+                  160 /* packet_len_samples */);
+  }
+  // Expect the filtered value to be
+  // (1 - (252/256) ^ |kTimes|) * |kValue|.
+  int expected_value = 14;
+  // filtered_current_level() returns the value in Q8.
+  EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8);
+
+  filter.Reset();
+  filter.SetTargetBufferLevel(7);  // Makes filter coefficient 253/256.
+  for (int i = 0; i < kTimes; ++i) {
+    filter.Update(kValue, 0 /* time_stretched_samples */,
+                  160 /* packet_len_samples */);
+  }
+  // Expect the filtered value to be
+  // (1 - (253/256) ^ |kTimes|) * |kValue|.
+  expected_value = 11;
+  // filtered_current_level() returns the value in Q8.
+  EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8);
+
+  filter.Reset();
+  filter.SetTargetBufferLevel(8);  // Makes filter coefficient 254/256.
+  for (int i = 0; i < kTimes; ++i) {
+    filter.Update(kValue, 0 /* time_stretched_samples */,
+                  160 /* packet_len_samples */);
+  }
+  // Expect the filtered value to be
+  // (1 - (254/256) ^ |kTimes|) * |kValue|.
+  expected_value = 7;
+  // filtered_current_level() returns the value in Q8.
+  EXPECT_EQ(expected_value, filter.filtered_current_level() >> 8);
+}
+
+
+TEST(BufferLevelFilter, TimeStretchedSamples) {
+  BufferLevelFilter filter;
+  filter.SetTargetBufferLevel(1);  // Makes filter coefficient 251/256.
+  // Update 10 times with value 100.
+  const int kTimes = 10;
+  const int kValue = 100;
+  const int kPacketSizeSamples = 160;
+  const int kNumPacketsStretched = 2;
+  const int kTimeStretchedSamples = kNumPacketsStretched * kPacketSizeSamples;
+  for (int i = 0; i < kTimes; ++i) {
+    // Packet size set to 0. Do not expect the parameter
+    // |kTimeStretchedSamples| to have any effect.
+    filter.Update(kValue, kTimeStretchedSamples, 0 /* packet_len_samples */);
+  }
+  // Expect the filtered value to be
+  // (1 - (251/256) ^ |kTimes|) * |kValue|.
+  const int kExpectedValue = 17;
+  // filtered_current_level() returns the value in Q8.
+  EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
+
+  // Update filter again, now with non-zero value for packet length.
+  // Set the current filtered value to be the input, in order to isolate the
+  // impact of |kTimeStretchedSamples|.
+  filter.Update(filter.filtered_current_level() >> 8, kTimeStretchedSamples,
+                kPacketSizeSamples);
+  EXPECT_EQ(kExpectedValue - kNumPacketsStretched,
+            filter.filtered_current_level() >> 8);
+  // Try negative value and verify that we come back to the previous result.
+  filter.Update(filter.filtered_current_level() >> 8, -kTimeStretchedSamples,
+                kPacketSizeSamples);
+  EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
+}
+
+TEST(BufferLevelFilter, TimeStretchedSamplesNegativeUnevenFrames) {
+  BufferLevelFilter filter;
+  filter.SetTargetBufferLevel(1);  // Makes filter coefficient 251/256.
+  // Update 10 times with value 100.
+  const int kTimes = 10;
+  const int kValue = 100;
+  const int kPacketSizeSamples = 160;
+  const int kTimeStretchedSamples = -3.1415 * kPacketSizeSamples;
+  for (int i = 0; i < kTimes; ++i) {
+    // Packet size set to 0. Do not expect the parameter
+    // |kTimeStretchedSamples| to have any effect.
+    filter.Update(kValue, kTimeStretchedSamples, 0 /* packet_len_samples */);
+  }
+  // Expect the filtered value to be
+  // (1 - (251/256) ^ |kTimes|) * |kValue|.
+  const int kExpectedValue = 17;
+  // filtered_current_level() returns the value in Q8.
+  EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
+
+  // Update filter again, now with non-zero value for packet length.
+  // Set the current filtered value to be the input, in order to isolate the
+  // impact of |kTimeStretchedSamples|.
+  filter.Update(filter.filtered_current_level() >> 8, kTimeStretchedSamples,
+                kPacketSizeSamples);
+  EXPECT_EQ(21, filter.filtered_current_level() >> 8);
+  // Try negative value and verify that we come back to the previous result.
+  filter.Update(filter.filtered_current_level() >> 8, -kTimeStretchedSamples,
+                kPacketSizeSamples);
+  EXPECT_EQ(kExpectedValue, filter.filtered_current_level() >> 8);
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/codereview.settings b/webrtc/modules/audio_coding/neteq4/codereview.settings
new file mode 100644
index 0000000..47e94de
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/codereview.settings
@@ -0,0 +1 @@
+CODE_REVIEW_SERVER: https://chromereviews.googleplex.com
diff --git a/webrtc/modules/audio_coding/neteq4/comfort_noise.cc b/webrtc/modules/audio_coding/neteq4/comfort_noise.cc
new file mode 100644
index 0000000..219a587
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/comfort_noise.cc
@@ -0,0 +1,134 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/comfort_noise.h"
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/codecs/cng/include/webrtc_cng.h"
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+void ComfortNoise::Reset() {
+  first_call_ = true;
+  internal_error_code_ = 0;
+}
+
+int ComfortNoise::UpdateParameters(Packet* packet) {
+  assert(packet);  // Existence is verified by caller.
+  // Get comfort noise decoder.
+  AudioDecoder* cng_decoder = decoder_database_->GetDecoder(
+      packet->header.payloadType);
+  if (!cng_decoder) {
+    delete [] packet->payload;
+    delete packet;
+    return kUnknownPayloadType;
+  }
+  decoder_database_->SetActiveCngDecoder(packet->header.payloadType);
+  CNG_dec_inst* cng_inst = static_cast<CNG_dec_inst*>(cng_decoder->state());
+  int16_t ret = WebRtcCng_UpdateSid(cng_inst,
+                                    packet->payload,
+                                    packet->payload_length);
+  delete [] packet->payload;
+  delete packet;
+  if (ret < 0) {
+    internal_error_code_ = WebRtcCng_GetErrorCodeDec(cng_inst);
+    return kInternalError;
+  }
+  return kOK;
+}
+
+int ComfortNoise::Generate(size_t requested_length,
+                           AudioMultiVector<int16_t>* output) {
+  // TODO(hlundin): Change to an enumerator and skip assert.
+  assert(fs_hz_ == 8000 || fs_hz_ == 16000 || fs_hz_ ==  32000 ||
+         fs_hz_ == 48000);
+  assert(output->Channels() == 1);  // Not adapted for multi-channel yet.
+  if (output->Channels() != 1) {
+    return kMultiChannelNotSupported;
+  }
+
+  int16_t number_of_samples = requested_length;
+  int16_t new_period = 0;
+  if (first_call_) {
+    // Generate noise and overlap slightly with old data.
+    number_of_samples = requested_length + overlap_length_;
+    new_period = 1;
+  }
+  output->AssertSize(number_of_samples);
+  // Get the decoder from the database.
+  AudioDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
+  if (!cng_decoder) {
+    return kUnknownPayloadType;
+  }
+  CNG_dec_inst* cng_inst = static_cast<CNG_dec_inst*>(cng_decoder->state());
+  // The expression &(*output)[0][0] is a pointer to the first element in
+  // the first channel.
+  if (WebRtcCng_Generate(cng_inst, &(*output)[0][0], number_of_samples,
+                         new_period) < 0) {
+    // Error returned.
+    output->Zeros(requested_length);
+    internal_error_code_ = WebRtcCng_GetErrorCodeDec(cng_inst);
+    return kInternalError;
+  }
+
+  if (first_call_) {
+    // Set tapering window parameters. Values are in Q15.
+    int16_t muting_window;  // Mixing factor for overlap data.
+    int16_t muting_window_increment;  // Mixing factor increment (negative).
+    int16_t unmuting_window;  // Mixing factor for comfort noise.
+    int16_t unmuting_window_increment;  // Mixing factor increment.
+    if (fs_hz_ == 8000) {
+      muting_window = DspHelper::kMuteFactorStart8kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement8kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart8kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement8kHz;
+    } else if (fs_hz_ == 16000) {
+      muting_window = DspHelper::kMuteFactorStart16kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement16kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart16kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement16kHz;
+    } else if (fs_hz_ == 32000) {
+      muting_window = DspHelper::kMuteFactorStart32kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement32kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart32kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement32kHz;
+    } else {  // fs_hz_ == 48000
+      muting_window = DspHelper::kMuteFactorStart48kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement48kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart48kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement48kHz;
+    }
+
+    // Do overlap-add between new vector and overlap.
+    size_t start_ix = sync_buffer_->Size() - overlap_length_;
+    for (size_t i = 0; i < overlap_length_; i++) {
+      /* overlapVec[i] = WinMute * overlapVec[i] + WinUnMute * outData[i] */
+      // The expression (*output)[0][i] is the i-th element in the first
+      // channel.
+      (*sync_buffer_)[0][start_ix + i] =
+          (((*sync_buffer_)[0][start_ix + i] * muting_window) +
+              ((*output)[0][i] * unmuting_window) + 16384) >> 15;
+      muting_window += muting_window_increment;
+      unmuting_window += unmuting_window_increment;
+    }
+    // Remove |overlap_length_| samples from the front of |output| since they
+    // were mixed into |sync_buffer_| above.
+    output->PopFront(overlap_length_);
+  }
+  first_call_ = false;
+  return kOK;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/comfort_noise.h b/webrtc/modules/audio_coding/neteq4/comfort_noise.h
new file mode 100644
index 0000000..af0501f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/comfort_noise.h
@@ -0,0 +1,73 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_COMFORT_NOISE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_COMFORT_NOISE_H_
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class DecoderDatabase;
+class SyncBuffer;
+struct Packet;
+
+// This class acts as an interface to the CNG generator.
+class ComfortNoise {
+ public:
+  enum ReturnCodes {
+    kOK = 0,
+    kUnknownPayloadType,
+    kInternalError,
+    kMultiChannelNotSupported
+  };
+
+  ComfortNoise(int fs_hz, DecoderDatabase* decoder_database,
+               SyncBuffer* sync_buffer)
+      : fs_hz_(fs_hz),
+        first_call_(true),
+        overlap_length_(5 * fs_hz_ / 8000),
+        decoder_database_(decoder_database),
+        sync_buffer_(sync_buffer),
+        internal_error_code_(0) {
+  }
+
+  // Resets the state. Should be called before each new comfort noise period.
+  void Reset();
+
+  // Update the comfort noise generator with the parameters in |packet|.
+  // Will delete the packet.
+  int UpdateParameters(Packet* packet);
+
+  // Generates |requested_length| samples of comfort noise and writes to
+  // |output|. If this is the first in call after Reset (or first after creating
+  // the object), it will also mix in comfort noise at the end of the
+  // SyncBuffer object provided in the constructor.
+  int Generate(size_t requested_length, AudioMultiVector<int16_t>* output);
+
+  // Returns the last error code that was produced by the comfort noise
+  // decoder. Returns 0 if no error has been encountered since the last reset.
+  int internal_error_code() { return internal_error_code_; }
+
+ private:
+  int fs_hz_;
+  bool first_call_;
+  size_t overlap_length_;
+  DecoderDatabase* decoder_database_;
+  SyncBuffer* sync_buffer_;
+  int internal_error_code_;
+  DISALLOW_COPY_AND_ASSIGN(ComfortNoise);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_COMFORT_NOISE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/comfort_noise_unittest.cc b/webrtc/modules/audio_coding/neteq4/comfort_noise_unittest.cc
new file mode 100644
index 0000000..0e84971
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/comfort_noise_unittest.cc
@@ -0,0 +1,31 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for ComfortNoise class.
+
+#include "webrtc/modules/audio_coding/neteq4/comfort_noise.h"
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+TEST(ComfortNoise, CreateAndDestroy) {
+  int fs = 8000;
+  MockDecoderDatabase db;
+  SyncBuffer sync_buffer(1, 1000);
+  ComfortNoise cn(fs, &db, &sync_buffer);
+  EXPECT_CALL(db, Die());  // Called when |db| goes out of scope.
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic.cc b/webrtc/modules/audio_coding/neteq4/decision_logic.cc
new file mode 100644
index 0000000..ce2c45e
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic.cc
@@ -0,0 +1,184 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/decision_logic.h"
+
+#include <algorithm>
+
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+#include "webrtc/modules/audio_coding/neteq4/decision_logic_fax.h"
+#include "webrtc/modules/audio_coding/neteq4/decision_logic_normal.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+#include "webrtc/system_wrappers/interface/logging.h"
+
+namespace webrtc {
+
+DecisionLogic* DecisionLogic::Create(int fs_hz,
+                                     int output_size_samples,
+                                     NetEqPlayoutMode playout_mode,
+                                     DecoderDatabase* decoder_database,
+                                     const PacketBuffer& packet_buffer,
+                                     DelayManager* delay_manager,
+                                     BufferLevelFilter* buffer_level_filter) {
+  switch (playout_mode) {
+    case kPlayoutOn:
+    case kPlayoutStreaming:
+      return new DecisionLogicNormal(fs_hz,
+                                     output_size_samples,
+                                     playout_mode,
+                                     decoder_database,
+                                     packet_buffer,
+                                     delay_manager,
+                                     buffer_level_filter);
+    case kPlayoutFax:
+    case kPlayoutOff:
+      return new DecisionLogicFax(fs_hz,
+                                  output_size_samples,
+                                  playout_mode,
+                                  decoder_database,
+                                  packet_buffer,
+                                  delay_manager,
+                                  buffer_level_filter);
+  }
+  // This line cannot be reached, but must be here to avoid compiler errors.
+  assert(false);
+  return NULL;
+}
+
+DecisionLogic::DecisionLogic(int fs_hz,
+                             int output_size_samples,
+                             NetEqPlayoutMode playout_mode,
+                             DecoderDatabase* decoder_database,
+                             const PacketBuffer& packet_buffer,
+                             DelayManager* delay_manager,
+                             BufferLevelFilter* buffer_level_filter)
+    : decoder_database_(decoder_database),
+      packet_buffer_(packet_buffer),
+      delay_manager_(delay_manager),
+      buffer_level_filter_(buffer_level_filter),
+      cng_state_(kCngOff),
+      generated_noise_samples_(0),
+      packet_length_samples_(0),
+      sample_memory_(0),
+      prev_time_scale_(false),
+      timescale_hold_off_(kMinTimescaleInterval),
+      num_consecutive_expands_(0),
+      playout_mode_(playout_mode) {
+  delay_manager_->set_streaming_mode(playout_mode_ == kPlayoutStreaming);
+  SetSampleRate(fs_hz, output_size_samples);
+}
+
+void DecisionLogic::Reset() {
+  cng_state_ = kCngOff;
+  generated_noise_samples_ = 0;
+  packet_length_samples_ = 0;
+  sample_memory_ = 0;
+  prev_time_scale_ = false;
+  timescale_hold_off_ = 0;
+  num_consecutive_expands_ = 0;
+}
+
+void DecisionLogic::SoftReset() {
+  packet_length_samples_ = 0;
+  sample_memory_ = 0;
+  prev_time_scale_ = false;
+  timescale_hold_off_ = kMinTimescaleInterval;
+}
+
+void DecisionLogic::SetSampleRate(int fs_hz, int output_size_samples) {
+  // TODO(hlundin): Change to an enumerator and skip assert.
+  assert(fs_hz == 8000 || fs_hz == 16000 || fs_hz ==  32000 || fs_hz == 48000);
+  fs_mult_ = fs_hz / 8000;
+  output_size_samples_ = output_size_samples;
+}
+
+Operations DecisionLogic::GetDecision(const SyncBuffer& sync_buffer,
+                                      const Expand& expand,
+                                      int decoder_frame_length,
+                                      const RTPHeader* packet_header,
+                                      Modes prev_mode,
+                                      bool play_dtmf, bool* reset_decoder) {
+  if (prev_mode == kModeRfc3389Cng ||
+      prev_mode == kModeCodecInternalCng ||
+      prev_mode == kModeExpand) {
+    // If last mode was CNG (or Expand, since this could be covering up for
+    // a lost CNG packet), increase the |generated_noise_samples_| counter.
+    generated_noise_samples_ += output_size_samples_;
+    // Remember that CNG is on. This is needed if comfort noise is interrupted
+    // by DTMF.
+    if (prev_mode == kModeRfc3389Cng) {
+      cng_state_ = kCngRfc3389On;
+    } else if (prev_mode == kModeCodecInternalCng) {
+      cng_state_ = kCngInternalOn;
+    }
+  }
+
+  const int samples_left = sync_buffer.FutureLength() - expand.overlap_length();
+  const int cur_size_samples =
+      samples_left + packet_buffer_.NumSamplesInBuffer(decoder_database_,
+                                                       decoder_frame_length);
+  LOG(LS_VERBOSE) << "Buffers: " << packet_buffer_.NumPacketsInBuffer() <<
+      " packets * " << decoder_frame_length << " samples/packet + " <<
+      samples_left << " samples in sync buffer = " << cur_size_samples;
+
+  prev_time_scale_ = prev_time_scale_ &&
+      (prev_mode == kModeAccelerateSuccess ||
+          prev_mode == kModeAccelerateLowEnergy ||
+          prev_mode == kModePreemptiveExpandSuccess ||
+          prev_mode == kModePreemptiveExpandLowEnergy);
+
+  FilterBufferLevel(cur_size_samples, prev_mode);
+
+  return GetDecisionSpecialized(sync_buffer, expand, decoder_frame_length,
+                                packet_header, prev_mode, play_dtmf,
+                                reset_decoder);
+}
+
+void DecisionLogic::ExpandDecision(bool is_expand_decision) {
+  if (is_expand_decision) {
+    num_consecutive_expands_++;
+  } else {
+    num_consecutive_expands_ = 0;
+  }
+}
+
+void DecisionLogic::FilterBufferLevel(int buffer_size_samples,
+                                      Modes prev_mode) {
+  const int elapsed_time_ms = output_size_samples_ / (8 * fs_mult_);
+  delay_manager_->UpdateCounters(elapsed_time_ms);
+
+  // Do not update buffer history if currently playing CNG since it will bias
+  // the filtered buffer level.
+  if ((prev_mode != kModeRfc3389Cng) && (prev_mode != kModeCodecInternalCng)) {
+    buffer_level_filter_->SetTargetBufferLevel(
+        delay_manager_->base_target_level());
+
+    int buffer_size_packets = 0;
+    if (packet_length_samples_ > 0) {
+      // Calculate size in packets.
+      buffer_size_packets = buffer_size_samples / packet_length_samples_;
+    }
+    int sample_memory_local = 0;
+    if (prev_time_scale_) {
+      sample_memory_local = sample_memory_;
+      timescale_hold_off_ = kMinTimescaleInterval;
+    }
+    buffer_level_filter_->Update(buffer_size_packets, sample_memory_local,
+                                 packet_length_samples_);
+    prev_time_scale_ = false;
+  }
+
+  timescale_hold_off_ = std::max(timescale_hold_off_ - 1, 0);
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic.h b/webrtc/modules/audio_coding/neteq4/decision_logic.h
new file mode 100644
index 0000000..aca5ca4
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic.h
@@ -0,0 +1,168 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_H_
+
+#include "webrtc/modules/audio_coding/neteq4/defines.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BufferLevelFilter;
+class DecoderDatabase;
+class DelayManager;
+class Expand;
+class PacketBuffer;
+class SyncBuffer;
+struct RTPHeader;
+
+// This is the base class for the decision tree implementations. Derived classes
+// must implement the method GetDecisionSpecialized().
+class DecisionLogic {
+ public:
+  // Static factory function which creates different types of objects depending
+  // on the |playout_mode|.
+  static DecisionLogic* Create(int fs_hz,
+                               int output_size_samples,
+                               NetEqPlayoutMode playout_mode,
+                               DecoderDatabase* decoder_database,
+                               const PacketBuffer& packet_buffer,
+                               DelayManager* delay_manager,
+                               BufferLevelFilter* buffer_level_filter);
+
+  // Constructor.
+  DecisionLogic(int fs_hz,
+                int output_size_samples,
+                NetEqPlayoutMode playout_mode,
+                DecoderDatabase* decoder_database,
+                const PacketBuffer& packet_buffer,
+                DelayManager* delay_manager,
+                BufferLevelFilter* buffer_level_filter);
+
+  // Destructor.
+  virtual ~DecisionLogic() {}
+
+  // Resets object to a clean state.
+  void Reset();
+
+  // Resets parts of the state. Typically done when switching codecs.
+  void SoftReset();
+
+  // Sets the sample rate and the output block size.
+  void SetSampleRate(int fs_hz, int output_size_samples);
+
+  // Returns the operation that should be done next. |sync_buffer| and |expand|
+  // are provided for reference. |decoder_frame_length| is the number of samples
+  // obtained from the last decoded frame. If there is a packet available, the
+  // packet header should be supplied in |packet_header|; otherwise it should
+  // be NULL. The mode resulting form the last call to NetEqImpl::GetAudio is
+  // supplied in |prev_mode|. If there is a DTMF event to play, |play_dtmf|
+  // should be set to true. The output variable |reset_decoder| will be set to
+  // true if a reset is required; otherwise it is left unchanged (i.e., it can
+  // remain true if it was true before the call).
+  // This method end with calling GetDecisionSpecialized to get the actual
+  // return value.
+  Operations GetDecision(const SyncBuffer& sync_buffer,
+                         const Expand& expand,
+                         int decoder_frame_length,
+                         const RTPHeader* packet_header,
+                         Modes prev_mode,
+                         bool play_dtmf,
+                         bool* reset_decoder);
+
+  // These methods test the |cng_state_| for different conditions.
+  bool CngRfc3389On() const { return cng_state_ == kCngRfc3389On; }
+  bool CngOff() const { return cng_state_ == kCngOff; }
+
+  // Resets the |cng_state_| to kCngOff.
+  void SetCngOff() { cng_state_ = kCngOff; }
+
+  // Reports back to DecisionLogic whether the decision to do expand remains or
+  // not. Note that this is necessary, since an expand decision can be changed
+  // to kNormal in NetEqImpl::GetDecision if there is still enough data in the
+  // sync buffer.
+  void ExpandDecision(bool is_expand_decision);
+
+  // Adds |value| to |sample_memory_|.
+  void AddSampleMemory(int32_t value) {
+    sample_memory_ += value;
+  }
+
+  // Accessors and mutators.
+  void set_sample_memory(int32_t value) { sample_memory_ = value; }
+  int generated_noise_samples() const { return generated_noise_samples_; }
+  void set_generated_noise_samples(int value) {
+    generated_noise_samples_ = value;
+  }
+  int packet_length_samples() const { return packet_length_samples_; }
+  void set_packet_length_samples(int value) {
+    packet_length_samples_ = value;
+  }
+  void set_prev_time_scale(bool value) { prev_time_scale_ = value; }
+  NetEqPlayoutMode playout_mode() const { return playout_mode_; }
+
+ protected:
+  // The value 6 sets maximum time-stretch rate to about 100 ms/s.
+  static const int kMinTimescaleInterval = 6;
+
+  enum CngState {
+    kCngOff,
+    kCngRfc3389On,
+    kCngInternalOn
+  };
+
+  // Returns the operation that should be done next. |sync_buffer| and |expand|
+  // are provided for reference. |decoder_frame_length| is the number of samples
+  // obtained from the last decoded frame. If there is a packet available, the
+  // packet header should be supplied in |packet_header|; otherwise it should
+  // be NULL. The mode resulting form the last call to NetEqImpl::GetAudio is
+  // supplied in |prev_mode|. If there is a DTMF event to play, |play_dtmf|
+  // should be set to true. The output variable |reset_decoder| will be set to
+  // true if a reset is required; otherwise it is left unchanged (i.e., it can
+  // remain true if it was true before the call).
+  // Should be implemented by derived classes.
+  virtual Operations GetDecisionSpecialized(const SyncBuffer& sync_buffer,
+                                            const Expand& expand,
+                                            int decoder_frame_length,
+                                            const RTPHeader* packet_header,
+                                            Modes prev_mode,
+                                            bool play_dtmf,
+                                            bool* reset_decoder) = 0;
+
+  // Updates the |buffer_level_filter_| with the current buffer level
+  // |buffer_size_packets|.
+  void FilterBufferLevel(int buffer_size_packets, Modes prev_mode);
+
+  DecoderDatabase* decoder_database_;
+  const PacketBuffer& packet_buffer_;
+  DelayManager* delay_manager_;
+  BufferLevelFilter* buffer_level_filter_;
+  int fs_mult_;
+  int output_size_samples_;
+  CngState cng_state_;  // Remember if comfort noise is interrupted by other
+                        // event (e.g., DTMF).
+  int generated_noise_samples_;
+  int packet_length_samples_;
+  int sample_memory_;
+  bool prev_time_scale_;
+  int timescale_hold_off_;
+  int num_consecutive_expands_;
+  const NetEqPlayoutMode playout_mode_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DecisionLogic);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_H_
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic_fax.cc b/webrtc/modules/audio_coding/neteq4/decision_logic_fax.cc
new file mode 100644
index 0000000..00c8bcf
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic_fax.cc
@@ -0,0 +1,102 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/decision_logic_fax.h"
+
+#include <assert.h>
+
+#include <algorithm>
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+Operations DecisionLogicFax::GetDecisionSpecialized(
+    const SyncBuffer& sync_buffer,
+    const Expand& expand,
+    int decoder_frame_length,
+    const RTPHeader* packet_header,
+    Modes prev_mode,
+    bool play_dtmf,
+    bool* reset_decoder) {
+  assert(playout_mode_ == kPlayoutFax || playout_mode_ == kPlayoutOff);
+  uint32_t target_timestamp = sync_buffer.end_timestamp();
+  uint32_t available_timestamp = 0;
+  int is_cng_packet = 0;
+  if (packet_header) {
+    available_timestamp = packet_header->timestamp;
+    is_cng_packet =
+        decoder_database_->IsComfortNoise(packet_header->payloadType);
+  }
+  if (is_cng_packet) {
+    if (static_cast<int32_t>((generated_noise_samples_ + target_timestamp)
+        - available_timestamp) >= 0) {
+      // Time to play this packet now.
+      return kRfc3389Cng;
+    } else {
+      // Wait before playing this packet.
+      return kRfc3389CngNoPacket;
+    }
+  }
+  if (!packet_header) {
+    // No packet. If in CNG mode, play as usual. Otherwise, use other method to
+    // generate data.
+    if (cng_state_ == kCngRfc3389On) {
+      // Continue playing comfort noise.
+      return kRfc3389CngNoPacket;
+    } else if (cng_state_ == kCngInternalOn) {
+      // Continue playing codec-internal comfort noise.
+      return kCodecInternalCng;
+    } else {
+      // Nothing to play. Generate some data to play out.
+      switch (playout_mode_) {
+        case kPlayoutOff:
+          return kAlternativePlc;
+        case kPlayoutFax:
+          return kAudioRepetition;
+        default:
+          assert(false);
+          return kUndefined;
+      }
+    }
+  } else if (target_timestamp == available_timestamp) {
+    return kNormal;
+  } else {
+    if (static_cast<int32_t>((generated_noise_samples_ + target_timestamp)
+        - available_timestamp) >= 0) {
+      return kNormal;
+    } else {
+      // If currently playing comfort noise, continue with that. Do not
+      // increase the timestamp counter since generated_noise_samples_ will
+      // be increased.
+      if (cng_state_ == kCngRfc3389On) {
+        return kRfc3389CngNoPacket;
+      } else if (cng_state_ == kCngInternalOn) {
+        return kCodecInternalCng;
+      } else {
+        // Otherwise, do packet-loss concealment and increase the
+        // timestamp while waiting for the time to play this packet.
+        switch (playout_mode_) {
+          case kPlayoutOff:
+            return kAlternativePlcIncreaseTimestamp;
+          case kPlayoutFax:
+            return kAudioRepetitionIncreaseTimestamp;
+          default:
+            assert(0);
+            return kUndefined;
+        }
+      }
+    }
+  }
+}
+
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic_fax.h b/webrtc/modules/audio_coding/neteq4/decision_logic_fax.h
new file mode 100644
index 0000000..91f6def
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic_fax.h
@@ -0,0 +1,63 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_FAX_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_FAX_H_
+
+#include "webrtc/modules/audio_coding/neteq4/decision_logic.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Implementation of the DecisionLogic class for playout modes kPlayoutFax and
+// kPlayoutOff.
+class DecisionLogicFax : public DecisionLogic {
+ public:
+  // Constructor.
+  DecisionLogicFax(int fs_hz,
+                   int output_size_samples,
+                   NetEqPlayoutMode playout_mode,
+                   DecoderDatabase* decoder_database,
+                   const PacketBuffer& packet_buffer,
+                   DelayManager* delay_manager,
+                   BufferLevelFilter* buffer_level_filter)
+      : DecisionLogic(fs_hz, output_size_samples, playout_mode,
+                      decoder_database, packet_buffer, delay_manager,
+                      buffer_level_filter) {
+  }
+
+  // Destructor.
+  virtual ~DecisionLogicFax() {}
+
+ protected:
+  // Returns the operation that should be done next. |sync_buffer| and |expand|
+  // are provided for reference. |decoder_frame_length| is the number of samples
+  // obtained from the last decoded frame. If there is a packet available, the
+  // packet header should be supplied in |packet_header|; otherwise it should
+  // be NULL. The mode resulting form the last call to NetEqImpl::GetAudio is
+  // supplied in |prev_mode|. If there is a DTMF event to play, |play_dtmf|
+  // should be set to true. The output variable |reset_decoder| will be set to
+  // true if a reset is required; otherwise it is left unchanged (i.e., it can
+  // remain true if it was true before the call).
+  virtual Operations GetDecisionSpecialized(const SyncBuffer& sync_buffer,
+                                            const Expand& expand,
+                                            int decoder_frame_length,
+                                            const RTPHeader* packet_header,
+                                            Modes prev_mode,
+                                            bool play_dtmf,
+                                            bool* reset_decoder);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DecisionLogicFax);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_FAX_H_
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic_normal.cc b/webrtc/modules/audio_coding/neteq4/decision_logic_normal.cc
new file mode 100644
index 0000000..e95c787
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic_normal.cc
@@ -0,0 +1,236 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/decision_logic_normal.h"
+
+#include <assert.h>
+
+#include <algorithm>
+
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+#include "webrtc/modules/interface/module_common_types.h"
+
+namespace webrtc {
+
+Operations DecisionLogicNormal::GetDecisionSpecialized(
+    const SyncBuffer& sync_buffer,
+    const Expand& expand,
+    int decoder_frame_length,
+    const RTPHeader* packet_header,
+    Modes prev_mode,
+    bool play_dtmf,
+    bool* reset_decoder) {
+  assert(playout_mode_ == kPlayoutOn || playout_mode_ == kPlayoutStreaming);
+  // Guard for errors, to avoid getting stuck in error mode.
+  if (prev_mode == kModeError) {
+    if (!packet_header) {
+      return kExpand;
+    } else {
+      return kUndefined;  // Use kUndefined to flag for a reset.
+    }
+  }
+
+  uint32_t target_timestamp = sync_buffer.end_timestamp();
+  uint32_t available_timestamp = 0;
+  int is_cng_packet = 0;
+  if (packet_header) {
+    available_timestamp = packet_header->timestamp;
+    is_cng_packet =
+        decoder_database_->IsComfortNoise(packet_header->payloadType);
+  }
+
+  if (is_cng_packet) {
+    return CngOperation(prev_mode, target_timestamp, available_timestamp);
+  }
+
+  // Handle the case with no packet at all available (except maybe DTMF).
+  if (!packet_header) {
+    return NoPacket(play_dtmf);
+  }
+
+  // If the expand period was very long, reset NetEQ since it is likely that the
+  // sender was restarted.
+  if (num_consecutive_expands_ > kReinitAfterExpands) {
+    *reset_decoder = true;
+    return kNormal;
+  }
+
+  // Check if the required packet is available.
+  if (target_timestamp == available_timestamp) {
+    return ExpectedPacketAvailable(prev_mode, play_dtmf);
+  } else if (available_timestamp > target_timestamp) {
+    // TODO(hlundin): Consider wrap-around too?
+    return FuturePacketAvailable(sync_buffer, expand, decoder_frame_length,
+                                 prev_mode, target_timestamp,
+                                 available_timestamp, play_dtmf);
+  } else {
+    // This implies that available_timestamp < target_timestamp, which can
+    // happen when a new stream or codec is received. Signal for a reset.
+    return kUndefined;
+  }
+}
+
+Operations DecisionLogicNormal::CngOperation(Modes prev_mode,
+                                             uint32_t target_timestamp,
+                                             uint32_t available_timestamp) {
+  // Signed difference between target and available timestamp.
+  int32_t timestamp_diff = (generated_noise_samples_ + target_timestamp) -
+      available_timestamp;
+  int32_t optimal_level_samp =
+      (delay_manager_->TargetLevel() * packet_length_samples_) >> 8;
+  int32_t excess_waiting_time_samp = -timestamp_diff - optimal_level_samp;
+
+  if (excess_waiting_time_samp > optimal_level_samp / 2) {
+    // The waiting time for this packet will be longer than 1.5
+    // times the wanted buffer delay. Advance the clock to cut
+    // waiting time down to the optimal.
+    generated_noise_samples_ += excess_waiting_time_samp;
+    timestamp_diff += excess_waiting_time_samp;
+  }
+
+  if (timestamp_diff < 0 && prev_mode == kModeRfc3389Cng) {
+    // Not time to play this packet yet. Wait another round before using this
+    // packet. Keep on playing CNG from previous CNG parameters.
+    return kRfc3389CngNoPacket;
+  } else {
+    // Otherwise, go for the CNG packet now.
+    return kRfc3389Cng;
+  }
+}
+
+Operations DecisionLogicNormal::NoPacket(bool play_dtmf) {
+  if (cng_state_ == kCngRfc3389On) {
+    // Keep on playing comfort noise.
+    return kRfc3389CngNoPacket;
+  } else if (cng_state_ == kCngInternalOn) {
+    // Keep on playing codec internal comfort noise.
+    return kCodecInternalCng;
+  } else if (play_dtmf) {
+    return kDtmf;
+  } else {
+    // Nothing to play, do expand.
+    return kExpand;
+  }
+}
+
+Operations DecisionLogicNormal::ExpectedPacketAvailable(Modes prev_mode,
+                                                        bool play_dtmf) {
+  if (prev_mode != kModeExpand && !play_dtmf) {
+    // Check criterion for time-stretching.
+    int low_limit, high_limit;
+    delay_manager_->BufferLimits(&low_limit, &high_limit);
+    if ((buffer_level_filter_->filtered_current_level() >= high_limit &&
+        TimescaleAllowed()) ||
+        buffer_level_filter_->filtered_current_level() >= high_limit << 2) {
+      // Buffer level higher than limit and time-scaling allowed,
+      // or buffer level really high.
+      return kAccelerate;
+    } else if ((buffer_level_filter_->filtered_current_level() < low_limit)
+        && TimescaleAllowed()) {
+      return kPreemptiveExpand;
+    }
+  }
+  return kNormal;
+}
+
+Operations DecisionLogicNormal::FuturePacketAvailable(
+    const SyncBuffer& sync_buffer,
+    const Expand& expand,
+    int decoder_frame_length,
+    Modes prev_mode,
+    uint32_t target_timestamp,
+    uint32_t available_timestamp,
+    bool play_dtmf) {
+  // Required packet is not available, but a future packet is.
+  // Check if we should continue with an ongoing expand because the new packet
+  // is too far into the future.
+  uint32_t timestamp_leap = available_timestamp - target_timestamp;
+  if ((prev_mode == kModeExpand) &&
+      !ReinitAfterExpands(timestamp_leap) &&
+      !MaxWaitForPacket() &&
+      PacketTooEarly(timestamp_leap) &&
+      UnderTargetLevel()) {
+    if (play_dtmf) {
+      // Still have DTMF to play, so do not do expand.
+      return kDtmf;
+    } else {
+      // Nothing to play.
+      return kExpand;
+    }
+  }
+
+  const int samples_left = sync_buffer.FutureLength() -
+      expand.overlap_length();
+  const int cur_size_samples = samples_left +
+      packet_buffer_.NumPacketsInBuffer() * decoder_frame_length;
+
+  // If previous was comfort noise, then no merge is needed.
+  if (prev_mode == kModeRfc3389Cng ||
+      prev_mode == kModeCodecInternalCng) {
+    // Keep the same delay as before the CNG (or maximum 70 ms in buffer as
+    // safety precaution), but make sure that the number of samples in buffer
+    // is no higher than 4 times the optimal level. (Note that TargetLevel()
+    // is in Q8.)
+    int32_t timestamp_diff = (generated_noise_samples_ + target_timestamp) -
+        available_timestamp;
+    if (timestamp_diff >= 0 ||
+        cur_size_samples >
+        4 * ((delay_manager_->TargetLevel() * packet_length_samples_) >> 8)) {
+      // Time to play this new packet.
+      return kNormal;
+    } else {
+      // Too early to play this new packet; keep on playing comfort noise.
+      if (prev_mode == kModeRfc3389Cng) {
+        return kRfc3389CngNoPacket;
+      } else {  // prevPlayMode == kModeCodecInternalCng.
+        return kCodecInternalCng;
+      }
+    }
+  }
+  // Do not merge unless we have done an expand before.
+  // (Convert kAllowMergeWithoutExpand from ms to samples by multiplying with
+  // fs_mult_ * 8 = fs / 1000.)
+  if (prev_mode == kModeExpand ||
+      (decoder_frame_length < output_size_samples_ &&
+       cur_size_samples > kAllowMergeWithoutExpandMs * fs_mult_ * 8)) {
+    return kMerge;
+  } else if (play_dtmf) {
+    // Play DTMF instead of expand.
+    return kDtmf;
+  } else {
+    return kExpand;
+  }
+}
+
+bool DecisionLogicNormal::UnderTargetLevel() const {
+  return buffer_level_filter_->filtered_current_level() <=
+      delay_manager_->TargetLevel();
+}
+
+bool DecisionLogicNormal::ReinitAfterExpands(uint32_t timestamp_leap) const {
+  return timestamp_leap >=
+      static_cast<uint32_t>(output_size_samples_ * kReinitAfterExpands);
+}
+
+bool DecisionLogicNormal::PacketTooEarly(uint32_t timestamp_leap) const {
+  return timestamp_leap >
+      static_cast<uint32_t>(output_size_samples_ * num_consecutive_expands_);
+}
+
+bool DecisionLogicNormal::MaxWaitForPacket() const {
+  return num_consecutive_expands_ >= kMaxWaitForPacket;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic_normal.h b/webrtc/modules/audio_coding/neteq4/decision_logic_normal.h
new file mode 100644
index 0000000..783b001
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic_normal.h
@@ -0,0 +1,106 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_NORMAL_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_NORMAL_H_
+
+#include "webrtc/modules/audio_coding/neteq4/decision_logic.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Implementation of the DecisionLogic class for playout modes kPlayoutOn and
+// kPlayoutStreaming.
+class DecisionLogicNormal : public DecisionLogic {
+ public:
+  // Constructor.
+  DecisionLogicNormal(int fs_hz,
+                      int output_size_samples,
+                      NetEqPlayoutMode playout_mode,
+                      DecoderDatabase* decoder_database,
+                      const PacketBuffer& packet_buffer,
+                      DelayManager* delay_manager,
+                      BufferLevelFilter* buffer_level_filter)
+      : DecisionLogic(fs_hz, output_size_samples, playout_mode,
+                      decoder_database, packet_buffer, delay_manager,
+                      buffer_level_filter) {
+  }
+
+  // Destructor.
+  virtual ~DecisionLogicNormal() {}
+
+ protected:
+  // Returns the operation that should be done next. |sync_buffer| and |expand|
+  // are provided for reference. |decoder_frame_length| is the number of samples
+  // obtained from the last decoded frame. If there is a packet available, the
+  // packet header should be supplied in |packet_header|; otherwise it should
+  // be NULL. The mode resulting form the last call to NetEqImpl::GetAudio is
+  // supplied in |prev_mode|. If there is a DTMF event to play, |play_dtmf|
+  // should be set to true. The output variable |reset_decoder| will be set to
+  // true if a reset is required; otherwise it is left unchanged (i.e., it can
+  // remain true if it was true before the call).
+  virtual Operations GetDecisionSpecialized(const SyncBuffer& sync_buffer,
+                                            const Expand& expand,
+                                            int decoder_frame_length,
+                                            const RTPHeader* packet_header,
+                                            Modes prev_mode, bool play_dtmf,
+                                            bool* reset_decoder);
+
+ private:
+  static const int kAllowMergeWithoutExpandMs = 20;  // 20 ms.
+  static const int kReinitAfterExpands = 100;
+  static const int kMaxWaitForPacket = 10;
+
+  // Returns the operation given that the next available packet is a comfort
+  // noise payload (RFC 3389 only, not codec-internal).
+  Operations CngOperation(Modes prev_mode, uint32_t target_timestamp,
+                          uint32_t available_timestamp);
+
+  // Returns the operation given that no packets are available (except maybe
+  // a DTMF event, flagged by setting |play_dtmf| true).
+  Operations NoPacket(bool play_dtmf);
+
+  // Returns the operation to do given that the expected packet is available.
+  Operations ExpectedPacketAvailable(Modes prev_mode, bool play_dtmf);
+
+  // Returns the operation to do given that the expected packet is not
+  // available, but a packet further into the future is at hand.
+  Operations FuturePacketAvailable(const SyncBuffer& sync_buffer,
+                                   const Expand& expand,
+                                   int decoder_frame_length, Modes prev_mode,
+                                   uint32_t target_timestamp,
+                                   uint32_t available_timestamp,
+                                   bool play_dtmf);
+
+  // Checks if enough time has elapsed since the last successful timescale
+  // operation was done (i.e., accelerate or preemptive expand).
+  bool TimescaleAllowed() const { return timescale_hold_off_ == 0; }
+
+  // Checks if the current (filtered) buffer level is under the target level.
+  bool UnderTargetLevel() const;
+
+  // Checks if |timestamp_leap| is so long into the future that a reset due
+  // to exceeding kReinitAfterExpands will be done.
+  bool ReinitAfterExpands(uint32_t timestamp_leap) const;
+
+  // Checks if we still have not done enough expands to cover the distance from
+  // the last decoded packet to the next available packet, the distance beeing
+  // conveyed in |timestamp_leap|.
+  bool PacketTooEarly(uint32_t timestamp_leap) const;
+
+  // Checks if num_consecutive_expands_ >= kMaxWaitForPacket.
+  bool MaxWaitForPacket() const;
+
+  DISALLOW_COPY_AND_ASSIGN(DecisionLogicNormal);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECISION_LOGIC_NORMAL_H_
diff --git a/webrtc/modules/audio_coding/neteq4/decision_logic_unittest.cc b/webrtc/modules/audio_coding/neteq4/decision_logic_unittest.cc
new file mode 100644
index 0000000..d596c05
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decision_logic_unittest.cc
@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for DecisionLogic class and derived classes.
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/decision_logic.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+
+namespace webrtc {
+
+TEST(DecisionLogic, CreateAndDestroy) {
+  int fs_hz = 8000;
+  int output_size_samples = fs_hz / 100;  // Samples per 10 ms.
+  DecoderDatabase decoder_database;
+  PacketBuffer packet_buffer(10, 1000);
+  DelayPeakDetector delay_peak_detector;
+  DelayManager delay_manager(240, &delay_peak_detector);
+  BufferLevelFilter buffer_level_filter;
+  DecisionLogic* logic = DecisionLogic::Create(fs_hz, output_size_samples,
+                                               kPlayoutOn, &decoder_database,
+                                               packet_buffer, &delay_manager,
+                                               &buffer_level_filter);
+  delete logic;
+  logic = DecisionLogic::Create(fs_hz, output_size_samples,
+                                kPlayoutStreaming,
+                                &decoder_database,
+                                packet_buffer, &delay_manager,
+                                &buffer_level_filter);
+  delete logic;
+  logic = DecisionLogic::Create(fs_hz, output_size_samples,
+                                kPlayoutFax,
+                                &decoder_database,
+                                packet_buffer, &delay_manager,
+                                &buffer_level_filter);
+  delete logic;
+  logic = DecisionLogic::Create(fs_hz, output_size_samples,
+                                kPlayoutOff,
+                                &decoder_database,
+                                packet_buffer, &delay_manager,
+                                &buffer_level_filter);
+  delete logic;
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/decoder_database.cc b/webrtc/modules/audio_coding/neteq4/decoder_database.cc
new file mode 100644
index 0000000..e62097e
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decoder_database.cc
@@ -0,0 +1,251 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+
+#include <assert.h>
+#include <utility>  // pair
+
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+
+namespace webrtc {
+
+DecoderDatabase::DecoderInfo::~DecoderInfo() {
+  if (!external) delete decoder;
+}
+
+void DecoderDatabase::Reset() {
+  decoders_.clear();
+  active_decoder_ = -1;
+  active_cng_decoder_ = -1;
+}
+
+int DecoderDatabase::RegisterPayload(uint8_t rtp_payload_type,
+                                     NetEqDecoder codec_type) {
+  if (rtp_payload_type > kMaxRtpPayloadType) {
+    return kInvalidRtpPayloadType;
+  }
+  if (!AudioDecoder::CodecSupported(codec_type)) {
+    return kCodecNotSupported;
+  }
+  int fs_hz = AudioDecoder::CodecSampleRateHz(codec_type);
+  std::pair<DecoderMap::iterator, bool> ret;
+  DecoderInfo info(codec_type, fs_hz, NULL, false);
+  ret = decoders_.insert(std::make_pair(rtp_payload_type, info));
+  if (ret.second == false) {
+    // Database already contains a decoder with type |rtp_payload_type|.
+    return kDecoderExists;
+  }
+  return kOK;
+}
+
+int DecoderDatabase::InsertExternal(uint8_t rtp_payload_type,
+                                    NetEqDecoder codec_type,
+                                    int fs_hz,
+                                    AudioDecoder* decoder) {
+  if (rtp_payload_type > 0x7F) {
+    return kInvalidRtpPayloadType;
+  }
+  if (!AudioDecoder::CodecSupported(codec_type)) {
+    return kCodecNotSupported;
+  }
+  if (fs_hz != 8000 && fs_hz != 16000 && fs_hz != 32000 && fs_hz != 48000) {
+    return kInvalidSampleRate;
+  }
+  if (!decoder) {
+    return kInvalidPointer;
+  }
+  decoder->Init();
+  std::pair<DecoderMap::iterator, bool> ret;
+  DecoderInfo info(codec_type, fs_hz, decoder, true);
+  ret = decoders_.insert(
+      std::pair<uint8_t, DecoderInfo>(rtp_payload_type, info));
+  if (ret.second == false) {
+    // Database already contains a decoder with type |rtp_payload_type|.
+    return kDecoderExists;
+  }
+  return kOK;
+}
+
+int DecoderDatabase::Remove(uint8_t rtp_payload_type) {
+  if (decoders_.erase(rtp_payload_type) == 0) {
+    // No decoder with that |rtp_payload_type|.
+    return kDecoderNotFound;
+  }
+  if (active_decoder_ == rtp_payload_type) {
+    active_decoder_ = -1;  // No active decoder.
+  }
+  if (active_cng_decoder_ == rtp_payload_type) {
+    active_cng_decoder_ = -1;  // No active CNG decoder.
+  }
+  return kOK;
+}
+
+const DecoderDatabase::DecoderInfo* DecoderDatabase::GetDecoderInfo(
+    uint8_t rtp_payload_type) const {
+  DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);
+  if (it == decoders_.end()) {
+    // Decoder not found.
+    return NULL;
+  }
+  return &(*it).second;
+}
+
+uint8_t DecoderDatabase::GetRtpPayloadType(
+    NetEqDecoder codec_type) const {
+  DecoderMap::const_iterator it;
+  for (it = decoders_.begin(); it != decoders_.end(); ++it) {
+    if ((*it).second.codec_type == codec_type) {
+      // Match found.
+      return (*it).first;
+    }
+  }
+  // No match.
+  return kRtpPayloadTypeError;
+}
+
+AudioDecoder* DecoderDatabase::GetDecoder(uint8_t rtp_payload_type) {
+  if (IsDtmf(rtp_payload_type) || IsRed(rtp_payload_type)) {
+    // These are not real decoders.
+    return NULL;
+  }
+  DecoderMap::iterator it = decoders_.find(rtp_payload_type);
+  if (it == decoders_.end()) {
+    // Decoder not found.
+    return NULL;
+  }
+  DecoderInfo* info = &(*it).second;
+  if (!info->decoder) {
+    // Create the decoder object.
+    AudioDecoder* decoder = AudioDecoder::CreateAudioDecoder(info->codec_type);
+    assert(decoder);  // Should not be able to have an unsupported codec here.
+    info->decoder = decoder;
+    info->decoder->Init();
+  }
+  return info->decoder;
+}
+
+bool DecoderDatabase::IsType(uint8_t rtp_payload_type,
+                             NetEqDecoder codec_type) const {
+  DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);
+  if (it == decoders_.end()) {
+    // Decoder not found.
+    return false;
+  }
+  return ((*it).second.codec_type == codec_type);
+}
+
+bool DecoderDatabase::IsComfortNoise(uint8_t rtp_payload_type) const {
+  if (IsType(rtp_payload_type, kDecoderCNGnb) ||
+      IsType(rtp_payload_type, kDecoderCNGwb) ||
+      IsType(rtp_payload_type, kDecoderCNGswb32kHz) ||
+      IsType(rtp_payload_type, kDecoderCNGswb48kHz)) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+bool DecoderDatabase::IsDtmf(uint8_t rtp_payload_type) const {
+  return IsType(rtp_payload_type, kDecoderAVT);
+}
+
+bool DecoderDatabase::IsRed(uint8_t rtp_payload_type) const {
+  return IsType(rtp_payload_type, kDecoderRED);
+}
+
+int DecoderDatabase::SetActiveDecoder(uint8_t rtp_payload_type,
+                                      bool* new_decoder) {
+  // Check that |rtp_payload_type| exists in the database.
+  DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);
+  if (it == decoders_.end()) {
+    // Decoder not found.
+    return kDecoderNotFound;
+  }
+  assert(new_decoder);
+  *new_decoder = false;
+  if (active_decoder_ < 0) {
+    // This is the first active decoder.
+    *new_decoder = true;
+  } else if (active_decoder_ != rtp_payload_type) {
+    // Moving from one active decoder to another. Delete the first one.
+    DecoderMap::iterator it = decoders_.find(active_decoder_);
+    if (it == decoders_.end()) {
+      // Decoder not found. This should not be possible.
+      assert(false);
+      return kDecoderNotFound;
+    }
+    if (!(*it).second.external) {
+      // Delete the AudioDecoder object, unless it is an externally created
+      // decoder.
+      delete (*it).second.decoder;
+      (*it).second.decoder = NULL;
+    }
+    *new_decoder = true;
+  }
+  active_decoder_ = rtp_payload_type;
+  return kOK;
+}
+
+AudioDecoder* DecoderDatabase::GetActiveDecoder() {
+  if (active_decoder_ < 0) {
+    // No active decoder.
+    return NULL;
+  }
+  return GetDecoder(active_decoder_);
+}
+
+int DecoderDatabase::SetActiveCngDecoder(uint8_t rtp_payload_type) {
+  // Check that |rtp_payload_type| exists in the database.
+  DecoderMap::const_iterator it = decoders_.find(rtp_payload_type);
+  if (it == decoders_.end()) {
+    // Decoder not found.
+    return kDecoderNotFound;
+  }
+  if (active_cng_decoder_ >= 0 && active_cng_decoder_ != rtp_payload_type) {
+    // Moving from one active CNG decoder to another. Delete the first one.
+    DecoderMap::iterator it = decoders_.find(active_cng_decoder_);
+    if (it == decoders_.end()) {
+      // Decoder not found. This should not be possible.
+      assert(false);
+      return kDecoderNotFound;
+    }
+    if (!(*it).second.external) {
+      // Delete the AudioDecoder object, unless it is an externally created
+      // decoder.
+      delete (*it).second.decoder;
+      (*it).second.decoder = NULL;
+    }
+  }
+  active_cng_decoder_ = rtp_payload_type;
+  return kOK;
+}
+
+AudioDecoder* DecoderDatabase::GetActiveCngDecoder() {
+  if (active_cng_decoder_ < 0) {
+    // No active CNG decoder.
+    return NULL;
+  }
+  return GetDecoder(active_cng_decoder_);
+}
+
+int DecoderDatabase::CheckPayloadTypes(const PacketList& packet_list) const {
+  PacketList::const_iterator it;
+  for (it = packet_list.begin(); it != packet_list.end(); ++it) {
+    if (decoders_.find((*it)->header.payloadType) == decoders_.end()) {
+      // Payload type is not found.
+      return kDecoderNotFound;
+    }
+  }
+  return kOK;
+}
+
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/decoder_database.h b/webrtc/modules/audio_coding/neteq4/decoder_database.h
new file mode 100644
index 0000000..203e502
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decoder_database.h
@@ -0,0 +1,161 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECODER_DATABASE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECODER_DATABASE_H_
+
+#include <map>
+
+#include "webrtc/common_types.h"  // NULL
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declaration.
+class AudioDecoder;
+
+class DecoderDatabase {
+ public:
+  enum DatabaseReturnCodes {
+    kOK = 0,
+    kInvalidRtpPayloadType = -1,
+    kCodecNotSupported = -2,
+    kInvalidSampleRate = -3,
+    kDecoderExists = -4,
+    kDecoderNotFound = -5,
+    kInvalidPointer = -6
+  };
+
+  // Struct used to store decoder info in the database.
+  struct DecoderInfo {
+    // Constructors.
+    DecoderInfo()
+        : codec_type(kDecoderArbitrary),
+          fs_hz(8000),
+          decoder(NULL),
+          external(false) {
+    }
+    DecoderInfo(NetEqDecoder ct, int fs, AudioDecoder* dec, bool ext)
+        : codec_type(ct),
+          fs_hz(fs),
+          decoder(dec),
+          external(ext) {
+    }
+    // Destructor. (Defined in decoder_database.cc.)
+    ~DecoderInfo();
+
+    NetEqDecoder codec_type;
+    int fs_hz;
+    AudioDecoder* decoder;
+    bool external;
+  };
+
+  static const uint8_t kMaxRtpPayloadType = 0x7F;  // Max for a 7-bit number.
+  // Maximum value for 8 bits, and an invalid RTP payload type (since it is
+  // only 7 bits).
+  static const uint8_t kRtpPayloadTypeError = 0xFF;
+
+  DecoderDatabase()
+      : active_decoder_(-1),
+        active_cng_decoder_(-1) {
+  }
+
+  virtual ~DecoderDatabase() {}
+
+  // Returns true if the database is empty.
+  virtual bool Empty() const { return decoders_.empty(); }
+
+  // Returns the number of decoders registered in the database.
+  virtual int Size() const { return decoders_.size(); }
+
+  // Resets the database, erasing all registered payload types, and deleting
+  // any AudioDecoder objects that were not externally created and inserted
+  // using InsertExternal().
+  virtual void Reset();
+
+  // Registers |rtp_payload_type| as a decoder of type |codec_type|. Returns
+  // kOK on success; otherwise an error code.
+  virtual int RegisterPayload(uint8_t rtp_payload_type,
+                              NetEqDecoder codec_type);
+
+  // Registers an externally created AudioDecoder object, and associates it
+  // as a decoder of type |codec_type| with |rtp_payload_type|.
+  virtual int InsertExternal(uint8_t rtp_payload_type,
+                             NetEqDecoder codec_type,
+                             int fs_hz, AudioDecoder* decoder);
+
+  // Removes the entry for |rtp_payload_type| from the database.
+  // Returns kDecoderNotFound or kOK depending on the outcome of the operation.
+  virtual int Remove(uint8_t rtp_payload_type);
+
+  // Returns a pointer to the DecoderInfo struct for |rtp_payload_type|. If
+  // no decoder is registered with that |rtp_payload_type|, NULL is returned.
+  virtual const DecoderInfo* GetDecoderInfo(uint8_t rtp_payload_type) const;
+
+  // Returns one RTP payload type associated with |codec_type|, or
+  // kDecoderNotFound if no entry exists for that value. Note that one
+  // |codec_type| may be registered with several RTP payload types, and the
+  // method may return any of them.
+  virtual uint8_t GetRtpPayloadType(NetEqDecoder codec_type) const;
+
+  // Returns a pointer to the AudioDecoder object associated with
+  // |rtp_payload_type|, or NULL if none is registered. If the AudioDecoder
+  // object does not exist for that decoder, the object is created.
+  virtual AudioDecoder* GetDecoder(uint8_t rtp_payload_type);
+
+  // Returns true if |rtp_payload_type| is registered as a |codec_type|.
+  virtual bool IsType(uint8_t rtp_payload_type,
+                      NetEqDecoder codec_type) const;
+
+  // Returns true if |rtp_payload_type| is registered as comfort noise.
+  virtual bool IsComfortNoise(uint8_t rtp_payload_type) const;
+
+  // Returns true if |rtp_payload_type| is registered as DTMF.
+  virtual bool IsDtmf(uint8_t rtp_payload_type) const;
+
+  // Returns true if |rtp_payload_type| is registered as RED.
+  virtual bool IsRed(uint8_t rtp_payload_type) const;
+
+  // Sets the active decoder to be |rtp_payload_type|. If this call results in a
+  // change of active decoder, |new_decoder| is set to true. The previous active
+  // decoder's AudioDecoder object is deleted.
+  virtual int SetActiveDecoder(uint8_t rtp_payload_type, bool* new_decoder);
+
+  // Returns the current active decoder, or NULL if no active decoder exists.
+  virtual AudioDecoder* GetActiveDecoder();
+
+  // Sets the active comfort noise decoder to be |rtp_payload_type|. If this
+  // call results in a change of active comfort noise decoder, the previous
+  // active decoder's AudioDecoder object is deleted.
+  virtual int SetActiveCngDecoder(uint8_t rtp_payload_type);
+
+  // Returns the current active comfort noise decoder, or NULL if no active
+  // comfort noise decoder exists.
+  virtual AudioDecoder* GetActiveCngDecoder();
+
+  // Returns kOK if all packets in |packet_list| carry payload types that are
+  // registered in the database. Otherwise, returns kDecoderNotFound.
+  virtual int CheckPayloadTypes(const PacketList& packet_list) const;
+
+ private:
+  typedef std::map<uint8_t, DecoderInfo> DecoderMap;
+
+  DecoderMap decoders_;
+  int active_decoder_;
+  int active_cng_decoder_;
+
+  DISALLOW_COPY_AND_ASSIGN(DecoderDatabase);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DECODER_DATABASE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/decoder_database_unittest.cc b/webrtc/modules/audio_coding/neteq4/decoder_database_unittest.cc
new file mode 100644
index 0000000..3b2364c
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/decoder_database_unittest.cc
@@ -0,0 +1,226 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <string>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_audio_decoder.h"
+
+namespace webrtc {
+
+TEST(DecoderDatabase, CreateAndDestroy) {
+  DecoderDatabase db;
+  EXPECT_EQ(0, db.Size());
+  EXPECT_TRUE(db.Empty());
+}
+
+TEST(DecoderDatabase, InsertAndRemove) {
+  DecoderDatabase db;
+  const uint8_t kPayloadType = 0;
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadType, kDecoderPCMu));
+  EXPECT_EQ(1, db.Size());
+  EXPECT_FALSE(db.Empty());
+  EXPECT_EQ(DecoderDatabase::kOK, db.Remove(kPayloadType));
+  EXPECT_EQ(0, db.Size());
+  EXPECT_TRUE(db.Empty());
+}
+
+TEST(DecoderDatabase, GetDecoderInfo) {
+  DecoderDatabase db;
+  const uint8_t kPayloadType = 0;
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadType, kDecoderPCMu));
+  const DecoderDatabase::DecoderInfo* info;
+  info = db.GetDecoderInfo(kPayloadType);
+  ASSERT_TRUE(info != NULL);
+  EXPECT_EQ(kDecoderPCMu, info->codec_type);
+  EXPECT_EQ(NULL, info->decoder);
+  EXPECT_EQ(8000, info->fs_hz);
+  EXPECT_FALSE(info->external);
+  info = db.GetDecoderInfo(kPayloadType + 1);  // Other payload type.
+  EXPECT_TRUE(info == NULL);  // Should not be found.
+}
+
+TEST(DecoderDatabase, GetRtpPayloadType) {
+  DecoderDatabase db;
+  const uint8_t kPayloadType = 0;
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadType, kDecoderPCMu));
+  EXPECT_EQ(kPayloadType, db.GetRtpPayloadType(kDecoderPCMu));
+  const uint8_t expected_value = DecoderDatabase::kRtpPayloadTypeError;
+  EXPECT_EQ(expected_value,
+            db.GetRtpPayloadType(kDecoderISAC));  // iSAC is not registered.
+}
+
+TEST(DecoderDatabase, GetDecoder) {
+  DecoderDatabase db;
+  const uint8_t kPayloadType = 0;
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadType, kDecoderILBC));
+  AudioDecoder* dec = db.GetDecoder(kPayloadType);
+  ASSERT_TRUE(dec != NULL);
+}
+
+TEST(DecoderDatabase, TypeTests) {
+  DecoderDatabase db;
+  const uint8_t kPayloadTypePcmU = 0;
+  const uint8_t kPayloadTypeCng = 13;
+  const uint8_t kPayloadTypeDtmf = 100;
+  const uint8_t kPayloadTypeRed = 101;
+  const uint8_t kPayloadNotUsed = 102;
+  // Load into database.
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadTypePcmU, kDecoderPCMu));
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadTypeCng, kDecoderCNGnb));
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadTypeDtmf, kDecoderAVT));
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.RegisterPayload(kPayloadTypeRed, kDecoderRED));
+  EXPECT_EQ(4, db.Size());
+  // Test.
+  EXPECT_FALSE(db.IsComfortNoise(kPayloadNotUsed));
+  EXPECT_FALSE(db.IsDtmf(kPayloadNotUsed));
+  EXPECT_FALSE(db.IsRed(kPayloadNotUsed));
+  EXPECT_FALSE(db.IsComfortNoise(kPayloadTypePcmU));
+  EXPECT_FALSE(db.IsDtmf(kPayloadTypePcmU));
+  EXPECT_FALSE(db.IsRed(kPayloadTypePcmU));
+  EXPECT_FALSE(db.IsType(kPayloadTypePcmU, kDecoderISAC));
+  EXPECT_TRUE(db.IsType(kPayloadTypePcmU, kDecoderPCMu));
+  EXPECT_TRUE(db.IsComfortNoise(kPayloadTypeCng));
+  EXPECT_TRUE(db.IsDtmf(kPayloadTypeDtmf));
+  EXPECT_TRUE(db.IsRed(kPayloadTypeRed));
+}
+
+TEST(DecoderDatabase, ExternalDecoder) {
+  DecoderDatabase db;
+  const uint8_t kPayloadType = 0;
+  MockAudioDecoder decoder;
+  // Load into database.
+  EXPECT_EQ(DecoderDatabase::kOK,
+            db.InsertExternal(kPayloadType, kDecoderPCMu, 8000,
+                               &decoder));
+  EXPECT_EQ(1, db.Size());
+  // Get decoder and make sure we get the external one.
+  EXPECT_EQ(&decoder, db.GetDecoder(kPayloadType));
+  // Get the decoder info struct and check it too.
+  const DecoderDatabase::DecoderInfo* info;
+  info = db.GetDecoderInfo(kPayloadType);
+  ASSERT_TRUE(info != NULL);
+  EXPECT_EQ(kDecoderPCMu, info->codec_type);
+  EXPECT_EQ(&decoder, info->decoder);
+  EXPECT_EQ(8000, info->fs_hz);
+  EXPECT_TRUE(info->external);
+  // Expect not to delete the decoder when removing it from the database, since
+  // it was declared externally.
+  EXPECT_CALL(decoder, Die()).Times(0);
+  EXPECT_EQ(DecoderDatabase::kOK, db.Remove(kPayloadType));
+  EXPECT_TRUE(db.Empty());
+
+  EXPECT_CALL(decoder, Die()).Times(1);  // Will be called when |db| is deleted.
+}
+
+TEST(DecoderDatabase, CheckPayloadTypes) {
+  DecoderDatabase db;
+  // Load a number of payloads into the database. Payload types are 0, 1, ...,
+  // while the decoder type is the same for all payload types (this does not
+  // matter for the test).
+  const int kNumPayloads = 10;
+  for (uint8_t payload_type = 0; payload_type < kNumPayloads; ++payload_type) {
+    EXPECT_EQ(DecoderDatabase::kOK,
+              db.RegisterPayload(payload_type, kDecoderArbitrary));
+  }
+  PacketList packet_list;
+  for (int i = 0; i < kNumPayloads + 1; ++i) {
+    // Create packet with payload type |i|. The last packet will have a payload
+    // type that is not registered in the decoder database.
+    Packet* packet = new Packet;
+    packet->header.payloadType = i;
+    packet_list.push_back(packet);
+  }
+
+  // Expect to return false, since the last packet is of an unknown type.
+  EXPECT_EQ(DecoderDatabase::kDecoderNotFound,
+            db.CheckPayloadTypes(packet_list));
+
+  delete packet_list.back();
+  packet_list.pop_back();  // Remove the unknown one.
+
+  EXPECT_EQ(DecoderDatabase::kOK, db.CheckPayloadTypes(packet_list));
+
+  // Delete all packets.
+  PacketList::iterator it = packet_list.begin();
+  while (it != packet_list.end()) {
+    delete packet_list.front();
+    it = packet_list.erase(it);
+  }
+}
+
+// Test the methods for setting and getting active speech and CNG decoders.
+TEST(DecoderDatabase, ActiveDecoders) {
+  DecoderDatabase db;
+  // Load payload types.
+  ASSERT_EQ(DecoderDatabase::kOK, db.RegisterPayload(0, kDecoderPCMu));
+  ASSERT_EQ(DecoderDatabase::kOK, db.RegisterPayload(103, kDecoderISAC));
+  ASSERT_EQ(DecoderDatabase::kOK, db.RegisterPayload(13, kDecoderCNGnb));
+  // Verify that no decoders are active from the start.
+  EXPECT_EQ(NULL, db.GetActiveDecoder());
+  EXPECT_EQ(NULL, db.GetActiveCngDecoder());
+
+  // Set active speech codec.
+  bool changed;  // Should be true when the active decoder changed.
+  EXPECT_EQ(DecoderDatabase::kOK, db.SetActiveDecoder(0, &changed));
+  EXPECT_TRUE(changed);
+  AudioDecoder* decoder = db.GetActiveDecoder();
+  ASSERT_FALSE(decoder == NULL);  // Should get a decoder here.
+  EXPECT_EQ(kDecoderPCMu, decoder->codec_type());
+
+  // Set the same again. Expect no change.
+  EXPECT_EQ(DecoderDatabase::kOK, db.SetActiveDecoder(0, &changed));
+  EXPECT_FALSE(changed);
+  decoder = db.GetActiveDecoder();
+  ASSERT_FALSE(decoder == NULL);  // Should get a decoder here.
+  EXPECT_EQ(kDecoderPCMu, decoder->codec_type());
+
+  // Change active decoder.
+  EXPECT_EQ(DecoderDatabase::kOK, db.SetActiveDecoder(103, &changed));
+  EXPECT_TRUE(changed);
+  decoder = db.GetActiveDecoder();
+  ASSERT_FALSE(decoder == NULL);  // Should get a decoder here.
+  EXPECT_EQ(kDecoderISAC, decoder->codec_type());
+
+  // Remove the active decoder, and verify that the active becomes NULL.
+  EXPECT_EQ(DecoderDatabase::kOK, db.Remove(103));
+  EXPECT_EQ(NULL, db.GetActiveDecoder());
+
+  // Set active CNG codec.
+  EXPECT_EQ(DecoderDatabase::kOK, db.SetActiveCngDecoder(13));
+  decoder = db.GetActiveCngDecoder();
+  ASSERT_FALSE(decoder == NULL);  // Should get a decoder here.
+  EXPECT_EQ(kDecoderCNGnb, decoder->codec_type());
+
+  // Remove the active CNG decoder, and verify that the active becomes NULL.
+  EXPECT_EQ(DecoderDatabase::kOK, db.Remove(13));
+  EXPECT_EQ(NULL, db.GetActiveCngDecoder());
+
+  // Try to set non-existing codecs as active.
+  EXPECT_EQ(DecoderDatabase::kDecoderNotFound,
+            db.SetActiveDecoder(17, &changed));
+  EXPECT_EQ(DecoderDatabase::kDecoderNotFound,
+            db.SetActiveCngDecoder(17));
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/defines.h b/webrtc/modules/audio_coding/neteq4/defines.h
new file mode 100644
index 0000000..b6f9eb2
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/defines.h
@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DEFINES_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DEFINES_H_
+
+namespace webrtc {
+
+enum Operations {
+  kNormal = 0,
+  kMerge,
+  kExpand,
+  kAccelerate,
+  kPreemptiveExpand,
+  kRfc3389Cng,
+  kRfc3389CngNoPacket,
+  kCodecInternalCng,
+  kDtmf,
+  kAlternativePlc,
+  kAlternativePlcIncreaseTimestamp,
+  kAudioRepetition,
+  kAudioRepetitionIncreaseTimestamp,
+  kUndefined = -1
+};
+
+enum Modes {
+  kModeNormal = 0,
+  kModeExpand,
+  kModeMerge,
+  kModeAccelerateSuccess,
+  kModeAccelerateLowEnergy,
+  kModeAccelerateFail,
+  kModePreemptiveExpandSuccess,
+  kModePreemptiveExpandLowEnergy,
+  kModePreemptiveExpandFail,
+  kModeRfc3389Cng,
+  kModeCodecInternalCng,
+  kModeDtmf,
+  kModeError,
+  kModeUndefined = -1
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DEFINES_H_
diff --git a/webrtc/modules/audio_coding/neteq4/delay_manager.cc b/webrtc/modules/audio_coding/neteq4/delay_manager.cc
new file mode 100644
index 0000000..58ca132
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/delay_manager.cc
@@ -0,0 +1,369 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+
+#include <assert.h>
+#include <math.h>
+
+#include <algorithm>  // max, min
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+#include "webrtc/system_wrappers/interface/logging.h"
+
+namespace webrtc {
+
+DelayManager::DelayManager(int max_packets_in_buffer,
+                           DelayPeakDetector* peak_detector)
+    : first_packet_received_(false),
+      max_packets_in_buffer_(max_packets_in_buffer),
+      iat_vector_(kMaxIat + 1, 0),
+      iat_factor_(0),
+      packet_iat_count_ms_(0),
+      base_target_level_(4),  // In Q0 domain.
+      target_level_(base_target_level_ << 8),  // In Q8 domain.
+      packet_len_ms_(0),
+      streaming_mode_(false),
+      last_seq_no_(0),
+      last_timestamp_(0),
+      extra_delay_ms_(0),
+      iat_cumulative_sum_(0),
+      max_iat_cumulative_sum_(0),
+      max_timer_ms_(0),
+      peak_detector_(*peak_detector),
+      last_pack_cng_or_dtmf_(1) {
+  assert(peak_detector);  // Should never be NULL.
+  Reset();
+}
+
+// Set the histogram vector to an exponentially decaying distribution
+// iat_vector_[i] = 0.5^(i+1), i = 0, 1, 2, ...
+// iat_vector_ is in Q30.
+void DelayManager::ResetHistogram() {
+  // Set temp_prob to (slightly more than) 1 in Q14. This ensures that the sum
+  // of iat_vector_ is 1.
+  uint16_t temp_prob = 0x4002;  // 16384 + 2 = 100000000000010 binary.
+  IATVector::iterator it = iat_vector_.begin();
+  for (; it < iat_vector_.end(); it++) {
+    temp_prob >>= 1;
+    (*it) = temp_prob << 16;
+  }
+  base_target_level_ = 4;
+  target_level_ = base_target_level_ << 8;
+}
+
+int DelayManager::Update(uint16_t sequence_number,
+                         uint32_t timestamp,
+                         int sample_rate_hz) {
+  if (sample_rate_hz <= 0) {
+    return -1;
+  }
+
+  if (!first_packet_received_) {
+    // Prepare for next packet arrival.
+    packet_iat_count_ms_ = 0;
+    last_seq_no_ = sequence_number;
+    last_timestamp_ = timestamp;
+    first_packet_received_ = true;
+    return 0;
+  }
+
+  // Try calculating packet length from current and previous timestamps.
+  // TODO(hlundin): Take care of wrap-around. Not done yet due to legacy
+  // bit-exactness.
+  int packet_len_ms;
+  if ((timestamp <= last_timestamp_) || (sequence_number <= last_seq_no_)) {
+    // Wrong timestamp or sequence order; use stored value.
+    packet_len_ms = packet_len_ms_;
+  } else {
+    // Calculate timestamps per packet and derive packet length in ms.
+    int packet_len_samp =
+        static_cast<uint32_t>(timestamp - last_timestamp_) /
+        static_cast<uint16_t>(sequence_number - last_seq_no_);
+    packet_len_ms = (1000 * packet_len_samp) / sample_rate_hz;
+  }
+
+  if (packet_len_ms > 0) {
+    // Cannot update statistics unless |packet_len_ms| is valid.
+    // Calculate inter-arrival time (IAT) in integer "packet times"
+    // (rounding down). This is the value used as index to the histogram
+    // vector |iat_vector_|.
+    int iat_packets = packet_iat_count_ms_ / packet_len_ms;
+
+    if (streaming_mode_) {
+      UpdateCumulativeSums(packet_len_ms, sequence_number);
+    }
+
+    // Check for discontinuous packet sequence and re-ordering.
+    if (sequence_number > last_seq_no_ + 1) {
+      // TODO(hlundin): Take care of wrap-around. Not done yet due to legacy
+      // bit-exactness.
+      // Compensate for gap in the sequence numbers. Reduce IAT with the
+      // expected extra time due to lost packets, but ensure that the IAT is
+      // not negative.
+      iat_packets -= sequence_number - last_seq_no_ - 1;
+      iat_packets = std::max(iat_packets, 0);
+    } else if (sequence_number < last_seq_no_) {
+      // TODO(hlundin): Take care of wrap-around.
+      // Compensate for re-ordering.
+      iat_packets += last_seq_no_ + 1 - sequence_number;
+    }
+
+    // Saturate IAT at maximum value.
+    const int max_iat = kMaxIat;
+    iat_packets = std::min(iat_packets, max_iat);
+    UpdateHistogram(iat_packets);
+    // Calculate new |target_level_| based on updated statistics.
+    target_level_ = CalculateTargetLevel(iat_packets);
+    if (streaming_mode_) {
+      target_level_ = std::max(target_level_, max_iat_cumulative_sum_);
+    }
+
+    LimitTargetLevel();
+  }  // End if (packet_len_ms > 0).
+
+  // Prepare for next packet arrival.
+  packet_iat_count_ms_ = 0;
+  last_seq_no_ = sequence_number;
+  last_timestamp_ = timestamp;
+  return 0;
+}
+
+void DelayManager::UpdateCumulativeSums(int packet_len_ms,
+                                        uint16_t sequence_number) {
+  // Calculate IAT in Q8, including fractions of a packet (i.e., more
+  // accurate than |iat_packets|.
+  int iat_packets_q8 = (packet_iat_count_ms_ << 8) / packet_len_ms;
+  // Calculate cumulative sum IAT with sequence number compensation. The sum
+  // is zero if there is no clock-drift.
+  iat_cumulative_sum_ += (iat_packets_q8 -
+      (static_cast<int>(sequence_number - last_seq_no_) << 8));
+  // Subtract drift term.
+  iat_cumulative_sum_ -= kCumulativeSumDrift;
+  // Ensure not negative.
+  iat_cumulative_sum_ = std::max(iat_cumulative_sum_, 0);
+  if (iat_cumulative_sum_ > max_iat_cumulative_sum_) {
+    // Found a new maximum.
+    max_iat_cumulative_sum_ = iat_cumulative_sum_;
+    max_timer_ms_ = 0;
+  }
+  if (max_timer_ms_ > kMaxStreamingPeakPeriodMs) {
+    // Too long since the last maximum was observed; decrease max value.
+    max_iat_cumulative_sum_ -= kCumulativeSumDrift;
+  }
+}
+
+// Each element in the vector is first multiplied by the forgetting factor
+// |iat_factor_|. Then the vector element indicated by |iat_packets| is then
+// increased (additive) by 1 - |iat_factor_|. This way, the probability of
+// |iat_packets| is slightly increased, while the sum of the histogram remains
+// constant (=1).
+// Due to inaccuracies in the fixed-point arithmetic, the histogram may no
+// longer sum up to 1 (in Q30) after the update. To correct this, a correction
+// term is added or subtracted from the first element (or elements) of the
+// vector.
+// The forgetting factor |iat_factor_| is also updated. When the DelayManager
+// is reset, the factor is set to 0 to facilitate rapid convergence in the
+// beginning. With each update of the histogram, the factor is increased towards
+// the steady-state value |kIatFactor_|.
+void DelayManager::UpdateHistogram(size_t iat_packets) {
+  assert(iat_packets < iat_vector_.size());
+  int vector_sum = 0;  // Sum up the vector elements as they are processed.
+  // Multiply each element in |iat_vector_| with |iat_factor_|.
+  for (IATVector::iterator it = iat_vector_.begin();
+      it != iat_vector_.end(); ++it) {
+    *it = (static_cast<int64_t>(*it) * iat_factor_) >> 15;
+    vector_sum += *it;
+  }
+
+  // Increase the probability for the currently observed inter-arrival time
+  // by 1 - |iat_factor_|. The factor is in Q15, |iat_vector_| in Q30.
+  // Thus, left-shift 15 steps to obtain result in Q30.
+  iat_vector_[iat_packets] += (32768 - iat_factor_) << 15;
+  vector_sum += (32768 - iat_factor_) << 15;  // Add to vector sum.
+
+  // |iat_vector_| should sum up to 1 (in Q30), but it may not due to
+  // fixed-point rounding errors.
+  vector_sum -= 1 << 30;  // Should be zero. Compensate if not.
+  if (vector_sum != 0) {
+    // Modify a few values early in |iat_vector_|.
+    int flip_sign = vector_sum > 0 ? -1 : 1;
+    IATVector::iterator it = iat_vector_.begin();
+    while (it != iat_vector_.end() && abs(vector_sum) > 0) {
+      // Add/subtract 1/16 of the element, but not more than |vector_sum|.
+      int correction = flip_sign * std::min(abs(vector_sum), (*it) >> 4);
+      *it += correction;
+      vector_sum += correction;
+      ++it;
+    }
+  }
+  assert(vector_sum == 0);  // Verify that the above is correct.
+
+  // Update |iat_factor_| (changes only during the first seconds after a reset).
+  // The factor converges to |kIatFactor_|.
+  iat_factor_ += (kIatFactor_ - iat_factor_ + 3) >> 2;
+}
+
+// Enforces upper limit for |target_level_|. The limit is chosen to be
+// 75% of |max_packets_in_buffer_|, to leave some headroom for natural
+// fluctuations around the target. If an extra delay is requested, the
+// cap is lowered even further. Note that in practice, this does not have
+// any impact, since the target level is far below the buffer capacity in
+// all reasonable cases.
+// TODO(hlundin): Move this check to the buffer logistics class.
+void DelayManager::LimitTargetLevel() {
+  int max_buffer_len = max_packets_in_buffer_;
+  if (extra_delay_ms_ > 0 && packet_len_ms_ > 0) {
+    max_buffer_len -= extra_delay_ms_ / packet_len_ms_;
+    max_buffer_len = std::max(max_buffer_len, 1);  // Sanity check.
+  }
+  max_buffer_len = (3 * (max_buffer_len << 8)) / 4;  // Shift to Q8, then 75%.
+  target_level_ = std::min(target_level_, max_buffer_len);
+}
+
+int DelayManager::CalculateTargetLevel(int iat_packets) {
+  int limit_probability = kLimitProbability;
+  if (streaming_mode_) {
+    limit_probability = kLimitProbabilityStreaming;
+  }
+
+  // Calculate target buffer level from inter-arrival time histogram.
+  // Find the |iat_index| for which the probability of observing an
+  // inter-arrival time larger than or equal to |iat_index| is less than or
+  // equal to |limit_probability|. The sought probability is estimated using
+  // the histogram as the reverse cumulant PDF, i.e., the sum of elements from
+  // the end up until |iat_index|. Now, since the sum of all elements is 1
+  // (in Q30) by definition, and since the solution is often a low value for
+  // |iat_index|, it is more efficient to start with |sum| = 1 and subtract
+  // elements from the start of the histogram.
+  size_t index = 0;  // Start from the beginning of |iat_vector_|.
+  int sum = 1 << 30;  // Assign to 1 in Q30.
+  sum -= iat_vector_[index];  // Ensure that target level is >= 1.
+
+  do {
+    // Subtract the probabilities one by one until the sum is no longer greater
+    // than limit_probability.
+    ++index;
+    sum -= iat_vector_[index];
+  } while ((sum > limit_probability) && (index < iat_vector_.size() - 1));
+
+  // This is the base value for the target buffer level.
+  int target_level = index;
+  base_target_level_ = index;
+
+  // Update detector for delay peaks.
+  bool delay_peak_found = peak_detector_.Update(iat_packets, target_level);
+  if (delay_peak_found) {
+    target_level = std::max(static_cast<int>(target_level),
+                            peak_detector_.MaxPeakHeight());
+  }
+
+  // Sanity check. |target_level| must be strictly positive.
+  target_level = std::max(target_level, 1);
+  // Scale to Q8 and assign to member variable.
+  target_level_ = target_level << 8;
+  return target_level_;
+}
+
+int DelayManager::SetPacketAudioLength(int length_ms) {
+  if (length_ms <= 0) {
+    LOG_F(LS_ERROR) << "length_ms = " << length_ms;
+    return -1;
+  }
+  packet_len_ms_ = length_ms;
+  peak_detector_.SetPacketAudioLength(packet_len_ms_);
+  packet_iat_count_ms_ = 0;
+  last_pack_cng_or_dtmf_ = 1;  // TODO(hlundin): Legacy. Remove?
+  return 0;
+}
+
+
+void DelayManager::Reset() {
+  packet_len_ms_ = 0;  // Packet size unknown.
+  streaming_mode_ = false;
+  peak_detector_.Reset();
+  ResetHistogram();  // Resets target levels too.
+  iat_factor_ = 0;  // Adapt the histogram faster for the first few packets.
+  packet_iat_count_ms_ = 0;
+  max_timer_ms_ = 0;
+  iat_cumulative_sum_ = 0;
+  max_iat_cumulative_sum_ = 0;
+  last_pack_cng_or_dtmf_ = 1;
+}
+
+int DelayManager::AverageIAT() const {
+  int32_t sum_q24 = 0;
+  assert(iat_vector_.size() == 65);  // Algorithm is hard-coded for this size.
+  for (size_t i = 0; i < iat_vector_.size(); ++i) {
+    // Shift 6 to fit worst case: 2^30 * 64.
+    sum_q24 += (iat_vector_[i] >> 6) * i;
+  }
+  // Subtract the nominal inter-arrival time 1 = 2^24 in Q24.
+  sum_q24 -= (1 << 24);
+  // Multiply with 1000000 / 2^24 = 15625 / 2^18 to get in parts-per-million.
+  // Shift 7 to Q17 first, then multiply with 15625 and shift another 11.
+  return ((sum_q24 >> 7) * 15625) >> 11;
+}
+
+bool DelayManager::PeakFound() const {
+  return peak_detector_.peak_found();
+}
+
+void DelayManager::UpdateCounters(int elapsed_time_ms) {
+  packet_iat_count_ms_ += elapsed_time_ms;
+  peak_detector_.IncrementCounter(elapsed_time_ms);
+  max_timer_ms_ += elapsed_time_ms;
+}
+
+void DelayManager::BufferLimits(int* lower_limit, int* higher_limit) const {
+  if (!lower_limit || !higher_limit) {
+    LOG_F(LS_ERROR) << "NULL pointers supplied as input";
+    assert(false);
+    return;
+  }
+
+  int extra_delay_packets_q8 = 0;
+  int window_20ms = 0x7FFF;  // Default large value for legacy bit-exactness.
+  if (packet_len_ms_ > 0) {
+    extra_delay_packets_q8 = (extra_delay_ms_ << 8) / packet_len_ms_;
+    window_20ms = (20 << 8) / packet_len_ms_;
+  }
+  // |lower_limit| is 75% of |target_level_| + extra delay.
+  // |target_level_| is in Q8 already.
+  *lower_limit = (target_level_ * 3) / 4 + extra_delay_packets_q8;
+  // |higher_limit| is equal to |target_level_| + extra delay, but should at
+  // least be 20 ms higher than |lower_limit_|.
+  *higher_limit = std::max(target_level_ + extra_delay_packets_q8,
+                           *lower_limit + window_20ms);
+}
+
+int DelayManager::TargetLevel() const {
+  if (packet_len_ms_ > 0) {
+    // Add |extra_delay_ms_| converted to packets in Q8.
+    return target_level_ + (extra_delay_ms_ << 8) / packet_len_ms_;
+  } else {
+    // Cannot convert |extra_delay_ms_|; simply return |target_level_|.
+    return target_level_;
+  }
+}
+
+void DelayManager::LastDecoderType(NetEqDecoder decoder_type) {
+  if (decoder_type == kDecoderAVT ||
+      decoder_type == kDecoderCNGnb ||
+      decoder_type == kDecoderCNGwb ||
+      decoder_type == kDecoderCNGswb32kHz ||
+      decoder_type == kDecoderCNGswb48kHz) {
+    last_pack_cng_or_dtmf_ = 1;
+  } else if (last_pack_cng_or_dtmf_ != 0) {
+    last_pack_cng_or_dtmf_ = -1;
+  }
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/delay_manager.h b/webrtc/modules/audio_coding/neteq4/delay_manager.h
new file mode 100644
index 0000000..7fa3897
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/delay_manager.h
@@ -0,0 +1,156 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DELAY_MANAGER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DELAY_MANAGER_H_
+
+#include <cstring>  // Provide access to size_t.
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declaration.
+class DelayPeakDetector;
+
+class DelayManager {
+ public:
+  typedef std::vector<int> IATVector;
+
+  // Create a DelayManager object. Notify the delay manager that the packet
+  // buffer can hold no more than |max_packets_in_buffer| packets (i.e., this
+  // is the number of packet slots in the buffer). Supply a PeakDetector
+  // object to the DelayManager.
+  DelayManager(int max_packets_in_buffer, DelayPeakDetector* peak_detector);
+
+  virtual ~DelayManager() {}
+
+  // Read the inter-arrival time histogram. Mainly for testing purposes.
+  virtual const IATVector& iat_vector() const { return iat_vector_; }
+
+  // Updates the delay manager with a new incoming packet, with
+  // |sequence_number| and |timestamp| from the RTP header. This updates the
+  // inter-arrival time histogram and other statistics, as well as the
+  // associated DelayPeakDetector. A new target buffer level is calculated.
+  // Returns 0 on success, -1 on failure (invalid sample rate).
+  virtual int Update(uint16_t sequence_number,
+                     uint32_t timestamp,
+                     int sample_rate_hz);
+
+  // Calculates a new target buffer level. Called from the Update() method.
+  // Sets target_level_ (in Q8) and returns the same value. Also calculates
+  // and updates base_target_level_, which is the target buffer level before
+  // taking delay peaks into account.
+  virtual int CalculateTargetLevel(int iat_packets);
+
+  // Notifies the DelayManager of how much audio data is carried in each packet.
+  // The method updates the DelayPeakDetector too, and resets the inter-arrival
+  // time counter. Returns 0 on success, -1 on failure.
+  virtual int SetPacketAudioLength(int length_ms);
+
+  // Resets the DelayManager and the associated DelayPeakDetector.
+  virtual void Reset();
+
+  // Calculates the average inter-arrival time deviation from the histogram.
+  // The result is returned as parts-per-million deviation from the nominal
+  // inter-arrival time. That is, if the average inter-arrival time is equal to
+  // the nominal frame time, the return value is zero. A positive value
+  // corresponds to packet spacing being too large, while a negative value means
+  // that the packets arrive with less spacing than expected.
+  virtual int AverageIAT() const;
+
+  // Returns true if peak-mode is active. That is, delay peaks were observed
+  // recently. This method simply asks for the same information from the
+  // DelayPeakDetector object.
+  virtual bool PeakFound() const;
+
+  // Notifies the counters in DelayManager and DelayPeakDetector that
+  // |elapsed_time_ms| have elapsed.
+  virtual void UpdateCounters(int elapsed_time_ms);
+
+  // Reset the inter-arrival time counter to 0.
+  virtual void ResetPacketIatCount() { packet_iat_count_ms_ = 0; }
+
+  // Writes the lower and higher limits which the buffer level should stay
+  // within to the corresponding pointers. The values are in (fractions of)
+  // packets in Q8.
+  virtual void BufferLimits(int* lower_limit, int* higher_limit) const;
+
+  // Gets the target buffer level, in (fractions of) packets in Q8. This value
+  // includes any extra delay set through the set_extra_delay_ms() method.
+  virtual int TargetLevel() const;
+
+  virtual void LastDecoderType(NetEqDecoder decoder_type);
+
+  // Accessors and mutators.
+  virtual void set_extra_delay_ms(int16_t delay) { extra_delay_ms_ = delay; }
+  virtual int base_target_level() const { return base_target_level_; }
+  virtual void set_streaming_mode(bool value) { streaming_mode_ = value; }
+  virtual int last_pack_cng_or_dtmf() const { return last_pack_cng_or_dtmf_; }
+  virtual void set_last_pack_cng_or_dtmf(int value) {
+    last_pack_cng_or_dtmf_ = value;
+  }
+
+ private:
+  static const int kLimitProbability = 53687091;  // 1/20 in Q30.
+  static const int kLimitProbabilityStreaming = 536871;  // 1/2000 in Q30.
+  static const int kMaxStreamingPeakPeriodMs = 600000;  // 10 minutes in ms.
+  static const int kCumulativeSumDrift = 2;  // Drift term for cumulative sum
+                                             // |iat_cumulative_sum_|.
+  // Steady-state forgetting factor for |iat_vector_|, 0.9993 in Q15.
+  static const int kIatFactor_ = 32745;
+  static const int kMaxIat = 64;  // Max inter-arrival time to register.
+
+  // Sets |iat_vector_| to the default start distribution and sets the
+  // |base_target_level_| and |target_level_| to the corresponding values.
+  void ResetHistogram();
+
+  // Updates |iat_cumulative_sum_| and |max_iat_cumulative_sum_|. (These are
+  // used by the streaming mode.) This method is called by Update().
+  void UpdateCumulativeSums(int packet_len_ms, uint16_t sequence_number);
+
+  // Updates the histogram |iat_vector_|. The probability for inter-arrival time
+  // equal to |iat_packets| (in integer packets) is increased slightly, while
+  // all other entries are decreased. This method is called by Update().
+  void UpdateHistogram(size_t iat_packets);
+
+  // Makes sure that |target_level_| is not too large, taking
+  // |max_packets_in_buffer_| and |extra_delay_ms_| into account. This method is
+  // called by Update().
+  void LimitTargetLevel();
+
+  bool first_packet_received_;
+  const int max_packets_in_buffer_;  // Capacity of the packet buffer.
+  IATVector iat_vector_;  // Histogram of inter-arrival times.
+  int iat_factor_;  // Forgetting factor for updating the IAT histogram (Q15).
+  int packet_iat_count_ms_;  // Milliseconds elapsed since last packet.
+  int base_target_level_;   // Currently preferred buffer level before peak
+                            // detection and streaming mode (Q0).
+  int target_level_;  // Currently preferred buffer level in (fractions)
+                      // of packets (Q8), before adding any extra delay.
+  int packet_len_ms_;  // Length of audio in each incoming packet [ms].
+  bool streaming_mode_;
+  uint16_t last_seq_no_;  // Sequence number for last received packet.
+  uint32_t last_timestamp_;  // Timestamp for the last received packet.
+  int extra_delay_ms_;  // Externally set extra delay.
+  int iat_cumulative_sum_;  // Cumulative sum of delta inter-arrival times.
+  int max_iat_cumulative_sum_;  // Max of |iat_cumulative_sum_|.
+  int max_timer_ms_;  // Time elapsed since maximum was observed.
+  DelayPeakDetector& peak_detector_;
+  int last_pack_cng_or_dtmf_;
+
+  DISALLOW_COPY_AND_ASSIGN(DelayManager);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DELAY_MANAGER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/delay_manager_unittest.cc b/webrtc/modules/audio_coding/neteq4/delay_manager_unittest.cc
new file mode 100644
index 0000000..7c08f34
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/delay_manager_unittest.cc
@@ -0,0 +1,231 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for DelayManager class.
+
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+
+#include <math.h>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_delay_peak_detector.h"
+
+namespace webrtc {
+
+using ::testing::Return;
+
+class DelayManagerTest : public ::testing::Test {
+ protected:
+  static const int kMaxNumberOfPackets = 240;
+  static const int kTimeStepMs = 10;
+  static const int kFs = 8000;
+  static const int kFrameSizeMs = 20;
+  static const int kTsIncrement = kFrameSizeMs * kFs / 1000;
+
+  DelayManagerTest();
+  virtual void SetUp();
+  virtual void TearDown();
+  void SetPacketAudioLength(int lengt_ms);
+  void InsertNextPacket();
+  void IncreaseTime(int inc_ms);
+
+  DelayManager* dm_;
+  MockDelayPeakDetector detector_;
+  uint16_t seq_no_;
+  uint32_t ts_;
+};
+
+DelayManagerTest::DelayManagerTest()
+    : dm_(NULL),
+      seq_no_(0x1234),
+      ts_(0x12345678) {
+}
+
+void DelayManagerTest::SetUp() {
+  EXPECT_CALL(detector_, Reset())
+            .Times(1);
+  dm_ = new DelayManager(kMaxNumberOfPackets, &detector_);
+}
+
+void DelayManagerTest::SetPacketAudioLength(int lengt_ms) {
+  EXPECT_CALL(detector_, SetPacketAudioLength(lengt_ms));
+  dm_->SetPacketAudioLength(lengt_ms);
+}
+
+void DelayManagerTest::InsertNextPacket() {
+  EXPECT_EQ(0, dm_->Update(seq_no_, ts_, kFs));
+  seq_no_ += 1;
+  ts_ += kTsIncrement;
+}
+
+void DelayManagerTest::IncreaseTime(int inc_ms) {
+  for (int t = 0; t < inc_ms; t += kTimeStepMs) {
+    EXPECT_CALL(detector_, IncrementCounter(kTimeStepMs))
+        .Times(1);
+    dm_->UpdateCounters(kTimeStepMs);
+  }
+}
+void DelayManagerTest::TearDown() {
+  EXPECT_CALL(detector_, Die());
+  delete dm_;
+}
+
+TEST_F(DelayManagerTest, CreateAndDestroy) {
+  // Nothing to do here. The test fixture creates and destroys the DelayManager
+  // object.
+}
+
+TEST_F(DelayManagerTest, VectorInitialization) {
+  const DelayManager::IATVector& vec = dm_->iat_vector();
+  double sum = 0.0;
+  for (size_t i = 0; i < vec.size(); i++) {
+    EXPECT_NEAR(ldexp(pow(0.5, static_cast<int>(i + 1)), 30), vec[i], 65536);
+    // Tolerance 65536 in Q30 corresponds to a delta of approximately 0.00006.
+    sum += vec[i];
+  }
+  EXPECT_EQ(1 << 30, static_cast<int>(sum));  // Should be 1 in Q30.
+}
+
+TEST_F(DelayManagerTest, SetPacketAudioLength) {
+  const int kLengthMs = 30;
+  // Expect DelayManager to pass on the new length to the detector object.
+  EXPECT_CALL(detector_, SetPacketAudioLength(kLengthMs))
+      .Times(1);
+  EXPECT_EQ(0, dm_->SetPacketAudioLength(kLengthMs));
+  EXPECT_EQ(-1, dm_->SetPacketAudioLength(-1));  // Illegal parameter value.
+}
+
+TEST_F(DelayManagerTest, PeakFound) {
+  // Expect DelayManager to pass on the question to the detector.
+  // Call twice, and let the detector return true the first time and false the
+  // second time.
+  EXPECT_CALL(detector_, peak_found())
+      .WillOnce(Return(true))
+      .WillOnce(Return(false));
+  EXPECT_TRUE(dm_->PeakFound());
+  EXPECT_FALSE(dm_->PeakFound());
+}
+
+TEST_F(DelayManagerTest, UpdateCounters) {
+  // Expect DelayManager to pass on the counter update to the detector.
+  EXPECT_CALL(detector_, IncrementCounter(kTimeStepMs))
+      .Times(1);
+  dm_->UpdateCounters(kTimeStepMs);
+}
+
+TEST_F(DelayManagerTest, UpdateNormal) {
+  SetPacketAudioLength(kFrameSizeMs);
+  // First packet arrival.
+  InsertNextPacket();
+  // Advance time by one frame size.
+  IncreaseTime(kFrameSizeMs);
+  // Second packet arrival.
+  // Expect detector update method to be called once with inter-arrival time
+  // equal to 1 packet, and (base) target level equal to 1 as well.
+  // Return false to indicate no peaks found.
+  EXPECT_CALL(detector_, Update(1, 1))
+      .WillOnce(Return(false));
+  InsertNextPacket();
+  EXPECT_EQ(1 << 8, dm_->TargetLevel());  // In Q8.
+  EXPECT_EQ(1, dm_->base_target_level());
+  int lower, higher;
+  dm_->BufferLimits(&lower, &higher);
+  // Expect |lower| to be 75% of target level, and |higher| to be target level,
+  // but also at least 20 ms higher than |lower|, which is the limiting case
+  // here.
+  EXPECT_EQ((1 << 8) * 3 / 4, lower);
+  EXPECT_EQ(lower + (20 << 8) / kFrameSizeMs, higher);
+}
+
+TEST_F(DelayManagerTest, UpdateLongInterArrivalTime) {
+  SetPacketAudioLength(kFrameSizeMs);
+  // First packet arrival.
+  InsertNextPacket();
+  // Advance time by two frame size.
+  IncreaseTime(2 * kFrameSizeMs);
+  // Second packet arrival.
+  // Expect detector update method to be called once with inter-arrival time
+  // equal to 1 packet, and (base) target level equal to 1 as well.
+  // Return false to indicate no peaks found.
+  EXPECT_CALL(detector_, Update(2, 2))
+      .WillOnce(Return(false));
+  InsertNextPacket();
+  EXPECT_EQ(2 << 8, dm_->TargetLevel());  // In Q8.
+  EXPECT_EQ(2, dm_->base_target_level());
+  int lower, higher;
+  dm_->BufferLimits(&lower, &higher);
+  // Expect |lower| to be 75% of target level, and |higher| to be target level,
+  // but also at least 20 ms higher than |lower|, which is the limiting case
+  // here.
+  EXPECT_EQ((2 << 8) * 3 / 4, lower);
+  EXPECT_EQ(lower + (20 << 8) / kFrameSizeMs, higher);
+}
+
+TEST_F(DelayManagerTest, UpdatePeakFound) {
+  SetPacketAudioLength(kFrameSizeMs);
+  // First packet arrival.
+  InsertNextPacket();
+  // Advance time by one frame size.
+  IncreaseTime(kFrameSizeMs);
+  // Second packet arrival.
+  // Expect detector update method to be called once with inter-arrival time
+  // equal to 1 packet, and (base) target level equal to 1 as well.
+  // Return true to indicate that peaks are found. Let the peak height be 5.
+  EXPECT_CALL(detector_, Update(1, 1))
+      .WillOnce(Return(true));
+  EXPECT_CALL(detector_, MaxPeakHeight())
+      .WillOnce(Return(5));
+  InsertNextPacket();
+  EXPECT_EQ(5 << 8, dm_->TargetLevel());
+  EXPECT_EQ(1, dm_->base_target_level());  // Base target level is w/o peaks.
+  int lower, higher;
+  dm_->BufferLimits(&lower, &higher);
+  // Expect |lower| to be 75% of target level, and |higher| to be target level.
+  EXPECT_EQ((5 << 8) * 3 / 4, lower);
+  EXPECT_EQ(5 << 8, higher);
+}
+
+TEST_F(DelayManagerTest, ExtraDelay) {
+  const int kExtraDelayMs = 200;
+  dm_->set_extra_delay_ms(kExtraDelayMs);
+  SetPacketAudioLength(kFrameSizeMs);
+  // First packet arrival.
+  InsertNextPacket();
+  // Advance time by one frame size.
+  IncreaseTime(kFrameSizeMs);
+  // Second packet arrival.
+  // Expect detector update method to be called once with inter-arrival time
+  // equal to 1 packet, and (base) target level equal to 1 as well.
+  // Return false to indicate no peaks found.
+  EXPECT_CALL(detector_, Update(1, 1))
+      .WillOnce(Return(false));
+  InsertNextPacket();
+  const int kExpectedTarget = 1 + kExtraDelayMs / kFrameSizeMs;
+  EXPECT_EQ(kExpectedTarget << 8, dm_->TargetLevel());  // In Q8.
+  EXPECT_EQ(1, dm_->base_target_level());
+  int lower, higher;
+  dm_->BufferLimits(&lower, &higher);
+  // Expect |lower| to be 75% of base target level + extra delay, and |higher|
+  // to be target level + extra delay, but at least leave 20 ms headroom from
+  // lower.
+  EXPECT_EQ((1 << 8) * 3 / 4 + (kExtraDelayMs << 8) / kFrameSizeMs, lower);
+  EXPECT_EQ(lower + (20 << 8) / kFrameSizeMs, higher);
+}
+
+TEST_F(DelayManagerTest, Failures) {
+  // Wrong sample rate.
+  EXPECT_EQ(-1, dm_->Update(0, 0, -1));
+  // Wrong packet size.
+  EXPECT_EQ(-1, dm_->SetPacketAudioLength(0));
+  EXPECT_EQ(-1, dm_->SetPacketAudioLength(-1));
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/delay_peak_detector.cc b/webrtc/modules/audio_coding/neteq4/delay_peak_detector.cc
new file mode 100644
index 0000000..fd5b9c0
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/delay_peak_detector.cc
@@ -0,0 +1,110 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+
+#include <algorithm>  // max
+
+namespace webrtc {
+
+// The DelayPeakDetector keeps track of severe inter-arrival times, called
+// delay peaks. When a peak is observed, the "height" (the time elapsed since
+// the previous packet arrival) and the peak "period" (the time since the last
+// observed peak) is recorded in a vector. When enough peaks have been observed,
+// peak-mode is engaged and the DelayManager asks the DelayPeakDetector for
+// the worst peak height.
+
+DelayPeakDetector::DelayPeakDetector()
+  : peak_found_(false),
+    peak_detection_threshold_(0),
+    peak_period_counter_ms_(-1) {
+}
+
+void DelayPeakDetector::Reset() {
+  peak_period_counter_ms_ = -1;  // Indicate that next peak is the first.
+  peak_found_ = false;
+  peak_history_.clear();
+}
+
+// Calculates the threshold in number of packets.
+void DelayPeakDetector::SetPacketAudioLength(int length_ms) {
+  if (length_ms > 0) {
+    peak_detection_threshold_ = kPeakHeightMs / length_ms;
+  }
+}
+
+int DelayPeakDetector::MaxPeakHeight() const {
+  int max_height = -1;  // Returns -1 for an empty history.
+  std::list<Peak>::const_iterator it;
+  for (it = peak_history_.begin(); it != peak_history_.end(); ++it) {
+    max_height = std::max(max_height, it->peak_height_packets);
+  }
+  return max_height;
+}
+
+int DelayPeakDetector::MaxPeakPeriod() const {
+  int max_period = -1;  // Returns -1 for an empty history.
+  std::list<Peak>::const_iterator it;
+  for (it = peak_history_.begin(); it != peak_history_.end(); ++it) {
+    max_period = std::max(max_period, it->period_ms);
+  }
+  return max_period;
+}
+
+bool DelayPeakDetector::Update(int inter_arrival_time, int target_level) {
+  if (inter_arrival_time > target_level + peak_detection_threshold_ ||
+      inter_arrival_time > 2 * target_level) {
+    // A delay peak is observed.
+    if (peak_period_counter_ms_ == -1) {
+      // This is the first peak. Reset the period counter.
+      peak_period_counter_ms_ = 0;
+    } else if (peak_period_counter_ms_ <= kMaxPeakPeriodMs) {
+      // This is not the first peak, and the period is valid.
+      // Store peak data in the vector.
+      Peak peak_data;
+      peak_data.period_ms = peak_period_counter_ms_;
+      peak_data.peak_height_packets = inter_arrival_time;
+      peak_history_.push_back(peak_data);
+      while (peak_history_.size() > kMaxNumPeaks) {
+        // Delete the oldest data point.
+        peak_history_.pop_front();
+      }
+      peak_period_counter_ms_ = 0;
+    } else if (peak_period_counter_ms_ <= 2 * kMaxPeakPeriodMs) {
+      // Invalid peak due to too long period. Reset period counter and start
+      // looking for next peak.
+      peak_period_counter_ms_ = 0;
+    } else {
+      // More than 2 times the maximum period has elapsed since the last peak
+      // was registered. It seams that the network conditions have changed.
+      // Reset the peak statistics.
+      Reset();
+    }
+  }
+  return CheckPeakConditions();
+}
+
+void DelayPeakDetector::IncrementCounter(int inc_ms) {
+  if (peak_period_counter_ms_ >= 0) {
+    peak_period_counter_ms_ += inc_ms;
+  }
+}
+
+bool DelayPeakDetector::CheckPeakConditions() {
+  size_t s = peak_history_.size();
+  if (s >= kMinPeaksToTrigger &&
+      peak_period_counter_ms_ <= 2 * MaxPeakPeriod()) {
+    peak_found_ = true;
+  } else {
+    peak_found_ = false;
+  }
+  return peak_found_;
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/delay_peak_detector.h b/webrtc/modules/audio_coding/neteq4/delay_peak_detector.h
new file mode 100644
index 0000000..daa41a1
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/delay_peak_detector.h
@@ -0,0 +1,75 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DELAY_PEAK_DETECTOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DELAY_PEAK_DETECTOR_H_
+
+#include <cstring>  // size_t
+#include <list>
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+
+namespace webrtc {
+
+class DelayPeakDetector {
+ public:
+  DelayPeakDetector();
+  virtual ~DelayPeakDetector() {}
+  virtual void Reset();
+
+  // Notifies the DelayPeakDetector of how much audio data is carried in each
+  // packet.
+  virtual void SetPacketAudioLength(int length_ms);
+
+  // Returns true if peak-mode is active. That is, delay peaks were observed
+  // recently.
+  virtual bool peak_found() { return peak_found_; }
+
+  // Calculates and returns the maximum delay peak height. Returns -1 if no
+  // delay peaks have been observed recently. The unit is number of packets.
+  virtual int MaxPeakHeight() const;
+
+  // Calculates and returns the maximum delay peak distance in ms.
+  // Returns -1 if no delay peaks have been observed recently.
+  virtual int MaxPeakPeriod() const;
+
+  // Updates the DelayPeakDetector with a new inter-arrival time (in packets)
+  // and the current target buffer level (needed to decide if a peak is observed
+  // or not). Returns true if peak-mode is active, false if not.
+  virtual bool Update(int inter_arrival_time, int target_level);
+
+  // Increments the |peak_period_counter_ms_| with |inc_ms|. Only increments
+  // the counter if it is non-negative. A negative denotes that no peak has
+  // been observed.
+  virtual void IncrementCounter(int inc_ms);
+
+ private:
+  static const size_t kMaxNumPeaks = 8;
+  static const size_t kMinPeaksToTrigger = 2;
+  static const int kPeakHeightMs = 78;
+  static const int kMaxPeakPeriodMs = 10000;
+
+  typedef struct {
+    int period_ms;
+    int peak_height_packets;
+  } Peak;
+
+  bool CheckPeakConditions();
+
+  std::list<Peak> peak_history_;
+  bool peak_found_;
+  int peak_detection_threshold_;
+  int peak_period_counter_ms_;
+
+  DISALLOW_COPY_AND_ASSIGN(DelayPeakDetector);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DELAY_PEAK_DETECTOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/delay_peak_detector_unittest.cc b/webrtc/modules/audio_coding/neteq4/delay_peak_detector_unittest.cc
new file mode 100644
index 0000000..59342ab
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/delay_peak_detector_unittest.cc
@@ -0,0 +1,121 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for DelayPeakDetector class.
+
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+
+#include "gtest/gtest.h"
+
+namespace webrtc {
+
+TEST(DelayPeakDetector, CreateAndDestroy) {
+  DelayPeakDetector* detector = new DelayPeakDetector();
+  EXPECT_FALSE(detector->peak_found());
+  delete detector;
+}
+
+TEST(DelayPeakDetector, EmptyHistory) {
+  DelayPeakDetector detector;
+  EXPECT_EQ(-1, detector.MaxPeakHeight());
+  EXPECT_EQ(-1, detector.MaxPeakPeriod());
+}
+
+// Inject a series of packet arrivals into the detector. Three of the packets
+// have suffered delays. After the third delay peak, peak-mode is expected to
+// start. This should then continue until it is disengaged due to lack of peaks.
+TEST(DelayPeakDetector, TriggerPeakMode) {
+  DelayPeakDetector detector;
+  const int kPacketSizeMs = 30;
+  detector.SetPacketAudioLength(kPacketSizeMs);
+
+  // Load up normal arrival times; 0 ms, 30 ms, 60 ms, 90 ms, ...
+  const int kNumPackets = 1000;
+  int arrival_times_ms[kNumPackets];
+  for (int i = 0; i < kNumPackets; ++i) {
+    arrival_times_ms[i] = i * kPacketSizeMs;
+  }
+
+  // Delay three packets.
+  const int kPeakDelayMs = 100;
+  // First delay peak.
+  arrival_times_ms[100] += kPeakDelayMs;
+  // Second delay peak.
+  arrival_times_ms[200] += kPeakDelayMs;
+  // Third delay peak. Trigger peak-mode after this packet.
+  arrival_times_ms[400] += kPeakDelayMs;
+  // The second peak period is the longest, 200 packets.
+  const int kWorstPeakPeriod = 200 * kPacketSizeMs;
+  int peak_mode_start_ms = arrival_times_ms[400];
+  // Expect to disengage after no peaks are observed for two period times.
+  int peak_mode_end_ms = peak_mode_start_ms + 2 * kWorstPeakPeriod;
+
+  // Load into detector.
+  int time = 0;
+  int next = 1;  // Start with the second packet to get a proper IAT.
+  while (next < kNumPackets) {
+    while (arrival_times_ms[next] <= time) {
+      int iat_packets = (arrival_times_ms[next] - arrival_times_ms[next - 1]) /
+          kPacketSizeMs;
+      const int kTargetBufferLevel = 1;  // Define peaks to be iat > 2.
+      if (time < peak_mode_start_ms || time > peak_mode_end_ms) {
+        EXPECT_FALSE(detector.Update(iat_packets, kTargetBufferLevel));
+      } else {
+        EXPECT_TRUE(detector.Update(iat_packets, kTargetBufferLevel));
+        EXPECT_EQ(kWorstPeakPeriod, detector.MaxPeakPeriod());
+        EXPECT_EQ(kPeakDelayMs / kPacketSizeMs + 1, detector.MaxPeakHeight());
+      }
+      ++next;
+    }
+    detector.IncrementCounter(10);
+    time += 10;  // Increase time 10 ms.
+  }
+}
+
+// Same test as TriggerPeakMode, but with base target buffer level increased to
+// 2, in order to raise the bar for delay peaks to inter-arrival times > 4.
+// The delay pattern has peaks with delay = 3, thus should not trigger.
+TEST(DelayPeakDetector, DoNotTriggerPeakMode) {
+  DelayPeakDetector detector;
+  const int kPacketSizeMs = 30;
+  detector.SetPacketAudioLength(kPacketSizeMs);
+
+  // Load up normal arrival times; 0 ms, 30 ms, 60 ms, 90 ms, ...
+  const int kNumPackets = 1000;
+  int arrival_times_ms[kNumPackets];
+  for (int i = 0; i < kNumPackets; ++i) {
+    arrival_times_ms[i] = i * kPacketSizeMs;
+  }
+
+  // Delay three packets.
+  const int kPeakDelayMs = 100;
+  // First delay peak.
+  arrival_times_ms[100] += kPeakDelayMs;
+  // Second delay peak.
+  arrival_times_ms[200] += kPeakDelayMs;
+  // Third delay peak.
+  arrival_times_ms[400] += kPeakDelayMs;
+
+  // Load into detector.
+  int time = 0;
+  int next = 1;  // Start with the second packet to get a proper IAT.
+  while (next < kNumPackets) {
+    while (arrival_times_ms[next] <= time) {
+      int iat_packets = (arrival_times_ms[next] - arrival_times_ms[next - 1]) /
+          kPacketSizeMs;
+      const int kTargetBufferLevel = 2;  // Define peaks to be iat > 4.
+      EXPECT_FALSE(detector.Update(iat_packets, kTargetBufferLevel));
+      ++next;
+    }
+    detector.IncrementCounter(10);
+    time += 10;  // Increase time 10 ms.
+  }
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/dsp_helper.cc b/webrtc/modules/audio_coding/neteq4/dsp_helper.cc
new file mode 100644
index 0000000..ebb3966
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dsp_helper.cc
@@ -0,0 +1,352 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
+
+#include <assert.h>
+
+#include <algorithm>  // Access to min, max.
+#include <cstring>  // Access to memset.
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+
+namespace webrtc {
+
+// Table of constants used in method DspHelper::ParabolicFit().
+const int16_t DspHelper::kParabolaCoefficients[17][3] = {
+    { 120, 32, 64 },
+    { 140, 44, 75 },
+    { 150, 50, 80 },
+    { 160, 57, 85 },
+    { 180, 72, 96 },
+    { 200, 89, 107 },
+    { 210, 98, 112 },
+    { 220, 108, 117 },
+    { 240, 128, 128 },
+    { 260, 150, 139 },
+    { 270, 162, 144 },
+    { 280, 174, 149 },
+    { 300, 200, 160 },
+    { 320, 228, 171 },
+    { 330, 242, 176 },
+    { 340, 257, 181 },
+    { 360, 288, 192 } };
+
+// Filter coefficients used when downsampling from the indicated sample rates
+// (8, 16, 32, 48 kHz) to 4 kHz. Coefficients are in Q12. The corresponding Q0
+// values are provided in the comments before each array.
+
+// Q0 values: {0.3, 0.4, 0.3}.
+const int16_t DspHelper::kDownsample8kHzTbl[3] = { 1229, 1638, 1229 };
+
+// Q0 values: {0.15, 0.2, 0.3, 0.2, 0.15}.
+const int16_t DspHelper::kDownsample16kHzTbl[5] = { 614, 819, 1229, 819, 614 };
+
+// Q0 values: {0.1425, 0.1251, 0.1525, 0.1628, 0.1525, 0.1251, 0.1425}.
+const int16_t DspHelper::kDownsample32kHzTbl[7] = {
+    584, 512, 625, 667, 625, 512, 584 };
+
+// Q0 values: {0.2487, 0.0952, 0.1042, 0.1074, 0.1042, 0.0952, 0.2487}.
+const int16_t DspHelper::kDownsample48kHzTbl[7] = {
+    1019, 390, 427, 440, 427, 390, 1019 };
+
+int DspHelper::RampSignal(const int16_t* input,
+                          size_t length,
+                          int factor,
+                          int increment,
+                          int16_t* output) {
+  int factor_q20 = (factor << 6) + 32;
+  // TODO(hlundin): Add 32 to factor_q20 when converting back to Q14?
+  for (size_t i = 0; i < length; ++i) {
+    output[i] = (factor * input[i] + 8192) >> 14;
+    factor_q20 += increment;
+    factor_q20 = std::max(factor_q20, 0);  // Never go negative.
+    factor = std::min(factor_q20 >> 6, 16384);
+  }
+  return factor;
+}
+
+int DspHelper::RampSignal(int16_t* signal,
+                          size_t length,
+                          int factor,
+                          int increment) {
+  return RampSignal(signal, length, factor, increment, signal);
+}
+
+int DspHelper::RampSignal(AudioMultiVector<int16_t>* signal,
+                          size_t start_index,
+                          size_t length,
+                          int factor,
+                          int increment) {
+  assert(start_index + length <= signal->Size());
+  if (start_index + length > signal->Size()) {
+    // Wrong parameters. Do nothing and return the scale factor unaltered.
+    return factor;
+  }
+  int end_factor = 0;
+  // Loop over the channels, starting at the same |factor| each time.
+  for (size_t channel = 0; channel < signal->Channels(); ++channel) {
+    end_factor =
+        RampSignal(&(*signal)[channel][start_index], length, factor, increment);
+  }
+  return end_factor;
+}
+
+void DspHelper::PeakDetection(int16_t* data, int data_length,
+                              int num_peaks, int fs_mult,
+                              int* peak_index, int16_t* peak_value) {
+  int16_t min_index = 0;
+  int16_t max_index = 0;
+
+  for (int i = 0; i <= num_peaks - 1; i++) {
+    if (num_peaks == 1) {
+      // Single peak.  The parabola fit assumes that an extra point is
+      // available; worst case it gets a zero on the high end of the signal.
+      // TODO(hlundin): This can potentially get much worse. It breaks the
+      // API contract, that the length of |data| is |data_length|.
+      data_length++;
+    }
+
+    peak_index[i] = WebRtcSpl_MaxIndexW16(data, data_length - 1);
+
+    if (i != num_peaks - 1) {
+      min_index = std::max(0, peak_index[i] - 2);
+      max_index = std::min(data_length - 1, peak_index[i] + 2);
+    }
+
+    if ((peak_index[i] != 0) && (peak_index[i] != (data_length - 2))) {
+      ParabolicFit(&data[peak_index[i] - 1], fs_mult, &peak_index[i],
+                   &peak_value[i]);
+    } else {
+      if (peak_index[i] == data_length - 2) {
+        if (data[peak_index[i]] > data[peak_index[i] + 1]) {
+          ParabolicFit(&data[peak_index[i] - 1], fs_mult, &peak_index[i],
+                       &peak_value[i]);
+        } else if (data[peak_index[i]] <= data[peak_index[i] + 1]) {
+          // Linear approximation.
+          peak_value[i] = (data[peak_index[i]] + data[peak_index[i] + 1]) >> 1;
+          peak_index[i] = (peak_index[i] * 2 + 1) * fs_mult;
+        }
+      } else {
+        peak_value[i] = data[peak_index[i]];
+        peak_index[i] = peak_index[i] * 2 * fs_mult;
+      }
+    }
+
+    if (i != num_peaks - 1) {
+      memset(&data[min_index], 0,
+             sizeof(data[0]) * (max_index - min_index + 1));
+    }
+  }
+}
+
+void DspHelper::ParabolicFit(int16_t* signal_points, int fs_mult,
+                             int* peak_index, int16_t* peak_value) {
+  uint16_t fit_index[13];
+  if (fs_mult == 1) {
+    fit_index[0] = 0;
+    fit_index[1] = 8;
+    fit_index[2] = 16;
+  } else if (fs_mult == 2) {
+    fit_index[0] = 0;
+    fit_index[1] = 4;
+    fit_index[2] = 8;
+    fit_index[3] = 12;
+    fit_index[4] = 16;
+  } else if (fs_mult == 4) {
+    fit_index[0] = 0;
+    fit_index[1] = 2;
+    fit_index[2] = 4;
+    fit_index[3] = 6;
+    fit_index[4] = 8;
+    fit_index[5] = 10;
+    fit_index[6] = 12;
+    fit_index[7] = 14;
+    fit_index[8] = 16;
+  } else {
+    fit_index[0] = 0;
+    fit_index[1] = 1;
+    fit_index[2] = 3;
+    fit_index[3] = 4;
+    fit_index[4] = 5;
+    fit_index[5] = 7;
+    fit_index[6] = 8;
+    fit_index[7] = 9;
+    fit_index[8] = 11;
+    fit_index[9] = 12;
+    fit_index[10] = 13;
+    fit_index[11] = 15;
+    fit_index[12] = 16;
+  }
+
+  //  num = -3 * signal_points[0] + 4 * signal_points[1] - signal_points[2];
+  //  den =      signal_points[0] - 2 * signal_points[1] + signal_points[2];
+  int32_t num = (signal_points[0] * -3) + (signal_points[1] * 4)
+      - signal_points[2];
+  int32_t den = signal_points[0] + (signal_points[1] * -2) + signal_points[2];
+  int32_t temp = num * 120;
+  int flag = 1;
+  int16_t stp = kParabolaCoefficients[fit_index[fs_mult]][0]
+      - kParabolaCoefficients[fit_index[fs_mult - 1]][0];
+  int16_t strt = (kParabolaCoefficients[fit_index[fs_mult]][0]
+      + kParabolaCoefficients[fit_index[fs_mult - 1]][0]) / 2;
+  int16_t lmt;
+  if (temp < -den * strt) {
+    lmt = strt - stp;
+    while (flag) {
+      if ((flag == fs_mult) || (temp > -den * lmt)) {
+        *peak_value = (den * kParabolaCoefficients[fit_index[fs_mult - flag]][1]
+            + num * kParabolaCoefficients[fit_index[fs_mult - flag]][2]
+            + signal_points[0] * 256) / 256;
+        *peak_index = *peak_index * 2 * fs_mult - flag;
+        flag = 0;
+      } else {
+        flag++;
+        lmt -= stp;
+      }
+    }
+  } else if (temp > -den * (strt + stp)) {
+    lmt = strt + 2 * stp;
+    while (flag) {
+      if ((flag == fs_mult) || (temp < -den * lmt)) {
+        int32_t temp_term_1 =
+            den * kParabolaCoefficients[fit_index[fs_mult+flag]][1];
+        int32_t temp_term_2 =
+            num * kParabolaCoefficients[fit_index[fs_mult+flag]][2];
+        int32_t temp_term_3 = signal_points[0] * 256;
+        *peak_value = (temp_term_1 + temp_term_2 + temp_term_3) / 256;
+        *peak_index = *peak_index * 2 * fs_mult + flag;
+        flag = 0;
+      } else {
+        flag++;
+        lmt += stp;
+      }
+    }
+  } else {
+    *peak_value = signal_points[1];
+    *peak_index = *peak_index * 2 * fs_mult;
+  }
+}
+
+int DspHelper::MinDistortion(const int16_t* signal, int min_lag,
+                             int max_lag, int length,
+                             int32_t* distortion_value) {
+  int best_index = -1;
+  int32_t min_distortion = WEBRTC_SPL_WORD32_MAX;
+  for (int i = min_lag; i <= max_lag; i++) {
+    int32_t sum_diff = 0;
+    const int16_t* data1 = signal;
+    const int16_t* data2 = signal - i;
+    for (int j = 0; j < length; j++) {
+      sum_diff += WEBRTC_SPL_ABS_W32(data1[j] - data2[j]);
+    }
+    // Compare with previous minimum.
+    if (sum_diff < min_distortion) {
+      min_distortion = sum_diff;
+      best_index = i;
+    }
+  }
+  *distortion_value = min_distortion;
+  return best_index;
+}
+
+void DspHelper::CrossFade(const int16_t* input1, const int16_t* input2,
+                          int length, int16_t* mix_factor,
+                          int16_t factor_decrement, int16_t* output) {
+  int16_t factor = *mix_factor;
+  int16_t complement_factor = 16384 - factor;
+  for (int i = 0; i < length; i++) {
+    output[i] =
+        (factor * input1[i] + complement_factor * input2[i] + 8192) >> 14;
+    factor -= factor_decrement;
+    complement_factor += factor_decrement;
+  }
+  *mix_factor = factor;
+}
+
+void DspHelper::UnmuteSignal(const int16_t* input, int length, int16_t* factor,
+                             int16_t increment, int16_t* output) {
+  uint16_t factor_16b = *factor;
+  int32_t factor_32b = (static_cast<int32_t>(factor_16b) << 6) + 32;
+  for (int i = 0; i < length; i++) {
+    output[i] = (factor_16b * input[i] + 8192) >> 14;
+    factor_32b = std::max(factor_32b + increment, 0);
+    factor_16b = std::min(16384, factor_32b >> 6);
+  }
+  *factor = factor_16b;
+}
+
+void DspHelper::MuteSignal(int16_t* signal, int16_t mute_slope, int length) {
+  int32_t factor = (16384 << 6) + 32;
+  for (int i = 0; i < length; i++) {
+    signal[i] = ((factor >> 6) * signal[i] + 8192) >> 14;
+    factor -= mute_slope;
+  }
+}
+
+int DspHelper::DownsampleTo4kHz(const int16_t* input, int input_length,
+                                int output_length, int input_rate_hz,
+                                bool compensate_delay, int16_t* output) {
+  // Set filter parameters depending on input frequency.
+  // NOTE: The phase delay values are wrong compared to the true phase delay
+  // of the filters. However, the error is preserved (through the +1 term) for
+  // consistency.
+  const int16_t* filter_coefficients;  // Filter coefficients.
+  int16_t filter_length;  // Number of coefficients.
+  int16_t filter_delay;  // Phase delay in samples.
+  int16_t factor;  // Conversion rate (inFsHz / 8000).
+  switch (input_rate_hz) {
+    case 8000: {
+      filter_length = 3;
+      factor = 2;
+      filter_coefficients = kDownsample8kHzTbl;
+      filter_delay = 1 + 1;
+      break;
+    }
+    case 16000: {
+      filter_length = 5;
+      factor = 4;
+      filter_coefficients = kDownsample16kHzTbl;
+      filter_delay = 2 + 1;
+      break;
+    }
+    case 32000: {
+      filter_length = 7;
+      factor = 8;
+      filter_coefficients = kDownsample32kHzTbl;
+      filter_delay = 3 + 1;
+      break;
+    }
+    case 48000: {
+      filter_length = 7;
+      factor = 12;
+      filter_coefficients = kDownsample48kHzTbl;
+      filter_delay = 3 + 1;
+      break;
+    }
+    default: {
+      assert(false);
+      return -1;
+    }
+  }
+
+  if (!compensate_delay) {
+    // Disregard delay compensation.
+    filter_delay = 0;
+  }
+
+  // Returns -1 if input signal is too short; 0 otherwise.
+  return WebRtcSpl_DownsampleFast(&input[filter_length - 1],
+                                  input_length - (filter_length - 1), output,
+                                  output_length, filter_coefficients,
+                                  filter_length, factor, filter_delay);
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/dsp_helper.h b/webrtc/modules/audio_coding/neteq4/dsp_helper.h
new file mode 100644
index 0000000..947824f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dsp_helper.h
@@ -0,0 +1,136 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DSP_HELPER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DSP_HELPER_H_
+
+#include <cstring>  // Access to size_t.
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// This class contains various signal processing functions, all implemented as
+// static methods.
+class DspHelper {
+ public:
+  // Filter coefficients used when downsampling from the indicated sample rates
+  // (8, 16, 32, 48 kHz) to 4 kHz. Coefficients are in Q12.
+  static const int16_t kDownsample8kHzTbl[3];
+  static const int16_t kDownsample16kHzTbl[5];
+  static const int16_t kDownsample32kHzTbl[7];
+  static const int16_t kDownsample48kHzTbl[7];
+
+  // Constants used to mute and unmute over 5 samples. The coefficients are
+  // in Q15.
+  static const int kMuteFactorStart8kHz = 27307;
+  static const int kMuteFactorIncrement8kHz = -5461;
+  static const int kUnmuteFactorStart8kHz = 5461;
+  static const int kUnmuteFactorIncrement8kHz = 5461;
+  static const int kMuteFactorStart16kHz = 29789;
+  static const int kMuteFactorIncrement16kHz = -2979;
+  static const int kUnmuteFactorStart16kHz = 2979;
+  static const int kUnmuteFactorIncrement16kHz = 2979;
+  static const int kMuteFactorStart32kHz = 31208;
+  static const int kMuteFactorIncrement32kHz = -1560;
+  static const int kUnmuteFactorStart32kHz = 1560;
+  static const int kUnmuteFactorIncrement32kHz = 1560;
+  static const int kMuteFactorStart48kHz = 31711;
+  static const int kMuteFactorIncrement48kHz = -1057;
+  static const int kUnmuteFactorStart48kHz = 1057;
+  static const int kUnmuteFactorIncrement48kHz = 1057;
+
+  // Multiplies the signal with a gradually changing factor.
+  // The first sample is multiplied with |factor| (in Q14). For each sample,
+  // |factor| is increased (additive) by the |increment| (in Q20), which can
+  // be negative. Returns the scale factor after the last increment.
+  static int RampSignal(const int16_t* input,
+                        size_t length,
+                        int factor,
+                        int increment,
+                        int16_t* output);
+
+  // Same as above, but with the samples of |signal| being modified in-place.
+  static int RampSignal(int16_t* signal,
+                        size_t length,
+                        int factor,
+                        int increment);
+
+  // Same as above, but processes |length| samples from |signal|, starting at
+  // |start_index|.
+  static int RampSignal(AudioMultiVector<int16_t>* signal,
+                        size_t start_index,
+                        size_t length,
+                        int factor,
+                        int increment);
+
+  // Peak detection with parabolic fit. Looks for |num_peaks| maxima in |data|,
+  // having length |data_length| and sample rate multiplier |fs_mult|. The peak
+  // locations and values are written to the arrays |peak_index| and
+  // |peak_value|, respectively. Both arrays must hold at least |num_peaks|
+  // elements.
+  static void PeakDetection(int16_t* data, int data_length,
+                            int num_peaks, int fs_mult,
+                            int* peak_index, int16_t* peak_value);
+
+  // Estimates the height and location of a maximum. The three values in the
+  // array |signal_points| are used as basis for a parabolic fit, which is then
+  // used to find the maximum in an interpolated signal. The |signal_points| are
+  // assumed to be from a 4 kHz signal, while the maximum, written to
+  // |peak_index| and |peak_value| is given in the full sample rate, as
+  // indicated by the sample rate multiplier |fs_mult|.
+  static void ParabolicFit(int16_t* signal_points, int fs_mult,
+                           int* peak_index, int16_t* peak_value);
+
+  // Calculates the sum-abs-diff for |signal| when compared to a displaced
+  // version of itself. Returns the displacement lag that results in the minimum
+  // distortion. The resulting distortion is written to |distortion_value|.
+  // The values of |min_lag| and |max_lag| are boundaries for the search.
+  static int MinDistortion(const int16_t* signal, int min_lag,
+                           int max_lag, int length, int32_t* distortion_value);
+
+  // Mixes |length| samples from |input1| and |input2| together and writes the
+  // result to |output|. The gain for |input1| starts at |mix_factor| (Q14) and
+  // is decreased by |factor_decrement| (Q14) for each sample. The gain for
+  // |input2| is the complement 16384 - mix_factor.
+  static void CrossFade(const int16_t* input1, const int16_t* input2,
+                        int length, int16_t* mix_factor,
+                        int16_t factor_decrement, int16_t* output);
+
+  // Scales |input| with an increasing gain. Applies |factor| (Q14) to the first
+  // sample and increases the gain by |increment| (Q20) for each sample. The
+  // result is written to |output|. |length| samples are processed.
+  static void UnmuteSignal(const int16_t* input, int length, int16_t* factor,
+                           int16_t increment, int16_t* output);
+
+  // Starts at unity gain and gradually fades out |signal|. For each sample,
+  // the gain is reduced by |mute_slope| (Q14). |length| samples are processed.
+  static void MuteSignal(int16_t* signal, int16_t mute_slope, int length);
+
+  // Downsamples |input| from |sample_rate_hz| to 4 kHz sample rate. The input
+  // has |input_length| samples, and the method will write |output_length|
+  // samples to |output|. Compensates for the phase delay of the downsampling
+  // filters if |compensate_delay| is true. Returns -1 if the input is too short
+  // to produce |output_length| samples, otherwise 0.
+  static int DownsampleTo4kHz(const int16_t* input, int input_length,
+                              int output_length, int input_rate_hz,
+                              bool compensate_delay, int16_t* output);
+
+ private:
+  // Table of constants used in method DspHelper::ParabolicFit().
+  static const int16_t kParabolaCoefficients[17][3];
+
+  DISALLOW_COPY_AND_ASSIGN(DspHelper);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DSP_HELPER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/dsp_helper_unittest.cc b/webrtc/modules/audio_coding/neteq4/dsp_helper_unittest.cc
new file mode 100644
index 0000000..d3c76df
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dsp_helper_unittest.cc
@@ -0,0 +1,89 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+TEST(DspHelper, RampSignalArray) {
+  static const int kLen = 100;
+  int16_t input[kLen];
+  int16_t output[kLen];
+  // Fill input with 1000.
+  for (int i = 0; i < kLen; ++i) {
+    input[i] = 1000;
+  }
+  int start_factor = 0;
+  // Ramp from 0 to 1 (in Q14) over the array. Note that |increment| is in Q20,
+  // while the factor is in Q14, hence the shift by 6.
+  int increment = (16384 << 6) / kLen;
+
+  // Test first method.
+  int stop_factor = DspHelper::RampSignal(input, kLen, start_factor, increment,
+                                          output);
+  EXPECT_EQ(16383, stop_factor);  // Almost reach 1 in Q14.
+  for (int i = 0; i < kLen; ++i) {
+    EXPECT_EQ(1000 * i / kLen, output[i]);
+  }
+
+  // Test second method. (Note that this modifies |input|.)
+  stop_factor = DspHelper::RampSignal(input, kLen, start_factor, increment);
+  EXPECT_EQ(16383, stop_factor);  // Almost reach 1 in Q14.
+  for (int i = 0; i < kLen; ++i) {
+    EXPECT_EQ(1000 * i / kLen, input[i]);
+  }
+}
+
+TEST(DspHelper, RampSignalAudioMultiVector) {
+  static const int kLen = 100;
+  static const int kChannels = 5;
+  AudioMultiVector<int16_t> input(kChannels, kLen * 3);
+  // Fill input with 1000.
+  for (int i = 0; i < kLen * 3; ++i) {
+    for (int channel = 0; channel < kChannels; ++channel) {
+      input[channel][i] = 1000;
+    }
+  }
+  // We want to start ramping at |start_index| and keep ramping for |kLen|
+  // samples.
+  int start_index = kLen;
+  int start_factor = 0;
+  // Ramp from 0 to 1 (in Q14) in |kLen| samples. Note that |increment| is in
+  // Q20, while the factor is in Q14, hence the shift by 6.
+  int increment = (16384 << 6) / kLen;
+
+  int stop_factor = DspHelper::RampSignal(&input, start_index, kLen,
+                                          start_factor, increment);
+  EXPECT_EQ(16383, stop_factor);  // Almost reach 1 in Q14.
+  // Verify that the first |kLen| samples are left untouched.
+  int i;
+  for (i = 0; i < kLen; ++i) {
+    for (int channel = 0; channel < kChannels; ++channel) {
+      EXPECT_EQ(1000, input[channel][i]);
+    }
+  }
+  // Verify that the next block of |kLen| samples are ramped.
+  for (; i < 2 * kLen; ++i) {
+    for (int channel = 0; channel < kChannels; ++channel) {
+      EXPECT_EQ(1000 * (i - kLen) / kLen, input[channel][i]);
+    }
+  }
+  // Verify the last |kLen| samples are left untouched.
+  for (; i < 3 * kLen; ++i) {
+    for (int channel = 0; channel < kChannels; ++channel) {
+      EXPECT_EQ(1000, input[channel][i]);
+    }
+  }
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/dtmf_buffer.cc b/webrtc/modules/audio_coding/neteq4/dtmf_buffer.cc
new file mode 100644
index 0000000..1c81ad9
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dtmf_buffer.cc
@@ -0,0 +1,226 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/dtmf_buffer.h"
+
+#include <assert.h>
+#include <algorithm>  // max
+
+// Modify the code to obtain backwards bit-exactness. Once bit-exactness is no
+// longer required, this #define should be removed (and the code that it
+// enables).
+#define LEGACY_BITEXACT
+
+namespace webrtc {
+
+// The ParseEvent method parses 4 bytes from |payload| according to this format
+// from RFC 4733:
+//
+//  0                   1                   2                   3
+//  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |     event     |E|R| volume    |          duration             |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//
+// Legend (adapted from RFC 4733)
+// - event:    The event field is a number between 0 and 255 identifying a
+//             specific telephony event. The buffer will not accept any event
+//             numbers larger than 15.
+// - E:        If set to a value of one, the "end" bit indicates that this
+//             packet contains the end of the event.  For long-lasting events
+//             that have to be split into segments, only the final packet for
+//             the final segment will have the E bit set.
+// - R:        Reserved.
+// - volume:   For DTMF digits and other events representable as tones, this
+//             field describes the power level of the tone, expressed in dBm0
+//             after dropping the sign.  Power levels range from 0 to -63 dBm0.
+//             Thus, larger values denote lower volume. The buffer discards
+//             values larger than 36 (i.e., lower than -36 dBm0).
+// - duration: The duration field indicates the duration of the event or segment
+//             being reported, in timestamp units, expressed as an unsigned
+//             integer in network byte order.  For a non-zero value, the event
+//             or segment began at the instant identified by the RTP timestamp
+//             and has so far lasted as long as indicated by this parameter.
+//             The event may or may not have ended.  If the event duration
+//             exceeds the maximum representable by the duration field, the
+//             event is split into several contiguous segments. The buffer will
+//             discard zero-duration events.
+//
+int DtmfBuffer::ParseEvent(uint32_t rtp_timestamp,
+                           const uint8_t* payload,
+                           int payload_length_bytes,
+                           DtmfEvent* event) {
+  if (!payload || !event) {
+    return kInvalidPointer;
+  }
+  if (payload_length_bytes < 4) {
+    return kPayloadTooShort;
+  }
+
+  event->event_no = payload[0];
+  event->end_bit = ((payload[1] & 0x80) != 0);
+  event->volume = (payload[1] & 0x3F);
+  event->duration = payload[2] << 8 | payload[3];
+  event->timestamp = rtp_timestamp;
+  return kOK;
+}
+
+// Inserts a DTMF event into the buffer. The event should be parsed from the
+// bit stream using the ParseEvent method above before inserting it in the
+// buffer.
+// DTMF events can be quite long, and in most cases the duration of the event
+// is not known when the first packet describing it is sent. To deal with that,
+// the RFC 4733 specifies that multiple packets are sent for one and the same
+// event as it is being created (typically, as the user is pressing the key).
+// These packets will all share the same start timestamp and event number,
+// while the duration will be the cumulative duration from the start. When
+// inserting a new event, the InsertEvent method tries to find a matching event
+// already in the buffer. If so, the new event is simply merged with the
+// existing one.
+int DtmfBuffer::InsertEvent(const DtmfEvent& event) {
+  if (event.event_no < 0 || event.event_no > 15 ||
+      event.volume < 0 || event.volume > 36 ||
+      event.duration <= 0 || event.duration > 65535) {
+    return kInvalidEventParameters;
+  }
+  DtmfList::iterator it = buffer_.begin();
+  while (it != buffer_.end()) {
+    if (MergeEvents(it, event)) {
+      // A matching event was found and the new event was merged.
+      return kOK;
+    }
+    ++it;
+  }
+  buffer_.push_back(event);
+  // Sort the buffer using CompareEvents to rank the events.
+  buffer_.sort(CompareEvents);
+  return kOK;
+}
+
+bool DtmfBuffer::GetEvent(uint32_t current_timestamp, DtmfEvent* event) {
+  DtmfList::iterator it = buffer_.begin();
+  while (it != buffer_.end()) {
+    // |event_end| is an estimate of where the current event ends. If the end
+    // bit is set, we know that the event ends at |timestamp| + |duration|.
+    uint32_t event_end = it->timestamp + it->duration;
+#ifdef LEGACY_BITEXACT
+    bool next_available = false;
+#endif
+    if (!it->end_bit) {
+      // If the end bit is not set, we allow extrapolation of the event for
+      // some time.
+      event_end += max_extrapolation_samples_;
+      DtmfList::iterator next = it;
+      ++next;
+      if (next != buffer_.end()) {
+        // If there is a next event in the buffer, we will not extrapolate over
+        // the start of that new event.
+        event_end = std::min(event_end, next->timestamp);
+#ifdef LEGACY_BITEXACT
+        next_available = true;
+#endif
+      }
+    }
+    if (current_timestamp >= it->timestamp
+        && current_timestamp <= event_end) {  // TODO(hlundin): Change to <.
+      // Found a matching event.
+      if (event) {
+        event->event_no = it->event_no;
+        event->end_bit = it->end_bit;
+        event->volume = it->volume;
+        event->duration = it->duration;
+        event->timestamp = it->timestamp;
+      }
+#ifdef LEGACY_BITEXACT
+      if (it->end_bit &&
+          current_timestamp + frame_len_samples_ >= event_end) {
+        // We are done playing this. Erase the event.
+        buffer_.erase(it);
+      }
+#endif
+      return true;
+    } else if (current_timestamp > event_end) {  // TODO(hlundin): Change to >=.
+      // Erase old event. Operation returns a valid pointer to the next element
+      // in the list.
+#ifdef LEGACY_BITEXACT
+      if (!next_available) {
+        if (event) {
+          event->event_no = it->event_no;
+          event->end_bit = it->end_bit;
+          event->volume = it->volume;
+          event->duration = it->duration;
+          event->timestamp = it->timestamp;
+        }
+        it = buffer_.erase(it);
+        return true;
+      } else {
+        it = buffer_.erase(it);
+      }
+#else
+      it = buffer_.erase(it);
+#endif
+    } else {
+      ++it;
+    }
+  }
+  return false;
+}
+
+int DtmfBuffer::SetSampleRate(int fs_hz) {
+  if (fs_hz != 8000 &&
+      fs_hz != 16000 &&
+      fs_hz != 32000 &&
+      fs_hz != 48000) {
+    return kInvalidSampleRate;
+  }
+  max_extrapolation_samples_ = 7 * fs_hz / 100;
+  frame_len_samples_ = fs_hz / 100;
+  return kOK;
+}
+
+// The method returns true if the two events are considered to be the same.
+// The are defined as equal if they share the same timestamp and event number.
+// The special case with long-lasting events that have to be split into segments
+// is not handled in this method. These will be treated as separate events in
+// the buffer.
+bool DtmfBuffer::SameEvent(const DtmfEvent& a, const DtmfEvent& b) {
+  return (a.event_no == b.event_no) && (a.timestamp == b.timestamp);
+}
+
+bool DtmfBuffer::MergeEvents(DtmfList::iterator it, const DtmfEvent& event) {
+  if (SameEvent(*it, event)) {
+    if (!it->end_bit) {
+      // Do not extend the duration of an event for which the end bit was
+      // already received.
+      it->duration = std::max(event.duration, it->duration);
+    }
+    if (event.end_bit) {
+      it->end_bit = true;
+    }
+    return true;
+  } else {
+    return false;
+  }
+}
+
+// Returns true if |a| goes before |b| in the sorting order ("|a| < |b|").
+// The events are ranked using their start timestamp (taking wrap-around into
+// account). In the unlikely situation that two events share the same start
+// timestamp, the event number is used to rank the two. Note that packets
+// that belong to the same events, and therefore sharing the same start
+// timestamp, have already been merged before the sort method is called.
+bool DtmfBuffer::CompareEvents(const DtmfEvent& a, const DtmfEvent& b) {
+  if (a.timestamp == b.timestamp) {
+    return a.event_no < b.event_no;
+  }
+  // Take wrap-around into account.
+  return (static_cast<uint32_t>(b.timestamp - a.timestamp) < 0xFFFFFFFF / 2);
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/dtmf_buffer.h b/webrtc/modules/audio_coding/neteq4/dtmf_buffer.h
new file mode 100644
index 0000000..d08b64f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dtmf_buffer.h
@@ -0,0 +1,116 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DTMF_BUFFER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DTMF_BUFFER_H_
+
+#include <list>
+#include <string>  // size_t
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+struct DtmfEvent {
+  uint32_t timestamp;
+  int event_no;
+  int volume;
+  int duration;
+  bool end_bit;
+
+  // Constructors
+  DtmfEvent()
+      : timestamp(0),
+        event_no(0),
+        volume(0),
+        duration(0),
+        end_bit(false) {
+  }
+  DtmfEvent(uint32_t ts, int ev, int vol, int dur, bool end)
+      : timestamp(ts),
+        event_no(ev),
+        volume(vol),
+        duration(dur),
+        end_bit(end) {
+  }
+};
+
+// This is the buffer holding DTMF events while waiting for them to be played.
+class DtmfBuffer {
+ public:
+  enum BufferReturnCodes {
+    kOK = 0,
+    kInvalidPointer,
+    kPayloadTooShort,
+    kInvalidEventParameters,
+    kInvalidSampleRate
+  };
+
+  // Set up the buffer for use at sample rate |fs_hz|.
+  explicit DtmfBuffer(int fs_hz) {
+    SetSampleRate(fs_hz);
+  }
+
+  virtual ~DtmfBuffer() {}
+
+  // Flushes the buffer.
+  virtual void Flush() { buffer_.clear(); }
+
+  // Static method to parse 4 bytes from |payload| as a DTMF event (RFC 4733)
+  // and write the parsed information into the struct |event|. Input variable
+  // |rtp_timestamp| is simply copied into the struct.
+  static int ParseEvent(uint32_t rtp_timestamp,
+                        const uint8_t* payload,
+                        int payload_length_bytes,
+                        DtmfEvent* event);
+
+  // Inserts |event| into the buffer. The method looks for a matching event and
+  // merges the two if a match is found.
+  virtual int InsertEvent(const DtmfEvent& event);
+
+  // Checks if a DTMF event should be played at time |current_timestamp|. If so,
+  // the method returns true; otherwise false. The parameters of the event to
+  // play will be written to |event|.
+  virtual bool GetEvent(uint32_t current_timestamp, DtmfEvent* event);
+
+  // Number of events in the buffer.
+  virtual size_t Length() const { return buffer_.size(); }
+
+  virtual bool Empty() const { return buffer_.empty(); }
+
+  // Set a new sample rate.
+  virtual int SetSampleRate(int fs_hz);
+
+ private:
+  typedef std::list<DtmfEvent> DtmfList;
+
+  int max_extrapolation_samples_;
+  int frame_len_samples_;  // TODO(hlundin): Remove this later.
+
+  // Compares two events and returns true if they are the same.
+  static bool SameEvent(const DtmfEvent& a, const DtmfEvent& b);
+
+  // Merges |event| to the event pointed out by |it|. The method checks that
+  // the two events are the same (using the SameEvent method), and merges them
+  // if that was the case, returning true. If the events are not the same, false
+  // is returned.
+  bool MergeEvents(DtmfList::iterator it, const DtmfEvent& event);
+
+  // Method used by the sort algorithm to rank events in the buffer.
+  static bool CompareEvents(const DtmfEvent& a, const DtmfEvent& b);
+
+  DtmfList buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DtmfBuffer);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DTMF_BUFFER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/dtmf_buffer_unittest.cc b/webrtc/modules/audio_coding/neteq4/dtmf_buffer_unittest.cc
new file mode 100644
index 0000000..0b5ed65
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dtmf_buffer_unittest.cc
@@ -0,0 +1,307 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/dtmf_buffer.h"
+
+#ifdef WIN32
+#include <winsock2.h>  // ntohl()
+#else
+#include <arpa/inet.h>  // ntohl()
+#endif
+
+#include <iostream>
+
+#include "gtest/gtest.h"
+
+// Modify the tests so that they pass with the modifications done to DtmfBuffer
+// for backwards bit-exactness. Once bit-exactness is no longer required, this
+// #define should be removed (and the code that it enables).
+#define LEGACY_BITEXACT
+
+namespace webrtc {
+
+static int sample_rate_hz = 8000;
+
+static uint32_t MakeDtmfPayload(int event, bool end, int volume, int duration) {
+  uint32_t payload = 0;
+//  0                   1                   2                   3
+//  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |     event     |E|R| volume    |          duration             |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+  payload |= (event & 0x00FF) << 24;
+  payload |= (end ? 0x00800000 : 0x00000000);
+  payload |= (volume & 0x003F) << 16;
+  payload |= (duration & 0xFFFF);
+  payload = ntohl(payload);
+  return payload;
+}
+
+static bool EqualEvents(const DtmfEvent& a,
+                        const DtmfEvent& b) {
+  return (a.duration == b.duration
+      && a.end_bit == b.end_bit
+      && a.event_no == b.event_no
+      && a.timestamp == b.timestamp
+      && a.volume == b.volume);
+}
+
+TEST(DtmfBuffer, CreateAndDestroy) {
+  DtmfBuffer* buffer = new DtmfBuffer(sample_rate_hz);
+  delete buffer;
+}
+
+// Test the event parser.
+TEST(DtmfBuffer, ParseEvent) {
+  int event_no = 7;
+  bool end_bit = true;
+  int volume = 17;
+  int duration = 4711;
+  uint32_t timestamp = 0x12345678;
+  uint32_t payload = MakeDtmfPayload(event_no, end_bit, volume, duration);
+  uint8_t* payload_ptr = reinterpret_cast<uint8_t*>(&payload);
+  DtmfEvent event;
+  EXPECT_EQ(DtmfBuffer::kOK,
+            DtmfBuffer::ParseEvent(timestamp, payload_ptr, sizeof(payload),
+                                   &event));
+  EXPECT_EQ(duration, event.duration);
+  EXPECT_EQ(end_bit, event.end_bit);
+  EXPECT_EQ(event_no, event.event_no);
+  EXPECT_EQ(timestamp, event.timestamp);
+  EXPECT_EQ(volume, event.volume);
+
+  EXPECT_EQ(DtmfBuffer::kInvalidPointer,
+            DtmfBuffer::ParseEvent(timestamp, NULL, 4, &event));
+
+  EXPECT_EQ(DtmfBuffer::kInvalidPointer,
+            DtmfBuffer::ParseEvent(timestamp, payload_ptr, 4, NULL));
+
+  EXPECT_EQ(DtmfBuffer::kPayloadTooShort,
+            DtmfBuffer::ParseEvent(timestamp, payload_ptr, 3, &event));
+}
+
+TEST(DtmfBuffer, SimpleInsertAndGet) {
+  int event_no = 7;
+  bool end_bit = true;
+  int volume = 17;
+  int duration = 4711;
+  uint32_t timestamp = 0x12345678;
+  DtmfEvent event(timestamp, event_no, volume, duration, end_bit);
+  DtmfBuffer buffer(sample_rate_hz);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event));
+  EXPECT_EQ(1u, buffer.Length());
+  EXPECT_FALSE(buffer.Empty());
+  DtmfEvent out_event;
+  // Too early to get event.
+  EXPECT_FALSE(buffer.GetEvent(timestamp - 10, &out_event));
+  EXPECT_EQ(1u, buffer.Length());
+  EXPECT_FALSE(buffer.Empty());
+  // Get the event at its starting timestamp.
+  EXPECT_TRUE(buffer.GetEvent(timestamp, &out_event));
+  EXPECT_TRUE(EqualEvents(event, out_event));
+  EXPECT_EQ(1u, buffer.Length());
+  EXPECT_FALSE(buffer.Empty());
+  // Get the event some time into the event.
+  EXPECT_TRUE(buffer.GetEvent(timestamp + duration / 2, &out_event));
+  EXPECT_TRUE(EqualEvents(event, out_event));
+  EXPECT_EQ(1u, buffer.Length());
+  EXPECT_FALSE(buffer.Empty());
+  // Give a "current" timestamp after the event has ended.
+#ifdef LEGACY_BITEXACT
+  EXPECT_TRUE(buffer.GetEvent(timestamp + duration + 10, &out_event));
+#endif
+  EXPECT_FALSE(buffer.GetEvent(timestamp + duration + 10, &out_event));
+  EXPECT_EQ(0u, buffer.Length());
+  EXPECT_TRUE(buffer.Empty());
+}
+
+TEST(DtmfBuffer, MergingPackets) {
+  int event_no = 0;
+  bool end_bit = false;
+  int volume = 17;
+  int duration = 80;
+  uint32_t timestamp = 0x12345678;
+  DtmfEvent event(timestamp, event_no, volume, duration, end_bit);
+  DtmfBuffer buffer(sample_rate_hz);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event));
+
+  event.duration += 80;
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event));
+
+  event.duration += 80;
+  event.end_bit = true;
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event));
+
+  EXPECT_EQ(1u, buffer.Length());
+
+  DtmfEvent out_event;
+  EXPECT_TRUE(buffer.GetEvent(timestamp, &out_event));
+  EXPECT_TRUE(EqualEvents(event, out_event));
+}
+
+// This test case inserts one shorter event completely overlapped by one longer
+// event. The expected outcome is that only the longer event is played.
+TEST(DtmfBuffer, OverlappingEvents) {
+  int event_no = 0;
+  bool end_bit = true;
+  int volume = 1;
+  int duration = 80;
+  uint32_t timestamp = 0x12345678 + 80;
+  DtmfEvent short_event(timestamp, event_no, volume, duration, end_bit);
+  DtmfBuffer buffer(sample_rate_hz);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(short_event));
+
+  event_no = 10;
+  end_bit = false;
+  timestamp = 0x12345678;
+  DtmfEvent long_event(timestamp, event_no, volume, duration, end_bit);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(long_event));
+
+  long_event.duration += 80;
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(long_event));
+
+  long_event.duration += 80;
+  long_event.end_bit = true;
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(long_event));
+
+  EXPECT_EQ(2u, buffer.Length());
+
+  DtmfEvent out_event;
+  // Expect to get the long event.
+  EXPECT_TRUE(buffer.GetEvent(timestamp, &out_event));
+  EXPECT_TRUE(EqualEvents(long_event, out_event));
+  // Expect no more events.
+#ifdef LEGACY_BITEXACT
+  EXPECT_TRUE(buffer.GetEvent(timestamp + long_event.duration + 10,
+                              &out_event));
+  EXPECT_TRUE(EqualEvents(long_event, out_event));
+  EXPECT_TRUE(buffer.GetEvent(timestamp + long_event.duration + 10,
+                              &out_event));
+  EXPECT_TRUE(EqualEvents(short_event, out_event));
+#else
+  EXPECT_FALSE(buffer.GetEvent(timestamp + long_event.duration + 10,
+                               &out_event));
+#endif
+  EXPECT_TRUE(buffer.Empty());
+}
+
+TEST(DtmfBuffer, ExtrapolationTime) {
+  int event_no = 0;
+  bool end_bit = false;
+  int volume = 1;
+  int duration = 80;
+  uint32_t timestamp = 0x12345678;
+  DtmfEvent event1(timestamp, event_no, volume, duration, end_bit);
+  DtmfBuffer buffer(sample_rate_hz);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event1));
+  EXPECT_EQ(1u, buffer.Length());
+
+  DtmfEvent out_event;
+  // Get the event at the start.
+  EXPECT_TRUE(buffer.GetEvent(timestamp, &out_event));
+  EXPECT_TRUE(EqualEvents(event1, out_event));
+  // Also get the event 100 samples after the end of the event (since we're
+  // missing the end bit).
+  uint32_t timestamp_now = timestamp + duration + 100;
+  EXPECT_TRUE(buffer.GetEvent(timestamp_now, &out_event));
+  EXPECT_TRUE(EqualEvents(event1, out_event));
+  // Insert another event starting back-to-back with the previous event.
+  timestamp += duration;
+  event_no = 1;
+  DtmfEvent event2(timestamp, event_no, volume, duration, end_bit);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event2));
+  EXPECT_EQ(2u, buffer.Length());
+  // Now we expect to get the new event when supplying |timestamp_now|.
+  EXPECT_TRUE(buffer.GetEvent(timestamp_now, &out_event));
+  EXPECT_TRUE(EqualEvents(event2, out_event));
+  // Expect the the first event to be erased now.
+  EXPECT_EQ(1u, buffer.Length());
+  // Move |timestamp_now| to more than 560 samples after the end of the second
+  // event. Expect that event to be erased.
+  timestamp_now = timestamp + duration + 600;
+#ifdef LEGACY_BITEXACT
+  EXPECT_TRUE(buffer.GetEvent(timestamp_now, &out_event));
+#endif
+  EXPECT_FALSE(buffer.GetEvent(timestamp_now, &out_event));
+  EXPECT_TRUE(buffer.Empty());
+}
+
+TEST(DtmfBuffer, TimestampWraparound) {
+  int event_no = 0;
+  bool end_bit = true;
+  int volume = 1;
+  int duration = 80;
+  uint32_t timestamp1 = 0xFFFFFFFF - duration;
+  DtmfEvent event1(timestamp1, event_no, volume, duration, end_bit);
+  uint32_t timestamp2 = 0;
+  DtmfEvent event2(timestamp2, event_no, volume, duration, end_bit);
+  DtmfBuffer buffer(sample_rate_hz);
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event1));
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event2));
+  EXPECT_EQ(2u, buffer.Length());
+  DtmfEvent out_event;
+  EXPECT_TRUE(buffer.GetEvent(timestamp1, &out_event));
+  EXPECT_TRUE(EqualEvents(event1, out_event));
+#ifdef LEGACY_BITEXACT
+  EXPECT_EQ(1u, buffer.Length());
+#else
+  EXPECT_EQ(2u, buffer.Length());
+#endif
+
+  buffer.Flush();
+  // Reverse the insert order. Expect same results.
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event2));
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event1));
+  EXPECT_EQ(2u, buffer.Length());
+  EXPECT_TRUE(buffer.GetEvent(timestamp1, &out_event));
+  EXPECT_TRUE(EqualEvents(event1, out_event));
+#ifdef LEGACY_BITEXACT
+  EXPECT_EQ(1u, buffer.Length());
+#else
+  EXPECT_EQ(2u, buffer.Length());
+#endif
+}
+
+TEST(DtmfBuffer, InvalidEvents) {
+  int event_no = 0;
+  bool end_bit = true;
+  int volume = 1;
+  int duration = 80;
+  uint32_t timestamp = 0x12345678;
+  DtmfEvent event(timestamp, event_no, volume, duration, end_bit);
+  DtmfBuffer buffer(sample_rate_hz);
+
+  // Invalid event number.
+  event.event_no = -1;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.event_no = 16;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.event_no = 0;  // Valid value;
+
+  // Invalid volume.
+  event.volume = -1;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.volume = 37;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.volume = 0;  // Valid value;
+
+  // Invalid duration.
+  event.duration = -1;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.duration = 0;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.duration = 0xFFFF + 1;
+  EXPECT_EQ(DtmfBuffer::kInvalidEventParameters, buffer.InsertEvent(event));
+  event.duration = 1;  // Valid value;
+
+  // Finish with a valid event, just to verify that all is ok.
+  EXPECT_EQ(DtmfBuffer::kOK, buffer.InsertEvent(event));
+}
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.cc b/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.cc
new file mode 100644
index 0000000..f8b13aa
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.cc
@@ -0,0 +1,192 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// This class provides a generator for DTMF tones. The tone generation is based
+// on a sinusoid recursion. Each sinusoid is generated using a recursion
+// formula; x[n] = a * x[n-1] - x[n-2], where the coefficient
+// a = 2*cos(2*pi*f/fs). The recursion is started with x[-1] = 0 and
+// x[-2] = sin(2*pi*f/fs). (Note that with this initialization, the resulting
+// sinusoid gets a "negative" rotation; x[n] = sin(-2*pi*f/fs * n + phi), but
+// kept this way due to historical reasons.)
+// TODO(hlundin): Change to positive rotation?
+//
+// Each key on the telephone keypad corresponds to an "event", 0-15. Each event
+// is mapped to a tone pair, with a low and a high frequency. There are four
+// low and four high frequencies, each corresponding to a row and column,
+// respectively, on the keypad as illustrated below.
+//
+//          1209 Hz  1336 Hz  1477 Hz  1633 Hz
+// 697 Hz      1        2        3       12
+// 770 Hz      4        5        6       13
+// 852 Hz      7        8        9       14
+// 941 Hz     10        0       11       15
+
+#include "webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h"
+
+#include <assert.h>
+
+namespace webrtc {
+
+// The filter coefficient a = 2*cos(2*pi*f/fs) for the low frequency tone, for
+// sample rates fs = {8000, 16000, 32000, 48000} Hz, and events 0 through 15.
+// Values are in Q14.
+const int DtmfToneGenerator::kCoeff1[4][16] = {
+    { 24219, 27980, 27980, 27980, 26956, 26956, 26956, 25701, 25701, 25701,
+      24219, 24219, 27980, 26956, 25701, 24219 },
+    { 30556, 31548, 31548, 31548, 31281, 31281, 31281, 30951, 30951, 30951,
+      30556, 30556, 31548, 31281, 30951, 30556 },
+    { 32210, 32462, 32462, 32462, 32394, 32394, 32394, 32311, 32311, 32311,
+      32210, 32210, 32462, 32394, 32311, 32210 },
+    { 32520, 32632, 32632, 32632, 32602, 32602, 32602, 32564, 32564, 32564,
+      32520, 32520, 32632, 32602, 32564, 32520 } };
+
+// The filter coefficient a = 2*cos(2*pi*f/fs) for the high frequency tone, for
+// sample rates fs = {8000, 16000, 32000, 48000} Hz, and events 0 through 15.
+// Values are in Q14.
+const int DtmfToneGenerator::kCoeff2[4][16] = {
+    { 16325, 19073, 16325, 13085, 19073, 16325, 13085, 19073, 16325, 13085,
+      19073, 13085, 9315, 9315, 9315, 9315},
+    { 28361, 29144, 28361, 27409, 29144, 28361, 27409, 29144, 28361, 27409,
+      29144, 27409, 26258, 26258, 26258, 26258},
+    { 31647, 31849, 31647, 31400, 31849, 31647, 31400, 31849, 31647, 31400,
+      31849, 31400, 31098, 31098, 31098, 31098},
+    { 32268, 32359, 32268, 32157, 32359, 32268, 32157, 32359, 32268, 32157,
+      32359, 32157, 32022, 32022, 32022, 32022} };
+
+// The initialization value x[-2] = sin(2*pi*f/fs) for the low frequency tone,
+// for sample rates fs = {8000, 16000, 32000, 48000} Hz, and events 0-15.
+// Values are in Q14.
+const int DtmfToneGenerator::kInitValue1[4][16] = {
+    { 11036, 8528, 8528, 8528, 9315, 9315, 9315, 10163, 10163, 10163, 11036,
+      11036, 8528, 9315, 10163, 11036},
+    { 5918, 4429, 4429, 4429, 4879, 4879, 4879, 5380, 5380, 5380, 5918, 5918,
+      4429, 4879, 5380, 5918},
+    { 3010, 2235, 2235, 2235, 2468, 2468, 2468, 2728, 2728, 2728, 3010, 3010,
+      2235, 2468, 2728, 3010},
+    { 2013, 1493, 1493, 1493, 1649, 1649, 1649, 1823, 1823, 1823, 2013, 2013,
+      1493, 1649, 1823, 2013 } };
+
+// The initialization value x[-2] = sin(2*pi*f/fs) for the high frequency tone,
+// for sample rates fs = {8000, 16000, 32000, 48000} Hz, and events 0-15.
+// Values are in Q14.
+const int DtmfToneGenerator::kInitValue2[4][16] = {
+    { 14206, 13323, 14206, 15021, 13323, 14206, 15021, 13323, 14206, 15021,
+      13323, 15021, 15708, 15708, 15708, 15708},
+    { 8207, 7490, 8207, 8979, 7490, 8207, 8979, 7490, 8207, 8979, 7490, 8979,
+      9801, 9801, 9801, 9801},
+    { 4249, 3853, 4249, 4685, 3853, 4249, 4685, 3853, 4249, 4685, 3853, 4685,
+      5164, 5164, 5164, 5164},
+    { 2851, 2582, 2851, 3148, 2582, 2851, 3148, 2582, 2851, 3148, 2582, 3148,
+      3476, 3476, 3476, 3476} };
+
+// Amplitude multipliers for volume values 0 through 36, corresponding to
+// 0 dBm0 through -36 dBm0. Values are in Q14.
+const int DtmfToneGenerator::kAmplitude[37] = {
+    16141, 14386, 12821, 11427, 10184, 9077, 8090, 7210, 6426, 5727, 5104, 4549,
+    4054, 3614, 3221, 2870, 2558, 2280, 2032, 1811, 1614, 1439, 1282, 1143,
+    1018, 908, 809, 721, 643, 573, 510, 455, 405, 361, 322, 287, 256 };
+
+// Constructor.
+DtmfToneGenerator::DtmfToneGenerator()
+    : initialized_(false),
+      coeff1_(0),
+      coeff2_(0),
+      amplitude_(0) {
+}
+
+// Initialize the DTMF generator with sample rate fs Hz (8000, 16000, 32000,
+// 48000), event (0-15) and attenuation (0-36 dB).
+// Returns 0 on success, otherwise an error code.
+int DtmfToneGenerator::Init(int fs, int event, int attenuation) {
+  initialized_ = false;
+  int fs_index;
+  if (fs == 8000) {
+    fs_index = 0;
+  } else if (fs == 16000) {
+    fs_index = 1;
+  } else if (fs == 32000) {
+    fs_index = 2;
+  } else if (fs == 48000) {
+    fs_index = 3;
+  } else {
+    assert(false);
+    fs_index = 1;  // Default to 8000 Hz.
+  }
+
+  if (event < 0 || event > 15) {
+    return kParameterError;  // Invalid event number.
+  }
+
+  if (attenuation < 0 || attenuation > 36) {
+    return kParameterError;  // Invalid attenuation.
+  }
+
+  // Look up oscillator coefficient for low and high frequencies.
+  coeff1_ = kCoeff1[fs_index][event];
+  coeff2_ = kCoeff2[fs_index][event];
+  // Look up amplitude multiplier.
+  amplitude_ = kAmplitude[attenuation];
+  // Initialize sample history.
+  sample_history1_[0] = kInitValue1[fs_index][event];
+  sample_history1_[1] = 0;
+  sample_history2_[0] = kInitValue2[fs_index][event];
+  sample_history2_[1] = 0;
+
+  initialized_ = true;
+  return 0;
+}
+
+// Reset tone generator to uninitialized state.
+void DtmfToneGenerator::Reset() {
+  initialized_ = false;
+}
+
+// Generate num_samples of DTMF signal and write to |output|.
+int DtmfToneGenerator::Generate(int num_samples,
+                                AudioMultiVector<int16_t>* output) {
+  if (!initialized_) {
+    return kNotInitialized;
+  }
+
+  if (num_samples < 0 || !output) {
+    return kParameterError;
+  }
+  assert(output->Channels() == 1);  // Not adapted for multi-channel yet.
+  if (output->Channels() != 1) {
+    return kStereoNotSupported;
+  }
+
+  output->AssertSize(num_samples);
+  for (int i = 0; i < num_samples; ++i) {
+    // Use recursion formula y[n] = a * y[n - 1] - y[n - 2].
+    int16_t temp_val_low = ((coeff1_ * sample_history1_[1] + 8192) >> 14)
+        - sample_history1_[0];
+    int16_t temp_val_high = ((coeff2_ * sample_history2_[1] + 8192) >> 14)
+        - sample_history2_[0];
+
+    // Update recursion memory.
+    sample_history1_[0] = sample_history1_[1];
+    sample_history1_[1] = temp_val_low;
+    sample_history2_[0] = sample_history2_[1];
+    sample_history2_[1] = temp_val_high;
+
+    // Attenuate the low frequency tone 3 dB.
+    int32_t temp_val = kAmpMultiplier * temp_val_low + (temp_val_high << 15);
+    // Normalize the signal to Q14 with proper rounding.
+    temp_val = (temp_val + 16384) >> 15;
+    // Scale the signal to correct volume.
+    (*output)[0][i] =
+        static_cast<int16_t>((temp_val * amplitude_ + 8192) >> 14);
+  }
+
+  return num_samples;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h b/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h
new file mode 100644
index 0000000..60500ec
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h
@@ -0,0 +1,56 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DTMF_TONE_GENERATOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DTMF_TONE_GENERATOR_H_
+
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// This class provides a generator for DTMF tones.
+class DtmfToneGenerator {
+ public:
+  enum ReturnCodes {
+    kNotInitialized = -1,
+    kParameterError = -2,
+    kStereoNotSupported = -3,
+  };
+
+  DtmfToneGenerator();
+  virtual ~DtmfToneGenerator() {}
+  virtual int Init(int fs, int event, int attenuation);
+  virtual void Reset();
+  virtual int Generate(int num_samples, AudioMultiVector<int16_t>* output);
+  virtual bool initialized() const { return initialized_; }
+
+ private:
+  static const int kCoeff1[4][16];  // 1st oscillator model coefficient table.
+  static const int kCoeff2[4][16];  // 2nd oscillator model coefficient table.
+  static const int kInitValue1[4][16];  // Initialization for 1st oscillator.
+  static const int kInitValue2[4][16];  // Initialization for 2nd oscillator.
+  static const int kAmplitude[37];  // Amplitude for 0 through -36 dBm0.
+  static const int16_t kAmpMultiplier = 23171;  // 3 dB attenuation (in Q15).
+
+  bool initialized_;            // True if generator is initialized properly.
+  int coeff1_;                  // 1st oscillator coefficient for this event.
+  int coeff2_;                  // 2nd oscillator coefficient for this event.
+  int amplitude_;               // Amplitude for this event.
+  int16_t sample_history1_[2];  // Last 2 samples for the 1st oscillator.
+  int16_t sample_history2_[2];  // Last 2 samples for the 2nd oscillator.
+
+  DISALLOW_COPY_AND_ASSIGN(DtmfToneGenerator);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_DTMF_TONE_GENERATOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator_unittest.cc b/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator_unittest.cc
new file mode 100644
index 0000000..acd0843
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/dtmf_tone_generator_unittest.cc
@@ -0,0 +1,142 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for DtmfToneGenerator class.
+
+#include "webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h"
+
+#include <cmath>
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+
+namespace webrtc {
+
+TEST(DtmfToneGenerator, CreateAndDestroy) {
+  DtmfToneGenerator* tone_gen = new DtmfToneGenerator();
+  delete tone_gen;
+}
+
+TEST(DtmfToneGenerator, TestErrors) {
+  DtmfToneGenerator tone_gen;
+  const int kNumSamples = 10;
+  AudioMultiVector<int16_t> signal(1);  // One channel.
+
+  // Try to generate tones without initializing.
+  EXPECT_EQ(DtmfToneGenerator::kNotInitialized,
+            tone_gen.Generate(kNumSamples, &signal));
+
+  const int fs = 16000;       // Valid sample rate.
+  const int event = 7;        // Valid event.
+  const int attenuation = 0;  // Valid attenuation.
+  // Initialize with invalid event -1.
+  EXPECT_EQ(DtmfToneGenerator::kParameterError,
+            tone_gen.Init(fs, -1, attenuation));
+  // Initialize with invalid event 16.
+  EXPECT_EQ(DtmfToneGenerator::kParameterError,
+            tone_gen.Init(fs, 16, attenuation));
+  // Initialize with invalid attenuation -1.
+  EXPECT_EQ(DtmfToneGenerator::kParameterError, tone_gen.Init(fs, event, -1));
+  // Initialize with invalid attenuation 37.
+  EXPECT_EQ(DtmfToneGenerator::kParameterError, tone_gen.Init(fs, event, 37));
+  EXPECT_FALSE(tone_gen.initialized());  // Should still be uninitialized.
+
+  // Initialize with valid parameters.
+  ASSERT_EQ(0, tone_gen.Init(fs, event, attenuation));
+  EXPECT_TRUE(tone_gen.initialized());
+  // Negative number of samples.
+  EXPECT_EQ(DtmfToneGenerator::kParameterError, tone_gen.Generate(-1, &signal));
+  // NULL pointer to destination.
+  EXPECT_EQ(DtmfToneGenerator::kParameterError,
+            tone_gen.Generate(kNumSamples, NULL));
+}
+
+TEST(DtmfToneGenerator, TestTones) {
+  DtmfToneGenerator tone_gen;
+  const int kAttenuation = 0;
+  const int kNumSamples = 10;
+  AudioMultiVector<int16_t> signal(1);  // One channel.
+
+  // Low and high frequencies for events 0 through 15.
+  const double low_freq_hz[] = { 941.0, 697.0, 697.0, 697.0, 770.0, 770.0,
+      770.0, 852.0, 852.0, 852.0, 941.0, 941.0, 697.0, 770.0, 852.0, 941.0 };
+  const double hi_freq_hz[] = { 1336.0, 1209.0, 1336.0, 1477.0, 1209.0, 1336.0,
+      1477.0, 1209.0, 1336.0, 1477.0, 1209.0, 1477.0, 1633.0, 1633.0, 1633.0,
+      1633.0 };
+  const double attenuate_3dB = 23171.0 / 32768;  // 3 dB attenuation.
+  const double base_attenuation = 16141.0 / 16384.0;  // This is the attenuation
+                                                      // applied to all cases.
+  const int fs_vec[] = { 8000, 16000, 32000, 48000 };
+  for (int f = 0; f < 4; ++f) {
+    int fs = fs_vec[f];
+    for (int event = 0; event <= 15; ++event) {
+      std::ostringstream ss;
+      ss << "Checking event " << event << " at sample rate " << fs;
+      SCOPED_TRACE(ss.str());
+      ASSERT_EQ(0, tone_gen.Init(fs, event, kAttenuation));
+      EXPECT_TRUE(tone_gen.initialized());
+      EXPECT_EQ(kNumSamples, tone_gen.Generate(kNumSamples, &signal));
+
+      double f1 = low_freq_hz[event];
+      double f2 = hi_freq_hz[event];
+      const double pi = 3.14159265358979323846;
+
+      for (int n = 0; n < kNumSamples; ++n) {
+        double x = attenuate_3dB * sin(2.0 * pi * f1 / fs * (-n - 1))
+            + sin(2.0 * pi * f2 / fs * (-n - 1));
+        x *= base_attenuation;
+        x = ldexp(x, 14);  // Scale to Q14.
+        static const int kChannel = 0;
+        EXPECT_NEAR(x, static_cast<double>(signal[kChannel][n]), 25);
+      }
+
+      tone_gen.Reset();
+      EXPECT_FALSE(tone_gen.initialized());
+    }
+  }
+}
+
+TEST(DtmfToneGenerator, TestAmplitudes) {
+  DtmfToneGenerator tone_gen;
+  const int kNumSamples = 10;
+  AudioMultiVector<int16_t> signal(1);  // One channel.
+  AudioMultiVector<int16_t> ref_signal(1);  // One channel.
+
+  const int fs_vec[] = { 8000, 16000, 32000, 48000 };
+  const int event_vec[] = { 0, 4, 9, 13 };  // Test a few events.
+  for (int f = 0; f < 4; ++f) {
+    int fs = fs_vec[f];
+    int event = event_vec[f];
+    // Create full-scale reference.
+    ASSERT_EQ(0, tone_gen.Init(fs, event, 0));  // 0 attenuation.
+    EXPECT_EQ(kNumSamples, tone_gen.Generate(kNumSamples, &ref_signal));
+    // Test every 5 steps (to save time).
+    for (int attenuation = 1; attenuation <= 36; attenuation += 5) {
+      std::ostringstream ss;
+      ss << "Checking event " << event << " at sample rate " << fs;
+      ss << "; attenuation " << attenuation;
+      SCOPED_TRACE(ss.str());
+      ASSERT_EQ(0, tone_gen.Init(fs, event, attenuation));
+      EXPECT_EQ(kNumSamples, tone_gen.Generate(kNumSamples, &signal));
+      for (int n = 0; n < kNumSamples; ++n) {
+        double attenuation_factor =
+            pow(10, -static_cast<double>(attenuation)/20);
+        // Verify that the attenuation is correct.
+        static const int kChannel = 0;
+        EXPECT_NEAR(attenuation_factor * ref_signal[kChannel][n],
+                    signal[kChannel][n], 2);
+      }
+
+      tone_gen.Reset();
+    }
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/expand.cc b/webrtc/modules/audio_coding/neteq4/expand.cc
new file mode 100644
index 0000000..6ea3203
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/expand.cc
@@ -0,0 +1,860 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+
+#include <assert.h>
+
+#include <algorithm>  // min, max
+#include <cstring>  // memset
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+void Expand::Reset() {
+  first_expand_ = true;
+  consecutive_expands_ = 0;
+  max_lag_ = 0;
+  for (size_t ix = 0; ix < num_channels_; ++ix) {
+    channel_parameters_[ix].expand_vector0.Clear();
+    channel_parameters_[ix].expand_vector1.Clear();
+  }
+}
+
+int Expand::Process(AudioMultiVector<int16_t>* output) {
+  int16_t random_vector[kMaxSampleRate / 8000 * 120 + 30];
+  int16_t scaled_random_vector[kMaxSampleRate / 8000 * 125];
+  static const int kTempDataSize = 3600;
+  int16_t temp_data[kTempDataSize];  // TODO(hlundin) Remove this.
+  int16_t* voiced_vector_storage = temp_data;
+  int16_t* voiced_vector = &voiced_vector_storage[overlap_length_];
+  static const int kNoiseLpcOrder = BackgroundNoise::kMaxLpcOrder;
+  int16_t unvoiced_array_memory[kNoiseLpcOrder + kMaxSampleRate / 8000 * 125];
+  int16_t* unvoiced_vector = unvoiced_array_memory + kUnvoicedLpcOrder;
+  int16_t* noise_vector = unvoiced_array_memory + kNoiseLpcOrder;
+
+  int fs_mult = fs_hz_ / 8000;
+
+  if (first_expand_) {
+    // Perform initial setup if this is the first expansion since last reset.
+    AnalyzeSignal(random_vector);
+    first_expand_ = false;
+  } else {
+    // This is not the first expansion, parameters are already estimated.
+    // Extract a noise segment.
+    int16_t rand_length = max_lag_;
+    // TODO(hlundin): This if-statement should not be needed. Should be just
+    // as good to generate all of the vector in one call in either case.
+    if (rand_length <= RandomVector::kRandomTableSize) {
+      random_vector_->IncreaseSeedIncrement(2);
+      random_vector_->Generate(rand_length, random_vector);
+    } else {
+      // This only applies to SWB where length could be larger than 256.
+      assert(rand_length <= kMaxSampleRate / 8000 * 120 + 30);
+      random_vector_->IncreaseSeedIncrement(2);
+      random_vector_->Generate(RandomVector::kRandomTableSize, random_vector);
+      random_vector_->IncreaseSeedIncrement(2);
+      random_vector_->Generate(rand_length - RandomVector::kRandomTableSize,
+                               &random_vector[RandomVector::kRandomTableSize]);
+    }
+  }
+
+
+  // Generate signal.
+  UpdateLagIndex();
+
+  // Voiced part.
+  // Generate a weighted vector with the current lag.
+  size_t expansion_vector_length = max_lag_ + overlap_length_;
+  size_t current_lag = expand_lags_[current_lag_index_];
+  // Copy lag+overlap data.
+  size_t expansion_vector_position = expansion_vector_length - current_lag -
+      overlap_length_;
+  size_t temp_length = current_lag + overlap_length_;
+  for (size_t channel_ix = 0; channel_ix < num_channels_; ++channel_ix) {
+    ChannelParameters& parameters = channel_parameters_[channel_ix];
+    if (current_lag_index_ == 0) {
+      // Use only expand_vector0.
+      assert(expansion_vector_position + temp_length <=
+             parameters.expand_vector0.Size());
+      memcpy(voiced_vector_storage,
+             &parameters.expand_vector0[expansion_vector_position],
+             sizeof(int16_t) * temp_length);
+    } else if (current_lag_index_ == 1) {
+      // Mix 3/4 of expand_vector0 with 1/4 of expand_vector1.
+      WebRtcSpl_ScaleAndAddVectorsWithRound(
+          &parameters.expand_vector0[expansion_vector_position], 3,
+          &parameters.expand_vector1[expansion_vector_position], 1, 2,
+          voiced_vector_storage, temp_length);
+    } else if (current_lag_index_ == 2) {
+      // Mix 1/2 of expand_vector0 with 1/2 of expand_vector1.
+      assert(expansion_vector_position + temp_length <=
+             parameters.expand_vector0.Size());
+      assert(expansion_vector_position + temp_length <=
+             parameters.expand_vector1.Size());
+      WebRtcSpl_ScaleAndAddVectorsWithRound(
+          &parameters.expand_vector0[expansion_vector_position], 1,
+          &parameters.expand_vector1[expansion_vector_position], 1, 1,
+          voiced_vector_storage, temp_length);
+    }
+
+    // Get tapering window parameters. Values are in Q15.
+    int16_t muting_window, muting_window_increment;
+    int16_t unmuting_window, unmuting_window_increment;
+    if (fs_hz_ == 8000) {
+      muting_window = DspHelper::kMuteFactorStart8kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement8kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart8kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement8kHz;
+    } else if (fs_hz_ == 16000) {
+      muting_window = DspHelper::kMuteFactorStart16kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement16kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart16kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement16kHz;
+    } else if (fs_hz_ == 32000) {
+      muting_window = DspHelper::kMuteFactorStart32kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement32kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart32kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement32kHz;
+    } else {  // fs_ == 48000
+      muting_window = DspHelper::kMuteFactorStart48kHz;
+      muting_window_increment = DspHelper::kMuteFactorIncrement48kHz;
+      unmuting_window = DspHelper::kUnmuteFactorStart48kHz;
+      unmuting_window_increment = DspHelper::kUnmuteFactorIncrement48kHz;
+    }
+
+    // Smooth the expanded if it has not been muted to a low amplitude and
+    // |current_voice_mix_factor| is larger than 0.5.
+    if ((parameters.mute_factor > 819) &&
+        (parameters.current_voice_mix_factor > 8192)) {
+      size_t start_ix = sync_buffer_->Size() - overlap_length_;
+      for (size_t i = 0; i < overlap_length_; i++) {
+        // Do overlap add between new vector and overlap.
+        (*sync_buffer_)[channel_ix][start_ix + i] =
+            (((*sync_buffer_)[channel_ix][start_ix + i] * muting_window) +
+                (((parameters.mute_factor * voiced_vector_storage[i]) >> 14) *
+                    unmuting_window) + 16384) >> 15;
+        muting_window += muting_window_increment;
+        unmuting_window += unmuting_window_increment;
+      }
+    } else if (parameters.mute_factor == 0) {
+      // The expanded signal will consist of only comfort noise if
+      // mute_factor = 0. Set the output length to 15 ms for best noise
+      // production.
+      // TODO(hlundin): This has been disabled since the length of
+      // parameters.expand_vector0 and parameters.expand_vector1 no longer
+      // match with expand_lags_, causing invalid reads and writes. Is it a good
+      // idea to enable this again, and solve the vector size problem?
+//      max_lag_ = fs_mult * 120;
+//      expand_lags_[0] = fs_mult * 120;
+//      expand_lags_[1] = fs_mult * 120;
+//      expand_lags_[2] = fs_mult * 120;
+    }
+
+    // Unvoiced part.
+    // Filter |scaled_random_vector| through |ar_filter_|.
+    memcpy(unvoiced_vector - kUnvoicedLpcOrder, parameters.ar_filter_state,
+           sizeof(int16_t) * kUnvoicedLpcOrder);
+    int32_t add_constant = 0;
+    if (parameters.ar_gain_scale > 0) {
+      add_constant = 1 << (parameters.ar_gain_scale - 1);
+    }
+    WebRtcSpl_AffineTransformVector(scaled_random_vector, random_vector,
+                                    parameters.ar_gain, add_constant,
+                                    parameters.ar_gain_scale, current_lag);
+    WebRtcSpl_FilterARFastQ12(scaled_random_vector, unvoiced_vector,
+                              parameters.ar_filter,
+                              kUnvoicedLpcOrder + 1, current_lag);
+    memcpy(parameters.ar_filter_state,
+           &(unvoiced_vector[current_lag - kUnvoicedLpcOrder]),
+           sizeof(int16_t) * kUnvoicedLpcOrder);
+
+    // Combine voiced and unvoiced contributions.
+
+    // Set a suitable cross-fading slope.
+    // For lag =
+    //   <= 31 * fs_mult            => go from 1 to 0 in about 8 ms;
+    //  (>= 31 .. <= 63) * fs_mult  => go from 1 to 0 in about 16 ms;
+    //   >= 64 * fs_mult            => go from 1 to 0 in about 32 ms.
+    // temp_shift = getbits(max_lag_) - 5.
+    int temp_shift = (31 - WebRtcSpl_NormW32(max_lag_)) - 5;
+    int16_t mix_factor_increment = 256 >> temp_shift;
+    if (stop_muting_) {
+      mix_factor_increment = 0;
+    }
+
+    // Create combined signal by shifting in more and more of unvoiced part.
+    temp_shift = 8 - temp_shift;  // = getbits(mix_factor_increment).
+    size_t temp_lenght = (parameters.current_voice_mix_factor -
+        parameters.voice_mix_factor) >> temp_shift;
+    temp_lenght = std::min(temp_lenght, current_lag);
+    DspHelper::CrossFade(voiced_vector, unvoiced_vector, temp_lenght,
+                         &parameters.current_voice_mix_factor,
+                         mix_factor_increment, temp_data);
+
+    // End of cross-fading period was reached before end of expanded signal
+    // path. Mix the rest with a fixed mixing factor.
+    if (temp_lenght < current_lag) {
+      if (mix_factor_increment != 0) {
+        parameters.current_voice_mix_factor = parameters.voice_mix_factor;
+      }
+      int temp_scale = 16384 - parameters.current_voice_mix_factor;
+      WebRtcSpl_ScaleAndAddVectorsWithRound(
+          voiced_vector + temp_lenght, parameters.current_voice_mix_factor,
+          unvoiced_vector + temp_lenght, temp_scale, 14,
+          temp_data + temp_lenght, current_lag - temp_lenght);
+    }
+
+    // Select muting slope depending on how many consecutive expands we have
+    // done.
+    if (consecutive_expands_ == 3) {
+      // Let the mute factor decrease from 1.0 to 0.95 in 6.25 ms.
+      // mute_slope = 0.0010 / fs_mult in Q20.
+      parameters.mute_slope = std::max(parameters.mute_slope,
+                                       static_cast<int16_t>(1049 / fs_mult));
+    }
+    if (consecutive_expands_ == 7) {
+      // Let the mute factor decrease from 1.0 to 0.90 in 6.25 ms.
+      // mute_slope = 0.0020 / fs_mult in Q20.
+      parameters.mute_slope = std::max(parameters.mute_slope,
+                                       static_cast<int16_t>(2097 / fs_mult));
+    }
+
+    // Mute segment according to slope value.
+    if ((consecutive_expands_ != 0) || !parameters.onset) {
+      // Mute to the previous level, then continue with the muting.
+      WebRtcSpl_AffineTransformVector(temp_data, temp_data,
+                                      parameters.mute_factor, 8192,
+                                      14, current_lag);
+
+      if (!stop_muting_) {
+        DspHelper::MuteSignal(temp_data, parameters.mute_slope, current_lag);
+
+        // Shift by 6 to go from Q20 to Q14.
+        // TODO(hlundin): Adding 8192 before shifting 6 steps seems wrong.
+        // Legacy.
+        int16_t gain = 16384 -
+            (((current_lag * parameters.mute_slope) + 8192) >> 6);
+        gain = ((gain * parameters.mute_factor) + 8192) >> 14;
+
+        // Guard against getting stuck with very small (but sometimes audible)
+        // gain.
+        if ((consecutive_expands_ > 3) && (gain >= parameters.mute_factor)) {
+          parameters.mute_factor = 0;
+        } else {
+          parameters.mute_factor = gain;
+        }
+      }
+    }
+
+    // Background noise part.
+    // TODO(hlundin): Move to separate method? In BackgroundNoise class?
+    if (background_noise_->initialized()) {
+      // Use background noise parameters.
+      memcpy(noise_vector - kNoiseLpcOrder,
+             background_noise_->FilterState(channel_ix),
+             sizeof(int16_t) * kNoiseLpcOrder);
+
+      if (background_noise_->ScaleShift(channel_ix) > 1) {
+        add_constant = 1 << (background_noise_->ScaleShift(channel_ix) - 1);
+      } else {
+        add_constant = 0;
+      }
+
+      // Scale random vector to correct energy level.
+      WebRtcSpl_AffineTransformVector(
+          scaled_random_vector, random_vector,
+          background_noise_->Scale(channel_ix), add_constant,
+          background_noise_->ScaleShift(channel_ix), current_lag);
+
+      WebRtcSpl_FilterARFastQ12(scaled_random_vector, noise_vector,
+                                background_noise_->Filter(channel_ix),
+                                kNoiseLpcOrder + 1,
+                                current_lag);
+
+      background_noise_->SetFilterState(
+          channel_ix,
+          &(noise_vector[current_lag - kNoiseLpcOrder]),
+          kNoiseLpcOrder);
+
+      // Unmute the background noise.
+      int16_t bgn_mute_factor = background_noise_->MuteFactor(channel_ix);
+      BackgroundNoise::BackgroundNoiseMode bgn_mode = background_noise_->mode();
+      if (bgn_mode == BackgroundNoise::kBgnFade &&
+          consecutive_expands_ >= kMaxConsecutiveExpands &&
+          bgn_mute_factor > 0) {
+        // Fade BGN to zero.
+        // Calculate muting slope, approximately -2^18 / fs_hz.
+        int16_t mute_slope;
+        if (fs_hz_ == 8000) {
+          mute_slope = -32;
+        } else if (fs_hz_ == 16000) {
+          mute_slope = -16;
+        } else if (fs_hz_ == 32000) {
+          mute_slope = -8;
+        } else {
+          mute_slope = -5;
+        }
+        // Use UnmuteSignal function with negative slope.
+        // |bgn_mute_factor| is in Q14. |mute_slope| is in Q20.
+        DspHelper::UnmuteSignal(noise_vector, current_lag, &bgn_mute_factor,
+                                mute_slope, noise_vector);
+      } else if (bgn_mute_factor < 16384) {
+        // If mode is kBgnOff, or if kBgnFade has started fading,
+        // Use regular |mute_slope|.
+        if (!stop_muting_ && bgn_mode != BackgroundNoise::kBgnOff &&
+            !(bgn_mode == BackgroundNoise::kBgnFade &&
+                consecutive_expands_ >= kMaxConsecutiveExpands)) {
+          DspHelper::UnmuteSignal(noise_vector, current_lag, &bgn_mute_factor,
+                                  parameters.mute_slope, noise_vector);
+        } else {
+          // kBgnOn and stop muting, or
+          // kBgnOff (mute factor is always 0), or
+          // kBgnFade has reached 0.
+          WebRtcSpl_AffineTransformVector(noise_vector, noise_vector,
+                                          bgn_mute_factor, 8192, 14,
+                                          current_lag);
+        }
+      }
+      // Update mute_factor in BackgroundNoise class.
+      background_noise_->SetMuteFactor(channel_ix, bgn_mute_factor);
+    } else {
+      // BGN parameters have not been initialized; use zero noise.
+      memset(noise_vector, 0, sizeof(int16_t) * current_lag);
+    }
+
+    // Add background noise to the combined voiced-unvoiced signal.
+    for (size_t i = 0; i < current_lag; i++) {
+      temp_data[i] = temp_data[i] + noise_vector[i];
+    }
+    if (channel_ix == 0) {
+      output->AssertSize(current_lag);
+    } else {
+      assert(output->Size() == current_lag);
+    }
+    memcpy(&(*output)[channel_ix][0], temp_data,
+           sizeof(temp_data[0]) * current_lag);
+  }
+
+  // Increase call number and cap it.
+  ++consecutive_expands_;
+  if (consecutive_expands_ > kMaxConsecutiveExpands) {
+    consecutive_expands_ = kMaxConsecutiveExpands;
+  }
+
+  return 0;
+}
+
+void Expand::SetParametersForNormalAfterExpand() {
+  current_lag_index_ = 0;
+  lag_index_direction_ = 0;
+  stop_muting_ = true;  // Do not mute signal any more.
+}
+
+void Expand::SetParametersForMergeAfterExpand() {
+  current_lag_index_ = -1; /* out of the 3 possible ones */
+  lag_index_direction_ = 1; /* make sure we get the "optimal" lag */
+  stop_muting_ = true;
+}
+
+void Expand::AnalyzeSignal(int16_t* random_vector) {
+  int32_t auto_correlation[kUnvoicedLpcOrder + 1];
+  int16_t reflection_coeff[kUnvoicedLpcOrder];
+  int16_t correlation_vector[kMaxSampleRate / 8000 * 102];
+  int best_correlation_index[kNumCorrelationCandidates];
+  int16_t best_correlation[kNumCorrelationCandidates];
+  int16_t best_distortion_index[kNumCorrelationCandidates];
+  int16_t best_distortion[kNumCorrelationCandidates];
+  int32_t correlation_vector2[(99 * kMaxSampleRate / 8000) + 1];
+  int32_t best_distortion_w32[kNumCorrelationCandidates];
+  static const int kNoiseLpcOrder = BackgroundNoise::kMaxLpcOrder;
+  int16_t unvoiced_array_memory[kNoiseLpcOrder + kMaxSampleRate / 8000 * 125];
+  int16_t* unvoiced_vector = unvoiced_array_memory + kUnvoicedLpcOrder;
+
+  int fs_mult = fs_hz_ / 8000;
+
+  // Pre-calculate common multiplications with fs_mult.
+  int fs_mult_4 = fs_mult * 4;
+  int fs_mult_20 = fs_mult * 20;
+  int fs_mult_120 = fs_mult * 120;
+  int fs_mult_dist_len = fs_mult * kDistortionLength;
+  int fs_mult_lpc_analysis_len = fs_mult * kLpcAnalysisLength;
+
+  const size_t signal_length = 256 * fs_mult;
+  const int16_t* audio_history =
+      &(*sync_buffer_)[0][sync_buffer_->Size() - signal_length];
+
+  // Initialize some member variables.
+  lag_index_direction_ = 1;
+  current_lag_index_ = -1;
+  stop_muting_ = false;
+  random_vector_->set_seed_increment(1);
+  consecutive_expands_ = 0;
+  for (size_t ix = 0; ix < num_channels_; ++ix) {
+    channel_parameters_[ix].current_voice_mix_factor = 16384;  // 1.0 in Q14.
+    channel_parameters_[ix].mute_factor = 16384;  // 1.0 in Q14.
+    // Start with 0 gain for background noise.
+    background_noise_->SetMuteFactor(ix, 0);
+  }
+
+  // Calculate correlation in downsampled domain (4 kHz sample rate).
+  int16_t correlation_scale;
+  int correlation_length = Correlation(audio_history, signal_length,
+                                       correlation_vector, &correlation_scale);
+  correlation_length = 51;  // TODO(hlundin): Legacy bit-exactness.
+
+  // Find peaks in correlation vector.
+  DspHelper::PeakDetection(correlation_vector, correlation_length,
+                           kNumCorrelationCandidates, fs_mult,
+                           best_correlation_index, best_correlation);
+
+  // Adjust peak locations; cross-correlation lags start at 2.5 ms
+  // (20 * fs_mult samples).
+  best_correlation_index[0] += fs_mult_20;
+  best_correlation_index[1] += fs_mult_20;
+  best_correlation_index[2] += fs_mult_20;
+
+  // Calculate distortion around the |kNumCorrelationCandidates| best lags.
+  int distortion_scale = 0;
+  for (int i = 0; i < kNumCorrelationCandidates; i++) {
+    int16_t min_index = std::max(fs_mult_20,
+                                 best_correlation_index[i] - fs_mult_4);
+    int16_t max_index = std::min(fs_mult_120 - 1,
+                                 best_correlation_index[i] + fs_mult_4);
+    best_distortion_index[i] = DspHelper::MinDistortion(
+        &(audio_history[signal_length - fs_mult_dist_len]), min_index,
+        max_index, fs_mult_dist_len, &best_distortion_w32[i]);
+    distortion_scale = std::max(16 - WebRtcSpl_NormW32(best_distortion_w32[i]),
+                                distortion_scale);
+  }
+  // Shift the distortion values to fit in 16 bits.
+  WebRtcSpl_VectorBitShiftW32ToW16(best_distortion, kNumCorrelationCandidates,
+                                   best_distortion_w32, distortion_scale);
+
+  // Find the maximizing index |i| of the cost function
+  // f[i] = best_correlation[i] / best_distortion[i].
+  int32_t best_ratio = -1;
+  int best_index = -1;
+  for (int i = 0; i < kNumCorrelationCandidates; ++i) {
+    int32_t ratio;
+    if (best_distortion[i] > 0) {
+      ratio = (best_correlation[i] << 16) / best_distortion[i];
+    } else {
+      assert(best_correlation[i] == 0);  // If one is zero, both must be.
+      ratio = 0;  // Divide zero by zero => set result to zero.
+    }
+    if (ratio > best_ratio) {
+      best_index = i;
+      best_ratio = ratio;
+    }
+  }
+
+  int distortion_lag = best_distortion_index[best_index];
+  int correlation_lag = best_correlation_index[best_index];
+  max_lag_ = std::max(distortion_lag, correlation_lag);
+
+  // Calculate the exact best correlation in the range between
+  // |correlation_lag| and |distortion_lag|.
+  correlation_length = distortion_lag + 10;
+  correlation_length = std::min(correlation_length, fs_mult_120);
+  correlation_length = std::max(correlation_length, 60 * fs_mult);
+
+  int start_index = std::min(distortion_lag, correlation_lag);
+  int correlation_lags = WEBRTC_SPL_ABS_W16((distortion_lag-correlation_lag))
+      + 1;
+  assert(correlation_lags <= 99 * fs_mult + 1);  // Cannot be larger.
+
+  for (size_t channel_ix = 0; channel_ix < num_channels_; ++channel_ix) {
+    ChannelParameters& parameters = channel_parameters_[channel_ix];
+    // Calculate suitable scaling.
+    int16_t signal_max = WebRtcSpl_MaxAbsValueW16(
+        &audio_history[signal_length - correlation_length - start_index
+                       - correlation_lags],
+                       correlation_length + start_index + correlation_lags - 1);
+    correlation_scale = ((31 - WebRtcSpl_NormW32(signal_max * signal_max))
+        + (31 - WebRtcSpl_NormW32(correlation_length))) - 31;
+    correlation_scale = std::max(static_cast<int16_t>(0), correlation_scale);
+
+    // Calculate the correlation, store in |correlation_vector2|.
+    WebRtcSpl_CrossCorrelation(
+        correlation_vector2,
+        &(audio_history[signal_length - correlation_length]),
+        &(audio_history[signal_length - correlation_length - start_index]),
+        correlation_length, correlation_lags, correlation_scale, -1);
+
+    // Find maximizing index.
+    best_index = WebRtcSpl_MaxIndexW32(correlation_vector2, correlation_lags);
+    int32_t max_correlation = correlation_vector2[best_index];
+    // Compensate index with start offset.
+    best_index = best_index + start_index;
+
+    // Calculate energies.
+    int32_t energy1 = WebRtcSpl_DotProductWithScale(
+        &(audio_history[signal_length - correlation_length]),
+        &(audio_history[signal_length - correlation_length]),
+        correlation_length, correlation_scale);
+    int32_t energy2 = WebRtcSpl_DotProductWithScale(
+        &(audio_history[signal_length - correlation_length - best_index]),
+        &(audio_history[signal_length - correlation_length - best_index]),
+        correlation_length, correlation_scale);
+
+    // Calculate the correlation coefficient between the two portions of the
+    // signal.
+    int16_t corr_coefficient;
+    if ((energy1 > 0) && (energy2 > 0)) {
+      int energy1_scale = std::max(16 - WebRtcSpl_NormW32(energy1), 0);
+      int energy2_scale = std::max(16 - WebRtcSpl_NormW32(energy2), 0);
+      // Make sure total scaling is even (to simplify scale factor after sqrt).
+      if ((energy1_scale + energy2_scale) & 1) {
+        // If sum is odd, add 1 to make it even.
+        energy1_scale += 1;
+      }
+      int16_t scaled_energy1 = energy1 >> energy1_scale;
+      int16_t scaled_energy2 = energy2 >> energy2_scale;
+      int16_t sqrt_energy_product = WebRtcSpl_SqrtFloor(
+          scaled_energy1 * scaled_energy2);
+      // Calculate max_correlation / sqrt(energy1 * energy2) in Q14.
+      int cc_shift = 14 - (energy1_scale + energy2_scale) / 2;
+      max_correlation = WEBRTC_SPL_SHIFT_W32(max_correlation, cc_shift);
+      corr_coefficient = WebRtcSpl_DivW32W16(max_correlation,
+                                             sqrt_energy_product);
+      corr_coefficient = std::min(static_cast<int16_t>(16384),
+                                  corr_coefficient);  // Cap at 1.0 in Q14.
+    } else {
+      corr_coefficient = 0;
+    }
+
+    // Extract the two vectors expand_vector0 and expand_vector1 from
+    // |audio_history|.
+    int16_t expansion_length = max_lag_ + overlap_length_;
+    const int16_t* vector1 = &(audio_history[signal_length - expansion_length]);
+    const int16_t* vector2 = vector1 - distortion_lag;
+    // Normalize the second vector to the same energy as the first.
+    energy1 = WebRtcSpl_DotProductWithScale(vector1, vector1, expansion_length,
+                                            correlation_scale);
+    energy2 = WebRtcSpl_DotProductWithScale(vector2, vector2, expansion_length,
+                                            correlation_scale);
+    // Confirm that amplitude ratio sqrt(energy1 / energy2) is within 0.5 - 2.0,
+    // i.e., energy1 / energy1 is within 0.25 - 4.
+    int16_t amplitude_ratio;
+    if ((energy1 / 4 < energy2) && (energy1 > energy2 / 4)) {
+      // Energy constraint fulfilled. Use both vectors and scale them
+      // accordingly.
+      int16_t scaled_energy2 = std::max(16 - WebRtcSpl_NormW32(energy2), 0);
+      int16_t scaled_energy1 = scaled_energy2 - 13;
+      // Calculate scaled_energy1 / scaled_energy2 in Q13.
+      int32_t energy_ratio = WebRtcSpl_DivW32W16(
+          WEBRTC_SPL_SHIFT_W32(energy1, -scaled_energy1),
+          WEBRTC_SPL_RSHIFT_W32(energy2, scaled_energy2));
+      // Calculate sqrt ratio in Q13 (sqrt of en1/en2 in Q26).
+      amplitude_ratio = WebRtcSpl_SqrtFloor(energy_ratio << 13);
+      // Copy the two vectors and give them the same energy.
+      parameters.expand_vector0.Clear();
+      parameters.expand_vector0.PushBack(vector1, expansion_length);
+      parameters.expand_vector1.Clear();
+      if (parameters.expand_vector1.Size() <
+          static_cast<size_t>(expansion_length)) {
+        parameters.expand_vector1.Extend(
+            expansion_length - parameters.expand_vector1.Size());
+      }
+      WebRtcSpl_AffineTransformVector(&parameters.expand_vector1[0],
+                                      const_cast<int16_t*>(vector2),
+                                      amplitude_ratio,
+                                      4096,
+                                      13,
+                                      expansion_length);
+    } else {
+      // Energy change constraint not fulfilled. Only use last vector.
+      parameters.expand_vector0.Clear();
+      parameters.expand_vector0.PushBack(vector1, expansion_length);
+      // Copy from expand_vector0 to expand_vector1.
+      parameters.expand_vector0.CopyFrom(&parameters.expand_vector1);
+      // Set the energy_ratio since it is used by muting slope.
+      if ((energy1 / 4 < energy2) || (energy2 == 0)) {
+        amplitude_ratio = 4096;  // 0.5 in Q13.
+      } else {
+        amplitude_ratio = 16384;  // 2.0 in Q13.
+      }
+    }
+
+    // Set the 3 lag values.
+    int lag_difference = distortion_lag - correlation_lag;
+    if (lag_difference == 0) {
+      // |distortion_lag| and |correlation_lag| are equal.
+      expand_lags_[0] = distortion_lag;
+      expand_lags_[1] = distortion_lag;
+      expand_lags_[2] = distortion_lag;
+    } else {
+      // |distortion_lag| and |correlation_lag| are not equal; use different
+      // combinations of the two.
+      // First lag is |distortion_lag| only.
+      expand_lags_[0] = distortion_lag;
+      // Second lag is the average of the two.
+      expand_lags_[1] = (distortion_lag + correlation_lag) / 2;
+      // Third lag is the average again, but rounding towards |correlation_lag|.
+      if (lag_difference > 0) {
+        expand_lags_[2] = (distortion_lag + correlation_lag - 1) / 2;
+      } else {
+        expand_lags_[2] = (distortion_lag + correlation_lag + 1) / 2;
+      }
+    }
+
+    // Calculate the LPC and the gain of the filters.
+    // Calculate scale value needed for auto-correlation.
+    correlation_scale = WebRtcSpl_MaxAbsValueW16(
+        &(audio_history[signal_length - fs_mult_lpc_analysis_len]),
+        fs_mult_lpc_analysis_len);
+
+    correlation_scale = std::min(16 - WebRtcSpl_NormW32(correlation_scale), 0);
+    correlation_scale = std::max(correlation_scale * 2 + 7, 0);
+
+    // Calculate kUnvoicedLpcOrder + 1 lags of the auto-correlation function.
+    size_t temp_index = signal_length - fs_mult_lpc_analysis_len -
+        kUnvoicedLpcOrder;
+    // Copy signal to temporary vector to be able to pad with leading zeros.
+    int16_t* temp_signal = new int16_t[fs_mult_lpc_analysis_len
+                                       + kUnvoicedLpcOrder];
+    memset(temp_signal, 0,
+           sizeof(int16_t) * (fs_mult_lpc_analysis_len + kUnvoicedLpcOrder));
+    memcpy(&temp_signal[kUnvoicedLpcOrder],
+           &audio_history[temp_index + kUnvoicedLpcOrder],
+           sizeof(int16_t) * fs_mult_lpc_analysis_len);
+    WebRtcSpl_CrossCorrelation(auto_correlation,
+                               &temp_signal[kUnvoicedLpcOrder],
+                               &temp_signal[kUnvoicedLpcOrder],
+                               fs_mult_lpc_analysis_len, kUnvoicedLpcOrder + 1,
+                               correlation_scale, -1);
+    delete [] temp_signal;
+
+    // Verify that variance is positive.
+    if (auto_correlation[0] > 0) {
+      // Estimate AR filter parameters using Levinson-Durbin algorithm;
+      // kUnvoicedLpcOrder + 1 filter coefficients.
+      int16_t stability = WebRtcSpl_LevinsonDurbin(auto_correlation,
+                                                   parameters.ar_filter,
+                                                   reflection_coeff,
+                                                   kUnvoicedLpcOrder);
+
+      // Keep filter parameters only if filter is stable.
+      if (stability != 1) {
+        // Set first coefficient to 4096 (1.0 in Q12).
+        parameters.ar_filter[0] = 4096;
+        // Set remaining |kUnvoicedLpcOrder| coefficients to zero.
+        WebRtcSpl_MemSetW16(parameters.ar_filter + 1, 0, kUnvoicedLpcOrder);
+      }
+    }
+
+    if (channel_ix == 0) {
+      // Extract a noise segment.
+      int16_t noise_length;
+      if (distortion_lag < 40) {
+        noise_length = 2 * distortion_lag + 30;
+      } else {
+        noise_length = distortion_lag + 30;
+      }
+      if (noise_length <= RandomVector::kRandomTableSize) {
+        memcpy(random_vector, RandomVector::kRandomTable,
+               sizeof(int16_t) * noise_length);
+      } else {
+        // Only applies to SWB where length could be larger than
+        // |kRandomTableSize|.
+        memcpy(random_vector, RandomVector::kRandomTable,
+               sizeof(int16_t) * RandomVector::kRandomTableSize);
+        assert(noise_length <= kMaxSampleRate / 8000 * 120 + 30);
+        random_vector_->IncreaseSeedIncrement(2);
+        random_vector_->Generate(
+            noise_length - RandomVector::kRandomTableSize,
+            &random_vector[RandomVector::kRandomTableSize]);
+      }
+    }
+
+    // Set up state vector and calculate scale factor for unvoiced filtering.
+    memcpy(parameters.ar_filter_state,
+           &(audio_history[signal_length - kUnvoicedLpcOrder]),
+           sizeof(int16_t) * kUnvoicedLpcOrder);
+    memcpy(unvoiced_vector - kUnvoicedLpcOrder,
+           &(audio_history[signal_length - 128 - kUnvoicedLpcOrder]),
+           sizeof(int16_t) * kUnvoicedLpcOrder);
+    WebRtcSpl_FilterMAFastQ12(
+        const_cast<int16_t*>(&audio_history[signal_length - 128]),
+        unvoiced_vector, parameters.ar_filter, kUnvoicedLpcOrder + 1, 128);
+    int16_t unvoiced_prescale;
+    if (WebRtcSpl_MaxAbsValueW16(unvoiced_vector, 128) > 4000) {
+      unvoiced_prescale = 4;
+    } else {
+      unvoiced_prescale = 0;
+    }
+    int32_t unvoiced_energy = WebRtcSpl_DotProductWithScale(unvoiced_vector,
+                                                            unvoiced_vector,
+                                                            128,
+                                                            unvoiced_prescale);
+
+    // Normalize |unvoiced_energy| to 28 or 29 bits to preserve sqrt() accuracy.
+    int16_t unvoiced_scale = WebRtcSpl_NormW32(unvoiced_energy) - 3;
+    // Make sure we do an odd number of shifts since we already have 7 shifts
+    // from dividing with 128 earlier. This will make the total scale factor
+    // even, which is suitable for the sqrt.
+    unvoiced_scale += ((unvoiced_scale & 0x1) ^ 0x1);
+    unvoiced_energy = WEBRTC_SPL_SHIFT_W32(unvoiced_energy, unvoiced_scale);
+    int32_t unvoiced_gain = WebRtcSpl_SqrtFloor(unvoiced_energy);
+    parameters.ar_gain_scale = 13
+        + (unvoiced_scale + 7 - unvoiced_prescale) / 2;
+    parameters.ar_gain = unvoiced_gain;
+
+    // Calculate voice_mix_factor from corr_coefficient.
+    // Let x = corr_coefficient. Then, we compute:
+    // if (x > 0.48)
+    //   voice_mix_factor = (-5179 + 19931x - 16422x^2 + 5776x^3) / 4096;
+    // else
+    //   voice_mix_factor = 0;
+    if (corr_coefficient > 7875) {
+      int16_t x1, x2, x3;
+      x1 = corr_coefficient;  // |corr_coefficient| is in Q14.
+      x2 = (x1 * x1) >> 14;   // Shift 14 to keep result in Q14.
+      x3 = (x1 * x2) >> 14;
+      static const int kCoefficients[4] = { -5179, 19931, -16422, 5776 };
+      int32_t temp_sum = kCoefficients[0] << 14;
+      temp_sum += kCoefficients[1] * x1;
+      temp_sum += kCoefficients[2] * x2;
+      temp_sum += kCoefficients[3] * x3;
+      parameters.voice_mix_factor = temp_sum / 4096;
+      parameters.voice_mix_factor = std::min(parameters.voice_mix_factor,
+                                             static_cast<int16_t>(16384));
+      parameters.voice_mix_factor = std::max(parameters.voice_mix_factor,
+                                             static_cast<int16_t>(0));
+    } else {
+      parameters.voice_mix_factor = 0;
+    }
+
+    // Calculate muting slope. Reuse value from earlier scaling of
+    // |expand_vector0| and |expand_vector1|.
+    int16_t slope = amplitude_ratio;
+    if (slope > 12288) {
+      // slope > 1.5.
+      // Calculate (1 - (1 / slope)) / distortion_lag =
+      // (slope - 1) / (distortion_lag * slope).
+      // |slope| is in Q13, so 1 corresponds to 8192. Shift up to Q25 before
+      // the division.
+      // Shift the denominator from Q13 to Q5 before the division. The result of
+      // the division will then be in Q20.
+      int16_t temp_ratio = WebRtcSpl_DivW32W16((slope - 8192) << 12,
+                                               (distortion_lag * slope) >> 8);
+      if (slope > 14746) {
+        // slope > 1.8.
+        // Divide by 2, with proper rounding.
+        parameters.mute_slope = (temp_ratio + 1) / 2;
+      } else {
+        // Divide by 8, with proper rounding.
+        parameters.mute_slope = (temp_ratio + 4) / 8;
+      }
+      parameters.onset = true;
+    } else {
+      // Calculate (1 - slope) / distortion_lag.
+      // Shift |slope| by 7 to Q20 before the division. The result is in Q20.
+      parameters.mute_slope = WebRtcSpl_DivW32W16((8192 - slope) << 7,
+                                                   distortion_lag);
+      if (parameters.voice_mix_factor <= 13107) {
+        // Make sure the mute factor decreases from 1.0 to 0.9 in no more than
+        // 6.25 ms.
+        // mute_slope >= 0.005 / fs_mult in Q20.
+        parameters.mute_slope = std::max(static_cast<int16_t>(5243 / fs_mult),
+                                         parameters.mute_slope);
+      } else if (slope > 8028) {
+        parameters.mute_slope = 0;
+      }
+      parameters.onset = false;
+    }
+  }
+}
+
+int16_t Expand::Correlation(const int16_t* input, int16_t input_length,
+                            int16_t* output, int16_t* output_scale) const {
+  // Set parameters depending on sample rate.
+  const int16_t* filter_coefficients;
+  int16_t num_coefficients;
+  int16_t downsampling_factor;
+  if (fs_hz_ == 8000) {
+    num_coefficients = 3;
+    downsampling_factor = 2;
+    filter_coefficients = DspHelper::kDownsample8kHzTbl;
+  } else if (fs_hz_ == 16000) {
+    num_coefficients = 5;
+    downsampling_factor = 4;
+    filter_coefficients = DspHelper::kDownsample16kHzTbl;
+  } else if (fs_hz_ == 32000) {
+    num_coefficients = 7;
+    downsampling_factor = 8;
+    filter_coefficients = DspHelper::kDownsample32kHzTbl;
+  } else {  // fs_hz_ == 48000.
+    num_coefficients = 7;
+    downsampling_factor = 12;
+    filter_coefficients = DspHelper::kDownsample48kHzTbl;
+  }
+
+  // Correlate from lag 10 to lag 60 in downsampled domain.
+  // (Corresponds to 20-120 for narrow-band, 40-240 for wide-band, and so on.)
+  static const int kCorrelationStartLag = 10;
+  static const int kNumCorrelationLags = 54;
+  static const int kCorrelationLength = 60;
+  // Downsample to 4 kHz sample rate.
+  static const int kDownsampledLength = kCorrelationStartLag
+      + kNumCorrelationLags + kCorrelationLength;
+  int16_t downsampled_input[kDownsampledLength];
+  static const int kFilterDelay = 0;
+  WebRtcSpl_DownsampleFast(
+      input + input_length - kDownsampledLength * downsampling_factor,
+      kDownsampledLength * downsampling_factor, downsampled_input,
+      kDownsampledLength, filter_coefficients, num_coefficients,
+      downsampling_factor, kFilterDelay);
+
+  // Normalize |downsampled_input| to using all 16 bits.
+  int16_t max_value = WebRtcSpl_MaxAbsValueW16(downsampled_input,
+                                               kDownsampledLength);
+  int16_t norm_shift = 16 - WebRtcSpl_NormW32(max_value);
+  WebRtcSpl_VectorBitShiftW16(downsampled_input, kDownsampledLength,
+                              downsampled_input, norm_shift);
+
+  int32_t correlation[kNumCorrelationLags];
+  static const int kCorrelationShift = 6;
+  WebRtcSpl_CrossCorrelation(
+      correlation,
+      &downsampled_input[kDownsampledLength - kCorrelationLength],
+      &downsampled_input[kDownsampledLength - kCorrelationLength
+          - kCorrelationStartLag],
+      kCorrelationLength, kNumCorrelationLags, kCorrelationShift, -1);
+
+  // Normalize and move data from 32-bit to 16-bit vector.
+  int32_t max_correlation = WebRtcSpl_MaxAbsValueW32(correlation,
+                                                     kNumCorrelationLags);
+  int16_t norm_shift2 = std::max(18 - WebRtcSpl_NormW32(max_correlation), 0);
+  WebRtcSpl_VectorBitShiftW32ToW16(output, kNumCorrelationLags, correlation,
+                                   norm_shift2);
+  // Total scale factor (right shifts) of correlation value.
+  *output_scale = 2 * norm_shift + kCorrelationShift + norm_shift2;
+  return kNumCorrelationLags;
+}
+
+void Expand::UpdateLagIndex() {
+  current_lag_index_ = current_lag_index_ + lag_index_direction_;
+  // Change direction if needed.
+  if (current_lag_index_ <= 0) {
+    lag_index_direction_ = 1;
+  }
+  if (current_lag_index_ >= kNumLags - 1) {
+    lag_index_direction_ = -1;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/expand.h b/webrtc/modules/audio_coding/neteq4/expand.h
new file mode 100644
index 0000000..3fc31f8
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/expand.h
@@ -0,0 +1,157 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_EXPAND_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_EXPAND_H_
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+class RandomVector;
+class SyncBuffer;
+
+// This class handles extrapolation of audio data from the sync_buffer to
+// produce packet-loss concealment.
+// TODO(hlundin): Refactor this class to divide the long methods into shorter
+// ones.
+class Expand {
+ public:
+  Expand(BackgroundNoise* background_noise,
+         SyncBuffer* sync_buffer,
+         RandomVector* random_vector,
+         int fs,
+         size_t num_channels)
+      : background_noise_(background_noise),
+        sync_buffer_(sync_buffer),
+        random_vector_(random_vector),
+        first_expand_(true),
+        fs_hz_(fs),
+        num_channels_(num_channels),
+        overlap_length_(5 * fs / 8000),
+        lag_index_direction_(0),
+        current_lag_index_(0),
+        stop_muting_(false),
+        channel_parameters_(new ChannelParameters[num_channels_]) {
+    assert(fs == 8000 || fs == 16000 || fs == 32000 || fs == 48000);
+    assert(fs <= kMaxSampleRate);  // Should not be possible.
+    assert(num_channels_ > 0);
+    memset(expand_lags_, 0, sizeof(expand_lags_));
+    Reset();
+  }
+
+  virtual ~Expand() {}
+
+  // Resets the object.
+  void Reset();
+
+  // The main method to produce concealment data. The data is appended to the
+  // end of |output|.
+  int Process(AudioMultiVector<int16_t>* output);
+
+  // Prepare the object to do extra expansion during normal operation following
+  // a period of expands.
+  void SetParametersForNormalAfterExpand();
+
+  // Prepare the object to do extra expansion during merge operation following
+  // a period of expands.
+  void SetParametersForMergeAfterExpand();
+
+  // Sets the mute factor for |channel| to |value|.
+  void SetMuteFactor(int16_t value, size_t channel) {
+    assert(channel < num_channels_);
+    channel_parameters_[channel].mute_factor = value;
+  }
+
+  // Returns the mute factor for |channel|.
+  int16_t MuteFactor(size_t channel) {
+    assert(channel < num_channels_);
+    return channel_parameters_[channel].mute_factor;
+  }
+
+  // Accessors and mutators.
+  size_t overlap_length() const { return overlap_length_; }
+  int16_t max_lag() const { return max_lag_; }
+
+ private:
+  static const int kUnvoicedLpcOrder = 6;
+  static const int kNumCorrelationCandidates = 3;
+  static const int kDistortionLength = 20;
+  static const int kLpcAnalysisLength = 160;
+  static const int kMaxSampleRate = 48000;
+  static const int kNumLags = 3;
+  static const int kMaxConsecutiveExpands = 200;
+
+  struct ChannelParameters {
+    // Constructor.
+    ChannelParameters()
+        : mute_factor(16384),
+          ar_gain(0),
+          ar_gain_scale(0),
+          voice_mix_factor(0),
+          current_voice_mix_factor(0),
+          onset(false),
+          mute_slope(0) {
+      memset(ar_filter, 0, sizeof(ar_filter));
+      memset(ar_filter_state, 0, sizeof(ar_filter_state));
+    }
+    int16_t mute_factor;
+    int16_t ar_filter[kUnvoicedLpcOrder + 1];
+    int16_t ar_filter_state[kUnvoicedLpcOrder];
+    int16_t ar_gain;
+    int16_t ar_gain_scale;
+    int16_t voice_mix_factor; /* Q14 */
+    int16_t current_voice_mix_factor; /* Q14 */
+    AudioVector<int16_t> expand_vector0;
+    AudioVector<int16_t> expand_vector1;
+    bool onset;
+    int16_t mute_slope; /* Q20 */
+  };
+
+  // Analyze the signal history in |sync_buffer_|, and set up all parameters
+  // necessary to produce concealment data.
+  void AnalyzeSignal(int16_t* random_vector);
+
+  // Calculate the auto-correlation of |input|, with length |input_length|
+  // samples. The correlation is calculated from a downsampled version of
+  // |input|, and is written to |output|. The scale factor is written to
+  // |output_scale|. Returns the length of the correlation vector.
+  int16_t Correlation(const int16_t* input, int16_t input_length,
+                      int16_t* output, int16_t* output_scale) const;
+
+  void UpdateLagIndex();
+
+  BackgroundNoise* background_noise_;
+  SyncBuffer* sync_buffer_;
+  RandomVector* random_vector_;
+  bool first_expand_;
+  int fs_hz_;
+  size_t num_channels_;
+  size_t overlap_length_;
+  int consecutive_expands_;
+  int16_t max_lag_;
+  size_t expand_lags_[kNumLags];
+  int lag_index_direction_;
+  int current_lag_index_;
+  bool stop_muting_;
+  scoped_array<ChannelParameters> channel_parameters_;
+
+  DISALLOW_COPY_AND_ASSIGN(Expand);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_EXPAND_H_
diff --git a/webrtc/modules/audio_coding/neteq4/expand_unittest.cc b/webrtc/modules/audio_coding/neteq4/expand_unittest.cc
new file mode 100644
index 0000000..a63ed14
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/expand_unittest.cc
@@ -0,0 +1,33 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for Expand class.
+
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+TEST(Expand, CreateAndDestroy) {
+  int fs = 8000;
+  size_t channels = 1;
+  BackgroundNoise bgn(channels);
+  SyncBuffer sync_buffer(1, 1000);
+  RandomVector random_vector;
+  Expand expand(&bgn, &sync_buffer, &random_vector, fs, channels);
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h b/webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h
new file mode 100644
index 0000000..0b23c76
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h
@@ -0,0 +1,144 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_INTERFACE_AUDIO_DECODER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_INTERFACE_AUDIO_DECODER_H_
+
+#include <stdlib.h>  // NULL
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+enum NetEqDecoder {
+  kDecoderPCMu,
+  kDecoderPCMa,
+  kDecoderPCMu_2ch,
+  kDecoderPCMa_2ch,
+  kDecoderILBC,
+  kDecoderISAC,
+  kDecoderISACswb,
+  kDecoderPCM16B,
+  kDecoderPCM16Bwb,
+  kDecoderPCM16Bswb32kHz,
+  kDecoderPCM16Bswb48kHz,
+  kDecoderPCM16B_2ch,
+  kDecoderPCM16Bwb_2ch,
+  kDecoderPCM16Bswb32kHz_2ch,
+  kDecoderPCM16Bswb48kHz_2ch,
+  kDecoderPCM16B_5ch,
+  kDecoderG722,
+  kDecoderG722_2ch,
+  kDecoderRED,
+  kDecoderAVT,
+  kDecoderCNGnb,
+  kDecoderCNGwb,
+  kDecoderCNGswb32kHz,
+  kDecoderCNGswb48kHz,
+  kDecoderArbitrary,
+  kDecoderOpus,
+  kDecoderOpus_2ch,
+  kDecoderCELT_32,
+  kDecoderCELT_32_2ch,
+};
+
+// This is the interface class for decoders in NetEQ. Each codec type will have
+// and implementation of this class.
+class AudioDecoder {
+ public:
+  enum SpeechType {
+    kSpeech = 1,
+    kComfortNoise = 2
+  };
+
+  // Used by PacketDuration below. Save the value -1 for errors.
+  enum { kNotImplemented = -2 };
+
+  explicit AudioDecoder(enum NetEqDecoder type)
+    : codec_type_(type),
+      channels_(1),
+      state_(NULL) {
+  }
+
+  virtual ~AudioDecoder() {}
+
+  // Decodes |encode_len| bytes from |encoded| and writes the result in
+  // |decoded|. The number of samples produced is in the return value. If the
+  // decoder produced comfort noise, |speech_type| is set to kComfortNoise,
+  // otherwise it is kSpeech.
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type) = 0;
+
+  // Same as Decode(), but interfaces to the decoders redundant decode function.
+  // The default implementation simply calls the regular Decode() method.
+  virtual int DecodeRedundant(const uint8_t* encoded, size_t encoded_len,
+                              int16_t* decoded, SpeechType* speech_type) {
+    return Decode(encoded, encoded_len, decoded, speech_type);
+  }
+
+  // Indicates if the decoder implements the DecodePlc method.
+  virtual bool HasDecodePlc() const { return false; }
+
+  // Calls the packet-loss concealment of the decoder to update the state after
+  // one or several lost packets.
+  virtual int DecodePlc(int num_frames, int16_t* decoded) { return -1; }
+
+  // Initializes the decoder.
+  virtual int Init() = 0;
+
+  // Notifies the decoder of an incoming packet to NetEQ.
+  virtual int IncomingPacket(const uint8_t* payload,
+                             size_t payload_len,
+                             uint16_t rtp_sequence_number,
+                             uint32_t rtp_timestamp,
+                             uint32_t arrival_timestamp) { return 0; }
+
+  // Returns the last error code from the decoder.
+  virtual int ErrorCode() { return 0; }
+
+  // Returns the duration in samples of the payload in |encoded| which is
+  // |encoded_len| bytes long. Returns kNotImplemented if no duration estimate
+  // is available, or -1 in case of an error.
+  virtual int PacketDuration(const uint8_t* encoded, size_t encoded_len) {
+    return kNotImplemented;
+  }
+
+  virtual NetEqDecoder codec_type() const { return codec_type_; }
+
+  // Returns the underlying decoder state.
+  void* state() { return state_; }
+
+  // Returns true if |codec_type| is supported.
+  static bool CodecSupported(NetEqDecoder codec_type);
+
+  // Returns the sample rate for |codec_type|.
+  static int CodecSampleRateHz(NetEqDecoder codec_type);
+
+  // Creates an AudioDecoder object of type |codec_type|. Returns NULL for
+  // for unsupported codecs, and when creating an AudioDecoder is not
+  // applicable (e.g., for RED and DTMF/AVT types).
+  static AudioDecoder* CreateAudioDecoder(NetEqDecoder codec_type);
+
+  size_t channels() { return channels_; }
+
+ protected:
+  static SpeechType ConvertSpeechType(int16_t type);
+
+  enum NetEqDecoder codec_type_;
+  size_t channels_;
+  void* state_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_INTERFACE_AUDIO_DECODER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/interface/neteq.h b/webrtc/modules/audio_coding/neteq4/interface/neteq.h
new file mode 100644
index 0000000..f9be8b4
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/interface/neteq.h
@@ -0,0 +1,227 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_INTERFACE_NETEQ_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_INTERFACE_NETEQ_H_
+
+#include <cstring>  // Provide access to size_t.
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+struct WebRtcRTPHeader;
+
+// RTCP statistics.
+struct RtcpStatistics {
+  uint16_t fraction_lost;
+  uint32_t cumulative_lost;
+  uint32_t extended_max;
+  uint32_t jitter;
+};
+
+struct NetEqNetworkStatistics {
+  uint16_t current_buffer_size_ms;  // Current jitter buffer size in ms.
+  uint16_t preferred_buffer_size_ms;  // Target buffer size in ms.
+  uint16_t jitter_peaks_found;  // 1 if adding extra delay due to peaky
+                                // jitter; 0 otherwise.
+  uint16_t packet_loss_rate;  // Loss rate (network + late) in Q14.
+  uint16_t packet_discard_rate;  // Late loss rate in Q14.
+  uint16_t expand_rate;  // Fraction (of original stream) of synthesized
+                         // speech inserted through expansion (in Q14).
+  uint16_t preemptive_rate;  // Fraction of data inserted through pre-emptive
+                             // expansion (in Q14).
+  uint16_t accelerate_rate;  // Fraction of data removed through acceleration
+                             // (in Q14).
+  int32_t clockdrift_ppm;  // Average clock-drift in parts-per-million
+                           // (positive or negative).
+  int added_zero_samples;  // Number of zero samples added in "off" mode.
+};
+
+enum NetEqOutputType {
+  kOutputNormal,
+  kOutputPLC,
+  kOutputCNG,
+  kOutputPLCtoCNG,
+  kOutputVADPassive
+};
+
+enum NetEqPlayoutMode {
+  kPlayoutOn,
+  kPlayoutOff,
+  kPlayoutFax,
+  kPlayoutStreaming
+};
+
+// This is the interface class for NetEq.
+class NetEq {
+ public:
+  enum ReturnCodes {
+    kOK = 0,
+    kFail = -1,
+    kNotImplemented = -2
+  };
+
+  enum ErrorCodes {
+    kNoError = 0,
+    kOtherError,
+    kInvalidRtpPayloadType,
+    kUnknownRtpPayloadType,
+    kCodecNotSupported,
+    kDecoderExists,
+    kDecoderNotFound,
+    kInvalidSampleRate,
+    kInvalidPointer,
+    kAccelerateError,
+    kPreemptiveExpandError,
+    kComfortNoiseErrorCode,
+    kDecoderErrorCode,
+    kOtherDecoderError,
+    kInvalidOperation,
+    kDtmfParameterError,
+    kDtmfParsingError,
+    kDtmfInsertError,
+    kStereoNotSupported,
+    kSampleUnderrun,
+    kDecodedTooMuch,
+    kFrameSplitError,
+    kRedundancySplitError,
+    kPacketBufferCorruption
+  };
+
+  static const int kMaxNumPacketsInBuffer = 240;  // TODO(hlundin): Remove.
+  static const int kMaxBytesInBuffer = 113280;  // TODO(hlundin): Remove.
+
+  // Creates a new NetEq object, starting at the sample rate |sample_rate_hz|.
+  // (Note that it will still change the sample rate depending on what payloads
+  // are being inserted; |sample_rate_hz| is just for startup configuration.)
+  static NetEq* Create(int sample_rate_hz);
+
+  virtual ~NetEq() {}
+
+  // Inserts a new packet into NetEq. The |receive_timestamp| is an indication
+  // of the time when the packet was received, and should be measured with
+  // the same tick rate as the RTP timestamp of the current payload.
+  // Returns 0 on success, -1 on failure.
+  virtual int InsertPacket(const WebRtcRTPHeader& rtp_header,
+                           const uint8_t* payload,
+                           int length_bytes,
+                           uint32_t receive_timestamp) = 0;
+
+  // Instructs NetEq to deliver 10 ms of audio data. The data is written to
+  // |output_audio|, which can hold (at least) |max_length| elements.
+  // The number of channels that were written to the output is provided in
+  // the output variable |num_channels|, and each channel contains
+  // |samples_per_channel| elements. If more than one channel is written,
+  // the samples are interleaved.
+  // The speech type is written to |type|, if |type| is not NULL.
+  // Returns kOK on success, or kFail in case of an error.
+  virtual int GetAudio(size_t max_length, int16_t* output_audio,
+                       int* samples_per_channel, int* num_channels,
+                       NetEqOutputType* type) = 0;
+
+  // Associates |rtp_payload_type| with |codec| and stores the information in
+  // the codec database. Returns 0 on success, -1 on failure.
+  virtual int RegisterPayloadType(enum NetEqDecoder codec,
+                                  uint8_t rtp_payload_type) = 0;
+
+  // Provides an externally created decoder object |decoder| to insert in the
+  // decoder database. The decoder implements a decoder of type |codec| and
+  // associates it with |rtp_payload_type|. The decoder operates at the
+  // frequency |sample_rate_hz|. Returns kOK on success, kFail on failure.
+  virtual int RegisterExternalDecoder(AudioDecoder* decoder,
+                                      enum NetEqDecoder codec,
+                                      int sample_rate_hz,
+                                      uint8_t rtp_payload_type) = 0;
+
+  // Removes |rtp_payload_type| from the codec database. Returns 0 on success,
+  // -1 on failure.
+  virtual int RemovePayloadType(uint8_t rtp_payload_type) = 0;
+
+  // Sets the desired extra delay on top of what NetEq already applies due to
+  // current network situation. Used for synchronization with video. Returns
+  // true if successful, otherwise false.
+  virtual bool SetExtraDelay(int extra_delay_ms) = 0;
+
+  // Not implemented.
+  virtual int SetTargetDelay() = 0;
+
+  // Not implemented.
+  virtual int TargetDelay() = 0;
+
+  // Not implemented.
+  virtual int CurrentDelay() = 0;
+
+  // Enables playout of DTMF tones.
+  virtual int EnableDtmf() = 0;
+
+  // Sets the playout mode to |mode|.
+  virtual void SetPlayoutMode(NetEqPlayoutMode mode) = 0;
+
+  // Returns the current playout mode.
+  virtual NetEqPlayoutMode PlayoutMode() const = 0;
+
+  // Writes the current network statistics to |stats|. The statistics are reset
+  // after the call.
+  virtual int NetworkStatistics(NetEqNetworkStatistics* stats) = 0;
+
+  // Writes the last packet waiting times (in ms) to |waiting_times|. The number
+  // of values written is no more than 100, but may be smaller if the interface
+  // is polled again before 100 packets has arrived.
+  virtual void WaitingTimes(std::vector<int>* waiting_times) = 0;
+
+  // Writes the current RTCP statistics to |stats|. The statistics are reset
+  // and a new report period is started with the call.
+  virtual void GetRtcpStatistics(RtcpStatistics* stats) = 0;
+
+  // Same as RtcpStatistics(), but does not reset anything.
+  virtual void GetRtcpStatisticsNoReset(RtcpStatistics* stats) = 0;
+
+  // Enables post-decode VAD. When enabled, GetAudio() will return
+  // kOutputVADPassive when the signal contains no speech.
+  virtual void EnableVad() = 0;
+
+  // Disables post-decode VAD.
+  virtual void DisableVad() = 0;
+
+  // Returns the RTP timestamp for the last sample delivered by GetAudio().
+  virtual uint32_t PlayoutTimestamp() = 0;
+
+  // Not implemented.
+  virtual int SetTargetNumberOfChannels() = 0;
+
+  // Not implemented.
+  virtual int SetTargetSampleRate() = 0;
+
+  // Returns the error code for the last occurred error. If no error has
+  // occurred, 0 is returned.
+  virtual int LastError() = 0;
+
+  // Returns the error code last returned by a decoder (audio or comfort noise).
+  // When LastError() returns kDecoderErrorCode or kComfortNoiseErrorCode, check
+  // this method to get the decoder's error code.
+  virtual int LastDecoderError() = 0;
+
+  // Flushes both the packet buffer and the sync buffer.
+  virtual void FlushBuffers() = 0;
+
+ protected:
+  NetEq() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(NetEq);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_INTERFACE_NETEQ_H_
diff --git a/webrtc/modules/audio_coding/neteq4/merge.cc b/webrtc/modules/audio_coding/neteq4/merge.cc
new file mode 100644
index 0000000..5c081fe
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/merge.cc
@@ -0,0 +1,361 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/merge.h"
+
+#include <assert.h>
+
+#include <algorithm>  // min, max
+#include <cstring>  // memmove, memcpy, memset, size_t
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+int Merge::Process(int16_t* input, int input_length,
+                   int16_t* external_mute_factor_array,
+                   AudioMultiVector<int16_t>* output) {
+  // TODO(hlundin): Change to an enumerator and skip assert.
+  assert(fs_hz_ == 8000 || fs_hz_ == 16000 || fs_hz_ ==  32000 ||
+         fs_hz_ == 48000);
+  assert(fs_hz_ <= kMaxSampleRate);  // Should not be possible.
+
+  int old_length;
+  int expand_period;
+  // Get expansion data to overlap and mix with.
+  int expanded_length = GetExpandedSignal(&old_length, &expand_period);
+
+  // Transfer input signal to an AudioMultiVector.
+  AudioMultiVector<int16_t> input_vector(num_channels_);
+  input_vector.PushBackInterleaved(input, input_length);
+  size_t input_length_per_channel = input_vector.Size();
+  assert(input_length_per_channel == input_length / num_channels_);
+
+  int16_t best_correlation_index = 0;
+  size_t output_length = 0;
+
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    int16_t* input_channel = &input_vector[channel][0];
+    int16_t* expanded_channel = &expanded_[channel][0];
+    int16_t expanded_max, input_max;
+    int16_t new_mute_factor = SignalScaling(input_channel,
+                                            input_length_per_channel,
+                                            expanded_channel, &expanded_max,
+                                            &input_max);
+
+    // Adjust muting factor (product of "main" muting factor and expand muting
+    // factor).
+    int16_t* external_mute_factor = &external_mute_factor_array[channel];
+    *external_mute_factor =
+        (*external_mute_factor * expand_->MuteFactor(channel)) >> 14;
+
+    // Update |external_mute_factor| if it is lower than |new_mute_factor|.
+    if (new_mute_factor > *external_mute_factor) {
+      *external_mute_factor = std::min(new_mute_factor,
+                                       static_cast<int16_t>(16384));
+    }
+
+    if (channel == 0) {
+      // Downsample, correlate, and find strongest correlation period for the
+      // master (i.e., first) channel only.
+      // Downsample to 4kHz sample rate.
+      Downsample(input_channel, input_length_per_channel, expanded_channel,
+                 expanded_length);
+
+      // Calculate the lag of the strongest correlation period.
+      best_correlation_index = CorrelateAndPeakSearch(expanded_max,
+                                                      input_max,
+                                                      old_length,
+                                                      input_length_per_channel,
+                                                      expand_period);
+    }
+
+    static const int kTempDataSize = 3600;
+    int16_t temp_data[kTempDataSize];  // TODO(hlundin) Remove this.
+    int16_t* decoded_output = temp_data + best_correlation_index;
+
+    // Mute the new decoded data if needed (and unmute it linearly).
+    // This is the overlapping part of expanded_signal.
+    int interpolation_length = std::min(
+        kMaxCorrelationLength * fs_mult_,
+        expanded_length - best_correlation_index);
+    interpolation_length = std::min(interpolation_length,
+                                    static_cast<int>(input_length_per_channel));
+    if (*external_mute_factor < 16384) {
+      // Set a suitable muting slope (Q20). 0.004 for NB, 0.002 for WB,
+      // and so on.
+      int increment = 4194 / fs_mult_;
+      *external_mute_factor = DspHelper::RampSignal(input_channel,
+                                                    interpolation_length,
+                                                    *external_mute_factor,
+                                                    increment);
+      DspHelper::UnmuteSignal(&input_channel[interpolation_length],
+                              input_length_per_channel - interpolation_length,
+                              external_mute_factor, increment,
+                              &decoded_output[interpolation_length]);
+    } else {
+      // No muting needed.
+      memmove(
+          &decoded_output[interpolation_length],
+          &input_channel[interpolation_length],
+          sizeof(int16_t) * (input_length_per_channel - interpolation_length));
+    }
+
+    // Do overlap and mix linearly.
+    int increment = 16384 / (interpolation_length + 1);  // In Q14.
+    int16_t mute_factor = 16384 - increment;
+    memmove(temp_data, expanded_channel,
+            sizeof(int16_t) * best_correlation_index);
+    DspHelper::CrossFade(&expanded_channel[best_correlation_index],
+                         input_channel, interpolation_length,
+                         &mute_factor, increment, decoded_output);
+
+    output_length = best_correlation_index + input_length_per_channel;
+    if (channel == 0) {
+      assert(output->Empty());  // Output should be empty at this point.
+      output->AssertSize(output_length);
+    } else {
+      assert(output->Size() == output_length);
+    }
+    memcpy(&(*output)[channel][0], temp_data,
+           sizeof(temp_data[0]) * output_length);
+  }
+
+  // Copy back the first part of the data to |sync_buffer_| and remove it from
+  // |output|.
+  sync_buffer_->ReplaceAtIndex(*output, old_length, sync_buffer_->next_index());
+  output->PopFront(old_length);
+
+  // Return new added length. |old_length| samples were borrowed from
+  // |sync_buffer_|.
+  return output_length - old_length;
+}
+
+int Merge::GetExpandedSignal(int* old_length, int* expand_period) {
+  // Check how much data that is left since earlier.
+  *old_length = sync_buffer_->FutureLength();
+  // Should never be less than overlap_length.
+  assert(*old_length >= static_cast<int>(expand_->overlap_length()));
+  // Generate data to merge the overlap with using expand.
+  expand_->SetParametersForMergeAfterExpand();
+
+  if (*old_length >= 210 * kMaxSampleRate / 8000) {
+    // TODO(hlundin): Write test case for this.
+    // The number of samples available in the sync buffer is more than what fits
+    // in expanded_signal. Keep the first 210 * kMaxSampleRate / 8000 samples,
+    // but shift them towards the end of the buffer. This is ok, since all of
+    // the buffer will be expand data anyway, so as long as the beginning is
+    // left untouched, we're fine.
+    int16_t length_diff = *old_length - 210 * kMaxSampleRate / 8000;
+    sync_buffer_->InsertZerosAtIndex(length_diff, sync_buffer_->next_index());
+    *old_length = 210 * kMaxSampleRate / 8000;
+    // This is the truncated length.
+  }
+  // This assert should always be true thanks to the if statement above.
+  assert(210 * kMaxSampleRate / 8000 - *old_length >= 0);
+
+  AudioMultiVector<int16_t> expanded_temp(num_channels_);
+  expand_->Process(&expanded_temp);
+  *expand_period = expanded_temp.Size();  // Samples per channel.
+
+  expanded_.Clear();
+  // Copy what is left since earlier into the expanded vector.
+  expanded_.PushBackFromIndex(*sync_buffer_, sync_buffer_->next_index());
+  assert(expanded_.Size() == static_cast<size_t>(*old_length));
+  assert(expanded_temp.Size() > 0);
+  // Do "ugly" copy and paste from the expanded in order to generate more data
+  // to correlate (but not interpolate) with.
+  const int required_length = (120 + 80 + 2) * fs_mult_;
+  if (expanded_.Size() < static_cast<size_t>(required_length)) {
+    while (expanded_.Size() < static_cast<size_t>(required_length)) {
+      // Append one more pitch period each time.
+      expanded_.PushBack(expanded_temp);
+    }
+    // Trim the length to exactly |required_length|.
+    expanded_.PopBack(expanded_.Size() - required_length);
+  }
+  assert(expanded_.Size() >= static_cast<size_t>(required_length));
+  return required_length;
+}
+
+int16_t Merge::SignalScaling(const int16_t* input, int input_length,
+                             const int16_t* expanded_signal,
+                             int16_t* expanded_max, int16_t* input_max) const {
+  // Adjust muting factor if new vector is more or less of the BGN energy.
+  const int mod_input_length = std::min(64 * fs_mult_, input_length);
+  *expanded_max = WebRtcSpl_MaxAbsValueW16(expanded_signal, mod_input_length);
+  *input_max = WebRtcSpl_MaxAbsValueW16(input, mod_input_length);
+
+  // Calculate energy of expanded signal.
+  // |log_fs_mult| is log2(fs_mult_), but is not exact for 48000 Hz.
+  int log_fs_mult = 30 - WebRtcSpl_NormW32(fs_mult_);
+  int expanded_shift = 6 + log_fs_mult
+      - WebRtcSpl_NormW32(*expanded_max * *expanded_max);
+  expanded_shift = std::max(expanded_shift, 0);
+  int32_t energy_expanded = WebRtcSpl_DotProductWithScale(expanded_signal,
+                                                          expanded_signal,
+                                                          mod_input_length,
+                                                          expanded_shift);
+
+  // Calculate energy of input signal.
+  int input_shift = 6 + log_fs_mult -
+      WebRtcSpl_NormW32(*input_max * *input_max);
+  input_shift = std::max(input_shift, 0);
+  int32_t energy_input = WebRtcSpl_DotProductWithScale(input, input,
+                                                       mod_input_length,
+                                                       input_shift);
+
+  // Align to the same Q-domain.
+  if (input_shift > expanded_shift) {
+    energy_expanded = energy_expanded >> (input_shift - expanded_shift);
+  } else {
+    energy_input = energy_input >> (expanded_shift - input_shift);
+  }
+
+  // Calculate muting factor to use for new frame.
+  int16_t mute_factor;
+  if (energy_input > energy_expanded) {
+    // Normalize |energy_input| to 14 bits.
+    int16_t temp_shift = WebRtcSpl_NormW32(energy_input) - 17;
+    energy_input = WEBRTC_SPL_SHIFT_W32(energy_input, temp_shift);
+    // Put |energy_expanded| in a domain 14 higher, so that
+    // energy_expanded / energy_input is in Q14.
+    energy_expanded = WEBRTC_SPL_SHIFT_W32(energy_expanded, temp_shift + 14);
+    // Calculate sqrt(energy_expanded / energy_input) in Q14.
+    mute_factor = WebRtcSpl_SqrtFloor((energy_expanded / energy_input) << 14);
+  } else {
+    // Set to 1 (in Q14) when |expanded| has higher energy than |input|.
+    mute_factor = 16384;
+  }
+
+  return mute_factor;
+}
+
+// TODO(hlundin): There are some parameter values in this method that seem
+// strange. Compare with Expand::Correlation.
+void Merge::Downsample(const int16_t* input, int input_length,
+                       const int16_t* expanded_signal, int expanded_length) {
+  const int16_t* filter_coefficients;
+  int num_coefficients;
+  int decimation_factor = fs_hz_ / 4000;
+  static const int kCompensateDelay = 0;
+  int length_limit = fs_hz_ / 100;
+  if (fs_hz_ == 8000) {
+    filter_coefficients = DspHelper::kDownsample8kHzTbl;
+    num_coefficients = 3;
+  } else if (fs_hz_ == 16000) {
+    filter_coefficients = DspHelper::kDownsample16kHzTbl;
+    num_coefficients = 5;
+  } else if (fs_hz_ == 32000) {
+    filter_coefficients = DspHelper::kDownsample32kHzTbl;
+    num_coefficients = 7;
+  } else {  // fs_hz_ == 48000
+    filter_coefficients = DspHelper::kDownsample48kHzTbl;
+    num_coefficients = 7;
+    // TODO(hlundin) Why is |length_limit| not 480 (legacy)?
+    length_limit = 320;
+  }
+  int signal_offset = num_coefficients - 1;
+  WebRtcSpl_DownsampleFast(&expanded_signal[signal_offset],
+                           expanded_length - signal_offset,
+                           expanded_downsampled_, kExpandDownsampLength,
+                           filter_coefficients, num_coefficients,
+                           decimation_factor, kCompensateDelay);
+  if (input_length <= length_limit) {
+    // Not quite long enough, so we have to cheat a bit.
+    int16_t temp_len = input_length - signal_offset;
+    // TODO(hlundin): Should |downsamp_temp_len| be corrected for round-off
+    // errors? I.e., (temp_len + decimation_factor - 1) / decimation_factor?
+    int16_t downsamp_temp_len = temp_len / decimation_factor;
+    WebRtcSpl_DownsampleFast(&input[signal_offset], temp_len,
+                             input_downsampled_, downsamp_temp_len,
+                             filter_coefficients, num_coefficients,
+                             decimation_factor, kCompensateDelay);
+    memset(&input_downsampled_[downsamp_temp_len], 0,
+           sizeof(int16_t) * (kInputDownsampLength - downsamp_temp_len));
+  } else {
+    WebRtcSpl_DownsampleFast(&input[signal_offset],
+                             input_length - signal_offset, input_downsampled_,
+                             kInputDownsampLength, filter_coefficients,
+                             num_coefficients, decimation_factor,
+                             kCompensateDelay);
+  }
+}
+
+int16_t Merge::CorrelateAndPeakSearch(int16_t expanded_max, int16_t input_max,
+                                      int start_position, int input_length,
+                                      int expand_period) const {
+  // Calculate correlation without any normalization.
+  const int max_corr_length = kMaxCorrelationLength;
+  int stop_position_downsamp = std::min(
+      max_corr_length, expand_->max_lag() / (fs_mult_ * 2) + 1);
+  int16_t correlation_shift = 0;
+  if (expanded_max * input_max > 26843546) {
+    correlation_shift = 3;
+  }
+
+  int32_t correlation[kMaxCorrelationLength];
+  WebRtcSpl_CrossCorrelation(correlation, input_downsampled_,
+                             expanded_downsampled_, kInputDownsampLength,
+                             stop_position_downsamp, correlation_shift, 1);
+
+  // Normalize correlation to 14 bits and copy to a 16-bit array.
+  static const int kPadLength = 4;
+  int16_t correlation16[kPadLength + kMaxCorrelationLength + kPadLength] = {0};
+  int16_t* correlation_ptr = &correlation16[kPadLength];
+  int32_t max_correlation = WebRtcSpl_MaxAbsValueW32(correlation,
+                                                     stop_position_downsamp);
+  int16_t norm_shift = std::max(0, 17 - WebRtcSpl_NormW32(max_correlation));
+  WebRtcSpl_VectorBitShiftW32ToW16(correlation_ptr, stop_position_downsamp,
+                                   correlation, norm_shift);
+
+  // Calculate allowed starting point for peak finding.
+  // The peak location bestIndex must fulfill two criteria:
+  // (1) w16_bestIndex + input_length <
+  //     timestamps_per_call_ + expand_->overlap_length();
+  // (2) w16_bestIndex + input_length < start_position.
+  int start_index = timestamps_per_call_ + expand_->overlap_length();
+  start_index = std::max(start_position, start_index);
+  start_index = std::max(start_index - input_length, 0);
+  // Downscale starting index to 4kHz domain. (fs_mult_ * 2 = fs_hz_ / 4000.)
+  int start_index_downsamp = start_index / (fs_mult_ * 2);
+
+  // Calculate a modified |stop_position_downsamp| to account for the increased
+  // start index |start_index_downsamp| and the effective array length.
+  int16_t modified_stop_pos =
+      std::min(stop_position_downsamp,
+               kMaxCorrelationLength + kPadLength - start_index_downsamp);
+  int best_correlation_index;
+  int16_t best_correlation;
+  static const int kNumCorrelationCandidates = 1;
+  DspHelper::PeakDetection(&correlation_ptr[start_index_downsamp],
+                           modified_stop_pos, kNumCorrelationCandidates,
+                           fs_mult_, &best_correlation_index,
+                           &best_correlation);
+  // Compensate for modified start index.
+  best_correlation_index += start_index;
+
+  // Ensure that underrun does not occur for 10ms case => we have to get at
+  // least 10ms + overlap . (This should never happen thanks to the above
+  // modification of peak-finding starting point.)
+  while ((best_correlation_index + input_length) <
+      static_cast<int>(timestamps_per_call_ + expand_->overlap_length()) ||
+      best_correlation_index + input_length < start_position) {
+    assert(false);  // Should never happen.
+    best_correlation_index += expand_period;  // Jump one lag ahead.
+  }
+  return best_correlation_index;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/merge.h b/webrtc/modules/audio_coding/neteq4/merge.h
new file mode 100644
index 0000000..fdb9a16
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/merge.h
@@ -0,0 +1,104 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MERGE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MERGE_H_
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class Expand;
+class SyncBuffer;
+
+// This class handles the transition from expansion to normal operation.
+// When a packet is not available for decoding when needed, the expand operation
+// is called to generate extrapolation data. If the missing packet arrives,
+// i.e., it was just delayed, it can be decoded and appended directly to the
+// end of the expanded data (thanks to how the Expand class operates). However,
+// if a later packet arrives instead, the loss is a fact, and the new data must
+// be stitched together with the end of the expanded data. This stitching is
+// what the Merge class does.
+class Merge {
+ public:
+  Merge(int fs_hz, size_t num_channels, Expand* expand, SyncBuffer* sync_buffer)
+      : fs_hz_(fs_hz),
+        fs_mult_(fs_hz_ / 8000),
+        num_channels_(num_channels),
+        timestamps_per_call_(fs_hz_ / 100),
+        expand_(expand),
+        sync_buffer_(sync_buffer),
+        expanded_(num_channels_) {
+    assert(num_channels_ > 0);
+  }
+
+  // The main method to produce the audio data. The decoded data is supplied in
+  // |input|, having |input_length| samples in total for all channels
+  // (interleaved). The result is written to |output|. The number of channels
+  // allocated in |output| defines the number of channels that will be used when
+  // de-interleaving |input|. The values in |external_mute_factor_array| (Q14)
+  // will be used to scale the audio, and is updated in the process. The array
+  // must have |num_channels_| elements.
+  int Process(int16_t* input, int input_length,
+              int16_t* external_mute_factor_array,
+              AudioMultiVector<int16_t>* output);
+
+ private:
+  static const int kMaxSampleRate = 48000;
+  static const int kExpandDownsampLength = 100;
+  static const int kInputDownsampLength = 40;
+  static const int kMaxCorrelationLength = 60;
+
+  // Calls |expand_| to get more expansion data to merge with. The data is
+  // written to |expanded_signal_|. Returns the length of the expanded data,
+  // while |expand_period| will be the number of samples in one expansion period
+  // (typically one pitch period). The value of |old_length| will be the number
+  // of samples that were taken from the |sync_buffer_|.
+  int GetExpandedSignal(int* old_length, int* expand_period);
+
+  // Analyzes |input| and |expanded_signal| to find maximum values. Returns
+  // a muting factor (Q14) to be used on the new data.
+  int16_t SignalScaling(const int16_t* input, int input_length,
+                        const int16_t* expanded_signal,
+                        int16_t* expanded_max, int16_t* input_max) const;
+
+  // Downsamples |input| (|input_length| samples) and |expanded_signal| to
+  // 4 kHz sample rate. The downsampled signals are written to
+  // |input_downsampled_| and |expanded_downsampled_|, respectively.
+  void Downsample(const int16_t* input, int input_length,
+                  const int16_t* expanded_signal, int expanded_length);
+
+  // Calculates cross-correlation between |input_downsampled_| and
+  // |expanded_downsampled_|, and finds the correlation maximum. The maximizing
+  // lag is returned.
+  int16_t CorrelateAndPeakSearch(int16_t expanded_max, int16_t input_max,
+                                 int start_position, int input_length,
+                                 int expand_period) const;
+
+  const int fs_hz_;
+  const int fs_mult_;  // fs_hz_ / 8000.
+  const size_t num_channels_;
+  const int timestamps_per_call_;
+  Expand* expand_;
+  SyncBuffer* sync_buffer_;
+  int16_t expanded_downsampled_[kExpandDownsampLength];
+  int16_t input_downsampled_[kInputDownsampLength];
+  AudioMultiVector<int16_t> expanded_;
+
+  DISALLOW_COPY_AND_ASSIGN(Merge);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MERGE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/merge_unittest.cc b/webrtc/modules/audio_coding/neteq4/merge_unittest.cc
new file mode 100644
index 0000000..1d7b1f1
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/merge_unittest.cc
@@ -0,0 +1,37 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for Merge class.
+
+#include "webrtc/modules/audio_coding/neteq4/merge.h"
+
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+TEST(Merge, CreateAndDestroy) {
+  int fs = 8000;
+  size_t channels = 1;
+  BackgroundNoise bgn(channels);
+  SyncBuffer sync_buffer(1, 1000);
+  RandomVector random_vector;
+  Expand expand(&bgn, &sync_buffer, &random_vector, fs, channels);
+  Merge merge(fs, channels, &expand, &sync_buffer);
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_audio_decoder.h b/webrtc/modules/audio_coding/neteq4/mock/mock_audio_decoder.h
new file mode 100644
index 0000000..a6d5874
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_audio_decoder.h
@@ -0,0 +1,38 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_AUDIO_DECODER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_AUDIO_DECODER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockAudioDecoder : public AudioDecoder {
+ public:
+  MockAudioDecoder() : AudioDecoder(kDecoderArbitrary) {}
+  virtual ~MockAudioDecoder() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_METHOD4(Decode, int(const uint8_t*, size_t, int16_t*,
+                           AudioDecoder::SpeechType*));
+  MOCK_CONST_METHOD0(HasDecodePlc, bool());
+  MOCK_METHOD2(DecodePlc, int(int, int16_t*));
+  MOCK_METHOD0(Init, int());
+  MOCK_METHOD5(IncomingPacket, int(const uint8_t*, size_t, uint16_t, uint32_t,
+                                   uint32_t));
+  MOCK_METHOD0(ErrorCode, int());
+  MOCK_CONST_METHOD0(codec_type, NetEqDecoder());
+  MOCK_METHOD1(CodecSupported, bool(NetEqDecoder));
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_AUDIO_DECODER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_audio_vector.h b/webrtc/modules/audio_coding/neteq4/mock/mock_audio_vector.h
new file mode 100644
index 0000000..7a4747b
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_audio_vector.h
@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_AUDIO_VECTOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_AUDIO_VECTOR_H_
+
+#include "webrtc/modules/audio_coding/neteq4/audio_vector.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockAudioVector : public AudioVector {
+ public:
+  MOCK_METHOD0(Clear,
+      void());
+  MOCK_CONST_METHOD1(CopyFrom,
+      void(AudioVector<T>* copy_to));
+  MOCK_METHOD1(PushFront,
+      void(const AudioVector<T>& prepend_this));
+  MOCK_METHOD2(PushFront,
+      void(const T* prepend_this, size_t length));
+  MOCK_METHOD1(PushBack,
+      void(const AudioVector<T>& append_this));
+  MOCK_METHOD2(PushBack,
+      void(const T* append_this, size_t length));
+  MOCK_METHOD1(PopFront,
+      void(size_t length));
+  MOCK_METHOD1(PopBack,
+      void(size_t length));
+  MOCK_METHOD1(Extend,
+      void(size_t extra_length));
+  MOCK_METHOD3(InsertAt,
+      void(const T* insert_this, size_t length, size_t position));
+  MOCK_METHOD3(OverwriteAt,
+      void(const T* insert_this, size_t length, size_t position));
+  MOCK_CONST_METHOD0(Size,
+      size_t());
+  MOCK_CONST_METHOD0(Empty,
+      bool());
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_AUDIO_VECTOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_buffer_level_filter.h b/webrtc/modules/audio_coding/neteq4/mock/mock_buffer_level_filter.h
new file mode 100644
index 0000000..8726551
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_buffer_level_filter.h
@@ -0,0 +1,37 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_BUFFER_LEVEL_FILTER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_BUFFER_LEVEL_FILTER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockBufferLevelFilter : public BufferLevelFilter {
+ public:
+  virtual ~MockBufferLevelFilter() { Die(); }
+  MOCK_METHOD0(Die,
+      void());
+  MOCK_METHOD0(Reset,
+      void());
+  MOCK_METHOD3(Update,
+      void(int buffer_size_packets, int time_stretched_samples,
+           int packet_len_samples));
+  MOCK_METHOD1(SetTargetBufferLevel,
+      void(int target_buffer_level));
+  MOCK_CONST_METHOD0(filtered_current_level,
+      int());
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_BUFFER_LEVEL_FILTER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h b/webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h
new file mode 100644
index 0000000..c4ca25a
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h
@@ -0,0 +1,64 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DECODER_DATABASE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DECODER_DATABASE_H_
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockDecoderDatabase : public DecoderDatabase {
+ public:
+  virtual ~MockDecoderDatabase() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_CONST_METHOD0(Empty,
+      bool());
+  MOCK_CONST_METHOD0(Size,
+      int());
+  MOCK_METHOD0(Reset,
+      void());
+  MOCK_METHOD2(RegisterPayload,
+      int(uint8_t rtp_payload_type, NetEqDecoder codec_type));
+  MOCK_METHOD4(InsertExternal,
+      int(uint8_t rtp_payload_type, NetEqDecoder codec_type, int fs_hz,
+          AudioDecoder* decoder));
+  MOCK_METHOD1(Remove,
+      int(uint8_t rtp_payload_type));
+  MOCK_CONST_METHOD1(GetDecoderInfo,
+      const DecoderInfo*(uint8_t rtp_payload_type));
+  MOCK_CONST_METHOD1(GetRtpPayloadType,
+      uint8_t(NetEqDecoder codec_type));
+  MOCK_METHOD1(GetDecoder,
+      AudioDecoder*(uint8_t rtp_payload_type));
+  MOCK_CONST_METHOD2(IsType,
+      bool(uint8_t rtp_payload_type, NetEqDecoder codec_type));
+  MOCK_CONST_METHOD1(IsComfortNoise,
+      bool(uint8_t rtp_payload_type));
+  MOCK_CONST_METHOD1(IsDtmf,
+      bool(uint8_t rtp_payload_type));
+  MOCK_CONST_METHOD1(IsRed,
+      bool(uint8_t rtp_payload_type));
+  MOCK_METHOD2(SetActiveDecoder,
+      int(uint8_t rtp_payload_type, bool* new_decoder));
+  MOCK_METHOD0(GetActiveDecoder,
+      AudioDecoder*());
+  MOCK_METHOD1(SetActiveCngDecoder,
+      int(uint8_t rtp_payload_type));
+  MOCK_METHOD0(GetActiveCngDecoder,
+      AudioDecoder*());
+  MOCK_CONST_METHOD1(CheckPayloadTypes,
+      int(const PacketList& packet_list));
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DECODER_DATABASE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_delay_manager.h b/webrtc/modules/audio_coding/neteq4/mock/mock_delay_manager.h
new file mode 100644
index 0000000..1edfb87
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_delay_manager.h
@@ -0,0 +1,63 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DELAY_MANAGER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DELAY_MANAGER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockDelayManager : public DelayManager {
+ public:
+  MockDelayManager(int max_packets_in_buffer, DelayPeakDetector* peak_detector)
+      : DelayManager(max_packets_in_buffer, peak_detector) {}
+  virtual ~MockDelayManager() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_CONST_METHOD0(iat_vector,
+      const IATVector&());
+  MOCK_METHOD3(Update,
+      int(uint16_t sequence_number, uint32_t timestamp, int sample_rate_hz));
+  MOCK_METHOD1(CalculateTargetLevel,
+      int(int iat_packets));
+  MOCK_METHOD1(SetPacketAudioLength,
+      int(int length_ms));
+  MOCK_METHOD0(Reset,
+      void());
+  MOCK_CONST_METHOD0(AverageIAT,
+      int());
+  MOCK_CONST_METHOD0(PeakFound,
+      bool());
+  MOCK_METHOD1(UpdateCounters,
+      void(int elapsed_time_ms));
+  MOCK_METHOD0(ResetPacketIatCount,
+      void());
+  MOCK_CONST_METHOD2(BufferLimits,
+      void(int* lower_limit, int* higher_limit));
+  MOCK_CONST_METHOD0(TargetLevel,
+      int());
+  MOCK_METHOD1(LastDecoderType,
+      void(NetEqDecoder decoder_type));
+  MOCK_METHOD1(set_extra_delay_ms,
+      void(int16_t delay));
+  MOCK_CONST_METHOD0(base_target_level,
+      int());
+  MOCK_METHOD1(set_streaming_mode,
+      void(bool value));
+  MOCK_CONST_METHOD0(last_pack_cng_or_dtmf,
+      int());
+  MOCK_METHOD1(set_last_pack_cng_or_dtmf,
+      void(int value));
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DELAY_MANAGER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_delay_peak_detector.h b/webrtc/modules/audio_coding/neteq4/mock/mock_delay_peak_detector.h
new file mode 100644
index 0000000..211b2b9
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_delay_peak_detector.h
@@ -0,0 +1,34 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DELAY_PEAK_DETECTOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DELAY_PEAK_DETECTOR_H_
+
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockDelayPeakDetector : public DelayPeakDetector {
+ public:
+  virtual ~MockDelayPeakDetector() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_METHOD0(Reset, void());
+  MOCK_METHOD1(SetPacketAudioLength, void(int length_ms));
+  MOCK_METHOD0(peak_found, bool());
+  MOCK_CONST_METHOD0(MaxPeakHeight, int());
+  MOCK_CONST_METHOD0(MaxPeakPeriod, int());
+  MOCK_METHOD2(Update, bool(int inter_arrival_time, int target_level));
+  MOCK_METHOD1(IncrementCounter, void(int inc_ms));
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DELAY_PEAK_DETECTOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_buffer.h b/webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_buffer.h
new file mode 100644
index 0000000..5a89db4
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_buffer.h
@@ -0,0 +1,38 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DTMF_BUFFER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DTMF_BUFFER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/dtmf_buffer.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockDtmfBuffer : public DtmfBuffer {
+ public:
+  MockDtmfBuffer(int fs) : DtmfBuffer(fs) {}
+  virtual ~MockDtmfBuffer() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_METHOD0(Flush,
+      void());
+  MOCK_METHOD1(InsertEvent,
+      int(const DtmfEvent& event));
+  MOCK_METHOD2(GetEvent,
+      bool(uint32_t current_timestamp, DtmfEvent* event));
+  MOCK_CONST_METHOD0(Length,
+      size_t());
+  MOCK_CONST_METHOD0(Empty,
+      bool());
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DTMF_BUFFER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_tone_generator.h b/webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_tone_generator.h
new file mode 100644
index 0000000..f8ab56f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_tone_generator.h
@@ -0,0 +1,35 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DTMF_TONE_GENERATOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DTMF_TONE_GENERATOR_H_
+
+#include "webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockDtmfToneGenerator : public DtmfToneGenerator {
+ public:
+  virtual ~MockDtmfToneGenerator() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_METHOD3(Init,
+      int(int fs, int event, int attenuation));
+  MOCK_METHOD0(Reset,
+      void());
+  MOCK_METHOD2(Generate,
+      int(int num_samples, AudioMultiVector<int16_t>* output));
+  MOCK_CONST_METHOD0(initialized,
+      bool());
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_DTMF_TONE_GENERATOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_external_decoder_pcm16b.h b/webrtc/modules/audio_coding/neteq4/mock/mock_external_decoder_pcm16b.h
new file mode 100644
index 0000000..efc0c71
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_external_decoder_pcm16b.h
@@ -0,0 +1,99 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_EXTERNAL_DECODER_PCM16B_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_EXTERNAL_DECODER_PCM16B_H_
+
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+
+#include "gmock/gmock.h"
+#include "webrtc/modules/audio_coding/codecs/pcm16b/include/pcm16b.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+using ::testing::_;
+using ::testing::Invoke;
+
+// Implement an external version of the PCM16b decoder. This is a copy from
+// audio_decoder_impl.{cc, h}.
+class ExternalPcm16B : public AudioDecoder {
+ public:
+  explicit ExternalPcm16B(enum NetEqDecoder type)
+      : AudioDecoder(type) {
+  }
+
+  virtual int Decode(const uint8_t* encoded, size_t encoded_len,
+                     int16_t* decoded, SpeechType* speech_type) {
+    int16_t temp_type;
+    int16_t ret = WebRtcPcm16b_DecodeW16(
+        state_, reinterpret_cast<int16_t*>(const_cast<uint8_t*>(encoded)),
+        static_cast<int16_t>(encoded_len), decoded, &temp_type);
+    *speech_type = ConvertSpeechType(temp_type);
+    return ret;
+  }
+
+  virtual int Init() { return 0; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ExternalPcm16B);
+};
+
+// Create a mock of ExternalPcm16B which delegates all calls to the real object.
+// The reason is that we can then track that the correct calls are being made.
+class MockExternalPcm16B : public ExternalPcm16B {
+ public:
+  explicit MockExternalPcm16B(enum NetEqDecoder type)
+      : ExternalPcm16B(type),
+        real_(type) {
+    // By default, all calls are delegated to the real object.
+    ON_CALL(*this, Decode(_, _, _, _))
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::Decode));
+    ON_CALL(*this, HasDecodePlc())
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::HasDecodePlc));
+    ON_CALL(*this, DecodePlc(_, _))
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::DecodePlc));
+    ON_CALL(*this, Init())
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::Init));
+    ON_CALL(*this, IncomingPacket(_, _, _, _, _))
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::IncomingPacket));
+    ON_CALL(*this, ErrorCode())
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::ErrorCode));
+    ON_CALL(*this, codec_type())
+        .WillByDefault(Invoke(&real_, &ExternalPcm16B::codec_type));
+  }
+  virtual ~MockExternalPcm16B() { Die(); }
+
+  MOCK_METHOD0(Die, void());
+  MOCK_METHOD4(Decode,
+      int(const uint8_t* encoded, size_t encoded_len, int16_t* decoded,
+          SpeechType* speech_type));
+  MOCK_CONST_METHOD0(HasDecodePlc,
+      bool());
+  MOCK_METHOD2(DecodePlc,
+      int(int num_frames, int16_t* decoded));
+  MOCK_METHOD0(Init,
+      int());
+  MOCK_METHOD5(IncomingPacket,
+      int(const uint8_t* payload, size_t payload_len,
+          uint16_t rtp_sequence_number, uint32_t rtp_timestamp,
+          uint32_t arrival_timestamp));
+  MOCK_METHOD0(ErrorCode,
+      int());
+  MOCK_CONST_METHOD0(codec_type,
+      NetEqDecoder());
+
+ private:
+  ExternalPcm16B real_;
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_EXTERNAL_DECODER_PCM16B_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_packet_buffer.h b/webrtc/modules/audio_coding/neteq4/mock/mock_packet_buffer.h
new file mode 100644
index 0000000..37fa90d
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_packet_buffer.h
@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_PACKET_BUFFER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_PACKET_BUFFER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockPacketBuffer : public PacketBuffer {
+ public:
+  MockPacketBuffer(size_t max_number_of_packets, size_t max_payload_memory)
+      : PacketBuffer(max_number_of_packets, max_payload_memory) {}
+  virtual ~MockPacketBuffer() { Die(); }
+  MOCK_METHOD0(Die, void());
+  MOCK_METHOD0(Flush,
+      void());
+  MOCK_CONST_METHOD0(Empty,
+      bool());
+  MOCK_METHOD1(InsertPacket,
+      int(Packet* packet));
+  MOCK_METHOD4(InsertPacketList,
+      int(PacketList* packet_list,
+          const DecoderDatabase& decoder_database,
+          uint8_t* current_rtp_payload_type,
+          uint8_t* current_cng_rtp_payload_type));
+  MOCK_CONST_METHOD1(NextTimestamp,
+      int(uint32_t* next_timestamp));
+  MOCK_CONST_METHOD2(NextHigherTimestamp,
+      int(uint32_t timestamp, uint32_t* next_timestamp));
+  MOCK_CONST_METHOD0(NextRtpHeader,
+      const RTPHeader*());
+  MOCK_METHOD1(GetNextPacket,
+      Packet*(int* discard_count));
+  MOCK_METHOD0(DiscardNextPacket,
+      int());
+  MOCK_METHOD1(DiscardOldPackets,
+      int(uint32_t timestamp_limit));
+  MOCK_CONST_METHOD0(NumPacketsInBuffer,
+      int());
+  MOCK_METHOD1(IncrementWaitingTimes,
+      void(int));
+  MOCK_CONST_METHOD0(current_memory_bytes,
+      int());
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_PACKET_BUFFER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/mock/mock_payload_splitter.h b/webrtc/modules/audio_coding/neteq4/mock/mock_payload_splitter.h
new file mode 100644
index 0000000..f3d8c9b
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/mock/mock_payload_splitter.h
@@ -0,0 +1,37 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_PAYLOAD_SPLITTER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_PAYLOAD_SPLITTER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/payload_splitter.h"
+
+#include "gmock/gmock.h"
+
+namespace webrtc {
+
+class MockPayloadSplitter : public PayloadSplitter {
+ public:
+  MOCK_METHOD1(SplitRed,
+      int(PacketList* packet_list));
+  MOCK_METHOD2(CheckRedPayloads,
+      int(PacketList* packet_list, const DecoderDatabase& decoder_database));
+  MOCK_METHOD2(SplitAudio,
+      int(PacketList* packet_list, const DecoderDatabase& decoder_database));
+  MOCK_METHOD4(SplitBySamples,
+      void(const Packet* packet, int bytes_per_ms, int timestamps_per_ms,
+           PacketList* new_packets));
+  MOCK_METHOD4(SplitByFrames,
+      int(const Packet* packet, int bytes_per_frame, int timestamps_per_frame,
+          PacketList* new_packets));
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_MOCK_MOCK_PAYLOAD_SPLITTER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/neteq.cc b/webrtc/modules/audio_coding/neteq4/neteq.cc
new file mode 100644
index 0000000..1ec71a2
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq.cc
@@ -0,0 +1,52 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+#include "webrtc/modules/audio_coding/neteq4/dtmf_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h"
+#include "webrtc/modules/audio_coding/neteq4/neteq_impl.h"
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/payload_splitter.h"
+#include "webrtc/modules/audio_coding/neteq4/timestamp_scaler.h"
+
+namespace webrtc {
+
+// Creates all classes needed and inject them into a new NetEqImpl object.
+// Return the new object.
+NetEq* NetEq::Create(int sample_rate_hz) {
+  BufferLevelFilter* buffer_level_filter = new BufferLevelFilter;
+  DecoderDatabase* decoder_database = new DecoderDatabase;
+  DelayPeakDetector* delay_peak_detector = new DelayPeakDetector;
+  DelayManager* delay_manager = new DelayManager(kMaxNumPacketsInBuffer,
+                                                 delay_peak_detector);
+  DtmfBuffer* dtmf_buffer = new DtmfBuffer(sample_rate_hz);
+  DtmfToneGenerator* dtmf_tone_generator = new DtmfToneGenerator;
+  PacketBuffer* packet_buffer = new PacketBuffer(kMaxNumPacketsInBuffer,
+                                                 kMaxBytesInBuffer);
+  PayloadSplitter* payload_splitter = new PayloadSplitter;
+  TimestampScaler* timestamp_scaler = new TimestampScaler(*decoder_database);
+  return new NetEqImpl(sample_rate_hz,
+                       buffer_level_filter,
+                       decoder_database,
+                       delay_manager,
+                       delay_peak_detector,
+                       dtmf_buffer,
+                       dtmf_tone_generator,
+                       packet_buffer,
+                       payload_splitter,
+                       timestamp_scaler);
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/neteq.gypi b/webrtc/modules/audio_coding/neteq4/neteq.gypi
new file mode 100644
index 0000000..9dc481a
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq.gypi
@@ -0,0 +1,228 @@
+# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+{
+  'variables': {
+    'neteq_dependencies': [
+      'G711',
+      'G722',
+      'PCM16B',
+      'iLBC',
+      'iSAC',
+      'iSACFix',
+      'CNG',
+      '<(webrtc_root)/common_audio/common_audio.gyp:signal_processing',
+      '<(webrtc_root)/common_audio/common_audio.gyp:vad',
+      '<(webrtc_root)/system_wrappers/source/system_wrappers.gyp:system_wrappers',
+    ],
+    'neteq_defines': [],
+    'conditions': [
+      ['include_opus==1', {
+        'neteq_dependencies': ['webrtc_opus',],
+        'neteq_defines': ['WEBRTC_CODEC_OPUS',],
+      }],
+    ],
+  },
+  'targets': [
+    {
+      'target_name': 'NetEq4',
+      'type': 'static_library',
+      'dependencies': [
+        '<@(neteq_dependencies)',
+      ],
+      'defines': [
+        '<@(neteq_defines)',
+      ],
+      'include_dirs': [
+        'interface',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          'interface',
+        ],
+      },
+      'sources': [
+        'interface/audio_decoder.h',
+        'interface/neteq.h',
+        'accelerate.cc',
+        'accelerate.h',
+        'audio_decoder_impl.cc',
+        'audio_decoder_impl.h',
+        'audio_decoder.cc',
+        'audio_multi_vector.cc',
+        'audio_multi_vector.h',
+        'audio_vector.cc',
+        'audio_vector.h',
+        'background_noise.cc',
+        'background_noise.h',
+        'buffer_level_filter.cc',
+        'buffer_level_filter.h',
+        'comfort_noise.cc',
+        'comfort_noise.h',
+        'decision_logic.cc',
+        'decision_logic.h',
+        'decision_logic_fax.cc',
+        'decision_logic_fax.h',
+        'decision_logic_normal.cc',
+        'decision_logic_normal.h',
+        'decoder_database.cc',
+        'decoder_database.h',
+        'defines.h',
+        'delay_manager.cc',
+        'delay_manager.h',
+        'delay_peak_detector.cc',
+        'delay_peak_detector.h',
+        'dsp_helper.cc',
+        'dsp_helper.h',
+        'dtmf_buffer.cc',
+        'dtmf_buffer.h',
+        'dtmf_tone_generator.cc',
+        'dtmf_tone_generator.h',
+        'expand.cc',
+        'expand.h',
+        'merge.cc',
+        'merge.h',
+        'neteq_impl.cc',
+        'neteq_impl.h',
+        'neteq.cc',
+        'statistics_calculator.cc',
+        'statistics_calculator.h',
+        'normal.cc',
+        'normal.h',
+        'packet_buffer.cc',
+        'packet_buffer.h',
+        'payload_splitter.cc',
+        'payload_splitter.h',
+        'post_decode_vad.cc',
+        'post_decode_vad.h',
+        'preemptive_expand.cc',
+        'preemptive_expand.h',
+        'random_vector.cc',
+        'random_vector.h',
+        'rtcp.cc',
+        'rtcp.h',
+        'sync_buffer.cc',
+        'sync_buffer.h',
+        'timestamp_scaler.cc',
+        'timestamp_scaler.h',
+        'time_stretch.cc',
+        'time_stretch.h',
+      ],
+    },
+  ], # targets
+  'conditions': [
+    ['include_tests==1', {
+      'includes': ['neteq_tests.gypi',],
+      'targets': [
+        {
+          'target_name': 'neteq4_unittests',
+          'type': 'executable',
+          'dependencies': [
+            'NetEq4',
+            'NetEq4TestTools',
+            'neteq_unittest_tools',
+            'PCM16B',
+            '<(DEPTH)/testing/gmock.gyp:gmock',
+            '<(DEPTH)/testing/gtest.gyp:gtest',
+            '<(webrtc_root)/test/test.gyp:test_support_main',
+          ],
+          'sources': [
+            'audio_multi_vector_unittest.cc',
+            'audio_vector_unittest.cc',
+            'background_noise_unittest.cc',
+            'buffer_level_filter_unittest.cc',
+            'comfort_noise_unittest.cc',
+            'decision_logic_unittest.cc',
+            'decoder_database_unittest.cc',
+            'delay_manager_unittest.cc',
+            'delay_peak_detector_unittest.cc',
+            'dsp_helper_unittest.cc',
+            'dtmf_buffer_unittest.cc',
+            'dtmf_tone_generator_unittest.cc',
+            'expand_unittest.cc',
+            'merge_unittest.cc',
+            'neteq_external_decoder_unittest.cc',
+            'neteq_impl_unittest.cc',
+            'neteq_stereo_unittest.cc',
+            'neteq_unittest.cc',
+            'normal_unittest.cc',
+            'packet_buffer_unittest.cc',
+            'payload_splitter_unittest.cc',
+            'post_decode_vad_unittest.cc',
+            'random_vector_unittest.cc',
+            'sync_buffer_unittest.cc',
+            'timestamp_scaler_unittest.cc',
+            'time_stretch_unittest.cc',
+            'mock/mock_audio_decoder.h',
+            'mock/mock_audio_vector.h',
+            'mock/mock_buffer_level_filter.h',
+            'mock/mock_decoder_database.h',
+            'mock/mock_delay_manager.h',
+            'mock/mock_delay_peak_detector.h',
+            'mock/mock_dtmf_buffer.h',
+            'mock/mock_dtmf_tone_generator.h',
+            'mock/mock_external_decoder_pcm16b.h',
+            'mock/mock_packet_buffer.h',
+            'mock/mock_payload_splitter.h',
+          ],
+        }, # neteq_unittests
+
+        {
+          'target_name': 'audio_decoder_unittests',
+          'type': 'executable',
+          'dependencies': [
+            '<@(neteq_dependencies)',
+            '<(DEPTH)/testing/gtest.gyp:gtest',
+            '<(webrtc_root)/common_audio/common_audio.gyp:resampler',
+            '<(webrtc_root)/test/test.gyp:test_support_main',
+          ],
+          'defines': [
+            'AUDIO_DECODER_UNITTEST',
+            'WEBRTC_CODEC_G722',
+            'WEBRTC_CODEC_ILBC',
+            'WEBRTC_CODEC_ISACFX',
+            'WEBRTC_CODEC_ISAC',
+            'WEBRTC_CODEC_PCM16',
+            '<@(neteq_defines)',
+          ],
+          'sources': [
+            'audio_decoder_impl.cc',
+            'audio_decoder_impl.h',
+            'audio_decoder_unittest.cc',
+            'audio_decoder.cc',
+            'interface/audio_decoder.h',
+          ],
+        }, # audio_decoder_unittest
+
+        {
+          'target_name': 'neteq_unittest_tools',
+          'type': 'static_library',
+          'dependencies': [
+            '<(DEPTH)/testing/gmock.gyp:gmock',
+            '<(DEPTH)/testing/gtest.gyp:gtest',
+            '<(webrtc_root)/test/test.gyp:test_support_main',
+          ],
+          'direct_dependent_settings': {
+            'include_dirs': [
+              'tools',
+            ],
+          },
+          'include_dirs': [
+            'tools',
+          ],
+          'sources': [
+            'tools/input_audio_file.cc',
+            'tools/input_audio_file.h',
+            'tools/rtp_generator.cc',
+            'tools/rtp_generator.h',
+          ],
+        }, # neteq_unittest_tools
+      ], # targets
+    }], # include_tests
+  ], # conditions
+}
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_external_decoder_unittest.cc b/webrtc/modules/audio_coding/neteq4/neteq_external_decoder_unittest.cc
new file mode 100644
index 0000000..c0a0fd3
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_external_decoder_unittest.cc
@@ -0,0 +1,208 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Test to verify correct operation for externally created decoders.
+
+#include <string>
+#include <list>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_external_decoder_pcm16b.h"
+#include "webrtc/modules/audio_coding/neteq4/tools/input_audio_file.h"
+#include "webrtc/modules/audio_coding/neteq4/tools/rtp_generator.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/test/testsupport/fileutils.h"
+
+namespace webrtc {
+
+using ::testing::_;
+
+// This test encodes a few packets of PCM16b 32 kHz data and inserts it into two
+// different NetEq instances. The first instance uses the internal version of
+// the decoder object, while the second one uses an externally created decoder
+// object (ExternalPcm16B wrapped in MockExternalPcm16B, both defined above).
+// The test verifies that the output from both instances match.
+class NetEqExternalDecoderTest : public ::testing::Test {
+ protected:
+  static const int kTimeStepMs = 10;
+  static const int kMaxBlockSize = 480;  // 10 ms @ 48 kHz.
+  static const uint8_t kPayloadType = 95;
+  static const int kSampleRateHz = 32000;
+
+  NetEqExternalDecoderTest()
+      : sample_rate_hz_(kSampleRateHz),
+        samples_per_ms_(sample_rate_hz_ / 1000),
+        frame_size_ms_(10),
+        frame_size_samples_(frame_size_ms_ * samples_per_ms_),
+        output_size_samples_(frame_size_ms_ * samples_per_ms_),
+        neteq_external_(NetEq::Create(sample_rate_hz_)),
+        neteq_(NetEq::Create(sample_rate_hz_)),
+        external_decoder_(new MockExternalPcm16B(kDecoderPCM16Bswb32kHz)),
+        rtp_generator_(samples_per_ms_),
+        payload_size_bytes_(0),
+        last_send_time_(0),
+        last_arrival_time_(0) {
+    input_ = new int16_t[frame_size_samples_];
+    encoded_ = new uint8_t[2 * frame_size_samples_];
+  }
+
+  ~NetEqExternalDecoderTest() {
+    delete neteq_external_;
+    delete neteq_;
+    // We will now delete the decoder ourselves, so expecting Die to be called.
+    EXPECT_CALL(*external_decoder_, Die()).Times(1);
+    delete external_decoder_;
+    delete [] input_;
+    delete [] encoded_;
+  }
+
+  virtual void SetUp() {
+    const std::string file_name =
+        webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm");
+    input_file_.reset(new test::InputAudioFile(file_name));
+    assert(sample_rate_hz_ == 32000);
+    NetEqDecoder decoder = kDecoderPCM16Bswb32kHz;
+    EXPECT_CALL(*external_decoder_, Init());
+    // NetEq is not allowed to delete the external decoder (hence Times(0)).
+    EXPECT_CALL(*external_decoder_, Die()).Times(0);
+    ASSERT_EQ(NetEq::kOK,
+              neteq_external_->RegisterExternalDecoder(external_decoder_,
+                                                       decoder,
+                                                       sample_rate_hz_,
+                                                       kPayloadType));
+    ASSERT_EQ(NetEq::kOK,
+              neteq_->RegisterPayloadType(decoder, kPayloadType));
+  }
+
+  virtual void TearDown() {}
+
+  int GetNewPackets() {
+    if (!input_file_->Read(frame_size_samples_, input_)) {
+      return -1;
+    }
+    payload_size_bytes_ = WebRtcPcm16b_Encode(input_, frame_size_samples_,
+                                             encoded_);
+    if (frame_size_samples_ * 2 != payload_size_bytes_) {
+      return -1;
+    }
+    int next_send_time = rtp_generator_.GetRtpHeader(kPayloadType,
+                                                     frame_size_samples_,
+                                                     &rtp_header_);
+    return next_send_time;
+  }
+
+  void VerifyOutput(size_t num_samples) {
+    for (size_t i = 0; i < num_samples; ++i) {
+      ASSERT_EQ(output_[i], output_external_[i]) <<
+          "Diff in sample " << i << ".";
+    }
+  }
+
+  virtual int GetArrivalTime(int send_time) {
+    int arrival_time = last_arrival_time_ + (send_time - last_send_time_);
+    last_send_time_ = send_time;
+    last_arrival_time_ = arrival_time;
+    return arrival_time;
+  }
+
+  virtual bool Lost() { return false; }
+
+  void RunTest(int num_loops) {
+    // Get next input packets (mono and multi-channel).
+    int next_send_time;
+    int next_arrival_time;
+    do {
+      next_send_time = GetNewPackets();
+      ASSERT_NE(-1, next_send_time);
+      next_arrival_time = GetArrivalTime(next_send_time);
+    } while (Lost());  // If lost, immediately read the next packet.
+
+    EXPECT_CALL(*external_decoder_, Decode(_, payload_size_bytes_, _, _))
+        .Times(num_loops);
+
+    int time_now = 0;
+    for (int k = 0; k < num_loops; ++k) {
+      while (time_now >= next_arrival_time) {
+        // Insert packet in regular instance.
+        ASSERT_EQ(NetEq::kOK,
+                  neteq_->InsertPacket(rtp_header_, encoded_,
+                                       payload_size_bytes_,
+                                       next_arrival_time));
+        // Insert packet in external decoder instance.
+        EXPECT_CALL(*external_decoder_,
+                    IncomingPacket(_, payload_size_bytes_,
+                                   rtp_header_.header.sequenceNumber,
+                                   rtp_header_.header.timestamp,
+                                   next_arrival_time));
+        ASSERT_EQ(NetEq::kOK,
+                  neteq_external_->InsertPacket(rtp_header_, encoded_,
+                                                payload_size_bytes_,
+                                                next_arrival_time));
+        // Get next input packet.
+        do {
+          next_send_time = GetNewPackets();
+          ASSERT_NE(-1, next_send_time);
+          next_arrival_time = GetArrivalTime(next_send_time);
+        } while (Lost());  // If lost, immediately read the next packet.
+      }
+      NetEqOutputType output_type;
+      // Get audio from regular instance.
+      int samples_per_channel;
+      int num_channels;
+      EXPECT_EQ(NetEq::kOK,
+                neteq_->GetAudio(kMaxBlockSize, output_,
+                                 &samples_per_channel, &num_channels,
+                                 &output_type));
+      EXPECT_EQ(1, num_channels);
+      EXPECT_EQ(output_size_samples_, samples_per_channel);
+      // Get audio from external decoder instance.
+      ASSERT_EQ(NetEq::kOK,
+                neteq_external_->GetAudio(kMaxBlockSize, output_external_,
+                                          &samples_per_channel, &num_channels,
+                                          &output_type));
+      EXPECT_EQ(1, num_channels);
+      EXPECT_EQ(output_size_samples_, samples_per_channel);
+      std::ostringstream ss;
+      ss << "Lap number " << k << ".";
+      SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+      // Compare mono and multi-channel.
+      ASSERT_NO_FATAL_FAILURE(VerifyOutput(output_size_samples_));
+
+      time_now += kTimeStepMs;
+    }
+  }
+
+  const int sample_rate_hz_;
+  const int samples_per_ms_;
+  const int frame_size_ms_;
+  const int frame_size_samples_;
+  const int output_size_samples_;
+  NetEq* neteq_external_;
+  NetEq* neteq_;
+  MockExternalPcm16B* external_decoder_;
+  test::RtpGenerator rtp_generator_;
+  int16_t* input_;
+  uint8_t* encoded_;
+  int16_t output_[kMaxBlockSize];
+  int16_t output_external_[kMaxBlockSize];
+  WebRtcRTPHeader rtp_header_;
+  int payload_size_bytes_;
+  int last_send_time_;
+  int last_arrival_time_;
+  scoped_ptr<test::InputAudioFile> input_file_;
+};
+
+TEST_F(NetEqExternalDecoderTest, RunTest) {
+  RunTest(100);  // Run 100 laps @ 10 ms each in the test loop.
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_impl.cc b/webrtc/modules/audio_coding/neteq4/neteq_impl.cc
new file mode 100644
index 0000000..38b8d7c
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_impl.cc
@@ -0,0 +1,1749 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/neteq_impl.h"
+
+#include <assert.h>
+#include <memory.h>  // memset
+
+#include <algorithm>
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/neteq4/accelerate.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/buffer_level_filter.h"
+#include "webrtc/modules/audio_coding/neteq4/comfort_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/decision_logic.h"
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/defines.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_peak_detector.h"
+#include "webrtc/modules/audio_coding/neteq4/dtmf_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/dtmf_tone_generator.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq4/merge.h"
+#include "webrtc/modules/audio_coding/neteq4/normal.h"
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/modules/audio_coding/neteq4/payload_splitter.h"
+#include "webrtc/modules/audio_coding/neteq4/post_decode_vad.h"
+#include "webrtc/modules/audio_coding/neteq4/preemptive_expand.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/timestamp_scaler.h"
+#include "webrtc/modules/interface/module_common_types.h"
+#include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
+#include "webrtc/system_wrappers/interface/logging.h"
+
+// Modify the code to obtain backwards bit-exactness. Once bit-exactness is no
+// longer required, this #define should be removed (and the code that it
+// enables).
+#define LEGACY_BITEXACT
+
+namespace webrtc {
+
+NetEqImpl::NetEqImpl(int fs,
+                     BufferLevelFilter* buffer_level_filter,
+                     DecoderDatabase* decoder_database,
+                     DelayManager* delay_manager,
+                     DelayPeakDetector* delay_peak_detector,
+                     DtmfBuffer* dtmf_buffer,
+                     DtmfToneGenerator* dtmf_tone_generator,
+                     PacketBuffer* packet_buffer,
+                     PayloadSplitter* payload_splitter,
+                     TimestampScaler* timestamp_scaler)
+    : background_noise_(NULL),
+      buffer_level_filter_(buffer_level_filter),
+      decoder_database_(decoder_database),
+      delay_manager_(delay_manager),
+      delay_peak_detector_(delay_peak_detector),
+      dtmf_buffer_(dtmf_buffer),
+      dtmf_tone_generator_(dtmf_tone_generator),
+      packet_buffer_(packet_buffer),
+      payload_splitter_(payload_splitter),
+      timestamp_scaler_(timestamp_scaler),
+      vad_(new PostDecodeVad()),
+      sync_buffer_(NULL),
+      expand_(NULL),
+      comfort_noise_(NULL),
+      last_mode_(kModeNormal),
+      mute_factor_array_(NULL),
+      decoded_buffer_length_(kMaxFrameSize),
+      decoded_buffer_(new int16_t[decoded_buffer_length_]),
+      playout_timestamp_(0),
+      new_codec_(false),
+      timestamp_(0),
+      reset_decoder_(false),
+      current_rtp_payload_type_(0xFF),  // Invalid RTP payload type.
+      current_cng_rtp_payload_type_(0xFF),  // Invalid RTP payload type.
+      ssrc_(0),
+      first_packet_(true),
+      dtmf_enabled_(true),
+      error_code_(0),
+      decoder_error_code_(0),
+      crit_sect_(CriticalSectionWrapper::CreateCriticalSection()) {
+  if (fs != 8000 && fs != 16000 && fs != 32000 && fs != 48000) {
+    LOG(LS_ERROR) << "Sample rate " << fs << " Hz not supported. " <<
+        "Changing to 8000 Hz.";
+    fs = 8000;
+  }
+  LOG(LS_INFO) << "Create NetEqImpl object with fs = " << fs << ".";
+  fs_hz_ = fs;
+  fs_mult_ = fs / 8000;
+  output_size_samples_ = kOutputSizeMs * 8 * fs_mult_;
+  decoder_frame_length_ = 3 * output_size_samples_;
+  WebRtcSpl_Init();
+  decision_logic_.reset(DecisionLogic::Create(fs_hz_, output_size_samples_,
+                                              kPlayoutOn,
+                                              decoder_database_.get(),
+                                              *packet_buffer_.get(),
+                                              delay_manager_.get(),
+                                              buffer_level_filter_.get()));
+  SetSampleRateAndChannels(fs, 1);  // Default is 1 channel.
+}
+
+NetEqImpl::~NetEqImpl() {
+  LOG(LS_INFO) << "Deleting NetEqImpl object.";
+  delete sync_buffer_;
+  delete background_noise_;
+  delete expand_;
+  delete comfort_noise_;
+  delete crit_sect_;
+}
+
+int NetEqImpl::InsertPacket(const WebRtcRTPHeader& rtp_header,
+                            const uint8_t* payload,
+                            int length_bytes,
+                            uint32_t receive_timestamp) {
+  CriticalSectionScoped lock(crit_sect_);
+  LOG(LS_VERBOSE) << "InsertPacket: ts=" << rtp_header.header.timestamp <<
+      ", sn=" << rtp_header.header.sequenceNumber <<
+      ", pt=" << static_cast<int>(rtp_header.header.payloadType) <<
+      ", ssrc=" << rtp_header.header.ssrc <<
+      ", len=" << length_bytes;
+  int error = InsertPacketInternal(rtp_header, payload, length_bytes,
+                                   receive_timestamp);
+  if (error != 0) {
+    LOG_FERR1(LS_WARNING, InsertPacketInternal, error);
+    error_code_ = error;
+    return kFail;
+  }
+  return kOK;
+}
+
+int NetEqImpl::GetAudio(size_t max_length, int16_t* output_audio,
+                        int* samples_per_channel, int* num_channels,
+                        NetEqOutputType* type) {
+  CriticalSectionScoped lock(crit_sect_);
+  LOG(LS_VERBOSE) << "GetAudio";
+  int error = GetAudioInternal(max_length, output_audio, samples_per_channel,
+                               num_channels);
+  LOG(LS_VERBOSE) << "Produced " << *samples_per_channel <<
+      " samples/channel for " << *num_channels << " channel(s)";
+  if (error != 0) {
+    LOG_FERR1(LS_WARNING, GetAudioInternal, error);
+    error_code_ = error;
+    return kFail;
+  }
+  if (type) {
+    *type = LastOutputType();
+  }
+  return kOK;
+}
+
+int NetEqImpl::RegisterPayloadType(enum NetEqDecoder codec,
+                                   uint8_t rtp_payload_type) {
+  CriticalSectionScoped lock(crit_sect_);
+  LOG_API2(static_cast<int>(rtp_payload_type), codec);
+  int ret = decoder_database_->RegisterPayload(rtp_payload_type, codec);
+  if (ret != DecoderDatabase::kOK) {
+    LOG_FERR2(LS_WARNING, RegisterPayload, rtp_payload_type, codec);
+    switch (ret) {
+      case DecoderDatabase::kInvalidRtpPayloadType:
+        error_code_ = kInvalidRtpPayloadType;
+        break;
+      case DecoderDatabase::kCodecNotSupported:
+        error_code_ = kCodecNotSupported;
+        break;
+      case DecoderDatabase::kDecoderExists:
+        error_code_ = kDecoderExists;
+        break;
+      default:
+        error_code_ = kOtherError;
+    }
+    return kFail;
+  }
+  return kOK;
+}
+
+int NetEqImpl::RegisterExternalDecoder(AudioDecoder* decoder,
+                                       enum NetEqDecoder codec,
+                                       int sample_rate_hz,
+                                       uint8_t rtp_payload_type) {
+  CriticalSectionScoped lock(crit_sect_);
+  LOG_API2(static_cast<int>(rtp_payload_type), codec);
+  if (!decoder) {
+    LOG(LS_ERROR) << "Cannot register external decoder with NULL pointer";
+    assert(false);
+    return kFail;
+  }
+  int ret = decoder_database_->InsertExternal(rtp_payload_type, codec,
+                                              sample_rate_hz, decoder);
+  if (ret != DecoderDatabase::kOK) {
+    LOG_FERR2(LS_WARNING, InsertExternal, rtp_payload_type, codec);
+    switch (ret) {
+      case DecoderDatabase::kInvalidRtpPayloadType:
+        error_code_ = kInvalidRtpPayloadType;
+        break;
+      case DecoderDatabase::kCodecNotSupported:
+        error_code_ = kCodecNotSupported;
+        break;
+      case DecoderDatabase::kDecoderExists:
+        error_code_ = kDecoderExists;
+        break;
+      case DecoderDatabase::kInvalidSampleRate:
+        error_code_ = kInvalidSampleRate;
+        break;
+      case DecoderDatabase::kInvalidPointer:
+        error_code_ = kInvalidPointer;
+        break;
+      default:
+        error_code_ = kOtherError;
+    }
+    return kFail;
+  }
+  return kOK;
+}
+
+int NetEqImpl::RemovePayloadType(uint8_t rtp_payload_type) {
+  CriticalSectionScoped lock(crit_sect_);
+  LOG_API1(static_cast<int>(rtp_payload_type));
+  int ret = decoder_database_->Remove(rtp_payload_type);
+  if (ret == DecoderDatabase::kOK) {
+    return kOK;
+  } else if (ret == DecoderDatabase::kDecoderNotFound) {
+    error_code_ = kDecoderNotFound;
+  } else {
+    error_code_ = kOtherError;
+  }
+  LOG_FERR1(LS_WARNING, Remove, rtp_payload_type);
+  return kFail;
+}
+
+bool NetEqImpl::SetExtraDelay(int extra_delay_ms) {
+  CriticalSectionScoped lock(crit_sect_);
+  if (extra_delay_ms >= 0 && extra_delay_ms < 10000) {
+    assert(delay_manager_.get());
+    delay_manager_->set_extra_delay_ms(extra_delay_ms);
+    return true;
+  }
+  return false;
+}
+
+int NetEqImpl::EnableDtmf() {
+  CriticalSectionScoped lock(crit_sect_);
+  dtmf_enabled_ = true;
+  return kOK;
+}
+
+void NetEqImpl::SetPlayoutMode(NetEqPlayoutMode mode) {
+  CriticalSectionScoped lock(crit_sect_);
+  if (!decision_logic_.get() || mode != decision_logic_->playout_mode()) {
+    // The reset() method calls delete for the old object.
+    decision_logic_.reset(DecisionLogic::Create(fs_hz_, output_size_samples_,
+                                                mode,
+                                                decoder_database_.get(),
+                                                *packet_buffer_.get(),
+                                                delay_manager_.get(),
+                                                buffer_level_filter_.get()));
+  }
+}
+
+NetEqPlayoutMode NetEqImpl::PlayoutMode() const {
+  CriticalSectionScoped lock(crit_sect_);
+  assert(decision_logic_.get());
+  return decision_logic_->playout_mode();
+}
+
+int NetEqImpl::NetworkStatistics(NetEqNetworkStatistics* stats) {
+  CriticalSectionScoped lock(crit_sect_);
+  assert(decoder_database_.get());
+  const int total_samples_in_buffers = packet_buffer_->NumSamplesInBuffer(
+      decoder_database_.get(), decoder_frame_length_) +
+          sync_buffer_->FutureLength();
+  assert(delay_manager_.get());
+  assert(decision_logic_.get());
+  stats_.GetNetworkStatistics(fs_hz_, total_samples_in_buffers,
+                              decoder_frame_length_, *delay_manager_.get(),
+                              *decision_logic_.get(), stats);
+  return 0;
+}
+
+void NetEqImpl::WaitingTimes(std::vector<int>* waiting_times) {
+  CriticalSectionScoped lock(crit_sect_);
+  stats_.WaitingTimes(waiting_times);
+}
+
+void NetEqImpl::GetRtcpStatistics(RtcpStatistics* stats) {
+  CriticalSectionScoped lock(crit_sect_);
+  if (stats) {
+    rtcp_.GetStatistics(false, stats);
+  }
+}
+
+void NetEqImpl::GetRtcpStatisticsNoReset(RtcpStatistics* stats) {
+  CriticalSectionScoped lock(crit_sect_);
+  if (stats) {
+    rtcp_.GetStatistics(true, stats);
+  }
+}
+
+void NetEqImpl::EnableVad() {
+  CriticalSectionScoped lock(crit_sect_);
+  assert(vad_.get());
+  vad_->Enable();
+}
+
+void NetEqImpl::DisableVad() {
+  CriticalSectionScoped lock(crit_sect_);
+  assert(vad_.get());
+  vad_->Disable();
+}
+
+uint32_t NetEqImpl::PlayoutTimestamp() {
+  CriticalSectionScoped lock(crit_sect_);
+  return timestamp_scaler_->ToExternal(playout_timestamp_);
+}
+
+int NetEqImpl::LastError() {
+  CriticalSectionScoped lock(crit_sect_);
+  return error_code_;
+}
+
+int NetEqImpl::LastDecoderError() {
+  CriticalSectionScoped lock(crit_sect_);
+  return decoder_error_code_;
+}
+
+void NetEqImpl::FlushBuffers() {
+  CriticalSectionScoped lock(crit_sect_);
+  LOG_API0();
+  packet_buffer_->Flush();
+  assert(sync_buffer_);
+  assert(expand_);
+  sync_buffer_->Flush();
+  sync_buffer_->set_next_index(sync_buffer_->next_index() -
+                               expand_->overlap_length());
+  // Set to wait for new codec.
+  first_packet_ = true;
+}
+
+// Methods below this line are private.
+
+
+int NetEqImpl::InsertPacketInternal(const WebRtcRTPHeader& rtp_header,
+                                    const uint8_t* payload,
+                                    int length_bytes,
+                                    uint32_t receive_timestamp) {
+  if (!payload) {
+    LOG_F(LS_ERROR) << "payload == NULL";
+    return kInvalidPointer;
+  }
+  PacketList packet_list;
+  RTPHeader main_header;
+  {
+    // Convert to webrtc::Packet.
+    // Create |packet| within this separate scope, since it should not be used
+    // directly once it's been inserted in the packet list. This way, |packet|
+    // is not defined outside of this block.
+    webrtc::Packet* packet = new webrtc::Packet;
+    packet->header.markerBit = false;
+    packet->header.payloadType = rtp_header.header.payloadType;
+    packet->header.sequenceNumber = rtp_header.header.sequenceNumber;
+    packet->header.timestamp = rtp_header.header.timestamp;
+    packet->header.ssrc = rtp_header.header.ssrc;
+    packet->header.numCSRCs = 0;
+    packet->payload_length = length_bytes;
+    packet->primary = true;
+    packet->waiting_time = 0;
+    packet->payload = new uint8_t[packet->payload_length];
+    LOG_F(LS_ERROR) << "Payload pointer is NULL.";
+    assert(payload);  // Already checked above.
+    memcpy(packet->payload, payload, packet->payload_length);
+    // Insert packet in a packet list.
+    packet_list.push_back(packet);
+    // Save main payloads header for later.
+    memcpy(&main_header, &packet->header, sizeof(main_header));
+  }
+
+  // Reinitialize NetEq if it's needed (changed SSRC or first call).
+  if ((main_header.ssrc != ssrc_) || first_packet_) {
+    rtcp_.Init(main_header.sequenceNumber);
+    first_packet_ = false;
+
+    // Flush the packet buffer and DTMF buffer.
+    packet_buffer_->Flush();
+    dtmf_buffer_->Flush();
+
+    // Store new SSRC.
+    ssrc_ = main_header.ssrc;
+
+    // Update codecs.
+    timestamp_ = main_header.timestamp;
+    current_rtp_payload_type_ = main_header.payloadType;
+
+    // Set MCU to update codec on next SignalMCU call.
+    new_codec_ = true;
+
+    // Reset timestamp scaling.
+    timestamp_scaler_->Reset();
+  }
+
+  // Update RTCP statistics.
+  rtcp_.Update(main_header, receive_timestamp);
+
+  // Check for RED payload type, and separate payloads into several packets.
+  if (decoder_database_->IsRed(main_header.payloadType)) {
+    if (payload_splitter_->SplitRed(&packet_list) != PayloadSplitter::kOK) {
+      LOG_FERR1(LS_WARNING, SplitRed, packet_list.size());
+      PacketBuffer::DeleteAllPackets(&packet_list);
+      return kRedundancySplitError;
+    }
+    // Only accept a few RED payloads of the same type as the main data,
+    // DTMF events and CNG.
+    payload_splitter_->CheckRedPayloads(&packet_list, *decoder_database_);
+    // Update the stored main payload header since the main payload has now
+    // changed.
+    memcpy(&main_header, &packet_list.front()->header, sizeof(main_header));
+  }
+
+  // Check payload types.
+  if (decoder_database_->CheckPayloadTypes(packet_list) ==
+      DecoderDatabase::kDecoderNotFound) {
+    LOG_FERR1(LS_WARNING, CheckPayloadTypes, packet_list.size());
+    PacketBuffer::DeleteAllPackets(&packet_list);
+    return kUnknownRtpPayloadType;
+  }
+
+  // Scale timestamp to internal domain (only for some codecs).
+  timestamp_scaler_->ToInternal(&packet_list);
+
+  // Process DTMF payloads. Cycle through the list of packets, and pick out any
+  // DTMF payloads found.
+  PacketList::iterator it = packet_list.begin();
+  while (it != packet_list.end()) {
+    Packet* current_packet = (*it);
+    assert(current_packet);
+    assert(current_packet->payload);
+    if (decoder_database_->IsDtmf(current_packet->header.payloadType)) {
+      if (dtmf_enabled_) {
+        DtmfEvent event;
+        int ret = DtmfBuffer::ParseEvent(
+            current_packet->header.timestamp,
+            current_packet->payload,
+            current_packet->payload_length,
+            &event);
+        if (ret != DtmfBuffer::kOK) {
+          LOG_FERR2(LS_WARNING, ParseEvent, ret,
+                    current_packet->payload_length);
+          PacketBuffer::DeleteAllPackets(&packet_list);
+          return kDtmfParsingError;
+        }
+        if (dtmf_buffer_->InsertEvent(event) != DtmfBuffer::kOK) {
+          LOG_FERR0(LS_WARNING, InsertEvent);
+          PacketBuffer::DeleteAllPackets(&packet_list);
+          return kDtmfInsertError;
+        }
+      }
+      // TODO(hlundin): Let the destructor of Packet handle the payload.
+      delete [] current_packet->payload;
+      delete current_packet;
+      it = packet_list.erase(it);
+    } else {
+      ++it;
+    }
+  }
+
+  // Split payloads into smaller chunks. This also verifies that all payloads
+  // are of a known payload type.
+  int ret = payload_splitter_->SplitAudio(&packet_list, *decoder_database_);
+  if (ret != PayloadSplitter::kOK) {
+    LOG_FERR1(LS_WARNING, SplitAudio, packet_list.size());
+    PacketBuffer::DeleteAllPackets(&packet_list);
+    switch (ret) {
+      case PayloadSplitter::kUnknownPayloadType:
+        return kUnknownRtpPayloadType;
+      case PayloadSplitter::kFrameSplitError:
+        return kFrameSplitError;
+      default:
+        return kOtherError;
+    }
+  }
+
+  // Update bandwidth estimate.
+  if (!packet_list.empty()) {
+    // The list can be empty here if we got nothing but DTMF payloads.
+    AudioDecoder* decoder =
+        decoder_database_->GetDecoder(main_header.payloadType);
+    assert(decoder);  // Should always get a valid object, since we have
+                      // already checked that the payload types are known.
+    decoder->IncomingPacket(packet_list.front()->payload,
+                            packet_list.front()->payload_length,
+                            packet_list.front()->header.sequenceNumber,
+                            packet_list.front()->header.timestamp,
+                            receive_timestamp);
+  }
+
+  // Insert packets in buffer.
+  int temp_bufsize = packet_buffer_->NumPacketsInBuffer();
+  ret = packet_buffer_->InsertPacketList(
+      &packet_list,
+      *decoder_database_,
+      &current_rtp_payload_type_,
+      &current_cng_rtp_payload_type_);
+  if (ret == PacketBuffer::kFlushed) {
+    // Reset DSP timestamp etc. if packet buffer flushed.
+    new_codec_ = true;
+    LOG_F(LS_WARNING) << "Packet buffer flushed";
+  } else if (ret != PacketBuffer::kOK) {
+    LOG_FERR1(LS_WARNING, InsertPacketList, packet_list.size());
+    PacketBuffer::DeleteAllPackets(&packet_list);
+    assert(false);
+    // TODO(hlundin): Take care of error codes.
+  }
+  if (current_rtp_payload_type_ != 0xFF) {
+    const DecoderDatabase::DecoderInfo* dec_info =
+        decoder_database_->GetDecoderInfo(current_rtp_payload_type_);
+    if (!dec_info) {
+      assert(false);  // Already checked that the payload type is known.
+    }
+  }
+
+  // TODO(hlundin): Move this code to DelayManager class.
+  const DecoderDatabase::DecoderInfo* dec_info =
+          decoder_database_->GetDecoderInfo(main_header.payloadType);
+  assert(dec_info);  // Already checked that the payload type is known.
+  delay_manager_->LastDecoderType(dec_info->codec_type);
+  if (delay_manager_->last_pack_cng_or_dtmf() == 0) {
+    // Calculate the total speech length carried in each packet.
+    temp_bufsize = packet_buffer_->NumPacketsInBuffer() - temp_bufsize;
+    temp_bufsize *= decoder_frame_length_;
+
+    if ((temp_bufsize > 0) &&
+        (temp_bufsize != decision_logic_->packet_length_samples())) {
+      decision_logic_->set_packet_length_samples(temp_bufsize);
+      delay_manager_->SetPacketAudioLength((1000 * temp_bufsize) / fs_hz_);
+    }
+
+    // Update statistics.
+    if ((WebRtc_Word32) (main_header.timestamp - timestamp_) >= 0 &&
+        !new_codec_) {
+      // Only update statistics if incoming packet is not older than last played
+      // out packet, and if new codec flag is not set.
+      delay_manager_->Update(main_header.sequenceNumber, main_header.timestamp,
+                             fs_hz_);
+    }
+  } else if (delay_manager_->last_pack_cng_or_dtmf() == -1) {
+    // This is first "normal" packet after CNG or DTMF.
+    // Reset packet time counter and measure time until next packet,
+    // but don't update statistics.
+    delay_manager_->set_last_pack_cng_or_dtmf(0);
+    delay_manager_->ResetPacketIatCount();
+  }
+  return 0;
+}
+
+int NetEqImpl::GetAudioInternal(size_t max_length, int16_t* output,
+                                int* samples_per_channel, int* num_channels) {
+  PacketList packet_list;
+  DtmfEvent dtmf_event;
+  Operations operation;
+  bool play_dtmf;
+  int return_value = GetDecision(&operation, &packet_list, &dtmf_event,
+                                 &play_dtmf);
+  if (return_value != 0) {
+    LOG_FERR1(LS_WARNING, GetDecision, return_value);
+    assert(false);
+    last_mode_ = kModeError;
+    return return_value;
+  }
+  LOG(LS_VERBOSE) << "GetDecision returned operation=" << operation <<
+      " and " << packet_list.size() << " packet(s)";
+
+  AudioDecoder::SpeechType speech_type;
+  int length = 0;
+  int decode_return_value = Decode(&packet_list, &operation,
+                                   &length, &speech_type);
+
+
+  assert(vad_.get());
+  bool sid_frame_available =
+      (operation == kRfc3389Cng && !packet_list.empty());
+  vad_->Update(decoded_buffer_.get(), length, speech_type,
+               sid_frame_available, fs_hz_);
+
+  AudioMultiVector<int16_t> algorithm_buffer(sync_buffer_->Channels());
+  switch (operation) {
+    case kNormal: {
+      DoNormal(decoded_buffer_.get(), length, speech_type, play_dtmf,
+               &algorithm_buffer);
+      break;
+    }
+    case kMerge: {
+      DoMerge(decoded_buffer_.get(), length, speech_type, play_dtmf,
+              &algorithm_buffer);
+      break;
+    }
+    case kExpand: {
+      return_value = DoExpand(play_dtmf, &algorithm_buffer);
+      break;
+    }
+    case kAccelerate: {
+      return_value = DoAccelerate(decoded_buffer_.get(), length, speech_type,
+                                  play_dtmf, &algorithm_buffer);
+      break;
+    }
+    case kPreemptiveExpand: {
+      return_value = DoPreemptiveExpand(decoded_buffer_.get(), length,
+                                        speech_type, play_dtmf,
+                                        &algorithm_buffer);
+      break;
+    }
+    case kRfc3389Cng:
+    case kRfc3389CngNoPacket: {
+      return_value = DoRfc3389Cng(&packet_list, play_dtmf, &algorithm_buffer);
+      break;
+    }
+    case kCodecInternalCng: {
+      // This handles the case when there is no transmission and the decoder
+      // should produce internal comfort noise.
+      // TODO(hlundin): Write test for codec-internal CNG.
+      DoCodecInternalCng(&algorithm_buffer);
+      break;
+    }
+    case kDtmf: {
+      // TODO(hlundin): Write test for this.
+      return_value = DoDtmf(dtmf_event, &play_dtmf, &algorithm_buffer);
+      break;
+    }
+    case kAlternativePlc: {
+      // TODO(hlundin): Write test for this.
+      DoAlternativePlc(false, &algorithm_buffer);
+      break;
+    }
+    case kAlternativePlcIncreaseTimestamp: {
+      // TODO(hlundin): Write test for this.
+      DoAlternativePlc(true, &algorithm_buffer);
+      break;
+    }
+    case kAudioRepetitionIncreaseTimestamp: {
+      // TODO(hlundin): Write test for this.
+      sync_buffer_->IncreaseEndTimestamp(output_size_samples_);
+      // Skipping break on purpose. Execution should move on into the
+      // next case.
+    }
+    case kAudioRepetition: {
+      // TODO(hlundin): Write test for this.
+      // Copy last |output_size_samples_| from |sync_buffer_| to
+      // |algorithm_buffer|.
+      algorithm_buffer.PushBackFromIndex(
+          *sync_buffer_, sync_buffer_->Size() - output_size_samples_);
+      expand_->Reset();
+      break;
+    }
+    case kUndefined: {
+      LOG_F(LS_ERROR) << "Invalid operation kUndefined.";
+      assert(false);  // This should not happen.
+      last_mode_ = kModeError;
+      return kInvalidOperation;
+    }
+  }  // End of switch.
+  if (return_value < 0) {
+    return return_value;
+  }
+
+  if (last_mode_ != kModeRfc3389Cng) {
+    comfort_noise_->Reset();
+  }
+
+  // Copy from |algorithm_buffer| to |sync_buffer_|.
+  sync_buffer_->PushBack(algorithm_buffer);
+
+  // Extract data from |sync_buffer_| to |output|.
+  int num_output_samples_per_channel = output_size_samples_;
+  int num_output_samples = output_size_samples_ * sync_buffer_->Channels();
+  if (num_output_samples > static_cast<int>(max_length)) {
+    LOG(LS_WARNING) << "Output array is too short. " << max_length << " < " <<
+        output_size_samples_ << " * " << sync_buffer_->Channels();
+    num_output_samples = max_length;
+    num_output_samples_per_channel = max_length / sync_buffer_->Channels();
+  }
+  int samples_from_sync = sync_buffer_->GetNextAudioInterleaved(
+      num_output_samples_per_channel, output);
+  *num_channels = sync_buffer_->Channels();
+  LOG(LS_VERBOSE) << "Sync buffer (" << *num_channels << " channel(s)):" <<
+      " insert " << algorithm_buffer.Size() << " samples, extract " <<
+      samples_from_sync << " samples";
+  if (samples_from_sync != output_size_samples_) {
+    LOG_F(LS_ERROR) << "samples_from_sync != output_size_samples_";
+    assert(false);
+    memset(output, 0, num_output_samples * sizeof(int16_t));
+    *samples_per_channel = output_size_samples_;
+    last_mode_ = kModeError;
+    return kSampleUnderrun;
+  }
+  *samples_per_channel = output_size_samples_;
+
+  // Should always have overlap samples left in the |sync_buffer_|.
+  assert(sync_buffer_->FutureLength() >= expand_->overlap_length());
+
+  if (play_dtmf) {
+    return_value = DtmfOverdub(dtmf_event, sync_buffer_->Channels(), output);
+  }
+
+  // Update the background noise parameters if last operation wrote data
+  // straight from the decoder to the |sync_buffer_|. That is, none of the
+  // operations that modify the signal can be followed by a parameter update.
+  if ((last_mode_ == kModeNormal) ||
+      (last_mode_ == kModeAccelerateFail) ||
+      (last_mode_ == kModePreemptiveExpandFail) ||
+      (last_mode_ == kModeRfc3389Cng) ||
+      (last_mode_ == kModeCodecInternalCng)) {
+    background_noise_->Update(*sync_buffer_, *vad_.get());
+  }
+
+  if (operation == kDtmf) {
+    // DTMF data was written the end of |sync_buffer_|.
+    // Update index to end of DTMF data in |sync_buffer_|.
+    sync_buffer_->set_dtmf_index(sync_buffer_->Size());
+  }
+
+  if ((last_mode_ != kModeExpand) && (last_mode_ != kModeRfc3389Cng)) {
+    // If last operation was neither expand, nor comfort noise, calculate the
+    // |playout_timestamp_| from the |sync_buffer_|. However, do not update the
+    // |playout_timestamp_| if it would be moved "backwards".
+    uint32_t temp_timestamp = sync_buffer_->end_timestamp() -
+            sync_buffer_->FutureLength();
+    if (static_cast<int32_t>(temp_timestamp - playout_timestamp_) > 0) {
+      playout_timestamp_ = temp_timestamp;
+    }
+  } else {
+    // Use dead reckoning to estimate the |playout_timestamp_|.
+    playout_timestamp_ += output_size_samples_;
+  }
+
+  if (decode_return_value) return decode_return_value;
+  return return_value;
+}
+
+int NetEqImpl::GetDecision(Operations* operation,
+                           PacketList* packet_list,
+                           DtmfEvent* dtmf_event,
+                           bool* play_dtmf) {
+  // Initialize output variables.
+  *play_dtmf = false;
+  *operation = kUndefined;
+
+  // Increment time counters.
+  packet_buffer_->IncrementWaitingTimes();
+  stats_.IncreaseCounter(output_size_samples_, fs_hz_);
+
+  assert(sync_buffer_);
+  uint32_t end_timestamp = sync_buffer_->end_timestamp();
+  if (!new_codec_) {
+    packet_buffer_->DiscardOldPackets(end_timestamp);
+  }
+  const RTPHeader* header = packet_buffer_->NextRtpHeader();
+
+  if (decision_logic_->CngRfc3389On()) {
+    // Because of timestamp peculiarities, we have to "manually" disallow using
+    // a CNG packet with the same timestamp as the one that was last played.
+    // This can happen when using redundancy and will cause the timing to shift.
+    while (header &&
+        decoder_database_->IsComfortNoise(header->payloadType) &&
+        end_timestamp >= header->timestamp) {
+      // Don't use this packet, discard it.
+      // TODO(hlundin): Write test for this case.
+      if (packet_buffer_->DiscardNextPacket() != PacketBuffer::kOK) {
+        assert(false);  // Must be ok by design.
+      }
+      // Check buffer again.
+      if (!new_codec_) {
+        packet_buffer_->DiscardOldPackets(end_timestamp);
+      }
+      header = packet_buffer_->NextRtpHeader();
+    }
+  }
+
+  assert(expand_);
+  const int samples_left = sync_buffer_->FutureLength() -
+      expand_->overlap_length();
+  if (last_mode_ == kModeAccelerateSuccess ||
+      last_mode_ == kModeAccelerateLowEnergy ||
+      last_mode_ == kModePreemptiveExpandSuccess ||
+      last_mode_ == kModePreemptiveExpandLowEnergy) {
+    // Subtract (samples_left + output_size_samples_) from sampleMemory.
+    decision_logic_->AddSampleMemory(-(samples_left + output_size_samples_));
+  }
+
+  // Check if it is time to play a DTMF event.
+  if (dtmf_buffer_->GetEvent(end_timestamp +
+                             decision_logic_->generated_noise_samples(),
+                             dtmf_event)) {
+    *play_dtmf = true;
+  }
+
+  // Get instruction.
+  assert(sync_buffer_);
+  assert(expand_);
+  *operation = decision_logic_->GetDecision(*sync_buffer_,
+                                            *expand_,
+                                            decoder_frame_length_,
+                                            header,
+                                            last_mode_,
+                                            *play_dtmf,
+                                            &reset_decoder_);
+
+  // Check if we already have enough samples in the |sync_buffer_|. If so,
+  // change decision to normal, unless the decision was merge, accelerate, or
+  // preemptive expand.
+  if (samples_left >= output_size_samples_ &&
+      *operation != kMerge &&
+      *operation != kAccelerate &&
+      *operation != kPreemptiveExpand) {
+    *operation = kNormal;
+    return 0;
+  }
+
+  decision_logic_->ExpandDecision(*operation == kExpand);
+
+  // Check conditions for reset.
+  if (new_codec_ || *operation == kUndefined) {
+    // The only valid reason to get kUndefined is that new_codec_ is set.
+    assert(new_codec_);
+    assert(header);
+    if (!header) {
+      LOG_F(LS_ERROR) << "Packet missing where it shouldn't.";
+      return -1;
+    }
+    timestamp_ = header->timestamp;
+    // Adjust |sync_buffer_| timestamp before setting |end_timestamp| to the
+    // new value.
+    sync_buffer_->IncreaseEndTimestamp(timestamp_ - end_timestamp);
+    end_timestamp = header->timestamp;
+    new_codec_ = false;
+    decision_logic_->SoftReset();
+    buffer_level_filter_->Reset();
+    delay_manager_->Reset();
+    stats_.ResetMcu();
+
+    if (*operation == kRfc3389CngNoPacket) {
+      // Change decision to CNG packet, since we do have a CNG packet, but it
+      // was considered too early to use. Now, use it anyway.
+      *operation = kRfc3389Cng;
+    } else if (*operation != kRfc3389Cng) {
+      *operation = kNormal;
+    }
+  }
+
+  int required_samples = output_size_samples_;
+  const int samples_10_ms = 80 * fs_mult_;
+  const int samples_20_ms = 2 * samples_10_ms;
+  const int samples_30_ms = 3 * samples_10_ms;
+
+  switch (*operation) {
+    case kExpand: {
+      timestamp_ = end_timestamp;
+      return 0;
+    }
+    case kRfc3389CngNoPacket:
+    case kCodecInternalCng: {
+      return 0;
+    }
+    case kDtmf: {
+      // TODO(hlundin): Write test for this.
+      // Update timestamp.
+      timestamp_ = end_timestamp;
+      if (decision_logic_->generated_noise_samples() > 0 &&
+          last_mode_ != kModeDtmf) {
+        // Make a jump in timestamp due to the recently played comfort noise.
+        uint32_t timestamp_jump = decision_logic_->generated_noise_samples();
+        sync_buffer_->IncreaseEndTimestamp(timestamp_jump);
+        timestamp_ += timestamp_jump;
+      }
+      decision_logic_->set_generated_noise_samples(0);
+      return 0;
+    }
+    case kAccelerate: {
+      // In order to do a accelerate we need at least 30 ms of audio data.
+      if (samples_left >= samples_30_ms) {
+        // Already have enough data, so we do not need to extract any more.
+        decision_logic_->set_sample_memory(samples_left);
+        decision_logic_->set_prev_time_scale(true);
+        return 0;
+      } else if (samples_left >= samples_10_ms &&
+          decoder_frame_length_ >= samples_30_ms) {
+        // Avoid decoding more data as it might overflow the playout buffer.
+        *operation = kNormal;
+        return 0;
+      } else if (samples_left < samples_20_ms &&
+          decoder_frame_length_ < samples_30_ms) {
+        // Build up decoded data by decoding at least 20 ms of audio data. Do
+        // not perform accelerate yet, but wait until we only need to do one
+        // decoding.
+        required_samples = 2 * output_size_samples_;
+        *operation = kNormal;
+      }
+      // If none of the above is true, we have one of two possible situations:
+      // (1) 20 ms <= samples_left < 30 ms and decoder_frame_length_ < 30 ms; or
+      // (2) samples_left < 10 ms and decoder_frame_length_ >= 30 ms.
+      // In either case, we move on with the accelerate decision, and decode one
+      // frame now.
+      break;
+    }
+    case kPreemptiveExpand: {
+      // In order to do a preemptive expand we need at least 30 ms of decoded
+      // audio data.
+      if ((samples_left >= samples_30_ms) ||
+          (samples_left >= samples_10_ms &&
+              decoder_frame_length_ >= samples_30_ms)) {
+        // Already have enough data, so we do not need to extract any more.
+        // Or, avoid decoding more data as it might overflow the playout buffer.
+        // Still try preemptive expand, though.
+        decision_logic_->set_sample_memory(samples_left);
+        decision_logic_->set_prev_time_scale(true);
+        return 0;
+      }
+      if (samples_left < samples_20_ms &&
+          decoder_frame_length_ < samples_30_ms) {
+        // Build up decoded data by decoding at least 20 ms of audio data.
+        // Still try to perform preemptive expand.
+        required_samples = 2 * output_size_samples_;
+      }
+      // Move on with the preemptive expand decision.
+      break;
+    }
+    default: {
+      // Do nothing.
+    }
+  }
+
+  // Get packets from buffer.
+  int extracted_samples = 0;
+  if (header &&
+      *operation != kAlternativePlc &&
+      *operation != kAlternativePlcIncreaseTimestamp &&
+      *operation != kAudioRepetition &&
+      *operation != kAudioRepetitionIncreaseTimestamp) {
+    sync_buffer_->IncreaseEndTimestamp(header->timestamp - end_timestamp);
+    if (decision_logic_->CngOff()) {
+      // Adjustment of timestamp only corresponds to an actual packet loss
+      // if comfort noise is not played. If comfort noise was just played,
+      // this adjustment of timestamp is only done to get back in sync with the
+      // stream timestamp; no loss to report.
+      stats_.LostSamples(header->timestamp - end_timestamp);
+    }
+
+    if (*operation != kRfc3389Cng) {
+      // We are about to decode and use a non-CNG packet.
+      decision_logic_->SetCngOff();
+    }
+    // Reset CNG timestamp as a new packet will be delivered.
+    // (Also if this is a CNG packet, since playedOutTS is updated.)
+    decision_logic_->set_generated_noise_samples(0);
+
+    extracted_samples = ExtractPackets(required_samples, packet_list);
+    if (extracted_samples < 0) {
+      LOG_F(LS_WARNING) << "Failed to extract packets from buffer.";
+      return kPacketBufferCorruption;
+    }
+  }
+
+  if (*operation == kAccelerate ||
+      *operation == kPreemptiveExpand) {
+    decision_logic_->set_sample_memory(samples_left + extracted_samples);
+    decision_logic_->set_prev_time_scale(true);
+  }
+
+  if (*operation == kAccelerate) {
+    // Check that we have enough data (30ms) to do accelerate.
+    if (extracted_samples + samples_left < samples_30_ms) {
+      // TODO(hlundin): Write test for this.
+      // Not enough, do normal operation instead.
+      *operation = kNormal;
+    }
+  }
+
+  timestamp_ = end_timestamp;
+  return 0;
+}
+
+int NetEqImpl::Decode(PacketList* packet_list, Operations* operation,
+                      int* decoded_length,
+                      AudioDecoder::SpeechType* speech_type) {
+  *speech_type = AudioDecoder::kSpeech;
+  AudioDecoder* decoder = NULL;
+  if (!packet_list->empty()) {
+    const Packet* packet = packet_list->front();
+    int payload_type = packet->header.payloadType;
+    if (!decoder_database_->IsComfortNoise(payload_type)) {
+      decoder = decoder_database_->GetDecoder(payload_type);
+      assert(decoder);
+      if (!decoder) {
+        LOG_FERR1(LS_WARNING, GetDecoder, payload_type);
+        PacketBuffer::DeleteAllPackets(packet_list);
+        return kDecoderNotFound;
+      }
+      bool decoder_changed;
+      decoder_database_->SetActiveDecoder(payload_type, &decoder_changed);
+      if (decoder_changed) {
+        // We have a new decoder. Re-init some values.
+        const DecoderDatabase::DecoderInfo* decoder_info = decoder_database_
+            ->GetDecoderInfo(payload_type);
+        assert(decoder_info);
+        if (!decoder_info) {
+          LOG_FERR1(LS_WARNING, GetDecoderInfo, payload_type);
+          PacketBuffer::DeleteAllPackets(packet_list);
+          return kDecoderNotFound;
+        }
+        SetSampleRateAndChannels(decoder_info->fs_hz, decoder->channels());
+        sync_buffer_->set_end_timestamp(timestamp_);
+        playout_timestamp_ = timestamp_;
+      }
+    }
+  }
+
+  if (reset_decoder_) {
+    // TODO(hlundin): Write test for this.
+    // Reset decoder.
+    if (decoder) {
+      decoder->Init();
+    }
+    // Reset comfort noise decoder.
+    AudioDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
+    if (cng_decoder) {
+      cng_decoder->Init();
+    }
+    reset_decoder_ = false;
+  }
+
+#ifdef LEGACY_BITEXACT
+  // Due to a bug in old SignalMCU, it could happen that CNG operation was
+  // decided, but a speech packet was provided. The speech packet will be used
+  // to update the comfort noise decoder, as if it was a SID frame, which is
+  // clearly wrong.
+  if (*operation == kRfc3389Cng) {
+    return 0;
+  }
+#endif
+
+  *decoded_length = 0;
+  // Update codec-internal PLC state.
+  if ((*operation == kMerge) && decoder && decoder->HasDecodePlc()) {
+    decoder->DecodePlc(1, &decoded_buffer_[*decoded_length]);
+  }
+
+  int return_value = DecodeLoop(packet_list, operation, decoder,
+                                decoded_length, speech_type);
+
+  if (*decoded_length < 0) {
+    // Error returned from the decoder.
+    *decoded_length = 0;
+    sync_buffer_->IncreaseEndTimestamp(decoder_frame_length_);
+    int error_code = 0;
+    if (decoder)
+      error_code = decoder->ErrorCode();
+    if (error_code != 0) {
+      // Got some error code from the decoder.
+      decoder_error_code_ = error_code;
+      return_value = kDecoderErrorCode;
+    } else {
+      // Decoder does not implement error codes. Return generic error.
+      return_value = kOtherDecoderError;
+    }
+    LOG_FERR2(LS_WARNING, DecodeLoop, error_code, packet_list->size());
+    *operation = kExpand;  // Do expansion to get data instead.
+  }
+  if (*speech_type != AudioDecoder::kComfortNoise) {
+    // Don't increment timestamp if codec returned CNG speech type
+    // since in this case, the we will increment the CNGplayedTS counter.
+    // Increase with number of samples per channel.
+    assert(*decoded_length == 0 ||
+           (decoder && decoder->channels() == sync_buffer_->Channels()));
+    sync_buffer_->IncreaseEndTimestamp(*decoded_length /
+                                       sync_buffer_->Channels());
+  }
+  return return_value;
+}
+
+int NetEqImpl::DecodeLoop(PacketList* packet_list, Operations* operation,
+                          AudioDecoder* decoder, int* decoded_length,
+                          AudioDecoder::SpeechType* speech_type) {
+  Packet* packet = NULL;
+  if (!packet_list->empty()) {
+    packet = packet_list->front();
+  }
+  // Do decoding.
+  while (packet &&
+      !decoder_database_->IsComfortNoise(packet->header.payloadType)) {
+    assert(decoder);  // At this point, we must have a decoder object.
+    // The number of channels in the |sync_buffer_| should be the same as the
+    // number decoder channels.
+    assert(sync_buffer_->Channels() == decoder->channels());
+    assert(decoded_buffer_length_ >= kMaxFrameSize * decoder->channels());
+    assert(*operation == kNormal || *operation == kAccelerate ||
+           *operation == kMerge || *operation == kPreemptiveExpand);
+    packet_list->pop_front();
+    int16_t decode_length;
+    if (!packet->primary) {
+      // This is a redundant payload; call the special decoder method.
+      LOG(LS_VERBOSE) << "Decoding packet (redundant):" <<
+          " ts=" << packet->header.timestamp <<
+          ", sn=" << packet->header.sequenceNumber <<
+          ", pt=" << static_cast<int>(packet->header.payloadType) <<
+          ", ssrc=" << packet->header.ssrc <<
+          ", len=" << packet->payload_length;
+      decode_length = decoder->DecodeRedundant(
+          packet->payload, packet->payload_length,
+          &decoded_buffer_[*decoded_length], speech_type);
+    } else {
+      LOG(LS_VERBOSE) << "Decoding packet: ts=" << packet->header.timestamp <<
+          ", sn=" << packet->header.sequenceNumber <<
+          ", pt=" << static_cast<int>(packet->header.payloadType) <<
+          ", ssrc=" << packet->header.ssrc <<
+          ", len=" << packet->payload_length;
+      decode_length = decoder->Decode(packet->payload,
+                                      packet->payload_length,
+                                      &decoded_buffer_[*decoded_length],
+                                      speech_type);
+    }
+
+    delete[] packet->payload;
+    delete packet;
+    if (decode_length > 0) {
+      *decoded_length += decode_length;
+      // Update |decoder_frame_length_| with number of samples per channel.
+      decoder_frame_length_ = decode_length / decoder->channels();
+      LOG(LS_VERBOSE) << "Decoded " << decode_length << " samples (" <<
+          decoder->channels() << " channel(s) -> " << decoder_frame_length_ <<
+          " samples per channel)";
+    } else if (decode_length < 0) {
+      // Error.
+      LOG_FERR2(LS_WARNING, Decode, decode_length, packet->payload_length);
+      *decoded_length = -1;
+      PacketBuffer::DeleteAllPackets(packet_list);
+      break;
+    }
+    if (*decoded_length > static_cast<int>(decoded_buffer_length_)) {
+      // Guard against overflow.
+      LOG_F(LS_WARNING) << "Decoded too much.";
+      PacketBuffer::DeleteAllPackets(packet_list);
+      return kDecodedTooMuch;
+    }
+    if (!packet_list->empty()) {
+      packet = packet_list->front();
+    } else {
+      packet = NULL;
+    }
+  }  // End of decode loop.
+
+  // If the list is not empty at this point, it must hold exactly one CNG
+  // packet.
+  assert(packet_list->empty() ||
+         (packet_list->size() == 1 &&
+             decoder_database_->IsComfortNoise(packet->header.payloadType)));
+  return 0;
+}
+
+void NetEqImpl::DoNormal(const int16_t* decoded_buffer, size_t decoded_length,
+                         AudioDecoder::SpeechType speech_type, bool play_dtmf,
+                         AudioMultiVector<int16_t>* algorithm_buffer) {
+  assert(decoder_database_.get());
+  assert(background_noise_);
+  assert(expand_);
+  Normal normal(fs_hz_, decoder_database_.get(), *background_noise_, expand_);
+  assert(mute_factor_array_.get());
+  normal.Process(decoded_buffer, decoded_length, last_mode_,
+                 mute_factor_array_.get(), algorithm_buffer);
+  if (decoded_length != 0) {
+    last_mode_ = kModeNormal;
+  }
+
+  // If last packet was decoded as an inband CNG, set mode to CNG instead.
+  if ((speech_type == AudioDecoder::kComfortNoise)
+      || ((last_mode_ == kModeCodecInternalCng)
+          && (decoded_length == 0))) {
+    // TODO(hlundin): Remove second part of || statement above.
+    last_mode_ = kModeCodecInternalCng;
+  }
+
+  if (!play_dtmf) {
+    dtmf_tone_generator_->Reset();
+  }
+}
+
+void NetEqImpl::DoMerge(int16_t* decoded_buffer, size_t decoded_length,
+                        AudioDecoder::SpeechType speech_type, bool play_dtmf,
+                        AudioMultiVector<int16_t>* algorithm_buffer) {
+  Merge merge(fs_hz_, algorithm_buffer->Channels(), expand_, sync_buffer_);
+  assert(mute_factor_array_.get());
+  int new_length = merge.Process(decoded_buffer, decoded_length,
+                                 mute_factor_array_.get(), algorithm_buffer);
+
+  // Update in-call and post-call statistics.
+  if (expand_->MuteFactor(0) == 0) {
+    // Expand generates only noise.
+    stats_.ExpandedNoiseSamples(new_length - decoded_length);
+  } else {
+    // Expansion generates more than only noise.
+    stats_.ExpandedVoiceSamples(new_length - decoded_length);
+  }
+
+  last_mode_ = kModeMerge;
+  // If last packet was decoded as an inband CNG, set mode to CNG instead.
+  if (speech_type == AudioDecoder::kComfortNoise) {
+    last_mode_ = kModeCodecInternalCng;
+  }
+  expand_->Reset();
+  if (!play_dtmf) {
+    dtmf_tone_generator_->Reset();
+  }
+}
+
+int NetEqImpl::DoExpand(bool play_dtmf,
+                        AudioMultiVector<int16_t>* algorithm_buffer) {
+  while ((sync_buffer_->FutureLength() - expand_->overlap_length()) <
+      static_cast<size_t>(output_size_samples_)) {
+    algorithm_buffer->Clear();
+    int return_value = expand_->Process(algorithm_buffer);
+    int length = algorithm_buffer->Size();
+
+    // Update in-call and post-call statistics.
+    if (expand_->MuteFactor(0) == 0) {
+      // Expand operation generates only noise.
+      stats_.ExpandedNoiseSamples(length);
+    } else {
+      // Expand operation generates more than only noise.
+      stats_.ExpandedVoiceSamples(length);
+    }
+
+    last_mode_ = kModeExpand;
+
+    if (return_value < 0) {
+      return return_value;
+    }
+
+    sync_buffer_->PushBack(*algorithm_buffer);
+    algorithm_buffer->Clear();
+  }
+  if (!play_dtmf) {
+    dtmf_tone_generator_->Reset();
+  }
+  return 0;
+}
+
+int NetEqImpl::DoAccelerate(int16_t* decoded_buffer, size_t decoded_length,
+                            AudioDecoder::SpeechType speech_type,
+                            bool play_dtmf,
+                            AudioMultiVector<int16_t>* algorithm_buffer) {
+  const size_t required_samples = 240 * fs_mult_;  // Must have 30 ms.
+  int borrowed_samples_per_channel = 0;
+  size_t num_channels = algorithm_buffer->Channels();
+  size_t decoded_length_per_channel = decoded_length / num_channels;
+  if (decoded_length_per_channel < required_samples) {
+    // Must move data from the |sync_buffer_| in order to get 30 ms.
+    borrowed_samples_per_channel = required_samples -
+        decoded_length_per_channel;
+    memmove(&decoded_buffer[borrowed_samples_per_channel * num_channels],
+            decoded_buffer,
+            sizeof(int16_t) * decoded_length);
+    sync_buffer_->ReadInterleavedFromEnd(borrowed_samples_per_channel,
+                                         decoded_buffer);
+    decoded_length = required_samples * num_channels;
+  }
+
+  int16_t samples_removed;
+  Accelerate accelerate(fs_hz_, num_channels, *background_noise_);
+  Accelerate::ReturnCodes return_code = accelerate.Process(decoded_buffer,
+                                                           decoded_length,
+                                                           algorithm_buffer,
+                                                           &samples_removed);
+  stats_.AcceleratedSamples(samples_removed);
+  switch (return_code) {
+    case Accelerate::kSuccess:
+      last_mode_ = kModeAccelerateSuccess;
+      break;
+    case Accelerate::kSuccessLowEnergy:
+      last_mode_ = kModeAccelerateLowEnergy;
+      break;
+    case Accelerate::kNoStretch:
+      last_mode_ = kModeAccelerateFail;
+      break;
+    case Accelerate::kError:
+      // TODO(hlundin): Map to kModeError instead?
+      last_mode_ = kModeAccelerateFail;
+      return kAccelerateError;
+  }
+
+  if (borrowed_samples_per_channel > 0) {
+    // Copy borrowed samples back to the |sync_buffer_|.
+    int length = algorithm_buffer->Size();
+    if (length < borrowed_samples_per_channel) {
+      // This destroys the beginning of the buffer, but will not cause any
+      // problems.
+      sync_buffer_->ReplaceAtIndex(*algorithm_buffer,
+                                   sync_buffer_->Size() -
+                                   borrowed_samples_per_channel);
+      sync_buffer_->PushFrontZeros(borrowed_samples_per_channel - length);
+      algorithm_buffer->PopFront(length);
+      assert(algorithm_buffer->Empty());
+    } else {
+      sync_buffer_->ReplaceAtIndex(*algorithm_buffer,
+                                   borrowed_samples_per_channel,
+                                   sync_buffer_->Size() -
+                                   borrowed_samples_per_channel);
+      algorithm_buffer->PopFront(borrowed_samples_per_channel);
+    }
+  }
+
+  // If last packet was decoded as an inband CNG, set mode to CNG instead.
+  if (speech_type == AudioDecoder::kComfortNoise) {
+    last_mode_ = kModeCodecInternalCng;
+  }
+  if (!play_dtmf) {
+    dtmf_tone_generator_->Reset();
+  }
+  expand_->Reset();
+  return 0;
+}
+
+int NetEqImpl::DoPreemptiveExpand(int16_t* decoded_buffer,
+                                  size_t decoded_length,
+                                  AudioDecoder::SpeechType speech_type,
+                                  bool play_dtmf,
+                                  AudioMultiVector<int16_t>* algorithm_buffer) {
+  const size_t required_samples = 240 * fs_mult_;  // Must have 30 ms.
+  size_t num_channels = algorithm_buffer->Channels();
+  int borrowed_samples_per_channel = 0;
+  int old_borrowed_samples_per_channel = 0;
+  size_t decoded_length_per_channel = decoded_length / num_channels;
+  if (decoded_length_per_channel < required_samples) {
+    // Must move data from the |sync_buffer_| in order to get 30 ms.
+    borrowed_samples_per_channel = required_samples -
+        decoded_length_per_channel;
+    // Calculate how many of these were already played out.
+    old_borrowed_samples_per_channel = borrowed_samples_per_channel -
+        sync_buffer_->FutureLength();
+    old_borrowed_samples_per_channel = std::max(
+        0, old_borrowed_samples_per_channel);
+    memmove(&decoded_buffer[borrowed_samples_per_channel * num_channels],
+            decoded_buffer,
+            sizeof(int16_t) * decoded_length);
+    sync_buffer_->ReadInterleavedFromEnd(borrowed_samples_per_channel,
+                                         decoded_buffer);
+    decoded_length = required_samples * num_channels;
+  }
+
+  int16_t samples_added;
+  PreemptiveExpand preemptive_expand(fs_hz_, num_channels, *background_noise_);
+  PreemptiveExpand::ReturnCodes return_code = preemptive_expand.Process(
+      decoded_buffer, decoded_length, old_borrowed_samples_per_channel,
+      algorithm_buffer, &samples_added);
+  stats_.PreemptiveExpandedSamples(samples_added);
+  switch (return_code) {
+    case PreemptiveExpand::kSuccess:
+      last_mode_ = kModePreemptiveExpandSuccess;
+      break;
+    case PreemptiveExpand::kSuccessLowEnergy:
+      last_mode_ = kModePreemptiveExpandLowEnergy;
+      break;
+    case PreemptiveExpand::kNoStretch:
+      last_mode_ = kModePreemptiveExpandFail;
+      break;
+    case PreemptiveExpand::kError:
+      // TODO(hlundin): Map to kModeError instead?
+      last_mode_ = kModePreemptiveExpandFail;
+      return kPreemptiveExpandError;
+  }
+
+  if (borrowed_samples_per_channel > 0) {
+    // Copy borrowed samples back to the |sync_buffer_|.
+    sync_buffer_->ReplaceAtIndex(
+        *algorithm_buffer, borrowed_samples_per_channel,
+        sync_buffer_->Size() - borrowed_samples_per_channel);
+    algorithm_buffer->PopFront(borrowed_samples_per_channel);
+  }
+
+  // If last packet was decoded as an inband CNG, set mode to CNG instead.
+  if (speech_type == AudioDecoder::kComfortNoise) {
+    last_mode_ = kModeCodecInternalCng;
+  }
+  if (!play_dtmf) {
+    dtmf_tone_generator_->Reset();
+  }
+  expand_->Reset();
+  return 0;
+}
+
+int NetEqImpl::DoRfc3389Cng(PacketList* packet_list, bool play_dtmf,
+                            AudioMultiVector<int16_t>* algorithm_buffer) {
+  if (!packet_list->empty()) {
+    // Must have exactly one SID frame at this point.
+    assert(packet_list->size() == 1);
+    Packet* packet = packet_list->front();
+    packet_list->pop_front();
+    // Temp hack to get correct PT for CNG.
+    // TODO(hlundin): Update universal.rtp and remove this hack.
+    if (fs_hz_ == 16000) {
+      packet->header.payloadType = 98;
+    } else if (fs_hz_ == 32000) {
+      packet->header.payloadType = 99;
+    }
+    // End of hack.
+    // UpdateParameters() deletes |packet|.
+    if (comfort_noise_->UpdateParameters(packet) ==
+        ComfortNoise::kInternalError) {
+      LOG_FERR0(LS_WARNING, UpdateParameters);
+      algorithm_buffer->Zeros(output_size_samples_);
+      return -comfort_noise_->internal_error_code();
+    }
+  }
+  int cn_return = comfort_noise_->Generate(output_size_samples_,
+                                           algorithm_buffer);
+  expand_->Reset();
+  last_mode_ = kModeRfc3389Cng;
+  if (!play_dtmf) {
+    dtmf_tone_generator_->Reset();
+  }
+  if (cn_return == ComfortNoise::kInternalError) {
+    LOG_FERR1(LS_WARNING, comfort_noise_->Generate, cn_return);
+    decoder_error_code_ = comfort_noise_->internal_error_code();
+    return kComfortNoiseErrorCode;
+  } else if (cn_return == ComfortNoise::kUnknownPayloadType) {
+    LOG_FERR1(LS_WARNING, comfort_noise_->Generate, cn_return);
+    return kUnknownRtpPayloadType;
+  }
+  return 0;
+}
+
+void NetEqImpl::DoCodecInternalCng(
+    AudioMultiVector<int16_t>* algorithm_buffer) {
+  int length = 0;
+  // TODO(hlundin): Will probably need a longer buffer for multi-channel.
+  int16_t decoded_buffer[kMaxFrameSize];
+  AudioDecoder* decoder = decoder_database_->GetActiveDecoder();
+  if (decoder) {
+    const uint8_t* dummy_payload = NULL;
+    AudioDecoder::SpeechType speech_type;
+    length = decoder->Decode(dummy_payload, 0, decoded_buffer, &speech_type);
+  }
+  Normal normal(fs_hz_, decoder_database_.get(), *background_noise_, expand_);
+  assert(mute_factor_array_.get());
+  normal.Process(decoded_buffer, length, last_mode_, mute_factor_array_.get(),
+                 algorithm_buffer);
+  last_mode_ = kModeCodecInternalCng;
+  expand_->Reset();
+}
+
+int NetEqImpl::DoDtmf(const DtmfEvent& dtmf_event, bool* play_dtmf,
+                      AudioMultiVector<int16_t>* algorithm_buffer) {
+  bool dtmf_switch = false;
+  if ((last_mode_ != kModeDtmf) && !dtmf_tone_generator_->initialized()) {
+    // Special case; see below.
+    // We must catch this before calling Generate, since |initialized| is
+    // modified in that call.
+    dtmf_switch = true;
+  }
+
+  int dtmf_return_value = 0;
+  if (!dtmf_tone_generator_->initialized()) {
+    // Initialize if not already done.
+    dtmf_return_value = dtmf_tone_generator_->Init(fs_hz_, dtmf_event.event_no,
+                                                   dtmf_event.volume);
+  }
+  if (dtmf_return_value == 0) {
+    // Generate DTMF signal.
+    dtmf_return_value = dtmf_tone_generator_->Generate(output_size_samples_,
+                                                       algorithm_buffer);
+  }
+  if (dtmf_return_value < 0) {
+    algorithm_buffer->Zeros(output_size_samples_);
+    return dtmf_return_value;
+  }
+
+  if (dtmf_switch) {
+    // This is the special case where the previous operation was DTMF overdub,
+    // but the current instruction is "regular" DTMF. We must make sure that the
+    // DTMF does not have any discontinuities. The first DTMF sample that we
+    // generate now must be played out immediately, wherefore it must be copied
+    // to the speech buffer.
+    // TODO(hlundin): This code seems incorrect. (Legacy.) Write test and
+    // verify correct operation.
+    assert(false);
+    // Must generate enough data to replace all of the |sync_buffer_| "future".
+    int required_length = sync_buffer_->FutureLength();
+    assert(dtmf_tone_generator_->initialized());
+    dtmf_return_value = dtmf_tone_generator_->Generate(required_length,
+                                                       algorithm_buffer);
+    assert((size_t) required_length == algorithm_buffer->Size());
+    if (dtmf_return_value < 0) {
+      algorithm_buffer->Zeros(output_size_samples_);
+      return dtmf_return_value;
+    }
+
+    // Overwrite the "future" part of the speech buffer with the new DTMF data.
+    // TODO(hlundin): It seems that this overwriting has gone lost.
+    // Not adapted for multi-channel yet.
+    assert(algorithm_buffer->Channels() == 1);
+    if (algorithm_buffer->Channels() != 1) {
+      LOG(LS_WARNING) << "DTMF not supported for more than one channel";
+      return kStereoNotSupported;
+    }
+    // Shuffle the remaining data to the beginning of algorithm buffer.
+    algorithm_buffer->PopFront(sync_buffer_->FutureLength());
+  }
+
+  sync_buffer_->IncreaseEndTimestamp(output_size_samples_);
+  expand_->Reset();
+  last_mode_ = kModeDtmf;
+
+  // Set to false because the DTMF is already in the algorithm buffer.
+  *play_dtmf = false;
+  return 0;
+}
+
+void NetEqImpl::DoAlternativePlc(bool increase_timestamp,
+                                 AudioMultiVector<int16_t>* algorithm_buffer) {
+  AudioDecoder* decoder = decoder_database_->GetActiveDecoder();
+  int length;
+  if (decoder && decoder->HasDecodePlc()) {
+    // Use the decoder's packet-loss concealment.
+    // TODO(hlundin): Will probably need a longer buffer for multi-channel.
+    int16_t decoded_buffer[kMaxFrameSize];
+    length = decoder->DecodePlc(1, decoded_buffer);
+    if (length > 0) {
+      algorithm_buffer->PushBackInterleaved(decoded_buffer, length);
+    } else {
+      length = 0;
+    }
+  } else {
+    // Do simple zero-stuffing.
+    length = output_size_samples_;
+    algorithm_buffer->Zeros(length);
+    // By not advancing the timestamp, NetEq inserts samples.
+    stats_.AddZeros(length);
+  }
+  if (increase_timestamp) {
+    sync_buffer_->IncreaseEndTimestamp(length);
+  }
+  expand_->Reset();
+}
+
+int NetEqImpl::DtmfOverdub(const DtmfEvent& dtmf_event, size_t num_channels,
+                           int16_t* output) const {
+  size_t out_index = 0;
+  int overdub_length = output_size_samples_;  // Default value.
+
+  if (sync_buffer_->dtmf_index() > sync_buffer_->next_index()) {
+    // Special operation for transition from "DTMF only" to "DTMF overdub".
+    out_index = std::min(
+        sync_buffer_->dtmf_index() - sync_buffer_->next_index(),
+        static_cast<size_t>(output_size_samples_));
+    overdub_length = output_size_samples_ - out_index;
+  }
+
+  AudioMultiVector<int16_t> dtmf_output(num_channels);
+  int dtmf_return_value = 0;
+  if (!dtmf_tone_generator_->initialized()) {
+    dtmf_return_value = dtmf_tone_generator_->Init(fs_hz_, dtmf_event.event_no,
+                                                   dtmf_event.volume);
+  }
+  if (dtmf_return_value == 0) {
+    dtmf_return_value = dtmf_tone_generator_->Generate(overdub_length,
+                                                       &dtmf_output);
+    assert((size_t) overdub_length == dtmf_output.Size());
+  }
+  dtmf_output.ReadInterleaved(overdub_length, &output[out_index]);
+  return dtmf_return_value < 0 ? dtmf_return_value : 0;
+}
+
+int NetEqImpl::ExtractPackets(int required_samples, PacketList* packet_list) {
+  bool first_packet = true;
+  uint8_t prev_payload_type = 0;
+  uint32_t prev_timestamp = 0;
+  uint16_t prev_sequence_number = 0;
+  bool next_packet_available = false;
+
+  const webrtc::RTPHeader* header = packet_buffer_->NextRtpHeader();
+  assert(header);
+  if (!header) {
+    return -1;
+  }
+  int32_t first_timestamp = header->timestamp;
+  int extracted_samples = 0;
+
+  // Packet extraction loop.
+  do {
+    timestamp_ = header->timestamp;
+    int discard_count = 0;
+    webrtc::Packet* packet = packet_buffer_->GetNextPacket(&discard_count);
+    // |header| may be invalid after the |packet_buffer_| operation.
+    header = NULL;
+    if (!packet) {
+      LOG_FERR1(LS_ERROR, GetNextPacket, discard_count) <<
+          "Should always be able to extract a packet here";
+      assert(false);  // Should always be able to extract a packet here.
+      return -1;
+    }
+    stats_.PacketsDiscarded(discard_count);
+    // Store waiting time in ms; packets->waiting_time is in "output blocks".
+    stats_.StoreWaitingTime(packet->waiting_time * kOutputSizeMs);
+    assert(packet->payload_length > 0);
+    packet_list->push_back(packet);  // Store packet in list.
+
+    if (first_packet) {
+      first_packet = false;
+      prev_sequence_number = packet->header.sequenceNumber;
+      prev_timestamp = packet->header.timestamp;
+      prev_payload_type = packet->header.payloadType;
+    }
+
+    // Store number of extracted samples.
+    int packet_duration = 0;
+    AudioDecoder* decoder = decoder_database_->GetDecoder(
+        packet->header.payloadType);
+    if (decoder) {
+      packet_duration = decoder->PacketDuration(packet->payload,
+                                                packet->payload_length);
+    } else {
+      LOG_FERR1(LS_WARNING, GetDecoder, packet->header.payloadType) <<
+          "Could not find a decoder for a packet about to be extracted.";
+      assert(false);
+    }
+    if (packet_duration <= 0) {
+      // Decoder did not return a packet duration. Assume that the packet
+      // contains the same number of samples as the previous one.
+      packet_duration = decoder_frame_length_;
+    }
+    extracted_samples = packet->header.timestamp - first_timestamp +
+        packet_duration;
+
+    // Check what packet is available next.
+    header = packet_buffer_->NextRtpHeader();
+    next_packet_available = false;
+    if (header && prev_payload_type == header->payloadType) {
+      int16_t seq_no_diff = header->sequenceNumber - prev_sequence_number;
+      int32_t ts_diff = header->timestamp - prev_timestamp;
+      if (seq_no_diff == 1 ||
+          (seq_no_diff == 0 && ts_diff == decoder_frame_length_)) {
+        // The next sequence number is available, or the next part of a packet
+        // that was split into pieces upon insertion.
+        next_packet_available = true;
+      }
+      prev_sequence_number = header->sequenceNumber;
+    }
+  } while (extracted_samples < required_samples && next_packet_available);
+
+  return extracted_samples;
+}
+
+void NetEqImpl::SetSampleRateAndChannels(int fs_hz, size_t channels) {
+  LOG_API2(fs_hz, channels);
+  // TODO(hlundin): Change to an enumerator and skip assert.
+  assert(fs_hz == 8000 || fs_hz == 16000 || fs_hz ==  32000 || fs_hz == 48000);
+  assert(channels > 0);
+
+  fs_hz_ = fs_hz;
+  fs_mult_ = fs_hz / 8000;
+  output_size_samples_ = kOutputSizeMs * 8 * fs_mult_;
+  decoder_frame_length_ = 3 * output_size_samples_;  // Initialize to 30ms.
+
+  last_mode_ = kModeNormal;
+
+  // Create a new array of mute factors and set all to 1.
+  mute_factor_array_.reset(new int16_t[channels]);
+  for (size_t i = 0; i < channels; ++i) {
+    mute_factor_array_[i] = 16384;  // 1.0 in Q14.
+  }
+
+  // Reset comfort noise decoder, if there is one active.
+  AudioDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
+  if (cng_decoder) {
+    cng_decoder->Init();
+  }
+
+  // Reinit post-decode VAD with new sample rate.
+  assert(vad_.get());  // Cannot be NULL here.
+  vad_->Init();
+
+  // Delete sync buffer and create a new one.
+  if (sync_buffer_) {
+    delete sync_buffer_;
+  }
+  sync_buffer_ = new SyncBuffer(channels, kSyncBufferSize * fs_mult_);
+
+  // Delete BackgroundNoise object and create a new one.
+  if (background_noise_) {
+    delete background_noise_;
+  }
+  background_noise_ = new BackgroundNoise(channels);
+
+  // Reset random vector.
+  random_vector_.Reset();
+
+  // Delete Expand object and create a new one.
+  if (expand_) {
+    delete expand_;
+  }
+  expand_ = new Expand(background_noise_, sync_buffer_, &random_vector_, fs_hz,
+                       channels);
+  // Move index so that we create a small set of future samples (all 0).
+  sync_buffer_->set_next_index(sync_buffer_->next_index() -
+                               expand_->overlap_length());
+
+  // Delete ComfortNoise object and create a new one.
+  if (comfort_noise_) {
+    delete comfort_noise_;
+  }
+  comfort_noise_ = new ComfortNoise(fs_hz, decoder_database_.get(),
+                                    sync_buffer_);
+
+  // Verify that |decoded_buffer_| is long enough.
+  if (decoded_buffer_length_ < kMaxFrameSize * channels) {
+    // Reallocate to larger size.
+    decoded_buffer_length_ = kMaxFrameSize * channels;
+    decoded_buffer_.reset(new int16_t[decoded_buffer_length_]);
+  }
+
+  // Communicate new sample rate and output size to DecisionLogic object.
+  assert(decision_logic_.get());
+  decision_logic_->SetSampleRate(fs_hz_, output_size_samples_);
+}
+
+NetEqOutputType NetEqImpl::LastOutputType() {
+  assert(vad_.get());
+  assert(expand_);
+  if (last_mode_ == kModeCodecInternalCng || last_mode_ == kModeRfc3389Cng) {
+    return kOutputCNG;
+  } else if (vad_->running() && !vad_->active_speech()) {
+    return kOutputVADPassive;
+  } else if (last_mode_ == kModeExpand && expand_->MuteFactor(0) == 0) {
+    // Expand mode has faded down to background noise only (very long expand).
+    return kOutputPLCtoCNG;
+
+  } else if (last_mode_ == kModeExpand) {
+    return kOutputPLC;
+
+  } else {
+    return kOutputNormal;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_impl.h b/webrtc/modules/audio_coding/neteq4/neteq_impl.h
new file mode 100644
index 0000000..18169dc
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_impl.h
@@ -0,0 +1,319 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_NETEQ_IMPL_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_NETEQ_IMPL_H_
+
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/defines.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"  // Declare PacketList.
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/rtcp.h"
+#include "webrtc/modules/audio_coding/neteq4/statistics_calculator.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+class BufferLevelFilter;
+class ComfortNoise;
+class CriticalSectionWrapper;
+class DecisionLogic;
+class DecoderDatabase;
+class DelayManager;
+class DelayPeakDetector;
+class DtmfBuffer;
+class DtmfToneGenerator;
+class Expand;
+class PacketBuffer;
+class PayloadSplitter;
+class PostDecodeVad;
+class RandomVector;
+class SyncBuffer;
+class TimestampScaler;
+struct DtmfEvent;
+
+class NetEqImpl : public webrtc::NetEq {
+ public:
+  // Creates a new NetEqImpl object. The object will assume ownership of all
+  // injected dependencies, and will delete them when done.
+  NetEqImpl(int fs,
+            BufferLevelFilter* buffer_level_filter,
+            DecoderDatabase* decoder_database,
+            DelayManager* delay_manager,
+            DelayPeakDetector* delay_peak_detector,
+            DtmfBuffer* dtmf_buffer,
+            DtmfToneGenerator* dtmf_tone_generator,
+            PacketBuffer* packet_buffer,
+            PayloadSplitter* payload_splitter,
+            TimestampScaler* timestamp_scaler);
+
+  virtual ~NetEqImpl();
+
+  // Inserts a new packet into NetEq. The |receive_timestamp| is an indication
+  // of the time when the packet was received, and should be measured with
+  // the same tick rate as the RTP timestamp of the current payload.
+  // Returns 0 on success, -1 on failure.
+  virtual int InsertPacket(const WebRtcRTPHeader& rtp_header,
+                           const uint8_t* payload,
+                           int length_bytes,
+                           uint32_t receive_timestamp);
+
+  // Instructs NetEq to deliver 10 ms of audio data. The data is written to
+  // |output_audio|, which can hold (at least) |max_length| elements.
+  // The number of channels that were written to the output is provided in
+  // the output variable |num_channels|, and each channel contains
+  // |samples_per_channel| elements. If more than one channel is written,
+  // the samples are interleaved.
+  // The speech type is written to |type|, if |type| is not NULL.
+  // Returns kOK on success, or kFail in case of an error.
+  virtual int GetAudio(size_t max_length, int16_t* output_audio,
+                       int* samples_per_channel, int* num_channels,
+                       NetEqOutputType* type);
+
+  // Associates |rtp_payload_type| with |codec| and stores the information in
+  // the codec database. Returns kOK on success, kFail on failure.
+  virtual int RegisterPayloadType(enum NetEqDecoder codec,
+                                  uint8_t rtp_payload_type);
+
+  // Provides an externally created decoder object |decoder| to insert in the
+  // decoder database. The decoder implements a decoder of type |codec| and
+  // associates it with |rtp_payload_type|. The decoder operates at the
+  // frequency |sample_rate_hz|. Returns kOK on success, kFail on failure.
+  virtual int RegisterExternalDecoder(AudioDecoder* decoder,
+                                      enum NetEqDecoder codec,
+                                      int sample_rate_hz,
+                                      uint8_t rtp_payload_type);
+
+  // Removes |rtp_payload_type| from the codec database. Returns 0 on success,
+  // -1 on failure.
+  virtual int RemovePayloadType(uint8_t rtp_payload_type);
+
+  // Sets the desired extra delay on top of what NetEq already applies due to
+  // current network situation. Used for synchronization with video. Returns
+  // true if successful, otherwise false.
+  virtual bool SetExtraDelay(int extra_delay_ms);
+
+  virtual int SetTargetDelay() { return kNotImplemented; }
+
+  virtual int TargetDelay() { return kNotImplemented; }
+
+  virtual int CurrentDelay() { return kNotImplemented; }
+
+  // Enables playout of DTMF tones.
+  virtual int EnableDtmf();
+
+  // Sets the playout mode to |mode|.
+  virtual void SetPlayoutMode(NetEqPlayoutMode mode);
+
+  // Returns the current playout mode.
+  virtual NetEqPlayoutMode PlayoutMode() const;
+
+  // Writes the current network statistics to |stats|. The statistics are reset
+  // after the call.
+  virtual int NetworkStatistics(NetEqNetworkStatistics* stats);
+
+  // Writes the last packet waiting times (in ms) to |waiting_times|. The number
+  // of values written is no more than 100, but may be smaller if the interface
+  // is polled again before 100 packets has arrived.
+  virtual void WaitingTimes(std::vector<int>* waiting_times);
+
+  // Writes the current RTCP statistics to |stats|. The statistics are reset
+  // and a new report period is started with the call.
+  virtual void GetRtcpStatistics(RtcpStatistics* stats);
+
+  // Same as RtcpStatistics(), but does not reset anything.
+  virtual void GetRtcpStatisticsNoReset(RtcpStatistics* stats);
+
+  // Enables post-decode VAD. When enabled, GetAudio() will return
+  // kOutputVADPassive when the signal contains no speech.
+  virtual void EnableVad();
+
+  // Disables post-decode VAD.
+  virtual void DisableVad();
+
+  // Returns the RTP timestamp for the last sample delivered by GetAudio().
+  virtual uint32_t PlayoutTimestamp();
+
+  virtual int SetTargetNumberOfChannels() { return kNotImplemented; }
+
+  virtual int SetTargetSampleRate() { return kNotImplemented; }
+
+  // Returns the error code for the last occurred error. If no error has
+  // occurred, 0 is returned.
+  virtual int LastError();
+
+  // Returns the error code last returned by a decoder (audio or comfort noise).
+  // When LastError() returns kDecoderErrorCode or kComfortNoiseErrorCode, check
+  // this method to get the decoder's error code.
+  virtual int LastDecoderError();
+
+  // Flushes both the packet buffer and the sync buffer.
+  virtual void FlushBuffers();
+
+ private:
+  static const int kOutputSizeMs = 10;
+  static const int kMaxFrameSize = 2880;  // 60 ms @ 48 kHz.
+  // TODO(hlundin): Provide a better value for kSyncBufferSize.
+  static const int kSyncBufferSize = 2 * kMaxFrameSize;
+
+  // Inserts a new packet into NetEq. This is used by the InsertPacket method
+  // above. Returns 0 on success, otherwise an error code.
+  // TODO(hlundin): Merge this with InsertPacket above?
+  int InsertPacketInternal(const WebRtcRTPHeader& rtp_header,
+                           const uint8_t* payload,
+                           int length_bytes,
+                           uint32_t receive_timestamp);
+
+
+  // Delivers 10 ms of audio to |output|. The number of samples produced is
+  // written to |output_length|. Returns 0 on success, or an error code.
+  int GetAudioInternal(size_t max_length, int16_t* output,
+                       int* samples_per_channel, int* num_channels);
+
+
+  // Provides a decision to the GetAudioInternal method. The decision what to
+  // do is written to |operation|. Packets to decode are written to
+  // |packet_list|, and a DTMF event to play is written to |dtmf_event|. When
+  // DTMF should be played, |play_dtmf| is set to true by the method.
+  // Returns 0 on success, otherwise an error code.
+  int GetDecision(Operations* operation,
+                  PacketList* packet_list,
+                  DtmfEvent* dtmf_event,
+                  bool* play_dtmf);
+
+  // Decodes the speech packets in |packet_list|, and writes the results to
+  // |decoded_buffer|, which is allocated to hold |decoded_buffer_length|
+  // elements. The length of the decoded data is written to |decoded_length|.
+  // The speech type -- speech or (codec-internal) comfort noise -- is written
+  // to |speech_type|. If |packet_list| contains any SID frames for RFC 3389
+  // comfort noise, those are not decoded.
+  int Decode(PacketList* packet_list, Operations* operation,
+             int* decoded_length, AudioDecoder::SpeechType* speech_type);
+
+  // Sub-method to Decode(). Performs the actual decoding.
+  int DecodeLoop(PacketList* packet_list, Operations* operation,
+                 AudioDecoder* decoder, int* decoded_length,
+                 AudioDecoder::SpeechType* speech_type);
+
+  // Sub-method which calls the Normal class to perform the normal operation.
+  void DoNormal(const int16_t* decoded_buffer, size_t decoded_length,
+                AudioDecoder::SpeechType speech_type, bool play_dtmf,
+                AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Sub-method which calls the Merge class to perform the merge operation.
+  void DoMerge(int16_t* decoded_buffer, size_t decoded_length,
+               AudioDecoder::SpeechType speech_type, bool play_dtmf,
+               AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Sub-method which calls the Expand class to perform the expand operation.
+  int DoExpand(bool play_dtmf, AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Sub-method which calls the Accelerate class to perform the accelerate
+  // operation.
+  int DoAccelerate(int16_t* decoded_buffer, size_t decoded_length,
+                   AudioDecoder::SpeechType speech_type, bool play_dtmf,
+                   AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Sub-method which calls the PreemptiveExpand class to perform the
+  // preemtive expand operation.
+  int DoPreemptiveExpand(int16_t* decoded_buffer, size_t decoded_length,
+                         AudioDecoder::SpeechType speech_type, bool play_dtmf,
+                         AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Sub-method which calls the ComfortNoise class to generate RFC 3389 comfort
+  // noise. |packet_list| can either contain one SID frame to update the
+  // noise parameters, or no payload at all, in which case the previously
+  // received parameters are used.
+  int DoRfc3389Cng(PacketList* packet_list, bool play_dtmf,
+                   AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Calls the audio decoder to generate codec-internal comfort noise when
+  // no packet was received.
+  void DoCodecInternalCng(AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Calls the DtmfToneGenerator class to generate DTMF tones.
+  int DoDtmf(const DtmfEvent& dtmf_event, bool* play_dtmf,
+             AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Produces packet-loss concealment using alternative methods. If the codec
+  // has an internal PLC, it is called to generate samples. Otherwise, the
+  // method performs zero-stuffing.
+  void DoAlternativePlc(bool increase_timestamp,
+                        AudioMultiVector<int16_t>* algorithm_buffer);
+
+  // Overdub DTMF on top of |output|.
+  int DtmfOverdub(const DtmfEvent& dtmf_event, size_t num_channels,
+                  int16_t* output) const;
+
+  // Extracts packets from |packet_buffer_| to produce at least
+  // |required_samples| samples. The packets are inserted into |packet_list|.
+  // Returns the number of samples that the packets in the list will produce, or
+  // -1 in case of an error.
+  int ExtractPackets(int required_samples, PacketList* packet_list);
+
+  // Resets various variables and objects to new values based on the sample rate
+  // |fs_hz| and |channels| number audio channels.
+  void SetSampleRateAndChannels(int fs_hz, size_t channels);
+
+  // Returns the output type for the audio produced by the latest call to
+  // GetAudio().
+  NetEqOutputType LastOutputType();
+
+  BackgroundNoise* background_noise_;
+  scoped_ptr<BufferLevelFilter> buffer_level_filter_;
+  scoped_ptr<DecoderDatabase> decoder_database_;
+  scoped_ptr<DelayManager> delay_manager_;
+  scoped_ptr<DelayPeakDetector> delay_peak_detector_;
+  scoped_ptr<DtmfBuffer> dtmf_buffer_;
+  scoped_ptr<DtmfToneGenerator> dtmf_tone_generator_;
+  scoped_ptr<PacketBuffer> packet_buffer_;
+  scoped_ptr<PayloadSplitter> payload_splitter_;
+  scoped_ptr<TimestampScaler> timestamp_scaler_;
+  scoped_ptr<DecisionLogic> decision_logic_;
+  scoped_ptr<PostDecodeVad> vad_;
+  SyncBuffer* sync_buffer_;
+  Expand* expand_;
+  RandomVector random_vector_;
+  ComfortNoise* comfort_noise_;
+  Rtcp rtcp_;
+  StatisticsCalculator stats_;
+  int fs_hz_;
+  int fs_mult_;
+  int output_size_samples_;
+  int decoder_frame_length_;
+  Modes last_mode_;
+  scoped_array<int16_t> mute_factor_array_;
+  size_t decoded_buffer_length_;
+  scoped_array<int16_t> decoded_buffer_;
+  uint32_t playout_timestamp_;
+  bool new_codec_;
+  uint32_t timestamp_;
+  bool reset_decoder_;
+  uint8_t current_rtp_payload_type_;
+  uint8_t current_cng_rtp_payload_type_;
+  uint32_t ssrc_;
+  bool first_packet_;
+  bool dtmf_enabled_;
+  int error_code_;  // Store last error code.
+  int decoder_error_code_;
+  CriticalSectionWrapper* crit_sect_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetEqImpl);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_NETEQ_IMPL_H_
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_impl_unittest.cc b/webrtc/modules/audio_coding/neteq4/neteq_impl_unittest.cc
new file mode 100644
index 0000000..47fa18e
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_impl_unittest.cc
@@ -0,0 +1,226 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/modules/audio_coding/neteq4/neteq_impl.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_buffer_level_filter.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_delay_manager.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_delay_peak_detector.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_dtmf_tone_generator.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_packet_buffer.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_payload_splitter.h"
+#include "webrtc/modules/audio_coding/neteq4/timestamp_scaler.h"
+
+using ::testing::Return;
+using ::testing::ReturnNull;
+using ::testing::_;
+using ::testing::SetArgPointee;
+using ::testing::InSequence;
+using ::testing::Invoke;
+using ::testing::WithArg;
+
+namespace webrtc {
+
+// This function is called when inserting a packet list into the mock packet
+// buffer. The purpose is to delete all inserted packets properly, to avoid
+// memory leaks in the test.
+int DeletePacketsAndReturnOk(PacketList* packet_list) {
+  PacketBuffer::DeleteAllPackets(packet_list);
+  return PacketBuffer::kOK;
+}
+
+class NetEqImplTest : public ::testing::Test {
+ protected:
+  static const int kInitSampleRateHz = 8000;
+  NetEqImplTest() {
+    buffer_level_filter_ = new MockBufferLevelFilter;
+    decoder_database_ = new MockDecoderDatabase;
+    delay_peak_detector_ = new MockDelayPeakDetector;
+    EXPECT_CALL(*delay_peak_detector_, Reset()).Times(1);
+    delay_manager_ = new MockDelayManager(NetEq::kMaxNumPacketsInBuffer,
+                                          delay_peak_detector_);
+    dtmf_buffer_ = new MockDtmfBuffer(kInitSampleRateHz);
+    dtmf_tone_generator_ = new MockDtmfToneGenerator;
+    packet_buffer_ = new MockPacketBuffer(NetEq::kMaxNumPacketsInBuffer,
+                                          NetEq::kMaxBytesInBuffer);
+    payload_splitter_ = new MockPayloadSplitter;
+    timestamp_scaler_ = new TimestampScaler(*decoder_database_);
+    EXPECT_CALL(*decoder_database_, GetActiveCngDecoder())
+        .WillOnce(ReturnNull());
+    neteq_ = new NetEqImpl(kInitSampleRateHz,
+                           buffer_level_filter_,
+                           decoder_database_,
+                           delay_manager_,
+                           delay_peak_detector_,
+                           dtmf_buffer_,
+                           dtmf_tone_generator_,
+                           packet_buffer_,
+                           payload_splitter_,
+                           timestamp_scaler_);
+  }
+
+  virtual ~NetEqImplTest() {
+    EXPECT_CALL(*buffer_level_filter_, Die()).Times(1);
+    EXPECT_CALL(*decoder_database_, Die()).Times(1);
+    EXPECT_CALL(*delay_manager_, Die()).Times(1);
+    EXPECT_CALL(*delay_peak_detector_, Die()).Times(1);
+    EXPECT_CALL(*dtmf_buffer_, Die()).Times(1);
+    EXPECT_CALL(*dtmf_tone_generator_, Die()).Times(1);
+    EXPECT_CALL(*packet_buffer_, Die()).Times(1);
+    delete neteq_;
+  }
+
+  NetEqImpl* neteq_;
+  MockBufferLevelFilter* buffer_level_filter_;
+  MockDecoderDatabase* decoder_database_;
+  MockDelayPeakDetector* delay_peak_detector_;
+  MockDelayManager* delay_manager_;
+  MockDtmfBuffer* dtmf_buffer_;
+  MockDtmfToneGenerator* dtmf_tone_generator_;
+  MockPacketBuffer* packet_buffer_;
+  MockPayloadSplitter* payload_splitter_;
+  TimestampScaler* timestamp_scaler_;
+};
+
+
+// This tests the interface class NetEq.
+// TODO(hlundin): Move to separate file?
+TEST(NetEq, CreateAndDestroy) {
+  NetEq* neteq = NetEq::Create(8000);
+  delete neteq;
+}
+
+TEST_F(NetEqImplTest, RegisterPayloadType) {
+  uint8_t rtp_payload_type = 0;
+  NetEqDecoder codec_type = kDecoderPCMu;
+  EXPECT_CALL(*decoder_database_,
+              RegisterPayload(rtp_payload_type, codec_type));
+  neteq_->RegisterPayloadType(codec_type, rtp_payload_type);
+}
+
+TEST_F(NetEqImplTest, RemovePayloadType) {
+  uint8_t rtp_payload_type = 0;
+  EXPECT_CALL(*decoder_database_,
+              Remove(rtp_payload_type))
+      .WillOnce(Return(DecoderDatabase::kDecoderNotFound));
+  // Check that kFail is returned when database returns kDecoderNotFound.
+  EXPECT_EQ(NetEq::kFail, neteq_->RemovePayloadType(rtp_payload_type));
+}
+
+TEST_F(NetEqImplTest, InsertPacket) {
+  const int kPayloadLength = 100;
+  const uint8_t kPayloadType = 0;
+  const uint16_t kFirstSequenceNumber = 0x1234;
+  const uint32_t kFirstTimestamp = 0x12345678;
+  const uint32_t kSsrc = 0x87654321;
+  const uint32_t kFirstReceiveTime = 17;
+  uint8_t payload[kPayloadLength] = {0};
+  WebRtcRTPHeader rtp_header;
+  rtp_header.header.payloadType = kPayloadType;
+  rtp_header.header.sequenceNumber = kFirstSequenceNumber;
+  rtp_header.header.timestamp = kFirstTimestamp;
+  rtp_header.header.ssrc = kSsrc;
+
+  // Create a mock decoder object.
+  MockAudioDecoder mock_decoder;
+  // BWE update function called with first packet.
+  EXPECT_CALL(mock_decoder, IncomingPacket(_,
+                                           kPayloadLength,
+                                           kFirstSequenceNumber,
+                                           kFirstTimestamp,
+                                           kFirstReceiveTime));
+  // BWE update function called with second packet.
+  EXPECT_CALL(mock_decoder, IncomingPacket(_,
+                                           kPayloadLength,
+                                           kFirstSequenceNumber + 1,
+                                           kFirstTimestamp + 160,
+                                           kFirstReceiveTime + 155));
+  EXPECT_CALL(mock_decoder, Die()).Times(1);  // Called when deleted.
+
+  // Expectations for decoder database.
+  EXPECT_CALL(*decoder_database_, IsRed(kPayloadType))
+      .WillRepeatedly(Return(false));  // This is not RED.
+  EXPECT_CALL(*decoder_database_, CheckPayloadTypes(_))
+      .Times(2)
+      .WillRepeatedly(Return(DecoderDatabase::kOK));  // Payload type is valid.
+  EXPECT_CALL(*decoder_database_, IsDtmf(kPayloadType))
+      .WillRepeatedly(Return(false));  // This is not DTMF.
+  EXPECT_CALL(*decoder_database_, GetDecoder(kPayloadType))
+      .Times(2)
+      .WillRepeatedly(Return(&mock_decoder));
+  EXPECT_CALL(*decoder_database_, IsComfortNoise(kPayloadType))
+      .WillRepeatedly(Return(false));  // This is not CNG.
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderPCMu;
+  EXPECT_CALL(*decoder_database_, GetDecoderInfo(kPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  // Expectations for packet buffer.
+  EXPECT_CALL(*packet_buffer_, NumPacketsInBuffer())
+      .WillOnce(Return(0))   // First packet.
+      .WillOnce(Return(1))   // Second packet.
+      .WillOnce(Return(2));  // Second packet, checking after it was inserted.
+  EXPECT_CALL(*packet_buffer_, Flush())
+      .Times(1);
+  EXPECT_CALL(*packet_buffer_, InsertPacketList(_, _, _, _))
+      .Times(2)
+      .WillRepeatedly(DoAll(SetArgPointee<2>(kPayloadType),
+                            WithArg<0>(Invoke(DeletePacketsAndReturnOk))));
+  // SetArgPointee<2>(kPayloadType) means that the third argument (zero-based
+  // index) is a pointer, and the variable pointed to is set to kPayloadType.
+  // Also invoke the function DeletePacketsAndReturnOk to properly delete all
+  // packets in the list (to avoid memory leaks in the test).
+
+  // Expectations for DTMF buffer.
+  EXPECT_CALL(*dtmf_buffer_, Flush())
+      .Times(1);
+
+  // Expectations for delay manager.
+  {
+    // All expectations within this block must be called in this specific order.
+    InSequence sequence;  // Dummy variable.
+    // Expectations when the first packet is inserted.
+    EXPECT_CALL(*delay_manager_, LastDecoderType(kDecoderPCMu))
+        .Times(1);
+    EXPECT_CALL(*delay_manager_, last_pack_cng_or_dtmf())
+        .Times(2)
+        .WillRepeatedly(Return(-1));
+    EXPECT_CALL(*delay_manager_, set_last_pack_cng_or_dtmf(0))
+        .Times(1);
+    EXPECT_CALL(*delay_manager_, ResetPacketIatCount()).Times(1);
+    // Expectations when the second packet is inserted. Slightly different.
+    EXPECT_CALL(*delay_manager_, LastDecoderType(kDecoderPCMu))
+        .Times(1);
+    EXPECT_CALL(*delay_manager_, last_pack_cng_or_dtmf())
+        .WillOnce(Return(0));
+  }
+
+  // Expectations for payload splitter.
+  EXPECT_CALL(*payload_splitter_, SplitAudio(_, _))
+      .Times(2)
+      .WillRepeatedly(Return(PayloadSplitter::kOK));
+
+  // Insert first packet.
+  neteq_->InsertPacket(rtp_header, payload, kPayloadLength, kFirstReceiveTime);
+
+  // Insert second packet.
+  rtp_header.header.timestamp += 160;
+  rtp_header.header.sequenceNumber += 1;
+  neteq_->InsertPacket(rtp_header, payload, kPayloadLength,
+                       kFirstReceiveTime + 155);
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_stereo_unittest.cc b/webrtc/modules/audio_coding/neteq4/neteq_stereo_unittest.cc
new file mode 100644
index 0000000..9c74e03
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_stereo_unittest.cc
@@ -0,0 +1,417 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Test to verify correct stereo and multi-channel operation.
+
+#include <string>
+#include <list>
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/codecs/pcm16b/include/pcm16b.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/modules/audio_coding/neteq4/tools/input_audio_file.h"
+#include "webrtc/modules/audio_coding/neteq4/tools/rtp_generator.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+#include "webrtc/test/testsupport/fileutils.h"
+
+namespace webrtc {
+
+struct TestParameters {
+  int frame_size;
+  int sample_rate;
+  int num_channels;
+};
+
+// This is a parameterized test. The test parameters are supplied through a
+// TestParameters struct, which is obtained through the GetParam() method.
+//
+// The objective of the test is to create a mono input signal and a
+// multi-channel input signal, where each channel is identical to the mono
+// input channel. The two input signals are processed through their respective
+// NetEq instances. After that, the output signals are compared. The expected
+// result is that each channel in the multi-channel output is identical to the
+// mono output.
+class NetEqStereoTest : public ::testing::TestWithParam<TestParameters> {
+ protected:
+  static const int kTimeStepMs = 10;
+  static const int kMaxBlockSize = 480;  // 10 ms @ 48 kHz.
+  static const uint8_t kPayloadTypeMono = 95;
+  static const uint8_t kPayloadTypeMulti = 96;
+
+  NetEqStereoTest()
+      : num_channels_(GetParam().num_channels),
+        sample_rate_hz_(GetParam().sample_rate),
+        samples_per_ms_(sample_rate_hz_ / 1000),
+        frame_size_ms_(GetParam().frame_size),
+        frame_size_samples_(frame_size_ms_ * samples_per_ms_),
+        output_size_samples_(10 * samples_per_ms_),
+        neteq_mono_(NetEq::Create(sample_rate_hz_)),
+        neteq_(NetEq::Create(sample_rate_hz_)),
+        rtp_generator_mono_(samples_per_ms_),
+        rtp_generator_(samples_per_ms_),
+        payload_size_bytes_(0),
+        multi_payload_size_bytes_(0),
+        last_send_time_(0),
+        last_arrival_time_(0) {
+    input_ = new int16_t[frame_size_samples_];
+    encoded_ = new uint8_t[2 * frame_size_samples_];
+    input_multi_channel_ = new int16_t[frame_size_samples_ * num_channels_];
+    encoded_multi_channel_ = new uint8_t[frame_size_samples_ * 2 *
+                                         num_channels_];
+    output_multi_channel_ = new int16_t[kMaxBlockSize * num_channels_];
+  }
+
+  ~NetEqStereoTest() {
+    delete neteq_mono_;
+    delete neteq_;
+    delete [] input_;
+    delete [] encoded_;
+    delete [] input_multi_channel_;
+    delete [] encoded_multi_channel_;
+    delete [] output_multi_channel_;
+  }
+
+  virtual void SetUp() {
+    const std::string file_name =
+        webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm");
+    input_file_.reset(new test::InputAudioFile(file_name));
+    NetEqDecoder mono_decoder;
+    NetEqDecoder multi_decoder;
+    switch (sample_rate_hz_) {
+      case 8000:
+        mono_decoder = kDecoderPCM16B;
+        if (num_channels_ == 2) {
+          multi_decoder = kDecoderPCM16B_2ch;
+        } else if (num_channels_ == 5) {
+          multi_decoder = kDecoderPCM16B_5ch;
+        } else {
+          FAIL() << "Only 2 and 5 channels supported for 8000 Hz.";
+        }
+        break;
+      case 16000:
+        mono_decoder = kDecoderPCM16Bwb;
+        if (num_channels_ == 2) {
+          multi_decoder = kDecoderPCM16Bwb_2ch;
+        } else {
+          FAIL() << "More than 2 channels is not supported for 16000 Hz.";
+        }
+        break;
+      case 32000:
+        mono_decoder = kDecoderPCM16Bswb32kHz;
+        if (num_channels_ == 2) {
+          multi_decoder = kDecoderPCM16Bswb32kHz_2ch;
+        } else {
+          FAIL() << "More than 2 channels is not supported for 32000 Hz.";
+        }
+        break;
+      case 48000:
+        mono_decoder = kDecoderPCM16Bswb48kHz;
+        if (num_channels_ == 2) {
+          multi_decoder = kDecoderPCM16Bswb48kHz_2ch;
+        } else {
+          FAIL() << "More than 2 channels is not supported for 48000 Hz.";
+        }
+        break;
+      default:
+        FAIL() << "We shouldn't get here.";
+    }
+    ASSERT_EQ(NetEq::kOK,
+              neteq_mono_->RegisterPayloadType(mono_decoder,
+                                               kPayloadTypeMono));
+    ASSERT_EQ(NetEq::kOK,
+              neteq_->RegisterPayloadType(multi_decoder,
+                                          kPayloadTypeMulti));
+  }
+
+  virtual void TearDown() {}
+
+  int GetNewPackets() {
+    if (!input_file_->Read(frame_size_samples_, input_)) {
+      return -1;
+    }
+    payload_size_bytes_ = WebRtcPcm16b_Encode(input_, frame_size_samples_,
+                                             encoded_);
+    if (frame_size_samples_ * 2 != payload_size_bytes_) {
+      return -1;
+    }
+    int next_send_time = rtp_generator_mono_.GetRtpHeader(kPayloadTypeMono,
+                                                          frame_size_samples_,
+                                                          &rtp_header_mono_);
+    test::InputAudioFile::DuplicateInterleaved(input_, frame_size_samples_,
+                                               num_channels_,
+                                               input_multi_channel_);
+    multi_payload_size_bytes_ = WebRtcPcm16b_Encode(
+        input_multi_channel_, frame_size_samples_ * num_channels_,
+        encoded_multi_channel_);
+    if (frame_size_samples_ * 2 * num_channels_ != multi_payload_size_bytes_) {
+      return -1;
+    }
+    rtp_generator_.GetRtpHeader(kPayloadTypeMulti, frame_size_samples_,
+                                &rtp_header_);
+    return next_send_time;
+  }
+
+  void VerifyOutput(size_t num_samples) {
+    for (size_t i = 0; i < num_samples; ++i) {
+      for (int j = 0; j < num_channels_; ++j) {
+        ASSERT_EQ(output_[i], output_multi_channel_[i * num_channels_ + j]) <<
+            "Diff in sample " << i << ", channel " << j << ".";
+      }
+    }
+  }
+
+  virtual int GetArrivalTime(int send_time) {
+    int arrival_time = last_arrival_time_ + (send_time - last_send_time_);
+    last_send_time_ = send_time;
+    last_arrival_time_ = arrival_time;
+    return arrival_time;
+  }
+
+  virtual bool Lost() { return false; }
+
+  void RunTest(int num_loops) {
+    // Get next input packets (mono and multi-channel).
+    int next_send_time;
+    int next_arrival_time;
+    do {
+      next_send_time = GetNewPackets();
+      ASSERT_NE(-1, next_send_time);
+      next_arrival_time = GetArrivalTime(next_send_time);
+    } while (Lost());  // If lost, immediately read the next packet.
+
+    int time_now = 0;
+    for (int k = 0; k < num_loops; ++k) {
+      while (time_now >= next_arrival_time) {
+        // Insert packet in mono instance.
+        ASSERT_EQ(NetEq::kOK,
+                  neteq_mono_->InsertPacket(rtp_header_mono_, encoded_,
+                                            payload_size_bytes_,
+                                            next_arrival_time));
+        // Insert packet in multi-channel instance.
+        ASSERT_EQ(NetEq::kOK,
+                  neteq_->InsertPacket(rtp_header_, encoded_multi_channel_,
+                                       multi_payload_size_bytes_,
+                                       next_arrival_time));
+        // Get next input packets (mono and multi-channel).
+        do {
+          next_send_time = GetNewPackets();
+          ASSERT_NE(-1, next_send_time);
+          next_arrival_time = GetArrivalTime(next_send_time);
+        } while (Lost());  // If lost, immediately read the next packet.
+      }
+      NetEqOutputType output_type;
+      // Get audio from mono instance.
+      int samples_per_channel;
+      int num_channels;
+      EXPECT_EQ(NetEq::kOK,
+                neteq_mono_->GetAudio(kMaxBlockSize, output_,
+                                      &samples_per_channel, &num_channels,
+                                      &output_type));
+      EXPECT_EQ(1, num_channels);
+      EXPECT_EQ(output_size_samples_, samples_per_channel);
+      // Get audio from multi-channel instance.
+      ASSERT_EQ(NetEq::kOK,
+                neteq_->GetAudio(kMaxBlockSize * num_channels_,
+                                 output_multi_channel_,
+                                 &samples_per_channel, &num_channels,
+                                 &output_type));
+      EXPECT_EQ(num_channels_, num_channels);
+      EXPECT_EQ(output_size_samples_, samples_per_channel);
+      std::ostringstream ss;
+      ss << "Lap number " << k << ".";
+      SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+      // Compare mono and multi-channel.
+      ASSERT_NO_FATAL_FAILURE(VerifyOutput(output_size_samples_));
+
+      time_now += kTimeStepMs;
+    }
+  }
+
+  const int num_channels_;
+  const int sample_rate_hz_;
+  const int samples_per_ms_;
+  const int frame_size_ms_;
+  const int frame_size_samples_;
+  const int output_size_samples_;
+  NetEq* neteq_mono_;
+  NetEq* neteq_;
+  test::RtpGenerator rtp_generator_mono_;
+  test::RtpGenerator rtp_generator_;
+  int16_t* input_;
+  int16_t* input_multi_channel_;
+  uint8_t* encoded_;
+  uint8_t* encoded_multi_channel_;
+  int16_t output_[kMaxBlockSize];
+  int16_t* output_multi_channel_;
+  WebRtcRTPHeader rtp_header_mono_;
+  WebRtcRTPHeader rtp_header_;
+  int payload_size_bytes_;
+  int multi_payload_size_bytes_;
+  int last_send_time_;
+  int last_arrival_time_;
+  scoped_ptr<test::InputAudioFile> input_file_;
+};
+
+class NetEqStereoTestNoJitter : public NetEqStereoTest {
+ protected:
+  NetEqStereoTestNoJitter()
+      : NetEqStereoTest() {
+    // Start the sender 100 ms before the receiver to pre-fill the buffer.
+    // This is to avoid doing preemptive expand early in the test.
+    // TODO(hlundin): Mock the decision making instead to control the modes.
+    last_arrival_time_ = -100;
+  }
+};
+
+TEST_P(NetEqStereoTestNoJitter, RunTest) {
+  RunTest(8);
+}
+
+class NetEqStereoTestPositiveDrift : public NetEqStereoTest {
+ protected:
+  NetEqStereoTestPositiveDrift()
+      : NetEqStereoTest(),
+        drift_factor(0.9) {
+    // Start the sender 100 ms before the receiver to pre-fill the buffer.
+    // This is to avoid doing preemptive expand early in the test.
+    // TODO(hlundin): Mock the decision making instead to control the modes.
+    last_arrival_time_ = -100;
+  }
+  virtual int GetArrivalTime(int send_time) {
+    int arrival_time = last_arrival_time_ +
+        drift_factor * (send_time - last_send_time_);
+    last_send_time_ = send_time;
+    last_arrival_time_ = arrival_time;
+    return arrival_time;
+  }
+
+  double drift_factor;
+};
+
+TEST_P(NetEqStereoTestPositiveDrift, RunTest) {
+  RunTest(100);
+}
+
+class NetEqStereoTestNegativeDrift : public NetEqStereoTestPositiveDrift {
+ protected:
+  NetEqStereoTestNegativeDrift()
+      : NetEqStereoTestPositiveDrift() {
+    drift_factor = 1.1;
+    last_arrival_time_ = 0;
+  }
+};
+
+TEST_P(NetEqStereoTestNegativeDrift, RunTest) {
+  RunTest(100);
+}
+
+class NetEqStereoTestDelays : public NetEqStereoTest {
+ protected:
+  static const int kDelayInterval = 10;
+  static const int kDelay = 1000;
+  NetEqStereoTestDelays()
+      : NetEqStereoTest(),
+        frame_index_(0) {
+  }
+
+  virtual int GetArrivalTime(int send_time) {
+    // Deliver immediately, unless we have a back-log.
+    int arrival_time = std::min(last_arrival_time_, send_time);
+    if (++frame_index_ % kDelayInterval == 0) {
+      // Delay this packet.
+      arrival_time += kDelay;
+    }
+    last_send_time_ = send_time;
+    last_arrival_time_ = arrival_time;
+    return arrival_time;
+  }
+
+  int frame_index_;
+};
+
+TEST_P(NetEqStereoTestDelays, RunTest) {
+  RunTest(1000);
+}
+
+class NetEqStereoTestLosses : public NetEqStereoTest {
+ protected:
+  static const int kLossInterval = 10;
+  NetEqStereoTestLosses()
+      : NetEqStereoTest(),
+        frame_index_(0) {
+  }
+
+  virtual bool Lost() {
+    return (++frame_index_) % kLossInterval == 0;
+  }
+
+  int frame_index_;
+};
+
+TEST_P(NetEqStereoTestLosses, RunTest) {
+  RunTest(100);
+}
+
+
+// Creates a list of parameter sets.
+std::list<TestParameters> GetTestParameters() {
+  std::list<TestParameters> l;
+  const int sample_rates[] = {8000, 16000, 32000};
+  const int num_rates = sizeof(sample_rates) / sizeof(sample_rates[0]);
+  // Loop through sample rates.
+  for (int rate_index = 0; rate_index < num_rates; ++rate_index) {
+    int sample_rate = sample_rates[rate_index];
+    // Loop through all frame sizes between 10 and 60 ms.
+    for (int frame_size = 10; frame_size <= 60; frame_size += 10) {
+      TestParameters p;
+      p.frame_size = frame_size;
+      p.sample_rate = sample_rate;
+      p.num_channels = 2;
+      l.push_back(p);
+      if (sample_rate == 8000) {
+        // Add a five-channel test for 8000 Hz.
+        p.num_channels = 5;
+        l.push_back(p);
+      }
+    }
+  }
+  return l;
+}
+
+// Pretty-printing the test parameters in case of an error.
+void PrintTo(const TestParameters& p, ::std::ostream* os) {
+  *os << "{frame_size = " << p.frame_size <<
+      ", num_channels = " << p.num_channels <<
+      ", sample_rate = " << p.sample_rate << "}";
+}
+
+// Instantiate the tests. Each test is instantiated using the function above,
+// so that all different parameter combinations are tested.
+INSTANTIATE_TEST_CASE_P(MultiChannel,
+                        NetEqStereoTestNoJitter,
+                        ::testing::ValuesIn(GetTestParameters()));
+
+INSTANTIATE_TEST_CASE_P(MultiChannel,
+                        NetEqStereoTestPositiveDrift,
+                        ::testing::ValuesIn(GetTestParameters()));
+
+INSTANTIATE_TEST_CASE_P(MultiChannel,
+                        NetEqStereoTestNegativeDrift,
+                        ::testing::ValuesIn(GetTestParameters()));
+
+INSTANTIATE_TEST_CASE_P(MultiChannel,
+                        NetEqStereoTestDelays,
+                        ::testing::ValuesIn(GetTestParameters()));
+
+INSTANTIATE_TEST_CASE_P(MultiChannel,
+                        NetEqStereoTestLosses,
+                        ::testing::ValuesIn(GetTestParameters()));
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_tests.gypi b/webrtc/modules/audio_coding/neteq4/neteq_tests.gypi
new file mode 100644
index 0000000..aa85f74
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_tests.gypi
@@ -0,0 +1,179 @@
+# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+{
+  'targets': [
+    {
+      'target_name': 'neteq_rtpplay',
+      'type': 'executable',
+      'dependencies': [
+        'NetEq4',
+        'NetEq4TestTools',
+        '<(webrtc_root)/test/test.gyp:test_support_main',
+        '<(DEPTH)/third_party/google-gflags/google-gflags.gyp:google-gflags',
+      ],
+      'sources': [
+        'tools/neteq_rtpplay.cc',
+      ],
+      'defines': [
+      ],
+    }, # neteq_rtpplay
+
+    {
+      'target_name': 'RTPencode',
+      'type': 'executable',
+      'dependencies': [
+        # TODO(hlundin): Make RTPencode use ACM to encode files.
+        'NetEq4TestTools',# Test helpers
+        'G711',
+        'G722',
+        'PCM16B',
+        'iLBC',
+        'iSAC',
+        'CNG',
+        '<(webrtc_root)/common_audio/common_audio.gyp:vad',
+      ],
+      'defines': [
+        'CODEC_ILBC',
+        'CODEC_PCM16B',
+        'CODEC_G711',
+        'CODEC_G722',
+        'CODEC_ISAC',
+        'CODEC_PCM16B_WB',
+        'CODEC_ISAC_SWB',
+        'CODEC_PCM16B_32KHZ',
+        'CODEC_CNGCODEC8',
+        'CODEC_CNGCODEC16',
+        'CODEC_CNGCODEC32',
+        'CODEC_ATEVENT_DECODE',
+        'CODEC_RED',
+      ],
+      'include_dirs': [
+        'interface',
+        'test',
+      ],
+      'sources': [
+        'test/RTPencode.cc',
+      ],
+    },
+
+    {
+      'target_name': 'RTPjitter',
+      'type': 'executable',
+      'dependencies': [
+        '<(DEPTH)/testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+        'test/RTPjitter.cc',
+      ],
+    },
+
+    {
+      'target_name': 'RTPanalyze',
+      'type': 'executable',
+      'dependencies': [
+        'NetEq4TestTools',
+        '<(DEPTH)/testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+        'test/RTPanalyze.cc',
+      ],
+    },
+
+    {
+      'target_name': 'RTPchange',
+      'type': 'executable',
+      'dependencies': [
+        'NetEq4TestTools',
+        '<(DEPTH)/testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+       'test/RTPchange.cc',
+      ],
+    },
+
+    {
+      'target_name': 'RTPtimeshift',
+      'type': 'executable',
+      'dependencies': [
+       'NetEq4TestTools',
+        '<(DEPTH)/testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+        'test/RTPtimeshift.cc',
+      ],
+    },
+
+    {
+      'target_name': 'RTPcat',
+      'type': 'executable',
+      'dependencies': [
+        'NetEq4TestTools',
+        '<(DEPTH)/testing/gtest.gyp:gtest',
+      ],
+      'sources': [
+        'test/RTPcat.cc',
+      ],
+    },
+
+    {
+      'target_name': 'rtp_to_text',
+      'type': 'executable',
+      'dependencies': [
+        'NetEq4TestTools',
+        '<(webrtc_root)/system_wrappers/source/system_wrappers.gyp:system_wrappers',
+      ],
+      'sources': [
+        'test/rtp_to_text.cc',
+      ],
+    },
+
+    {
+     'target_name': 'NetEq4TestTools',
+      # Collection of useful functions used in other tests.
+      'type': 'static_library',
+      'variables': {
+        # Expects RTP packets without payloads when enabled.
+        'neteq_dummy_rtp%': 0,
+      },
+      'dependencies': [
+        'G711',
+        'G722',
+        'PCM16B',
+        'iLBC',
+        'iSAC',
+        'CNG',
+        '<(DEPTH)/testing/gtest.gyp:gtest',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          'interface',
+          'test',
+        ],
+      },
+      'defines': [
+      ],
+      'include_dirs': [
+        'interface',
+        'test',
+      ],
+      'sources': [
+        'test/NETEQTEST_DummyRTPpacket.cc',
+        'test/NETEQTEST_DummyRTPpacket.h',
+        'test/NETEQTEST_RTPpacket.cc',
+        'test/NETEQTEST_RTPpacket.h',
+      ],
+    },
+  ], # targets
+}
+
+# Local Variables:
+# tab-width:2
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=2 shiftwidth=2:
diff --git a/webrtc/modules/audio_coding/neteq4/neteq_unittest.cc b/webrtc/modules/audio_coding/neteq4/neteq_unittest.cc
new file mode 100644
index 0000000..c5b44d8
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/neteq_unittest.cc
@@ -0,0 +1,694 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/*
+ * This file includes unit tests for NetEQ.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+
+#include <stdlib.h>
+#include <string.h>  // memset
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h"
+#include "webrtc/test/testsupport/fileutils.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+class RefFiles {
+ public:
+  RefFiles(const std::string& input_file, const std::string& output_file);
+  ~RefFiles();
+  template<class T> void ProcessReference(const T& test_results);
+  template<typename T, size_t n> void ProcessReference(
+      const T (&test_results)[n],
+      size_t length);
+  template<typename T, size_t n> void WriteToFile(
+      const T (&test_results)[n],
+      size_t length);
+  template<typename T, size_t n> void ReadFromFileAndCompare(
+      const T (&test_results)[n],
+      size_t length);
+  void WriteToFile(const NetEqNetworkStatistics& stats);
+  void ReadFromFileAndCompare(const NetEqNetworkStatistics& stats);
+  void WriteToFile(const RtcpStatistics& stats);
+  void ReadFromFileAndCompare(const RtcpStatistics& stats);
+
+  FILE* input_fp_;
+  FILE* output_fp_;
+};
+
+RefFiles::RefFiles(const std::string &input_file,
+                   const std::string &output_file)
+    : input_fp_(NULL),
+      output_fp_(NULL) {
+  if (!input_file.empty()) {
+    input_fp_ = fopen(input_file.c_str(), "rb");
+    EXPECT_TRUE(input_fp_ != NULL);
+  }
+  if (!output_file.empty()) {
+    output_fp_ = fopen(output_file.c_str(), "wb");
+    EXPECT_TRUE(output_fp_ != NULL);
+  }
+}
+
+RefFiles::~RefFiles() {
+  if (input_fp_) {
+    EXPECT_EQ(EOF, fgetc(input_fp_));  // Make sure that we reached the end.
+    fclose(input_fp_);
+  }
+  if (output_fp_) fclose(output_fp_);
+}
+
+template<class T>
+void RefFiles::ProcessReference(const T& test_results) {
+  WriteToFile(test_results);
+  ReadFromFileAndCompare(test_results);
+}
+
+template<typename T, size_t n>
+void RefFiles::ProcessReference(const T (&test_results)[n], size_t length) {
+  WriteToFile(test_results, length);
+  ReadFromFileAndCompare(test_results, length);
+}
+
+template<typename T, size_t n>
+void RefFiles::WriteToFile(const T (&test_results)[n], size_t length) {
+  if (output_fp_) {
+    ASSERT_EQ(length, fwrite(&test_results, sizeof(T), length, output_fp_));
+  }
+}
+
+template<typename T, size_t n>
+void RefFiles::ReadFromFileAndCompare(const T (&test_results)[n],
+                                      size_t length) {
+  if (input_fp_) {
+    // Read from ref file.
+    T* ref = new T[length];
+    ASSERT_EQ(length, fread(ref, sizeof(T), length, input_fp_));
+    // Compare
+    ASSERT_EQ(0, memcmp(&test_results, ref, sizeof(T) * length));
+    delete [] ref;
+  }
+}
+
+void RefFiles::WriteToFile(const NetEqNetworkStatistics& stats) {
+  if (output_fp_) {
+    ASSERT_EQ(1u, fwrite(&stats, sizeof(NetEqNetworkStatistics), 1,
+                         output_fp_));
+  }
+}
+
+void RefFiles::ReadFromFileAndCompare(
+    const NetEqNetworkStatistics& stats) {
+  if (input_fp_) {
+    // Read from ref file.
+    size_t stat_size = sizeof(NetEqNetworkStatistics);
+    NetEqNetworkStatistics ref_stats;
+    ASSERT_EQ(1u, fread(&ref_stats, stat_size, 1, input_fp_));
+    // Compare
+    EXPECT_EQ(0, memcmp(&stats, &ref_stats, stat_size));
+  }
+}
+
+void RefFiles::WriteToFile(const RtcpStatistics& stats) {
+  if (output_fp_) {
+    ASSERT_EQ(1u, fwrite(&(stats.fraction_lost), sizeof(stats.fraction_lost), 1,
+                         output_fp_));
+    ASSERT_EQ(1u, fwrite(&(stats.cumulative_lost),
+                         sizeof(stats.cumulative_lost), 1, output_fp_));
+    ASSERT_EQ(1u, fwrite(&(stats.extended_max), sizeof(stats.extended_max), 1,
+                         output_fp_));
+    ASSERT_EQ(1u, fwrite(&(stats.jitter), sizeof(stats.jitter), 1,
+                         output_fp_));
+  }
+}
+
+void RefFiles::ReadFromFileAndCompare(
+    const RtcpStatistics& stats) {
+  if (input_fp_) {
+    // Read from ref file.
+    RtcpStatistics ref_stats;
+    ASSERT_EQ(1u, fread(&(ref_stats.fraction_lost),
+                        sizeof(ref_stats.fraction_lost), 1, input_fp_));
+    ASSERT_EQ(1u, fread(&(ref_stats.cumulative_lost),
+                        sizeof(ref_stats.cumulative_lost), 1, input_fp_));
+    ASSERT_EQ(1u, fread(&(ref_stats.extended_max),
+                        sizeof(ref_stats.extended_max), 1, input_fp_));
+    ASSERT_EQ(1u, fread(&(ref_stats.jitter), sizeof(ref_stats.jitter), 1,
+                        input_fp_));
+    // Compare
+    EXPECT_EQ(ref_stats.fraction_lost, stats.fraction_lost);
+    EXPECT_EQ(ref_stats.cumulative_lost, stats.cumulative_lost);
+    EXPECT_EQ(ref_stats.extended_max, stats.extended_max);
+    EXPECT_EQ(ref_stats.jitter, stats.jitter);
+  }
+}
+
+class NetEqDecodingTest : public ::testing::Test {
+ protected:
+  // NetEQ must be polled for data once every 10 ms. Thus, neither of the
+  // constants below can be changed.
+  static const int kTimeStepMs = 10;
+  static const int kBlockSize8kHz = kTimeStepMs * 8;
+  static const int kBlockSize16kHz = kTimeStepMs * 16;
+  static const int kBlockSize32kHz = kTimeStepMs * 32;
+  static const int kMaxBlockSize = kBlockSize32kHz;
+  static const int kInitSampleRateHz = 8000;
+
+  NetEqDecodingTest();
+  virtual void SetUp();
+  virtual void TearDown();
+  void SelectDecoders(NetEqDecoder* used_codec);
+  void LoadDecoders();
+  void OpenInputFile(const std::string &rtp_file);
+  void Process(NETEQTEST_RTPpacket* rtp_ptr, int* out_len);
+  void DecodeAndCompare(const std::string &rtp_file,
+                        const std::string &ref_file);
+  void DecodeAndCheckStats(const std::string &rtp_file,
+                           const std::string &stat_ref_file,
+                           const std::string &rtcp_ref_file);
+  static void PopulateRtpInfo(int frame_index,
+                              int timestamp,
+                              WebRtcRTPHeader* rtp_info);
+  static void PopulateCng(int frame_index,
+                          int timestamp,
+                          WebRtcRTPHeader* rtp_info,
+                          uint8_t* payload,
+                          int* payload_len);
+
+  NetEq* neteq_;
+  FILE* rtp_fp_;
+  unsigned int sim_clock_;
+  int16_t out_data_[kMaxBlockSize];
+  int output_sample_rate_;
+};
+
+// Allocating the static const so that it can be passed by reference.
+const int NetEqDecodingTest::kTimeStepMs;
+const int NetEqDecodingTest::kBlockSize8kHz;
+const int NetEqDecodingTest::kBlockSize16kHz;
+const int NetEqDecodingTest::kBlockSize32kHz;
+const int NetEqDecodingTest::kMaxBlockSize;
+const int NetEqDecodingTest::kInitSampleRateHz;
+
+NetEqDecodingTest::NetEqDecodingTest()
+    : neteq_(NULL),
+      rtp_fp_(NULL),
+      sim_clock_(0),
+      output_sample_rate_(kInitSampleRateHz) {
+  memset(out_data_, 0, sizeof(out_data_));
+}
+
+void NetEqDecodingTest::SetUp() {
+  neteq_ = NetEq::Create(kInitSampleRateHz);
+  ASSERT_TRUE(neteq_);
+  LoadDecoders();
+}
+
+void NetEqDecodingTest::TearDown() {
+  delete neteq_;
+  if (rtp_fp_)
+    fclose(rtp_fp_);
+}
+
+void NetEqDecodingTest::LoadDecoders() {
+  // Load PCMu.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderPCMu, 0));
+  // Load PCMa.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderPCMa, 8));
+  // Load iLBC.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderILBC, 102));
+  // Load iSAC.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderISAC, 103));
+  // Load iSAC SWB.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderISACswb, 104));
+  // Load PCM16B nb.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderPCM16B, 93));
+  // Load PCM16B wb.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderPCM16Bwb, 94));
+  // Load PCM16B swb32.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderPCM16Bswb32kHz, 95));
+  // Load CNG 8 kHz.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderCNGnb, 13));
+  // Load CNG 16 kHz.
+  ASSERT_EQ(0, neteq_->RegisterPayloadType(kDecoderCNGwb, 98));
+}
+
+void NetEqDecodingTest::OpenInputFile(const std::string &rtp_file) {
+  rtp_fp_ = fopen(rtp_file.c_str(), "rb");
+  ASSERT_TRUE(rtp_fp_ != NULL);
+  ASSERT_EQ(0, NETEQTEST_RTPpacket::skipFileHeader(rtp_fp_));
+}
+
+void NetEqDecodingTest::Process(NETEQTEST_RTPpacket* rtp, int* out_len) {
+  // Check if time to receive.
+  while ((sim_clock_ >= rtp->time()) &&
+         (rtp->dataLen() >= 0)) {
+    if (rtp->dataLen() > 0) {
+      WebRtcRTPHeader rtpInfo;
+      rtp->parseHeader(&rtpInfo);
+      ASSERT_EQ(0, neteq_->InsertPacket(
+          rtpInfo,
+          rtp->payload(),
+          rtp->payloadLen(),
+          rtp->time() * (output_sample_rate_ / 1000)));
+    }
+    // Get next packet.
+    ASSERT_NE(-1, rtp->readFromFile(rtp_fp_));
+  }
+
+  // RecOut
+  NetEqOutputType type;
+  int num_channels;
+  ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, out_len,
+                                &num_channels, &type));
+  ASSERT_TRUE((*out_len == kBlockSize8kHz) ||
+              (*out_len == kBlockSize16kHz) ||
+              (*out_len == kBlockSize32kHz));
+  output_sample_rate_ = *out_len / 10 * 1000;
+
+  // Increase time.
+  sim_clock_ += kTimeStepMs;
+}
+
+void NetEqDecodingTest::DecodeAndCompare(const std::string &rtp_file,
+                                         const std::string &ref_file) {
+  OpenInputFile(rtp_file);
+
+  std::string ref_out_file = "";
+  if (ref_file.empty()) {
+    ref_out_file = webrtc::test::OutputPath() + "neteq_out.pcm";
+  }
+  RefFiles ref_files(ref_file, ref_out_file);
+
+  NETEQTEST_RTPpacket rtp;
+  ASSERT_GT(rtp.readFromFile(rtp_fp_), 0);
+  int i = 0;
+  while (rtp.dataLen() >= 0) {
+    std::ostringstream ss;
+    ss << "Lap number " << i++ << " in DecodeAndCompare while loop";
+    SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+    int out_len;
+    ASSERT_NO_FATAL_FAILURE(Process(&rtp, &out_len));
+    ASSERT_NO_FATAL_FAILURE(ref_files.ProcessReference(out_data_, out_len));
+  }
+}
+
+void NetEqDecodingTest::DecodeAndCheckStats(const std::string &rtp_file,
+                                            const std::string &stat_ref_file,
+                                            const std::string &rtcp_ref_file) {
+  OpenInputFile(rtp_file);
+  std::string stat_out_file = "";
+  if (stat_ref_file.empty()) {
+    stat_out_file = webrtc::test::OutputPath() +
+        "neteq_network_stats.dat";
+  }
+  RefFiles network_stat_files(stat_ref_file, stat_out_file);
+
+  std::string rtcp_out_file = "";
+  if (rtcp_ref_file.empty()) {
+    rtcp_out_file = webrtc::test::OutputPath() +
+        "neteq_rtcp_stats.dat";
+  }
+  RefFiles rtcp_stat_files(rtcp_ref_file, rtcp_out_file);
+
+  NETEQTEST_RTPpacket rtp;
+  ASSERT_GT(rtp.readFromFile(rtp_fp_), 0);
+  while (rtp.dataLen() >= 0) {
+    int out_len;
+    Process(&rtp, &out_len);
+
+    // Query the network statistics API once per second
+    if (sim_clock_ % 1000 == 0) {
+      // Process NetworkStatistics.
+      NetEqNetworkStatistics network_stats;
+      ASSERT_EQ(0, neteq_->NetworkStatistics(&network_stats));
+      network_stat_files.ProcessReference(network_stats);
+
+      // Process RTCPstat.
+      RtcpStatistics rtcp_stats;
+      neteq_->GetRtcpStatistics(&rtcp_stats);
+      rtcp_stat_files.ProcessReference(rtcp_stats);
+    }
+  }
+}
+
+void NetEqDecodingTest::PopulateRtpInfo(int frame_index,
+                                        int timestamp,
+                                        WebRtcRTPHeader* rtp_info) {
+  rtp_info->header.sequenceNumber = frame_index;
+  rtp_info->header.timestamp = timestamp;
+  rtp_info->header.ssrc = 0x1234;  // Just an arbitrary SSRC.
+  rtp_info->header.payloadType = 94;  // PCM16b WB codec.
+  rtp_info->header.markerBit = 0;
+}
+
+void NetEqDecodingTest::PopulateCng(int frame_index,
+                                    int timestamp,
+                                    WebRtcRTPHeader* rtp_info,
+                                    uint8_t* payload,
+                                    int* payload_len) {
+  rtp_info->header.sequenceNumber = frame_index;
+  rtp_info->header.timestamp = timestamp;
+  rtp_info->header.ssrc = 0x1234;  // Just an arbitrary SSRC.
+  rtp_info->header.payloadType = 98;  // WB CNG.
+  rtp_info->header.markerBit = 0;
+  payload[0] = 64;  // Noise level -64 dBov, quite arbitrarily chosen.
+  *payload_len = 1;  // Only noise level, no spectral parameters.
+}
+
+TEST_F(NetEqDecodingTest, TestBitExactness) {
+  const std::string kInputRtpFile = webrtc::test::ProjectRootPath() +
+      "resources/neteq_universal.rtp";
+  const std::string kInputRefFile =
+      webrtc::test::ResourcePath("neteq_universal_ref", "pcm");
+  DecodeAndCompare(kInputRtpFile, kInputRefFile);
+}
+
+TEST_F(NetEqDecodingTest, TestNetworkStatistics) {
+  const std::string kInputRtpFile = webrtc::test::ProjectRootPath() +
+      "resources/neteq_universal.rtp";
+  const std::string kNetworkStatRefFile =
+      webrtc::test::ResourcePath("neteq_network_stats", "dat");
+  const std::string kRtcpStatRefFile =
+      webrtc::test::ResourcePath("neteq_rtcp_stats", "dat");
+  DecodeAndCheckStats(kInputRtpFile, kNetworkStatRefFile, kRtcpStatRefFile);
+}
+
+// TODO(hlundin): Re-enable test once the statistics interface is up and again.
+TEST_F(NetEqDecodingTest, TestFrameWaitingTimeStatistics) {
+  // Use fax mode to avoid time-scaling. This is to simplify the testing of
+  // packet waiting times in the packet buffer.
+  neteq_->SetPlayoutMode(kPlayoutFax);
+  ASSERT_EQ(kPlayoutFax, neteq_->PlayoutMode());
+  // Insert 30 dummy packets at once. Each packet contains 10 ms 16 kHz audio.
+  size_t num_frames = 30;
+  const int kSamples = 10 * 16;
+  const int kPayloadBytes = kSamples * 2;
+  for (size_t i = 0; i < num_frames; ++i) {
+    uint16_t payload[kSamples] = {0};
+    WebRtcRTPHeader rtp_info;
+    rtp_info.header.sequenceNumber = i;
+    rtp_info.header.timestamp = i * kSamples;
+    rtp_info.header.ssrc = 0x1234;  // Just an arbitrary SSRC.
+    rtp_info.header.payloadType = 94;  // PCM16b WB codec.
+    rtp_info.header.markerBit = 0;
+    ASSERT_EQ(0, neteq_->InsertPacket(
+        rtp_info,
+        reinterpret_cast<uint8_t*>(payload),
+        kPayloadBytes, 0));
+  }
+  // Pull out all data.
+  for (size_t i = 0; i < num_frames; ++i) {
+    int out_len;
+    int num_channels;
+    NetEqOutputType type;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+  }
+
+  std::vector<int> waiting_times;
+  neteq_->WaitingTimes(&waiting_times);
+  int len = waiting_times.size();
+  EXPECT_EQ(num_frames, waiting_times.size());
+  // Since all frames are dumped into NetEQ at once, but pulled out with 10 ms
+  // spacing (per definition), we expect the delay to increase with 10 ms for
+  // each packet.
+  for (size_t i = 0; i < waiting_times.size(); ++i) {
+    EXPECT_EQ(static_cast<int>(i + 1) * 10, waiting_times[i]);
+  }
+
+  // Check statistics again and make sure it's been reset.
+  neteq_->WaitingTimes(&waiting_times);
+  len = waiting_times.size();
+  EXPECT_EQ(0, len);
+
+  // Process > 100 frames, and make sure that that we get statistics
+  // only for 100 frames. Note the new SSRC, causing NetEQ to reset.
+  num_frames = 110;
+  for (size_t i = 0; i < num_frames; ++i) {
+    uint16_t payload[kSamples] = {0};
+    WebRtcRTPHeader rtp_info;
+    rtp_info.header.sequenceNumber = i;
+    rtp_info.header.timestamp = i * kSamples;
+    rtp_info.header.ssrc = 0x1235;  // Just an arbitrary SSRC.
+    rtp_info.header.payloadType = 94;  // PCM16b WB codec.
+    rtp_info.header.markerBit = 0;
+    ASSERT_EQ(0, neteq_->InsertPacket(
+        rtp_info,
+        reinterpret_cast<uint8_t*>(payload),
+        kPayloadBytes, 0));
+    int out_len;
+    int num_channels;
+    NetEqOutputType type;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+  }
+
+  neteq_->WaitingTimes(&waiting_times);
+  EXPECT_EQ(100u, waiting_times.size());
+}
+
+TEST_F(NetEqDecodingTest, TestAverageInterArrivalTimeNegative) {
+  const int kNumFrames = 3000;  // Needed for convergence.
+  int frame_index = 0;
+  const int kSamples = 10 * 16;
+  const int kPayloadBytes = kSamples * 2;
+  while (frame_index < kNumFrames) {
+    // Insert one packet each time, except every 10th time where we insert two
+    // packets at once. This will create a negative clock-drift of approx. 10%.
+    int num_packets = (frame_index % 10 == 0 ? 2 : 1);
+    for (int n = 0; n < num_packets; ++n) {
+      uint8_t payload[kPayloadBytes] = {0};
+      WebRtcRTPHeader rtp_info;
+      PopulateRtpInfo(frame_index, frame_index * kSamples, &rtp_info);
+      ASSERT_EQ(0, neteq_->InsertPacket(rtp_info, payload, kPayloadBytes, 0));
+      ++frame_index;
+    }
+
+    // Pull out data once.
+    int out_len;
+    int num_channels;
+    NetEqOutputType type;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+  }
+
+  NetEqNetworkStatistics network_stats;
+  ASSERT_EQ(0, neteq_->NetworkStatistics(&network_stats));
+  EXPECT_EQ(-103196, network_stats.clockdrift_ppm);
+}
+
+TEST_F(NetEqDecodingTest, TestAverageInterArrivalTimePositive) {
+  const int kNumFrames = 5000;  // Needed for convergence.
+  int frame_index = 0;
+  const int kSamples = 10 * 16;
+  const int kPayloadBytes = kSamples * 2;
+  for (int i = 0; i < kNumFrames; ++i) {
+    // Insert one packet each time, except every 10th time where we don't insert
+    // any packet. This will create a positive clock-drift of approx. 11%.
+    int num_packets = (i % 10 == 9 ? 0 : 1);
+    for (int n = 0; n < num_packets; ++n) {
+      uint8_t payload[kPayloadBytes] = {0};
+      WebRtcRTPHeader rtp_info;
+      PopulateRtpInfo(frame_index, frame_index * kSamples, &rtp_info);
+      ASSERT_EQ(0, neteq_->InsertPacket(rtp_info, payload, kPayloadBytes, 0));
+      ++frame_index;
+    }
+
+    // Pull out data once.
+    int out_len;
+    int num_channels;
+    NetEqOutputType type;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+  }
+
+  NetEqNetworkStatistics network_stats;
+  ASSERT_EQ(0, neteq_->NetworkStatistics(&network_stats));
+  EXPECT_EQ(110946, network_stats.clockdrift_ppm);
+}
+
+TEST_F(NetEqDecodingTest, LongCngWithClockDrift) {
+  uint16_t seq_no = 0;
+  uint32_t timestamp = 0;
+  const int kFrameSizeMs = 30;
+  const int kSamples = kFrameSizeMs * 16;
+  const int kPayloadBytes = kSamples * 2;
+  // Apply a clock drift of -25 ms / s (sender faster than receiver).
+  const double kDriftFactor = 1000.0 / (1000.0 + 25.0);
+  double next_input_time_ms = 0.0;
+  double t_ms;
+  NetEqOutputType type;
+
+  // Insert speech for 5 seconds.
+  const int kSpeechDurationMs = 5000;
+  for (t_ms = 0; t_ms < kSpeechDurationMs; t_ms += 10) {
+    // Each turn in this for loop is 10 ms.
+    while (next_input_time_ms <= t_ms) {
+      // Insert one 30 ms speech frame.
+      uint8_t payload[kPayloadBytes] = {0};
+      WebRtcRTPHeader rtp_info;
+      PopulateRtpInfo(seq_no, timestamp, &rtp_info);
+      ASSERT_EQ(0, neteq_->InsertPacket(rtp_info, payload, kPayloadBytes, 0));
+      ++seq_no;
+      timestamp += kSamples;
+      next_input_time_ms += static_cast<double>(kFrameSizeMs) * kDriftFactor;
+    }
+    // Pull out data once.
+    int out_len;
+    int num_channels;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+  }
+
+  EXPECT_EQ(kOutputNormal, type);
+  int32_t delay_before = timestamp - neteq_->PlayoutTimestamp();
+
+  // Insert CNG for 1 minute (= 60000 ms).
+  const int kCngPeriodMs = 100;
+  const int kCngPeriodSamples = kCngPeriodMs * 16;  // Period in 16 kHz samples.
+  const int kCngDurationMs = 60000;
+  for (; t_ms < kSpeechDurationMs + kCngDurationMs; t_ms += 10) {
+    // Each turn in this for loop is 10 ms.
+    while (next_input_time_ms <= t_ms) {
+      // Insert one CNG frame each 100 ms.
+      uint8_t payload[kPayloadBytes];
+      int payload_len;
+      WebRtcRTPHeader rtp_info;
+      PopulateCng(seq_no, timestamp, &rtp_info, payload, &payload_len);
+      ASSERT_EQ(0, neteq_->InsertPacket(rtp_info, payload, payload_len, 0));
+      ++seq_no;
+      timestamp += kCngPeriodSamples;
+      next_input_time_ms += static_cast<double>(kCngPeriodMs) * kDriftFactor;
+    }
+    // Pull out data once.
+    int out_len;
+    int num_channels;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+  }
+
+  EXPECT_EQ(kOutputCNG, type);
+
+  // Insert speech again until output type is speech.
+  while (type != kOutputNormal) {
+    // Each turn in this for loop is 10 ms.
+    while (next_input_time_ms <= t_ms) {
+      // Insert one 30 ms speech frame.
+      uint8_t payload[kPayloadBytes] = {0};
+      WebRtcRTPHeader rtp_info;
+      PopulateRtpInfo(seq_no, timestamp, &rtp_info);
+      ASSERT_EQ(0, neteq_->InsertPacket(rtp_info, payload, kPayloadBytes, 0));
+      ++seq_no;
+      timestamp += kSamples;
+      next_input_time_ms += static_cast<double>(kFrameSizeMs) * kDriftFactor;
+    }
+    // Pull out data once.
+    int out_len;
+    int num_channels;
+    ASSERT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_, &out_len,
+                                  &num_channels, &type));
+    ASSERT_EQ(kBlockSize16kHz, out_len);
+    // Increase clock.
+    t_ms += 10;
+  }
+
+  int32_t delay_after = timestamp - neteq_->PlayoutTimestamp();
+  // Compare delay before and after, and make sure it differs less than 20 ms.
+  EXPECT_LE(delay_after, delay_before + 20 * 16);
+  EXPECT_GE(delay_after, delay_before - 20 * 16);
+}
+
+TEST_F(NetEqDecodingTest, UnknownPayloadType) {
+  const int kPayloadBytes = 100;
+  uint8_t payload[kPayloadBytes] = {0};
+  WebRtcRTPHeader rtp_info;
+  PopulateRtpInfo(0, 0, &rtp_info);
+  rtp_info.header.payloadType = 1;  // Not registered as a decoder.
+  EXPECT_EQ(NetEq::kFail,
+            neteq_->InsertPacket(rtp_info, payload, kPayloadBytes, 0));
+  EXPECT_EQ(NetEq::kUnknownRtpPayloadType, neteq_->LastError());
+}
+
+TEST_F(NetEqDecodingTest, DecoderError) {
+  const int kPayloadBytes = 100;
+  uint8_t payload[kPayloadBytes] = {0};
+  WebRtcRTPHeader rtp_info;
+  PopulateRtpInfo(0, 0, &rtp_info);
+  rtp_info.header.payloadType = 103;  // iSAC, but the payload is invalid.
+  EXPECT_EQ(0, neteq_->InsertPacket(rtp_info, payload, kPayloadBytes, 0));
+  NetEqOutputType type;
+  // Set all of |out_data_| to 1, and verify that it was set to 0 by the call
+  // to GetAudio.
+  for (int i = 0; i < kMaxBlockSize; ++i) {
+    out_data_[i] = 1;
+  }
+  int num_channels;
+  int samples_per_channel;
+  EXPECT_EQ(NetEq::kFail,
+            neteq_->GetAudio(kMaxBlockSize, out_data_,
+                             &samples_per_channel, &num_channels, &type));
+  // Verify that there is a decoder error to check.
+  EXPECT_EQ(NetEq::kDecoderErrorCode, neteq_->LastError());
+  // Code 6730 is an iSAC error code.
+  EXPECT_EQ(6730, neteq_->LastDecoderError());
+  // Verify that the first 160 samples are set to 0, and that the remaining
+  // samples are left unmodified.
+  static const int kExpectedOutputLength = 160;  // 10 ms at 16 kHz sample rate.
+  for (int i = 0; i < kExpectedOutputLength; ++i) {
+    std::ostringstream ss;
+    ss << "i = " << i;
+    SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+    EXPECT_EQ(0, out_data_[i]);
+  }
+  for (int i = kExpectedOutputLength; i < kMaxBlockSize; ++i) {
+    std::ostringstream ss;
+    ss << "i = " << i;
+    SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+    EXPECT_EQ(1, out_data_[i]);
+  }
+}
+
+TEST_F(NetEqDecodingTest, GetAudioBeforeInsertPacket) {
+  NetEqOutputType type;
+  // Set all of |out_data_| to 1, and verify that it was set to 0 by the call
+  // to GetAudio.
+  for (int i = 0; i < kMaxBlockSize; ++i) {
+    out_data_[i] = 1;
+  }
+  int num_channels;
+  int samples_per_channel;
+  EXPECT_EQ(0, neteq_->GetAudio(kMaxBlockSize, out_data_,
+                                &samples_per_channel,
+                                &num_channels, &type));
+  // Verify that the first block of samples is set to 0.
+  static const int kExpectedOutputLength =
+      kInitSampleRateHz / 100;  // 10 ms at initial sample rate.
+  for (int i = 0; i < kExpectedOutputLength; ++i) {
+    std::ostringstream ss;
+    ss << "i = " << i;
+    SCOPED_TRACE(ss.str());  // Print out the parameter values on failure.
+    EXPECT_EQ(0, out_data_[i]);
+  }
+}
+}  // namespace
diff --git a/webrtc/modules/audio_coding/neteq4/normal.cc b/webrtc/modules/audio_coding/neteq4/normal.cc
new file mode 100644
index 0000000..ddbea4c
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/normal.cc
@@ -0,0 +1,189 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/normal.h"
+
+#include <algorithm>  // min
+#include <cstring>  // memset, memcpy
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/codecs/cng/include/webrtc_cng.h"
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+
+namespace webrtc {
+
+int Normal::Process(const int16_t* input,
+                    size_t length,
+                    Modes last_mode,
+                    int16_t* external_mute_factor_array,
+                    AudioMultiVector<int16_t>* output) {
+  if (length == 0) {
+    // Nothing to process.
+    output->Clear();
+    return length;
+  }
+
+  assert(output->Empty());
+  // Output should be empty at this point.
+  output->PushBackInterleaved(input, length);
+  int16_t* signal = &(*output)[0][0];
+
+  const unsigned fs_mult = fs_hz_ / 8000;
+  assert(fs_mult > 0);
+  // fs_shift = log2(fs_mult), rounded down.
+  // Note that |fs_shift| is not "exact" for 48 kHz.
+  // TODO(hlundin): Investigate this further.
+  const int fs_shift = 30 - WebRtcSpl_NormW32(fs_mult);
+
+  // Check if last RecOut call resulted in an Expand. If so, we have to take
+  // care of some cross-fading and unmuting.
+  if (last_mode == kModeExpand) {
+    // Generate interpolation data using Expand.
+    // First, set Expand parameters to appropriate values.
+    expand_->SetParametersForNormalAfterExpand();
+
+    // Call Expand.
+    AudioMultiVector<int16_t> expanded(output->Channels());
+    expand_->Process(&expanded);
+    expand_->Reset();
+
+    for (size_t channel_ix = 0; channel_ix < output->Channels(); ++channel_ix) {
+      // Adjust muting factor (main muting factor times expand muting factor).
+      external_mute_factor_array[channel_ix] = static_cast<int16_t>(
+          WEBRTC_SPL_MUL_16_16_RSFT(external_mute_factor_array[channel_ix],
+                                    expand_->MuteFactor(channel_ix), 14));
+
+      int16_t* signal = &(*output)[channel_ix][0];
+      size_t length_per_channel = length / output->Channels();
+      // Find largest absolute value in new data.
+      int16_t decoded_max = WebRtcSpl_MaxAbsValueW16(signal,
+                                                     length_per_channel);
+      // Adjust muting factor if needed (to BGN level).
+      int energy_length = std::min(static_cast<size_t>(fs_mult * 64),
+                                   length_per_channel);
+      int scaling = 6 + fs_shift
+          - WebRtcSpl_NormW32(decoded_max * decoded_max);
+      scaling = std::max(scaling, 0);  // |scaling| should always be >= 0.
+      int32_t energy = WebRtcSpl_DotProductWithScale(signal, signal,
+                                                     energy_length, scaling);
+      energy = energy / (energy_length >> scaling);
+
+      int mute_factor;
+      if ((energy != 0) &&
+          (energy > background_noise_.Energy(channel_ix))) {
+        // Normalize new frame energy to 15 bits.
+        scaling = WebRtcSpl_NormW32(energy) - 16;
+        // We want background_noise_.energy() / energy in Q14.
+        int32_t bgn_energy =
+            background_noise_.Energy(channel_ix) << (scaling+14);
+        int16_t energy_scaled = energy << scaling;
+        int16_t ratio = WebRtcSpl_DivW32W16(bgn_energy, energy_scaled);
+        mute_factor = WebRtcSpl_SqrtFloor(static_cast<int32_t>(ratio) << 14);
+      } else {
+        mute_factor = 16384;  // 1.0 in Q14.
+      }
+      if (mute_factor > external_mute_factor_array[channel_ix]) {
+        external_mute_factor_array[channel_ix] = std::min(mute_factor, 16384);
+      }
+
+      // If muted increase by 0.64 for every 20 ms (NB/WB 0.0040/0.0020 in Q14).
+      int16_t increment = 64 / fs_mult;
+      for (size_t i = 0; i < length_per_channel; i++) {
+        // Scale with mute factor.
+        assert(channel_ix < output->Channels());
+        assert(i < output->Size());
+        int32_t scaled_signal = (*output)[channel_ix][i] *
+            external_mute_factor_array[channel_ix];
+        // Shift 14 with proper rounding.
+        (*output)[channel_ix][i] = (scaled_signal + 8192) >> 14;
+        // Increase mute_factor towards 16384.
+        external_mute_factor_array[channel_ix] =
+            std::min(external_mute_factor_array[channel_ix] + increment, 16384);
+      }
+
+      // Interpolate the expanded data into the new vector.
+      // (NB/WB/SWB32/SWB48 8/16/32/48 samples.)
+      assert(fs_shift < 3);  // Will always be 0, 1, or, 2.
+      increment = 4 >> fs_shift;
+      int fraction = increment;
+      for (size_t i = 0; i < 8 * fs_mult; i++) {
+        // TODO(hlundin): Add 16 instead of 8 for correct rounding. Keeping 8
+        // now for legacy bit-exactness.
+        assert(channel_ix < output->Channels());
+        assert(i < output->Size());
+        (*output)[channel_ix][i] =
+            (fraction * (*output)[channel_ix][i] +
+                (32 - fraction) * expanded[channel_ix][i] + 8) >> 5;
+        fraction += increment;
+      }
+    }
+  } else if (last_mode == kModeRfc3389Cng) {
+    assert(output->Channels() == 1);  // Not adapted for multi-channel yet.
+    static const int kCngLength = 32;
+    int16_t cng_output[kCngLength];
+    // Reset mute factor and start up fresh.
+    external_mute_factor_array[0] = 16384;
+    AudioDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
+
+    if (cng_decoder) {
+      CNG_dec_inst* cng_inst = static_cast<CNG_dec_inst*>(cng_decoder->state());
+      // Generate long enough for 32kHz.
+      if (WebRtcCng_Generate(cng_inst, cng_output, kCngLength, 0) < 0) {
+        // Error returned; set return vector to all zeros.
+        memset(cng_output, 0, sizeof(cng_output));
+      }
+    } else {
+      // If no CNG instance is defined, just copy from the decoded data.
+      // (This will result in interpolating the decoded with itself.)
+      memcpy(cng_output, signal, fs_mult * 8 * sizeof(int16_t));
+    }
+    // Interpolate the CNG into the new vector.
+    // (NB/WB/SWB32/SWB48 8/16/32/48 samples.)
+    assert(fs_shift < 3);  // Will always be 0, 1, or, 2.
+    int16_t increment = 4 >> fs_shift;
+    int16_t fraction = increment;
+    for (size_t i = 0; i < 8 * fs_mult; i++) {
+      // TODO(hlundin): Add 16 instead of 8 for correct rounding. Keeping 8 now
+      // for legacy bit-exactness.
+      signal[i] =
+          (fraction * signal[i] + (32 - fraction) * cng_output[i] + 8) >> 5;
+      fraction += increment;
+    }
+  } else if (external_mute_factor_array[0] < 16384) {
+    // Previous was neither of Expand, FadeToBGN or RFC3389_CNG, but we are
+    // still ramping up from previous muting.
+    // If muted increase by 0.64 for every 20 ms (NB/WB 0.0040/0.0020 in Q14).
+    int16_t increment = 64 / fs_mult;
+    size_t length_per_channel = length / output->Channels();
+    for (size_t i = 0; i < length_per_channel; i++) {
+      for (size_t channel_ix = 0; channel_ix < output->Channels();
+          ++channel_ix) {
+        // Scale with mute factor.
+        assert(channel_ix < output->Channels());
+        assert(i < output->Size());
+        int32_t scaled_signal = (*output)[channel_ix][i] *
+            external_mute_factor_array[channel_ix];
+        // Shift 14 with proper rounding.
+        (*output)[channel_ix][i] = (scaled_signal + 8192) >> 14;
+        // Increase mute_factor towards 16384.
+        external_mute_factor_array[channel_ix] =
+            std::min(16384, external_mute_factor_array[channel_ix] + increment);
+      }
+    }
+  }
+
+  return length;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/normal.h b/webrtc/modules/audio_coding/neteq4/normal.h
new file mode 100644
index 0000000..aba55c4
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/normal.h
@@ -0,0 +1,67 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_NORMAL_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_NORMAL_H_
+
+#include <cstring>  // Access to size_t.
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/defines.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+class DecoderDatabase;
+class Expand;
+
+// This class provides the "Normal" DSP operation, that is performed when
+// there is no data loss, no need to stretch the timing of the signal, and
+// no other "special circumstances" are at hand.
+class Normal {
+ public:
+  Normal(int fs_hz, DecoderDatabase* decoder_database,
+         const BackgroundNoise& background_noise,
+         Expand* expand)
+      : fs_hz_(fs_hz),
+        decoder_database_(decoder_database),
+        background_noise_(background_noise),
+        expand_(expand) {
+  }
+
+  virtual ~Normal() {}
+
+  // Performs the "Normal" operation. The decoder data is supplied in |input|,
+  // having |length| samples in total for all channels (interleaved). The
+  // result is written to |output|. The number of channels allocated in
+  // |output| defines the number of channels that will be used when
+  // de-interleaving |input|. |last_mode| contains the mode used in the previous
+  // GetAudio call (i.e., not the current one), and |external_mute_factor| is
+  // a pointer to the mute factor in the NetEqImpl class.
+  int Process(const int16_t* input, size_t length,
+              Modes last_mode,
+              int16_t* external_mute_factor_array,
+              AudioMultiVector<int16_t>* output);
+
+ private:
+  int fs_hz_;
+  DecoderDatabase* decoder_database_;
+  const BackgroundNoise& background_noise_;
+  Expand* expand_;
+
+  DISALLOW_COPY_AND_ASSIGN(Normal);
+};
+
+}  // namespace webrtc
+#endif  // SRC_MODULES_AUDIO_CODING_NETEQ4_NORMAL_H_
diff --git a/webrtc/modules/audio_coding/neteq4/normal_unittest.cc b/webrtc/modules/audio_coding/neteq4/normal_unittest.cc
new file mode 100644
index 0000000..2bd7b89
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/normal_unittest.cc
@@ -0,0 +1,40 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for Normal class.
+
+#include "webrtc/modules/audio_coding/neteq4/normal.h"
+
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/expand.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+TEST(Normal, CreateAndDestroy) {
+  MockDecoderDatabase db;
+  int fs = 8000;
+  size_t channels = 1;
+  BackgroundNoise bgn(channels);
+  SyncBuffer sync_buffer(1, 1000);
+  RandomVector random_vector;
+  Expand expand(&bgn, &sync_buffer, &random_vector, fs, channels);
+  Normal normal(fs, &db, bgn, &expand);
+  EXPECT_CALL(db, Die());  // Called when |db| goes out of scope.
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/packet.h b/webrtc/modules/audio_coding/neteq4/packet.h
new file mode 100644
index 0000000..90994a9
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/packet.h
@@ -0,0 +1,71 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PACKET_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PACKET_H_
+
+#include <list>
+
+#include "webrtc/modules/interface/module_common_types.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Struct for holding RTP packets.
+struct Packet {
+  RTPHeader header;
+  uint8_t* payload;  // Datagram excluding RTP header and header extension.
+  int payload_length;
+  bool primary;  // Primary, i.e., not redundant payload.
+  int waiting_time;
+
+  // Constructor.
+  Packet()
+      : payload(NULL),
+        payload_length(0),
+        primary(true),
+        waiting_time(0) {
+  }
+
+  // Comparison operators. Establish a packet ordering based on (1) timestamp,
+  // (2) sequence number, and (3) redundancy. Timestamp and sequence numbers
+  // are compared taking wrap-around into account. If both timestamp and
+  // sequence numbers are identical, a primary payload is considered "smaller"
+  // than a secondary.
+  bool operator==(const Packet& rhs) const {
+    return (this->header.timestamp == rhs.header.timestamp &&
+        this->header.sequenceNumber == rhs.header.sequenceNumber &&
+        this->primary == rhs.primary);
+  }
+  bool operator!=(const Packet& rhs) const { return !operator==(rhs); }
+  bool operator<(const Packet& rhs) const {
+    if (this->header.timestamp == rhs.header.timestamp) {
+      if (this->header.sequenceNumber == rhs.header.sequenceNumber) {
+        // Timestamp and sequence numbers are identical. Deem left hand side
+        // to be "smaller" (i.e., "earlier") if it is primary, and right hand
+        // side is not.
+        return (this->primary && !rhs.primary);
+      }
+      return (static_cast<uint16_t>(rhs.header.sequenceNumber
+          - this->header.sequenceNumber) < 0xFFFF / 2);
+    }
+    return (static_cast<uint32_t>(rhs.header.timestamp
+        - this->header.timestamp) < 0xFFFFFFFF / 2);
+  }
+  bool operator>(const Packet& rhs) const { return rhs.operator<(*this); }
+  bool operator<=(const Packet& rhs) const { return !operator>(rhs); }
+  bool operator>=(const Packet& rhs) const { return !operator<(rhs); }
+};
+
+// A list of packets.
+typedef std::list<Packet*> PacketList;
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PACKET_H_
diff --git a/webrtc/modules/audio_coding/neteq4/packet_buffer.cc b/webrtc/modules/audio_coding/neteq4/packet_buffer.cc
new file mode 100644
index 0000000..416661e
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/packet_buffer.cc
@@ -0,0 +1,278 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// This is the implementation of the PacketBuffer class. It is mostly based on
+// an STL list. The list is kept sorted at all times so that the next packet to
+// decode is at the beginning of the list.
+
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+
+#include <algorithm>  // find_if()
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+
+namespace webrtc {
+
+// Predicate used when inserting packets in the buffer list.
+// Operator() returns true when |packet| goes before |new_packet|.
+class NewTimestampIsLarger {
+ public:
+  explicit NewTimestampIsLarger(const Packet* new_packet)
+      : new_packet_(new_packet) {
+  }
+  bool operator()(Packet* packet) {
+    return (*new_packet_ >= *packet);
+  }
+
+ private:
+  const Packet* new_packet_;
+};
+
+// Constructor. The arguments define the maximum number of slots and maximum
+// payload memory (excluding RTP headers) that the buffer will accept.
+PacketBuffer::PacketBuffer(size_t max_number_of_packets,
+                           size_t max_memory_bytes)
+    : max_number_of_packets_(max_number_of_packets),
+      max_memory_bytes_(max_memory_bytes),
+      current_memory_bytes_(0) {
+}
+
+// Destructor. All packets in the buffer will be destroyed.
+PacketBuffer::~PacketBuffer() {
+  Flush();
+}
+
+// Flush the buffer. All packets in the buffer will be destroyed.
+void PacketBuffer::Flush() {
+  DeleteAllPackets(&buffer_);
+  current_memory_bytes_ = 0;
+}
+
+int PacketBuffer::InsertPacket(Packet* packet) {
+  if (!packet || !packet->payload) {
+    if (packet) {
+      delete packet;
+    }
+    return kInvalidPacket;
+  }
+
+  int return_val = kOK;
+
+  if ((buffer_.size() >= max_number_of_packets_) ||
+      (current_memory_bytes_ + packet->payload_length
+          > static_cast<int>(max_memory_bytes_))) {
+    // Buffer is full. Flush it.
+    Flush();
+    return_val = kFlushed;
+    if ((buffer_.size() >= max_number_of_packets_) ||
+        (current_memory_bytes_ + packet->payload_length
+            > static_cast<int>(max_memory_bytes_))) {
+      // Buffer is still too small for the packet. Either the buffer limits are
+      // really small, or the packet is really large. Delete the packet and
+      // return an error.
+      delete [] packet->payload;
+      delete packet;
+      return kOversizePacket;
+    }
+  }
+
+  // Get an iterator pointing to the place in the buffer where the new packet
+  // should be inserted. The list is searched from the back, since the most
+  // likely case is that the new packet should be near the end of the list.
+  PacketList::reverse_iterator rit = std::find_if(
+      buffer_.rbegin(), buffer_.rend(),
+      NewTimestampIsLarger(packet));
+  buffer_.insert(rit.base(), packet);  // Insert the packet at that position.
+  current_memory_bytes_ += packet->payload_length;
+
+  return return_val;
+}
+
+int PacketBuffer::InsertPacketList(PacketList* packet_list,
+                                   const DecoderDatabase& decoder_database,
+                                   uint8_t* current_rtp_payload_type,
+                                   uint8_t* current_cng_rtp_payload_type) {
+  bool flushed = false;
+  while (!packet_list->empty()) {
+    Packet* packet = packet_list->front();
+    if (decoder_database.IsComfortNoise(packet->header.payloadType)) {
+      if (*current_cng_rtp_payload_type != 0xFF &&
+          *current_cng_rtp_payload_type != packet->header.payloadType) {
+        // New CNG payload type implies new codec type.
+        *current_rtp_payload_type = 0xFF;
+        Flush();
+        flushed = true;
+      }
+      *current_cng_rtp_payload_type = packet->header.payloadType;
+    } else if (!decoder_database.IsDtmf(packet->header.payloadType)) {
+      // This must be speech.
+      if (*current_rtp_payload_type != 0xFF &&
+          *current_rtp_payload_type != packet->header.payloadType) {
+        *current_cng_rtp_payload_type = 0xFF;
+        Flush();
+        flushed = true;
+      }
+      *current_rtp_payload_type = packet->header.payloadType;
+    }
+    int return_val = InsertPacket(packet);
+    packet_list->pop_front();
+    if (return_val == kFlushed) {
+      // The buffer flushed, but this is not an error. We can still continue.
+      flushed = true;
+    } else if (return_val != kOK) {
+      // An error occurred. Delete remaining packets in list and return.
+      DeleteAllPackets(packet_list);
+      return return_val;
+    }
+  }
+  return flushed ? kFlushed : kOK;
+}
+
+int PacketBuffer::NextTimestamp(uint32_t* next_timestamp) const {
+  if (Empty()) {
+    return kBufferEmpty;
+  }
+  if (!next_timestamp) {
+    return kInvalidPointer;
+  }
+  *next_timestamp = buffer_.front()->header.timestamp;
+  return kOK;
+}
+
+int PacketBuffer::NextHigherTimestamp(uint32_t timestamp,
+                                      uint32_t* next_timestamp) const {
+  if (Empty()) {
+    return kBufferEmpty;
+  }
+  if (!next_timestamp) {
+    return kInvalidPointer;
+  }
+  PacketList::const_iterator it;
+  for (it = buffer_.begin(); it != buffer_.end(); ++it) {
+    if ((*it)->header.timestamp >= timestamp) {
+      // Found a packet matching the search.
+      *next_timestamp = (*it)->header.timestamp;
+      return kOK;
+    }
+  }
+  return kNotFound;
+}
+
+const RTPHeader* PacketBuffer::NextRtpHeader() const {
+  if (Empty()) {
+    return NULL;
+  }
+  return const_cast<const RTPHeader*>(&(buffer_.front()->header));
+}
+
+Packet* PacketBuffer::GetNextPacket(int* discard_count) {
+  if (Empty()) {
+    // Buffer is empty.
+    return NULL;
+  }
+
+  Packet* packet = buffer_.front();
+  // Assert that the packet sanity checks in InsertPacket method works.
+  assert(packet && packet->payload);
+  buffer_.pop_front();
+  current_memory_bytes_ -= packet->payload_length;
+  assert(current_memory_bytes_ >= 0);  // Assert bookkeeping is correct.
+  // Discard other packets with the same timestamp. These are duplicates or
+  // redundant payloads that should not be used.
+  if (discard_count) {
+    *discard_count = 0;
+  }
+  while (!Empty() &&
+      buffer_.front()->header.timestamp == packet->header.timestamp) {
+    if (DiscardNextPacket() != kOK) {
+      assert(false);  // Must be ok by design.
+    }
+    if (discard_count) {
+      ++(*discard_count);
+    }
+  }
+  return packet;
+}
+
+int PacketBuffer::DiscardNextPacket() {
+  if (Empty()) {
+    return kBufferEmpty;
+  }
+  Packet* temp_packet = buffer_.front();
+  // Assert that the packet sanity checks in InsertPacket method works.
+  assert(temp_packet && temp_packet->payload);
+  current_memory_bytes_ -= temp_packet->payload_length;
+  assert(current_memory_bytes_ >= 0);  // Assert bookkeeping is correct.
+  DeleteFirstPacket(&buffer_);
+  return kOK;
+}
+
+int PacketBuffer::DiscardOldPackets(uint32_t timestamp_limit) {
+  int discard_count = 0;
+  while (!Empty() &&
+      timestamp_limit != buffer_.front()->header.timestamp &&
+      static_cast<uint32_t>(timestamp_limit
+                            - buffer_.front()->header.timestamp) <
+                            0xFFFFFFFF / 2) {
+    if (DiscardNextPacket() != kOK) {
+      assert(false);  // Must be ok by design.
+    }
+    ++discard_count;
+  }
+  return 0;
+}
+
+int PacketBuffer::NumSamplesInBuffer(DecoderDatabase* decoder_database,
+                                     int last_decoded_length) const {
+  PacketList::const_iterator it;
+  int num_samples = 0;
+  for (it = buffer_.begin(); it != buffer_.end(); ++it) {
+    Packet* packet = (*it);
+    AudioDecoder* decoder =
+        decoder_database->GetDecoder(packet->header.payloadType);
+    if (decoder) {
+      int duration = decoder->PacketDuration(packet->payload,
+                                             packet->payload_length);
+      if (duration >= 0) {
+        num_samples += duration;
+        continue;  // Go to next packet in loop.
+      }
+    }
+    num_samples += last_decoded_length;
+  }
+  return num_samples;
+}
+
+void PacketBuffer::IncrementWaitingTimes(int inc) {
+  PacketList::iterator it;
+  for (it = buffer_.begin(); it != buffer_.end(); ++it) {
+    (*it)->waiting_time += inc;
+  }
+}
+
+bool PacketBuffer::DeleteFirstPacket(PacketList* packet_list) {
+  if (packet_list->empty()) {
+    return false;
+  }
+  Packet* first_packet = packet_list->front();
+  delete [] first_packet->payload;
+  delete first_packet;
+  packet_list->pop_front();
+  return true;
+}
+
+void PacketBuffer::DeleteAllPackets(PacketList* packet_list) {
+  while (DeleteFirstPacket(packet_list)) {
+    // Continue while the list is not empty.
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/packet_buffer.h b/webrtc/modules/audio_coding/neteq4/packet_buffer.h
new file mode 100644
index 0000000..3e203af
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/packet_buffer.h
@@ -0,0 +1,139 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PACKET_BUFFER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PACKET_BUFFER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declaration.
+class DecoderDatabase;
+
+// This is the actual buffer holding the packets before decoding.
+class PacketBuffer {
+ public:
+  enum BufferReturnCodes {
+    kOK = 0,
+    kFlushed,
+    kNotFound,
+    kBufferEmpty,
+    kInvalidPacket,
+    kInvalidPointer,
+    kOversizePacket
+  };
+
+  // Constructor creates a buffer which can hold a maximum of
+  // |max_number_of_packets| packets and |max_payload_memory| bytes of payload,
+  // excluding RTP headers.
+  PacketBuffer(size_t max_number_of_packets, size_t max_payload_memory);
+
+  // Deletes all packets in the buffer before destroying the buffer.
+  virtual ~PacketBuffer();
+
+  // Flushes the buffer and deletes all packets in it.
+  virtual void Flush();
+
+  // Returns true for an empty buffer.
+  virtual bool Empty() const { return buffer_.empty(); }
+
+  // Inserts |packet| into the buffer. The buffer will take over ownership of
+  // the packet object.
+  // Returns PacketBuffer::kOK on success, PacketBuffer::kFlushed if the buffer
+  // was flushed due to overfilling.
+  virtual int InsertPacket(Packet* packet);
+
+  // Inserts a list of packets into the buffer. The buffer will take over
+  // ownership of the packet objects.
+  // Returns PacketBuffer::kOK if all packets were inserted successfully.
+  // If the buffer was flushed due to overfilling, only a subset of the list is
+  // inserted, and PacketBuffer::kFlushed is returned.
+  // The last three parameters are included for legacy compatibility.
+  // TODO(hlundin): Redesign to not use current_*_payload_type and
+  // decoder_database.
+  virtual int InsertPacketList(PacketList* packet_list,
+                               const DecoderDatabase& decoder_database,
+                               uint8_t* current_rtp_payload_type,
+                               uint8_t* current_cng_rtp_payload_type);
+
+  // Gets the timestamp for the first packet in the buffer and writes it to the
+  // output variable |next_timestamp|.
+  // Returns PacketBuffer::kBufferEmpty if the buffer is empty,
+  // PacketBuffer::kOK otherwise.
+  virtual int NextTimestamp(uint32_t* next_timestamp) const;
+
+  // Gets the timestamp for the first packet in the buffer with a timestamp no
+  // lower than the input limit |timestamp|. The result is written to the output
+  // variable |next_timestamp|.
+  // Returns PacketBuffer::kBufferEmpty if the buffer is empty,
+  // PacketBuffer::kOK otherwise.
+  virtual int NextHigherTimestamp(uint32_t timestamp,
+                                  uint32_t* next_timestamp) const;
+
+  // Returns a (constant) pointer the RTP header of the first packet in the
+  // buffer. Returns NULL if the buffer is empty.
+  virtual const RTPHeader* NextRtpHeader() const;
+
+  // Extracts the first packet in the buffer and returns a pointer to it.
+  // Returns NULL if the buffer is empty. The caller is responsible for deleting
+  // the packet.
+  // Subsequent packets with the same timestamp as the one extracted will be
+  // discarded and properly deleted. The number of discarded packets will be
+  // written to the output variable |discard_count|.
+  virtual Packet* GetNextPacket(int* discard_count);
+
+  // Discards the first packet in the buffer. The packet is deleted.
+  // Returns PacketBuffer::kBufferEmpty if the buffer is empty,
+  // PacketBuffer::kOK otherwise.
+  virtual int DiscardNextPacket();
+
+  // Discards all packets that are (strictly) older than |timestamp_limit|.
+  // Returns number of packets discarded.
+  virtual int DiscardOldPackets(uint32_t timestamp_limit);
+
+  // Returns the number of packets in the buffer, including duplicates and
+  // redundant packets.
+  virtual int NumPacketsInBuffer() const {
+    return static_cast<int>(buffer_.size());
+  }
+
+  // Returns the number of samples in the buffer, including samples carried in
+  // duplicate and redundant packets.
+  virtual int NumSamplesInBuffer(DecoderDatabase* decoder_database,
+                                 int last_decoded_length) const;
+
+  // Increase the waiting time counter for every packet in the buffer by |inc|.
+  // The default value for |inc| is 1.
+  virtual void IncrementWaitingTimes(int inc = 1);
+
+  virtual int current_memory_bytes() const { return current_memory_bytes_; }
+
+  // Static method that properly deletes the first packet, and its payload
+  // array, in |packet_list|. Returns false if |packet_list| already was empty,
+  // otherwise true.
+  static bool DeleteFirstPacket(PacketList* packet_list);
+
+  // Static method that properly deletes all packets, and their payload arrays,
+  // in |packet_list|.
+  static void DeleteAllPackets(PacketList* packet_list);
+
+ private:
+  size_t max_number_of_packets_;
+  size_t max_memory_bytes_;
+  int current_memory_bytes_;
+  PacketList buffer_;
+  DISALLOW_COPY_AND_ASSIGN(PacketBuffer);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PACKET_BUFFER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/packet_buffer_unittest.cc b/webrtc/modules/audio_coding/neteq4/packet_buffer_unittest.cc
new file mode 100644
index 0000000..c8109dc
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/packet_buffer_unittest.cc
@@ -0,0 +1,560 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for PacketBuffer class.
+
+#include "webrtc/modules/audio_coding/neteq4/packet_buffer.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+
+using ::testing::Return;
+using ::testing::_;
+
+namespace webrtc {
+
+// Helper class to generate packets. Packets must be deleted by the user.
+class PacketGenerator {
+ public:
+  PacketGenerator(uint16_t seq_no, uint32_t ts, uint8_t pt, int frame_size);
+  virtual ~PacketGenerator() {}
+  Packet* NextPacket(int payload_size_bytes);
+  void SkipPacket();
+
+  uint16_t seq_no_;
+  uint32_t ts_;
+  uint8_t pt_;
+  int frame_size_;
+};
+
+PacketGenerator::PacketGenerator(uint16_t seq_no, uint32_t ts, uint8_t pt,
+                                 int frame_size)
+    : seq_no_(seq_no),
+      ts_(ts),
+      pt_(pt),
+      frame_size_(frame_size) {
+}
+
+Packet* PacketGenerator::NextPacket(int payload_size_bytes) {
+  Packet* packet = new Packet;
+  packet->header.sequenceNumber = seq_no_;
+  packet->header.timestamp = ts_;
+  packet->header.payloadType = pt_;
+  packet->header.markerBit = false;
+  packet->header.ssrc = 0x12345678;
+  packet->header.numCSRCs = 0;
+  packet->header.paddingLength = 0;
+  packet->payload_length = payload_size_bytes;
+  packet->primary = true;
+  packet->payload = new uint8_t[payload_size_bytes];
+  ++seq_no_;
+  ts_ += frame_size_;
+  return packet;
+}
+
+void PacketGenerator::SkipPacket() {
+  ++seq_no_;
+  ts_ += frame_size_;
+}
+
+
+// Start of test definitions.
+
+TEST(PacketBuffer, CreateAndDestroy) {
+  PacketBuffer* buffer = new PacketBuffer(10, 1000);  // 10 packets, 1000 bytes.
+  EXPECT_TRUE(buffer->Empty());
+  delete buffer;
+}
+
+TEST(PacketBuffer, InsertPacket) {
+  PacketBuffer buffer(10, 1000);  // 10 packets, 1000 bytes.
+  PacketGenerator gen(17u, 4711u, 0, 10);
+
+  const int payload_len = 100;
+  Packet* packet = gen.NextPacket(payload_len);
+
+  EXPECT_EQ(0, buffer.InsertPacket(packet));
+  uint32_t next_ts;
+  EXPECT_EQ(PacketBuffer::kOK, buffer.NextTimestamp(&next_ts));
+  EXPECT_EQ(4711u, next_ts);
+  EXPECT_FALSE(buffer.Empty());
+  EXPECT_EQ(1, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(payload_len, buffer.current_memory_bytes());
+  const RTPHeader* hdr = buffer.NextRtpHeader();
+  EXPECT_EQ(&(packet->header), hdr);  // Compare pointer addresses.
+
+  // Do not explicitly flush buffer or delete packet to test that it is deleted
+  // with the buffer. (Tested with Valgrind or similar tool.)
+}
+
+// Test to flush buffer.
+TEST(PacketBuffer, FlushBuffer) {
+  PacketBuffer buffer(10, 1000);  // 10 packets, 1000 bytes.
+  PacketGenerator gen(0, 0, 0, 10);
+  const int payload_len = 10;
+
+  // Insert 10 small packets; should be ok.
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacket(packet));
+  }
+  EXPECT_EQ(10, buffer.NumPacketsInBuffer());
+  EXPECT_FALSE(buffer.Empty());
+  EXPECT_EQ(10 * payload_len, buffer.current_memory_bytes());
+
+  buffer.Flush();
+  // Buffer should delete the payloads itself.
+  EXPECT_EQ(0, buffer.NumPacketsInBuffer());
+  EXPECT_TRUE(buffer.Empty());
+  EXPECT_EQ(0, buffer.current_memory_bytes());
+}
+
+// Test to fill the buffer over the limits, and verify that it flushes.
+TEST(PacketBuffer, OverfillBuffer) {
+  PacketBuffer buffer(10, 1000);  // 10 packets, 1000 bytes.
+  PacketGenerator gen(0, 0, 0, 10);
+
+  // Insert 10 small packets; should be ok.
+  const int payload_len = 10;
+  int i;
+  for (i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacket(packet));
+  }
+  EXPECT_EQ(10, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(10 * payload_len, buffer.current_memory_bytes());
+  uint32_t next_ts;
+  EXPECT_EQ(PacketBuffer::kOK, buffer.NextTimestamp(&next_ts));
+  EXPECT_EQ(0u, next_ts);  // Expect first inserted packet to be first in line.
+
+  // Insert 11th packet; should flush the buffer and insert it after flushing.
+  Packet* packet = gen.NextPacket(payload_len);
+  EXPECT_EQ(PacketBuffer::kFlushed, buffer.InsertPacket(packet));
+  EXPECT_EQ(1, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(payload_len, buffer.current_memory_bytes());
+  EXPECT_EQ(PacketBuffer::kOK, buffer.NextTimestamp(&next_ts));
+  // Expect last inserted packet to be first in line.
+  EXPECT_EQ(packet->header.timestamp, next_ts);
+
+  // Insert 2 large packets; expect to flush when inserting the second one.
+  const int large_payload_len = 500;
+  packet = gen.NextPacket(large_payload_len);
+  EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacket(packet));
+  EXPECT_EQ(2, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(payload_len + large_payload_len, buffer.current_memory_bytes());
+
+  packet = gen.NextPacket(large_payload_len);
+  EXPECT_EQ(PacketBuffer::kFlushed, buffer.InsertPacket(packet));
+  EXPECT_EQ(1, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(large_payload_len, buffer.current_memory_bytes());
+
+  // Flush buffer to delete remaining packets.
+  buffer.Flush();
+}
+
+// Test inserting a list of packets.
+TEST(PacketBuffer, InsertPacketList) {
+  PacketBuffer buffer(10, 1000);  // 10 packets, 1000 bytes.
+  PacketGenerator gen(0, 0, 0, 10);
+  PacketList list;
+  const int payload_len = 10;
+
+  // Insert 10 small packets.
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    list.push_back(packet);
+  }
+
+  MockDecoderDatabase decoder_database;
+  EXPECT_CALL(decoder_database, IsComfortNoise(0))
+      .WillRepeatedly(Return(false));
+  EXPECT_CALL(decoder_database, IsDtmf(0))
+      .WillRepeatedly(Return(false));
+  uint8_t current_pt = 0xFF;
+  uint8_t current_cng_pt = 0xFF;
+  EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacketList(&list,
+                                                       decoder_database,
+                                                       &current_pt,
+                                                       &current_cng_pt));
+  EXPECT_TRUE(list.empty());  // The PacketBuffer should have depleted the list.
+  EXPECT_EQ(10, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(10 * payload_len, buffer.current_memory_bytes());
+  EXPECT_EQ(0, current_pt);  // Current payload type changed to 0.
+  EXPECT_EQ(0xFF, current_cng_pt);  // CNG payload type not changed.
+
+  buffer.Flush();  // Clean up.
+
+  EXPECT_CALL(decoder_database, Die());  // Called when object is deleted.
+}
+
+// Test inserting a list of packets. Last packet is of a different payload type.
+// Expecting the buffer to flush.
+// TODO(hlundin): Remove this test when legacy operation is no longer needed.
+TEST(PacketBuffer, InsertPacketListChangePayloadType) {
+  PacketBuffer buffer(10, 1000);  // 10 packets, 1000 bytes.
+  PacketGenerator gen(0, 0, 0, 10);
+  PacketList list;
+  const int payload_len = 10;
+
+  // Insert 10 small packets.
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    list.push_back(packet);
+  }
+  // Insert 11th packet of another payload type (not CNG).
+  Packet* packet = gen.NextPacket(payload_len);
+  packet->header.payloadType = 1;
+  list.push_back(packet);
+
+
+  MockDecoderDatabase decoder_database;
+  EXPECT_CALL(decoder_database, IsComfortNoise(_))
+      .WillRepeatedly(Return(false));
+  EXPECT_CALL(decoder_database, IsDtmf(_))
+      .WillRepeatedly(Return(false));
+  uint8_t current_pt = 0xFF;
+  uint8_t current_cng_pt = 0xFF;
+  EXPECT_EQ(PacketBuffer::kFlushed, buffer.InsertPacketList(&list,
+                                                            decoder_database,
+                                                            &current_pt,
+                                                            &current_cng_pt));
+  EXPECT_TRUE(list.empty());  // The PacketBuffer should have depleted the list.
+  EXPECT_EQ(1, buffer.NumPacketsInBuffer());  // Only the last packet.
+  EXPECT_EQ(1 * payload_len, buffer.current_memory_bytes());
+  EXPECT_EQ(1, current_pt);  // Current payload type changed to 0.
+  EXPECT_EQ(0xFF, current_cng_pt);  // CNG payload type not changed.
+
+  buffer.Flush();  // Clean up.
+
+  EXPECT_CALL(decoder_database, Die());  // Called when object is deleted.
+}
+
+// Test inserting a number of packets, and verifying correct extraction order.
+// The packets inserted are as follows:
+// Packet no.  Seq. no.    Primary TS    Secondary TS
+// 0           0xFFFD      0xFFFFFFD7    -
+// 1           0xFFFE      0xFFFFFFE1    0xFFFFFFD7
+// 2           0xFFFF      0xFFFFFFEB    0xFFFFFFE1
+// 3           0x0000      0xFFFFFFF5    0xFFFFFFEB
+// 4           0x0001      0xFFFFFFFF    0xFFFFFFF5
+// 5           0x0002      0x0000000A    0xFFFFFFFF
+// 6  MISSING--0x0003------0x00000014----0x0000000A--MISSING
+// 7           0x0004      0x0000001E    0x00000014
+// 8           0x0005      0x00000028    0x0000001E
+// 9           0x0006      0x00000032    0x00000028
+TEST(PacketBuffer, ExtractOrderRedundancy) {
+  PacketBuffer buffer(100, 1000);  // 100 packets, 1000 bytes.
+  const uint32_t ts_increment = 10;  // Samples per packet.
+  const uint16_t start_seq_no = 0xFFFF - 2;  // Wraps after 3 packets.
+  const uint32_t start_ts = 0xFFFFFFFF -
+      4 * ts_increment;  // Wraps after 5 packets.
+  const uint8_t primary_pt = 0;
+  const uint8_t secondary_pt = 1;
+  PacketGenerator gen(start_seq_no, start_ts, primary_pt, ts_increment);
+  // Insert secondary payloads too. (Simulating RED.)
+  PacketGenerator red_gen(start_seq_no + 1, start_ts, secondary_pt,
+                          ts_increment);
+
+  // Insert 9 small packets (skip one).
+  for (int i = 0; i < 10; ++i) {
+    const int payload_len = 10;
+    if (i == 6) {
+      // Skip this packet.
+      gen.SkipPacket();
+      red_gen.SkipPacket();
+      continue;
+    }
+    // Primary payload.
+    Packet* packet = gen.NextPacket(payload_len);
+    EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacket(packet));
+    if (i >= 1) {
+      // Secondary payload.
+      packet = red_gen.NextPacket(payload_len);
+      packet->primary = false;
+      EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacket(packet));
+    }
+  }
+  EXPECT_EQ(17, buffer.NumPacketsInBuffer());  // 9 primary + 8 secondary
+
+  uint16_t current_seq_no = start_seq_no;
+  uint32_t current_ts = start_ts;
+
+  for (int i = 0; i < 10; ++i) {
+    // Extract packets.
+    int drop_count = 0;
+    Packet* packet = buffer.GetNextPacket(&drop_count);
+    ASSERT_FALSE(packet == NULL);
+    if (i == 6) {
+      // Special case for the dropped primary payload.
+      // Expect secondary payload, and one step higher sequence number.
+      EXPECT_EQ(current_seq_no + 1, packet->header.sequenceNumber);
+      EXPECT_EQ(current_ts, packet->header.timestamp);
+      EXPECT_FALSE(packet->primary);
+      EXPECT_EQ(1, packet->header.payloadType);
+      EXPECT_EQ(0, drop_count);
+    } else {
+      EXPECT_EQ(current_seq_no, packet->header.sequenceNumber);
+      EXPECT_EQ(current_ts, packet->header.timestamp);
+      EXPECT_TRUE(packet->primary);
+      EXPECT_EQ(0, packet->header.payloadType);
+      if (i == 5 || i == 9) {
+        // No duplicate TS for dropped packet or for last primary payload.
+        EXPECT_EQ(0, drop_count);
+      } else {
+        EXPECT_EQ(1, drop_count);
+      }
+    }
+    ++current_seq_no;
+    current_ts += ts_increment;
+    delete [] packet->payload;
+    delete packet;
+  }
+}
+
+TEST(PacketBuffer, DiscardPackets) {
+  PacketBuffer buffer(100, 1000);  // 100 packets, 1000 bytes.
+  const uint16_t start_seq_no = 17;
+  const uint32_t start_ts = 4711;
+  const uint32_t ts_increment = 10;
+  PacketGenerator gen(start_seq_no, start_ts, 0, ts_increment);
+  PacketList list;
+  const int payload_len = 10;
+
+  // Insert 10 small packets.
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    buffer.InsertPacket(packet);
+  }
+  EXPECT_EQ(10, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(10 * payload_len, buffer.current_memory_bytes());
+
+  // Discard them one by one and make sure that the right packets are at the
+  // front of the buffer.
+  uint32_t current_ts = start_ts;
+  for (int i = 0; i < 10; ++i) {
+    uint32_t ts;
+    EXPECT_EQ(PacketBuffer::kOK, buffer.NextTimestamp(&ts));
+    EXPECT_EQ(current_ts, ts);
+    EXPECT_EQ(PacketBuffer::kOK, buffer.DiscardNextPacket());
+    current_ts += ts_increment;
+  }
+  EXPECT_TRUE(buffer.Empty());
+}
+
+TEST(PacketBuffer, Reordering) {
+  PacketBuffer buffer(100, 1000);  // 100 packets, 1000 bytes.
+  const uint16_t start_seq_no = 17;
+  const uint32_t start_ts = 4711;
+  const uint32_t ts_increment = 10;
+  PacketGenerator gen(start_seq_no, start_ts, 0, ts_increment);
+  const int payload_len = 10;
+
+  // Generate 10 small packets and insert them into a PacketList. Insert every
+  // odd packet to the front, and every even packet to the back, thus creating
+  // a (rather strange) reordering.
+  PacketList list;
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    if (i % 2) {
+      list.push_front(packet);
+    } else {
+      list.push_back(packet);
+    }
+  }
+
+  MockDecoderDatabase decoder_database;
+  EXPECT_CALL(decoder_database, IsComfortNoise(0))
+      .WillRepeatedly(Return(false));
+  EXPECT_CALL(decoder_database, IsDtmf(0))
+      .WillRepeatedly(Return(false));
+  uint8_t current_pt = 0xFF;
+  uint8_t current_cng_pt = 0xFF;
+
+  EXPECT_EQ(PacketBuffer::kOK, buffer.InsertPacketList(&list,
+                                                       decoder_database,
+                                                       &current_pt,
+                                                       &current_cng_pt));
+  EXPECT_EQ(10, buffer.NumPacketsInBuffer());
+  EXPECT_EQ(10 * payload_len, buffer.current_memory_bytes());
+
+  // Extract them and make sure that come out in the right order.
+  uint32_t current_ts = start_ts;
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = buffer.GetNextPacket(NULL);
+    ASSERT_FALSE(packet == NULL);
+    EXPECT_EQ(current_ts, packet->header.timestamp);
+    current_ts += ts_increment;
+    delete [] packet->payload;
+    delete packet;
+  }
+  EXPECT_TRUE(buffer.Empty());
+
+  EXPECT_CALL(decoder_database, Die());  // Called when object is deleted.
+}
+
+TEST(PacketBuffer, Failures) {
+  const uint16_t start_seq_no = 17;
+  const uint32_t start_ts = 4711;
+  const uint32_t ts_increment = 10;
+  int payload_len = 100;
+  PacketGenerator gen(start_seq_no, start_ts, 0, ts_increment);
+
+  PacketBuffer* buffer = new PacketBuffer(0, 1000);  // 0 packets, 1000 bytes.
+  Packet* packet = gen.NextPacket(payload_len);
+  EXPECT_EQ(PacketBuffer::kOversizePacket, buffer->InsertPacket(packet));
+  delete buffer;
+
+  buffer = new PacketBuffer(100, 10);  // 100 packets, 10 bytes.
+  packet = gen.NextPacket(payload_len);
+  EXPECT_EQ(PacketBuffer::kOversizePacket, buffer->InsertPacket(packet));
+  delete buffer;
+
+  buffer = new PacketBuffer(100, 10000);  // 100 packets, 10000 bytes.
+  packet = NULL;
+  EXPECT_EQ(PacketBuffer::kInvalidPacket, buffer->InsertPacket(packet));
+  packet = gen.NextPacket(payload_len);
+  delete [] packet->payload;
+  packet->payload = NULL;
+  EXPECT_EQ(PacketBuffer::kInvalidPacket, buffer->InsertPacket(packet));
+  // Packet is deleted by the PacketBuffer.
+
+  // Buffer should still be empty. Test all empty-checks.
+  uint32_t temp_ts;
+  EXPECT_EQ(PacketBuffer::kBufferEmpty, buffer->NextTimestamp(&temp_ts));
+  EXPECT_EQ(PacketBuffer::kBufferEmpty,
+            buffer->NextHigherTimestamp(0, &temp_ts));
+  EXPECT_EQ(NULL, buffer->NextRtpHeader());
+  EXPECT_EQ(NULL, buffer->GetNextPacket(NULL));
+  EXPECT_EQ(PacketBuffer::kBufferEmpty, buffer->DiscardNextPacket());
+  EXPECT_EQ(0, buffer->DiscardOldPackets(0));  // 0 packets discarded.
+
+  // Insert one packet to make the buffer non-empty.
+  packet = gen.NextPacket(payload_len);
+  EXPECT_EQ(PacketBuffer::kOK, buffer->InsertPacket(packet));
+  EXPECT_EQ(PacketBuffer::kInvalidPointer, buffer->NextTimestamp(NULL));
+  EXPECT_EQ(PacketBuffer::kInvalidPointer,
+            buffer->NextHigherTimestamp(0, NULL));
+  delete buffer;
+
+  // Insert packet list of three packets, where the second packet has an invalid
+  // payload.  Expect first packet to be inserted, and the remaining two to be
+  // discarded.
+  buffer = new PacketBuffer(100, 1000);  // 100 packets, 1000 bytes.
+  PacketList list;
+  list.push_back(gen.NextPacket(payload_len));  // Valid packet.
+  packet = gen.NextPacket(payload_len);
+  delete [] packet->payload;
+  packet->payload = NULL;  // Invalid.
+  list.push_back(packet);
+  list.push_back(gen.NextPacket(payload_len));  // Valid packet.
+  MockDecoderDatabase decoder_database;
+  EXPECT_CALL(decoder_database, IsComfortNoise(0))
+      .WillRepeatedly(Return(false));
+  EXPECT_CALL(decoder_database, IsDtmf(0))
+      .WillRepeatedly(Return(false));
+  uint8_t current_pt = 0xFF;
+  uint8_t current_cng_pt = 0xFF;
+  EXPECT_EQ(PacketBuffer::kInvalidPacket,
+            buffer->InsertPacketList(&list,
+                                     decoder_database,
+                                     &current_pt,
+                                     &current_cng_pt));
+  EXPECT_TRUE(list.empty());  // The PacketBuffer should have depleted the list.
+  EXPECT_EQ(1, buffer->NumPacketsInBuffer());
+  delete buffer;
+  EXPECT_CALL(decoder_database, Die());  // Called when object is deleted.
+}
+
+// Test packet comparison function.
+// The function should return true if the first packet "goes before" the second.
+TEST(PacketBuffer, ComparePackets) {
+  PacketGenerator gen(0, 0, 0, 10);
+  Packet* a = gen.NextPacket(10);  // SN = 0, TS = 0.
+  Packet* b = gen.NextPacket(10);  // SN = 1, TS = 10.
+  EXPECT_FALSE(*a == *b);
+  EXPECT_TRUE(*a != *b);
+  EXPECT_TRUE(*a < *b);
+  EXPECT_FALSE(*a > *b);
+  EXPECT_TRUE(*a <= *b);
+  EXPECT_FALSE(*a >= *b);
+
+  // Testing wrap-around case; 'a' is earlier but has a larger timestamp value.
+  a->header.timestamp = 0xFFFFFFFF - 10;
+  EXPECT_FALSE(*a == *b);
+  EXPECT_TRUE(*a != *b);
+  EXPECT_TRUE(*a < *b);
+  EXPECT_FALSE(*a > *b);
+  EXPECT_TRUE(*a <= *b);
+  EXPECT_FALSE(*a >= *b);
+
+  // Test equal packets.
+  EXPECT_TRUE(*a == *a);
+  EXPECT_FALSE(*a != *a);
+  EXPECT_FALSE(*a < *a);
+  EXPECT_FALSE(*a > *a);
+  EXPECT_TRUE(*a <= *a);
+  EXPECT_TRUE(*a >= *a);
+
+  // Test equal timestamps but different sequence numbers (0 and 1).
+  a->header.timestamp = b->header.timestamp;
+  EXPECT_FALSE(*a == *b);
+  EXPECT_TRUE(*a != *b);
+  EXPECT_TRUE(*a < *b);
+  EXPECT_FALSE(*a > *b);
+  EXPECT_TRUE(*a <= *b);
+  EXPECT_FALSE(*a >= *b);
+
+  // Test equal timestamps but different sequence numbers (32767 and 1).
+  a->header.sequenceNumber = 0xFFFF;
+  EXPECT_FALSE(*a == *b);
+  EXPECT_TRUE(*a != *b);
+  EXPECT_TRUE(*a < *b);
+  EXPECT_FALSE(*a > *b);
+  EXPECT_TRUE(*a <= *b);
+  EXPECT_FALSE(*a >= *b);
+
+  // Test equal timestamps and sequence numbers, but only 'b' is primary.
+  a->header.sequenceNumber = b->header.sequenceNumber;
+  a->primary = false;
+  b->primary = true;
+  EXPECT_FALSE(*a == *b);
+  EXPECT_TRUE(*a != *b);
+  EXPECT_FALSE(*a < *b);
+  EXPECT_TRUE(*a > *b);
+  EXPECT_FALSE(*a <= *b);
+  EXPECT_TRUE(*a >= *b);
+
+  delete [] a->payload;
+  delete a;
+  delete [] b->payload;
+  delete b;
+}
+
+// Test the DeleteFirstPacket DeleteAllPackets methods.
+TEST(PacketBuffer, DeleteAllPackets) {
+  PacketGenerator gen(0, 0, 0, 10);
+  PacketList list;
+  const int payload_len = 10;
+
+  // Insert 10 small packets.
+  for (int i = 0; i < 10; ++i) {
+    Packet* packet = gen.NextPacket(payload_len);
+    list.push_back(packet);
+  }
+  EXPECT_TRUE(PacketBuffer::DeleteFirstPacket(&list));
+  EXPECT_EQ(9u, list.size());
+  PacketBuffer::DeleteAllPackets(&list);
+  EXPECT_TRUE(list.empty());
+  EXPECT_FALSE(PacketBuffer::DeleteFirstPacket(&list));
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/payload_splitter.cc b/webrtc/modules/audio_coding/neteq4/payload_splitter.cc
new file mode 100644
index 0000000..62ed5da
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/payload_splitter.cc
@@ -0,0 +1,368 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/payload_splitter.h"
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+
+namespace webrtc {
+
+// The method loops through a list of packets {A, B, C, ...}. Each packet is
+// split into its corresponding RED payloads, {A1, A2, ...}, which is
+// temporarily held in the list |new_packets|.
+// When the first packet in |packet_list| has been processed, the orignal packet
+// is replaced by the new ones in |new_packets|, so that |packet_list| becomes:
+// {A1, A2, ..., B, C, ...}. The method then continues with B, and C, until all
+// the original packets have been replaced by their split payloads.
+int PayloadSplitter::SplitRed(PacketList* packet_list) {
+  int ret = kOK;
+  PacketList::iterator it = packet_list->begin();
+  while (it != packet_list->end()) {
+    PacketList new_packets;  // An empty list to store the split packets in.
+    Packet* red_packet = (*it);
+    assert(red_packet->payload);
+    uint8_t* payload_ptr = red_packet->payload;
+
+    // Read RED headers (according to RFC 2198):
+    //
+    //    0                   1                   2                   3
+    //    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    //   |F|   block PT  |  timestamp offset         |   block length    |
+    //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    // Last RED header:
+    //    0 1 2 3 4 5 6 7
+    //   +-+-+-+-+-+-+-+-+
+    //   |0|   Block PT  |
+    //   +-+-+-+-+-+-+-+-+
+
+    bool last_block = false;
+    int sum_length = 0;
+    while (!last_block) {
+      Packet* new_packet = new Packet;
+      new_packet->header = red_packet->header;
+      // Check the F bit. If F == 0, this was the last block.
+      last_block = ((*payload_ptr & 0x80) == 0);
+      // Bits 1 through 7 are payload type.
+      new_packet->header.payloadType = payload_ptr[0] & 0x7F;
+      if (last_block) {
+        // No more header data to read.
+        ++sum_length;  // Account for RED header size of 1 byte.
+        new_packet->payload_length = red_packet->payload_length - sum_length;
+        new_packet->primary = true;  // Last block is always primary.
+        payload_ptr += 1;  // Advance to first payload byte.
+      } else {
+        // Bits 8 through 21 are timestamp offset.
+        int timestamp_offset = (payload_ptr[1] << 6) +
+            ((payload_ptr[2] & 0xFC) >> 2);
+        new_packet->header.timestamp = red_packet->header.timestamp -
+            timestamp_offset;
+        // Bits 22 through 31 are payload length.
+        new_packet->payload_length = ((payload_ptr[2] & 0x03) << 8) +
+            payload_ptr[3];
+        new_packet->primary = false;
+        payload_ptr += 4;  // Advance to next RED header.
+      }
+      sum_length += new_packet->payload_length;
+      sum_length += 4;  // Account for RED header size of 4 bytes.
+      // Store in new list of packets.
+      new_packets.push_back(new_packet);
+    }
+
+    // Populate the new packets with payload data.
+    // |payload_ptr| now points at the first payload byte.
+    PacketList::iterator new_it;
+    for (new_it = new_packets.begin(); new_it != new_packets.end(); ++new_it) {
+      int payload_length = (*new_it)->payload_length;
+      if (payload_ptr + payload_length >
+          red_packet->payload + red_packet->payload_length) {
+        // The block lengths in the RED headers do not match the overall packet
+        // length. Something is corrupt. Discard this and the remaining
+        // payloads from this packet.
+        while (new_it != new_packets.end()) {
+          // Payload should not have been allocated yet.
+          assert(!(*new_it)->payload);
+          delete (*new_it);
+          new_it = new_packets.erase(new_it);
+        }
+        ret = kRedLengthMismatch;
+        break;
+      }
+      (*new_it)->payload = new uint8_t[payload_length];
+      memcpy((*new_it)->payload, payload_ptr, payload_length);
+      payload_ptr += payload_length;
+    }
+    // Reverse the order of the new packets, so that the primary payload is
+    // always first.
+    new_packets.reverse();
+    // Insert new packets into original list, before the element pointed to by
+    // iterator |it|.
+    packet_list->splice(it, new_packets, new_packets.begin(),
+                        new_packets.end());
+    // Delete old packet payload.
+    delete [] (*it)->payload;
+    delete (*it);
+    // Remove |it| from the packet list. This operation effectively moves the
+    // iterator |it| to the next packet in the list. Thus, we do not have to
+    // increment it manually.
+    it = packet_list->erase(it);
+  }
+  return ret;
+}
+
+int PayloadSplitter::CheckRedPayloads(PacketList* packet_list,
+                                      const DecoderDatabase& decoder_database) {
+  PacketList::iterator it = packet_list->begin();
+  int main_payload_type = -1;
+  int num_deleted_packets = 0;
+  while (it != packet_list->end()) {
+    uint8_t this_payload_type = (*it)->header.payloadType;
+    if (!decoder_database.IsDtmf(this_payload_type) &&
+        !decoder_database.IsComfortNoise(this_payload_type)) {
+      if (main_payload_type == -1) {
+        // This is the first packet in the list which is non-DTMF non-CNG.
+        main_payload_type = this_payload_type;
+      } else {
+        if (this_payload_type != main_payload_type) {
+          // We do not allow redundant payloads of a different type.
+          // Discard this payload.
+          delete [] (*it)->payload;
+          delete (*it);
+          // Remove |it| from the packet list. This operation effectively
+          // moves the iterator |it| to the next packet in the list. Thus, we
+          // do not have to increment it manually.
+          it = packet_list->erase(it);
+          ++num_deleted_packets;
+          continue;
+        }
+      }
+    }
+    ++it;
+  }
+  return num_deleted_packets;
+}
+
+int PayloadSplitter::SplitAudio(PacketList* packet_list,
+                                const DecoderDatabase& decoder_database) {
+  PacketList::iterator it = packet_list->begin();
+  // Iterate through all packets in |packet_list|.
+  while (it != packet_list->end()) {
+    Packet* packet = (*it);  // Just to make the notation more intuitive.
+    // Get codec type for this payload.
+    const DecoderDatabase::DecoderInfo* info =
+        decoder_database.GetDecoderInfo(packet->header.payloadType);
+    if (!info) {
+      return kUnknownPayloadType;
+    }
+    PacketList new_packets;
+    switch (info->codec_type) {
+      case kDecoderPCMu:
+      case kDecoderPCMa: {
+        // 8 bytes per ms; 8 timestamps per ms.
+        SplitBySamples(packet, 8, 8, &new_packets);
+        break;
+      }
+      case kDecoderPCMu_2ch:
+      case kDecoderPCMa_2ch: {
+        // 2 * 8 bytes per ms; 8 timestamps per ms.
+        SplitBySamples(packet, 2 * 8, 8, &new_packets);
+        break;
+      }
+      case kDecoderG722: {
+        // 8 bytes per ms; 16 timestamps per ms.
+        SplitBySamples(packet, 8, 16, &new_packets);
+        break;
+      }
+      case kDecoderPCM16B: {
+        // 16 bytes per ms; 8 timestamps per ms.
+        SplitBySamples(packet, 16, 8, &new_packets);
+        break;
+      }
+      case kDecoderPCM16Bwb: {
+        // 32 bytes per ms; 16 timestamps per ms.
+        SplitBySamples(packet, 32, 16, &new_packets);
+        break;
+      }
+      case kDecoderPCM16Bswb32kHz: {
+        // 64 bytes per ms; 32 timestamps per ms.
+        SplitBySamples(packet, 64, 32, &new_packets);
+        break;
+      }
+      case kDecoderPCM16Bswb48kHz: {
+        // 96 bytes per ms; 48 timestamps per ms.
+        SplitBySamples(packet, 96, 48, &new_packets);
+        break;
+      }
+      case kDecoderPCM16B_2ch: {
+        // 2 * 16 bytes per ms; 8 timestamps per ms.
+        SplitBySamples(packet, 2 * 16, 8, &new_packets);
+        break;
+      }
+      case kDecoderPCM16Bwb_2ch: {
+        // 2 * 32 bytes per ms; 16 timestamps per ms.
+        SplitBySamples(packet, 2 * 32, 16, &new_packets);
+        break;
+      }
+      case kDecoderPCM16Bswb32kHz_2ch: {
+        // 2 * 64 bytes per ms; 32 timestamps per ms.
+        SplitBySamples(packet, 2 * 64, 32, &new_packets);
+        break;
+      }
+      case kDecoderPCM16Bswb48kHz_2ch: {
+        // 2 * 96 bytes per ms; 48 timestamps per ms.
+        SplitBySamples(packet, 2 * 96, 48, &new_packets);
+        break;
+      }
+      case kDecoderPCM16B_5ch: {
+        // 5 * 16 bytes per ms; 8 timestamps per ms.
+        SplitBySamples(packet, 5 * 16, 8, &new_packets);
+        break;
+      }
+      case kDecoderILBC: {
+        int bytes_per_frame;
+        int timestamps_per_frame;
+        if (packet->payload_length >= 950) {
+          return kTooLargePayload;
+        } else if (packet->payload_length % 38 == 0) {
+          // 20 ms frames.
+          bytes_per_frame = 38;
+          timestamps_per_frame = 160;
+        } else if (packet->payload_length % 50 == 0) {
+          // 30 ms frames.
+          bytes_per_frame = 50;
+          timestamps_per_frame = 240;
+        } else {
+          return kFrameSplitError;
+        }
+        int ret = SplitByFrames(packet, bytes_per_frame, timestamps_per_frame,
+                                &new_packets);
+        if (ret < 0) {
+          return ret;
+        } else if (ret == kNoSplit) {
+          // Do not split at all. Simply advance to the next packet in the list.
+          ++it;
+          // We do not have any new packets to insert, and should not delete the
+          // old one. Skip the code after the switch case, and jump straight to
+          // the next packet in the while loop.
+          continue;
+        }
+        break;
+      }
+      default: {
+        // Do not split at all. Simply advance to the next packet in the list.
+        ++it;
+        // We do not have any new packets to insert, and should not delete the
+        // old one. Skip the code after the switch case, and jump straight to
+        // the next packet in the while loop.
+        continue;
+      }
+    }
+    // Insert new packets into original list, before the element pointed to by
+    // iterator |it|.
+    packet_list->splice(it, new_packets, new_packets.begin(),
+                        new_packets.end());
+    // Delete old packet payload.
+    delete [] (*it)->payload;
+    delete (*it);
+    // Remove |it| from the packet list. This operation effectively moves the
+    // iterator |it| to the next packet in the list. Thus, we do not have to
+    // increment it manually.
+    it = packet_list->erase(it);
+  }
+  return 0;
+}
+
+void PayloadSplitter::SplitBySamples(const Packet* packet,
+                                     int bytes_per_ms,
+                                     int timestamps_per_ms,
+                                     PacketList* new_packets) {
+  assert(packet);
+  assert(new_packets);
+
+  int split_size_bytes = packet->payload_length;
+
+  // Find a "chunk size" >= 20 ms and < 40 ms.
+  int min_chunk_size = bytes_per_ms * 20;
+  // Reduce the split size by half as long as |split_size_bytes| is at least
+  // twice the minimum chunk size (so that the resulting size is at least as
+  // large as the minimum chunk size).
+  while (split_size_bytes >= 2 * min_chunk_size) {
+    split_size_bytes >>= 1;
+  }
+  int timestamps_per_chunk =
+      split_size_bytes * timestamps_per_ms / bytes_per_ms;
+  uint32_t timestamp = packet->header.timestamp;
+
+  uint8_t* payload_ptr = packet->payload;
+  int len = packet->payload_length;
+  while (len >= (2 * split_size_bytes)) {
+    Packet* new_packet = new Packet;
+    new_packet->payload_length = split_size_bytes;
+    new_packet->header = packet->header;
+    new_packet->header.timestamp = timestamp;
+    timestamp += timestamps_per_chunk;
+    new_packet->primary = packet->primary;
+    new_packet->payload = new uint8_t[split_size_bytes];
+    memcpy(new_packet->payload, payload_ptr, split_size_bytes);
+    payload_ptr += split_size_bytes;
+    new_packets->push_back(new_packet);
+    len -= split_size_bytes;
+  }
+
+  if (len > 0) {
+    Packet* new_packet = new Packet;
+    new_packet->payload_length = len;
+    new_packet->header = packet->header;
+    new_packet->header.timestamp = timestamp;
+    new_packet->primary = packet->primary;
+    new_packet->payload = new uint8_t[len];
+    memcpy(new_packet->payload, payload_ptr, len);
+    payload_ptr += len;
+    new_packets->push_back(new_packet);
+  }
+}
+
+int PayloadSplitter::SplitByFrames(const Packet* packet,
+                                   int bytes_per_frame,
+                                   int timestamps_per_frame,
+                                   PacketList* new_packets) {
+  if (packet->payload_length % bytes_per_frame != 0) {
+    return kFrameSplitError;
+  }
+
+  int num_frames = packet->payload_length / bytes_per_frame;
+  if (num_frames == 1) {
+    // Special case. Do not split the payload.
+    return kNoSplit;
+  }
+
+  uint32_t timestamp = packet->header.timestamp;
+  uint8_t* payload_ptr = packet->payload;
+  int len = packet->payload_length;
+  while (len > 0) {
+    assert(len >= bytes_per_frame);
+    Packet* new_packet = new Packet;
+    new_packet->payload_length = bytes_per_frame;
+    new_packet->header = packet->header;
+    new_packet->header.timestamp = timestamp;
+    timestamp += timestamps_per_frame;
+    new_packet->primary = packet->primary;
+    new_packet->payload = new uint8_t[bytes_per_frame];
+    memcpy(new_packet->payload, payload_ptr, bytes_per_frame);
+    payload_ptr += bytes_per_frame;
+    new_packets->push_back(new_packet);
+    len -= bytes_per_frame;
+  }
+  return kOK;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/payload_splitter.h b/webrtc/modules/audio_coding/neteq4/payload_splitter.h
new file mode 100644
index 0000000..3768c2f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/payload_splitter.h
@@ -0,0 +1,83 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PAYLOAD_SPLITTER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PAYLOAD_SPLITTER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class DecoderDatabase;
+
+// This class handles splitting of payloads into smaller parts.
+// The class does not have any member variables, and the methods could have
+// been made static. The reason for not making them static is testability.
+// With this design, the splitting functionality can be mocked during testing
+// of the NetEqImpl class.
+class PayloadSplitter {
+ public:
+  enum SplitterReturnCodes {
+    kOK = 0,
+    kNoSplit = 1,
+    kTooLargePayload = -1,
+    kFrameSplitError = -2,
+    kUnknownPayloadType = -3,
+    kRedLengthMismatch = -4
+  };
+
+  PayloadSplitter() {}
+
+  virtual ~PayloadSplitter() {}
+
+  // Splits each packet in |packet_list| into its separate RED payloads. Each
+  // RED payload is packetized into a Packet. The original elements in
+  // |packet_list| are properly deleted, and replaced by the new packets.
+  // Note that all packets in |packet_list| must be RED payloads, i.e., have
+  // RED headers according to RFC 2198 at the very beginning of the payload.
+  // Returns kOK or an error.
+  virtual int SplitRed(PacketList* packet_list);
+
+  // Checks all packets in |packet_list|. Packets that are DTMF events or
+  // comfort noise payloads are kept. Except that, only one single payload type
+  // is accepted. Any packet with another payload type is discarded.
+  virtual int CheckRedPayloads(PacketList* packet_list,
+                               const DecoderDatabase& decoder_database);
+
+  // Iterates through |packet_list| and, if possible, splits each audio payload
+  // into suitable size chunks. The result is written back to |packet_list| as
+  // new packets. The decoder database is needed to get information about which
+  // payload type each packet contains.
+  virtual int SplitAudio(PacketList* packet_list,
+                         const DecoderDatabase& decoder_database);
+
+ private:
+  // Splits the payload in |packet|. The payload is assumed to be from a
+  // sample-based codec.
+  virtual void SplitBySamples(const Packet* packet,
+                              int bytes_per_ms,
+                              int timestamps_per_ms,
+                              PacketList* new_packets);
+
+  // Splits the payload in |packet|. The payload will be split into chunks of
+  // size |bytes_per_frame|, corresponding to a |timestamps_per_frame|
+  // RTP timestamps.
+  virtual int SplitByFrames(const Packet* packet,
+                            int bytes_per_frame,
+                            int timestamps_per_frame,
+                            PacketList* new_packets);
+
+  DISALLOW_COPY_AND_ASSIGN(PayloadSplitter);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PAYLOAD_SPLITTER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/payload_splitter_unittest.cc b/webrtc/modules/audio_coding/neteq4/payload_splitter_unittest.cc
new file mode 100644
index 0000000..5a7a6ca
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/payload_splitter_unittest.cc
@@ -0,0 +1,694 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for PayloadSplitter class.
+
+#include "webrtc/modules/audio_coding/neteq4/payload_splitter.h"
+
+#include <assert.h>
+
+#include <utility>  // pair
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+
+using ::testing::Return;
+using ::testing::ReturnNull;
+
+namespace webrtc {
+
+static const int kRedPayloadType = 100;
+static const int kPayloadLength = 10;
+static const int kRedHeaderLength = 4;  // 4 bytes RED header.
+static const uint16_t kSequenceNumber = 0;
+static const uint32_t kBaseTimestamp = 0x12345678;
+
+// RED headers (according to RFC 2198):
+//
+//    0                   1                   2                   3
+//    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//   |F|   block PT  |  timestamp offset         |   block length    |
+//   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//
+// Last RED header:
+//    0 1 2 3 4 5 6 7
+//   +-+-+-+-+-+-+-+-+
+//   |0|   Block PT  |
+//   +-+-+-+-+-+-+-+-+
+
+// Creates a RED packet, with |num_payloads| payloads, with payload types given
+// by the values in array |payload_types| (which must be of length
+// |num_payloads|). Each redundant payload is |timestamp_offset| samples
+// "behind" the the previous payload.
+Packet* CreateRedPayload(int num_payloads,
+                         uint8_t* payload_types,
+                         int timestamp_offset) {
+  Packet* packet = new Packet;
+  packet->header.payloadType = kRedPayloadType;
+  packet->header.timestamp = kBaseTimestamp;
+  packet->header.sequenceNumber = kSequenceNumber;
+  packet->payload_length = (kPayloadLength + 1) +
+      (num_payloads - 1) * (kPayloadLength + kRedHeaderLength);
+  uint8_t* payload = new uint8_t[packet->payload_length];
+  uint8_t* payload_ptr = payload;
+  for (int i = 0; i < num_payloads; ++i) {
+    // Write the RED headers.
+    if (i == num_payloads - 1) {
+      // Special case for last payload.
+      *payload_ptr = payload_types[i] & 0x7F;  // F = 0;
+      ++payload_ptr;
+      break;
+    }
+    *payload_ptr = payload_types[i] & 0x7F;
+    // Not the last block; set F = 1.
+    *payload_ptr |= 0x80;
+    ++payload_ptr;
+    int this_offset = (num_payloads - i - 1) * timestamp_offset;
+    *payload_ptr = this_offset >> 6;
+    ++payload_ptr;
+    assert(kPayloadLength <= 1023);  // Max length described by 10 bits.
+    *payload_ptr = ((this_offset & 0x3F) << 2) | (kPayloadLength >> 8);
+    ++payload_ptr;
+    *payload_ptr = kPayloadLength & 0xFF;
+    ++payload_ptr;
+  }
+  for (int i = 0; i < num_payloads; ++i) {
+    // Write |i| to all bytes in each payload.
+    memset(payload_ptr, i, kPayloadLength);
+    payload_ptr += kPayloadLength;
+  }
+  packet->payload = payload;
+  return packet;
+}
+
+// Create a packet with all payload bytes set to |payload_value|.
+Packet* CreatePacket(uint8_t payload_type, int payload_length,
+                     uint8_t payload_value) {
+  Packet* packet = new Packet;
+  packet->header.payloadType = payload_type;
+  packet->header.timestamp = kBaseTimestamp;
+  packet->header.sequenceNumber = kSequenceNumber;
+  packet->payload_length = payload_length;
+  uint8_t* payload = new uint8_t[packet->payload_length];
+  memset(payload, payload_value, payload_length);
+  packet->payload = payload;
+  return packet;
+}
+
+// Checks that |packet| has the attributes given in the remaining parameters.
+void VerifyPacket(const Packet* packet,
+                  int payload_length,
+                  uint8_t payload_type,
+                  uint16_t sequence_number,
+                  uint32_t timestamp,
+                  uint8_t payload_value,
+                  bool primary = true) {
+  EXPECT_EQ(payload_length, packet->payload_length);
+  EXPECT_EQ(payload_type, packet->header.payloadType);
+  EXPECT_EQ(sequence_number, packet->header.sequenceNumber);
+  EXPECT_EQ(timestamp, packet->header.timestamp);
+  EXPECT_EQ(primary, packet->primary);
+  ASSERT_FALSE(packet->payload == NULL);
+  for (int i = 0; i < packet->payload_length; ++i) {
+    EXPECT_EQ(payload_value, packet->payload[i]);
+  }
+}
+
+// Start of test definitions.
+
+TEST(PayloadSplitter, CreateAndDestroy) {
+  PayloadSplitter* splitter = new PayloadSplitter;
+  delete splitter;
+}
+
+// Packet A is split into A1 and A2.
+TEST(RedPayloadSplitter, OnePacketTwoPayloads) {
+  uint8_t payload_types[] = {0, 0};
+  const int kTimestampOffset = 160;
+  Packet* packet = CreateRedPayload(2, payload_types, kTimestampOffset);
+  PacketList packet_list;
+  packet_list.push_back(packet);
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kOK, splitter.SplitRed(&packet_list));
+  ASSERT_EQ(2u, packet_list.size());
+  // Check first packet. The first in list should always be the primary payload.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[1], kSequenceNumber,
+               kBaseTimestamp, 1, true);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check second packet.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[0], kSequenceNumber,
+               kBaseTimestamp - kTimestampOffset, 0, false);
+  delete [] packet->payload;
+  delete packet;
+}
+
+// Packets A and B are not split at all. Only the RED header in each packet is
+// removed.
+TEST(RedPayloadSplitter, TwoPacketsOnePayload) {
+  uint8_t payload_types[] = {0};
+  const int kTimestampOffset = 160;
+  // Create first packet, with a single RED payload.
+  Packet* packet = CreateRedPayload(1, payload_types, kTimestampOffset);
+  PacketList packet_list;
+  packet_list.push_back(packet);
+  // Create second packet, with a single RED payload.
+  packet = CreateRedPayload(1, payload_types, kTimestampOffset);
+  // Manually change timestamp and sequence number of second packet.
+  packet->header.timestamp += kTimestampOffset;
+  packet->header.sequenceNumber++;
+  packet_list.push_back(packet);
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kOK, splitter.SplitRed(&packet_list));
+  ASSERT_EQ(2u, packet_list.size());
+  // Check first packet.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[0], kSequenceNumber,
+               kBaseTimestamp, 0, true);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check second packet.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[0], kSequenceNumber + 1,
+               kBaseTimestamp + kTimestampOffset, 0, true);
+  delete [] packet->payload;
+  delete packet;
+}
+
+// Packets A and B are split into packets A1, A2, A3, B1, B2, B3, with
+// attributes as follows:
+//
+//                  A1*   A2    A3    B1*   B2    B3
+// Payload type     0     1     2     0     1     2
+// Timestamp        b     b-o   b-2o  b+o   b     b-o
+// Sequence number  0     0     0     1     1     1
+//
+// b = kBaseTimestamp, o = kTimestampOffset, * = primary.
+TEST(RedPayloadSplitter, TwoPacketsThreePayloads) {
+  uint8_t payload_types[] = {2, 1, 0};  // Primary is the last one.
+  const int kTimestampOffset = 160;
+  // Create first packet, with 3 RED payloads.
+  Packet* packet = CreateRedPayload(3, payload_types, kTimestampOffset);
+  PacketList packet_list;
+  packet_list.push_back(packet);
+  // Create first packet, with 3 RED payloads.
+  packet = CreateRedPayload(3, payload_types, kTimestampOffset);
+  // Manually change timestamp and sequence number of second packet.
+  packet->header.timestamp += kTimestampOffset;
+  packet->header.sequenceNumber++;
+  packet_list.push_back(packet);
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kOK, splitter.SplitRed(&packet_list));
+  ASSERT_EQ(6u, packet_list.size());
+  // Check first packet, A1.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[2], kSequenceNumber,
+               kBaseTimestamp, 2, true);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check second packet, A2.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[1], kSequenceNumber,
+               kBaseTimestamp - kTimestampOffset, 1, false);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check third packet, A3.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[0], kSequenceNumber,
+               kBaseTimestamp - 2 * kTimestampOffset, 0, false);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check fourth packet, B1.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[2], kSequenceNumber + 1,
+               kBaseTimestamp + kTimestampOffset, 2, true);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check fifth packet, B2.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[1], kSequenceNumber + 1,
+               kBaseTimestamp, 1, false);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+  // Check sixth packet, B3.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[0], kSequenceNumber + 1,
+               kBaseTimestamp - kTimestampOffset, 0, false);
+  delete [] packet->payload;
+  delete packet;
+}
+
+// Creates a list with 4 packets with these payload types:
+// 0 = CNGnb
+// 1 = PCMu
+// 2 = DTMF (AVT)
+// 3 = iLBC
+// We expect the method CheckRedPayloads to discard the iLBC packet, since it
+// is a non-CNG, non-DTMF payload of another type than the first speech payload
+// found in the list (which is PCMu).
+TEST(RedPayloadSplitter, CheckRedPayloads) {
+  PacketList packet_list;
+  for (int i = 0; i <= 3; ++i) {
+    // Create packet with payload type |i|, payload length 10 bytes, all 0.
+    Packet* packet = CreatePacket(i, 10, 0);
+    packet_list.push_back(packet);
+  }
+
+  // Use a real DecoderDatabase object here instead of a mock, since it is
+  // easier to just register the payload types and let the actual implementation
+  // do its job.
+  DecoderDatabase decoder_database;
+  decoder_database.RegisterPayload(0, kDecoderCNGnb);
+  decoder_database.RegisterPayload(1, kDecoderPCMu);
+  decoder_database.RegisterPayload(2, kDecoderAVT);
+  decoder_database.RegisterPayload(3, kDecoderILBC);
+
+  PayloadSplitter splitter;
+  splitter.CheckRedPayloads(&packet_list, decoder_database);
+
+  ASSERT_EQ(3u, packet_list.size());  // Should have dropped the last packet.
+  // Verify packets. The loop verifies that payload types 0, 1, and 2 are in the
+  // list.
+  for (int i = 0; i <= 2; ++i) {
+    Packet* packet = packet_list.front();
+    VerifyPacket(packet, 10, i, kSequenceNumber, kBaseTimestamp, 0, true);
+    delete [] packet->payload;
+    delete packet;
+    packet_list.pop_front();
+  }
+  EXPECT_TRUE(packet_list.empty());
+}
+
+// Packet A is split into A1, A2 and A3. But the length parameter is off, so
+// the last payloads should be discarded.
+TEST(RedPayloadSplitter, WrongPayloadLength) {
+  uint8_t payload_types[] = {0, 0, 0};
+  const int kTimestampOffset = 160;
+  Packet* packet = CreateRedPayload(3, payload_types, kTimestampOffset);
+  // Manually tamper with the payload length of the packet.
+  // This is one byte too short for the second payload (out of three).
+  // We expect only the first payload to be returned.
+  packet->payload_length -= kPayloadLength + 1;
+  PacketList packet_list;
+  packet_list.push_back(packet);
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kRedLengthMismatch,
+            splitter.SplitRed(&packet_list));
+  ASSERT_EQ(1u, packet_list.size());
+  // Check first packet.
+  packet = packet_list.front();
+  VerifyPacket(packet, kPayloadLength, payload_types[0], kSequenceNumber,
+               kBaseTimestamp - 2 * kTimestampOffset, 0, false);
+  delete [] packet->payload;
+  delete packet;
+  packet_list.pop_front();
+}
+
+// Test that iSAC, iSAC-swb, RED, DTMF, CNG, and "Arbitrary" payloads do not
+// get split.
+TEST(AudioPayloadSplitter, NonSplittable) {
+  // Set up packets with different RTP payload types. The actual values do not
+  // matter, since we are mocking the decoder database anyway.
+  PacketList packet_list;
+  for (int i = 0; i < 6; ++i) {
+    // Let the payload type be |i|, and the payload value 10 * |i|.
+    packet_list.push_back(CreatePacket(i, kPayloadLength, 10 * i));
+  }
+
+  MockDecoderDatabase decoder_database;
+  // Tell the mock decoder database to return DecoderInfo structs with different
+  // codec types.
+  // Use scoped pointers to avoid having to delete them later.
+  scoped_ptr<DecoderDatabase::DecoderInfo> info0(
+      new DecoderDatabase::DecoderInfo(kDecoderISAC, 16000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(0))
+      .WillRepeatedly(Return(info0.get()));
+  scoped_ptr<DecoderDatabase::DecoderInfo> info1(
+      new DecoderDatabase::DecoderInfo(kDecoderISACswb, 32000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(1))
+      .WillRepeatedly(Return(info1.get()));
+  scoped_ptr<DecoderDatabase::DecoderInfo> info2(
+      new DecoderDatabase::DecoderInfo(kDecoderRED, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(2))
+      .WillRepeatedly(Return(info2.get()));
+  scoped_ptr<DecoderDatabase::DecoderInfo> info3(
+      new DecoderDatabase::DecoderInfo(kDecoderAVT, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(3))
+      .WillRepeatedly(Return(info3.get()));
+  scoped_ptr<DecoderDatabase::DecoderInfo> info4(
+      new DecoderDatabase::DecoderInfo(kDecoderCNGnb, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(4))
+      .WillRepeatedly(Return(info4.get()));
+  scoped_ptr<DecoderDatabase::DecoderInfo> info5(
+      new DecoderDatabase::DecoderInfo(kDecoderArbitrary, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(5))
+      .WillRepeatedly(Return(info5.get()));
+
+  PayloadSplitter splitter;
+  EXPECT_EQ(0, splitter.SplitAudio(&packet_list, decoder_database));
+  EXPECT_EQ(6u, packet_list.size());
+
+  // Check that all payloads are intact.
+  uint8_t payload_type = 0;
+  PacketList::iterator it = packet_list.begin();
+  while (it != packet_list.end()) {
+    VerifyPacket((*it), kPayloadLength, payload_type, kSequenceNumber,
+                 kBaseTimestamp, 10 * payload_type);
+    ++payload_type;
+    delete [] (*it)->payload;
+    delete (*it);
+    it = packet_list.erase(it);
+  }
+
+  // The destructor is called when decoder_database goes out of scope.
+  EXPECT_CALL(decoder_database, Die());
+}
+
+// Test unknown payload type.
+TEST(AudioPayloadSplitter, UnknownPayloadType) {
+  PacketList packet_list;
+  static const uint8_t kPayloadType = 17;  // Just a random number.
+  int kPayloadLengthBytes = 4711;  // Random number.
+  packet_list.push_back(CreatePacket(kPayloadType, kPayloadLengthBytes, 0));
+
+  MockDecoderDatabase decoder_database;
+  // Tell the mock decoder database to return NULL when asked for decoder info.
+  // This signals that the decoder database does not recognize the payload type.
+  EXPECT_CALL(decoder_database, GetDecoderInfo(kPayloadType))
+      .WillRepeatedly(ReturnNull());
+
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kUnknownPayloadType,
+            splitter.SplitAudio(&packet_list, decoder_database));
+  EXPECT_EQ(1u, packet_list.size());
+
+
+  // Delete the packets and payloads to avoid having the test leak memory.
+  PacketList::iterator it = packet_list.begin();
+  while (it != packet_list.end()) {
+    delete [] (*it)->payload;
+    delete (*it);
+    it = packet_list.erase(it);
+  }
+
+  // The destructor is called when decoder_database goes out of scope.
+  EXPECT_CALL(decoder_database, Die());
+}
+
+class SplitBySamplesTest : public ::testing::TestWithParam<NetEqDecoder> {
+ protected:
+  virtual void SetUp() {
+    decoder_type_ = GetParam();
+    switch (decoder_type_) {
+      case kDecoderPCMu:
+      case kDecoderPCMa:
+        bytes_per_ms_ = 8;
+        samples_per_ms_ = 8;
+        break;
+      case kDecoderPCMu_2ch:
+      case kDecoderPCMa_2ch:
+        bytes_per_ms_ = 2 * 8;
+        samples_per_ms_ = 8;
+        break;
+      case kDecoderG722:
+        bytes_per_ms_ = 8;
+        samples_per_ms_ = 16;
+        break;
+      case kDecoderPCM16B:
+        bytes_per_ms_ = 16;
+        samples_per_ms_ = 8;
+        break;
+      case kDecoderPCM16Bwb:
+        bytes_per_ms_ = 32;
+        samples_per_ms_ = 16;
+        break;
+      case kDecoderPCM16Bswb32kHz:
+        bytes_per_ms_ = 64;
+        samples_per_ms_ = 32;
+        break;
+      case kDecoderPCM16Bswb48kHz:
+        bytes_per_ms_ = 96;
+        samples_per_ms_ = 48;
+        break;
+      case kDecoderPCM16B_2ch:
+        bytes_per_ms_ = 2 * 16;
+        samples_per_ms_ = 8;
+        break;
+      case kDecoderPCM16Bwb_2ch:
+        bytes_per_ms_ = 2 * 32;
+        samples_per_ms_ = 16;
+        break;
+      case kDecoderPCM16Bswb32kHz_2ch:
+        bytes_per_ms_ = 2 * 64;
+        samples_per_ms_ = 32;
+        break;
+      case kDecoderPCM16Bswb48kHz_2ch:
+        bytes_per_ms_ = 2 * 96;
+        samples_per_ms_ = 48;
+        break;
+      case kDecoderPCM16B_5ch:
+        bytes_per_ms_ = 5 * 16;
+        samples_per_ms_ = 8;
+        break;
+      default:
+        assert(false);
+        break;
+    }
+  }
+  int bytes_per_ms_;
+  int samples_per_ms_;
+  NetEqDecoder decoder_type_;
+};
+
+// Test splitting sample-based payloads.
+TEST_P(SplitBySamplesTest, PayloadSizes) {
+  PacketList packet_list;
+  static const uint8_t kPayloadType = 17;  // Just a random number.
+  for (int payload_size_ms = 10; payload_size_ms <= 60; payload_size_ms += 10) {
+    // The payload values are set to be the same as the payload_size, so that
+    // one can distinguish from which packet the split payloads come from.
+    int payload_size_bytes = payload_size_ms * bytes_per_ms_;
+    packet_list.push_back(CreatePacket(kPayloadType, payload_size_bytes,
+                                       payload_size_ms));
+  }
+
+  MockDecoderDatabase decoder_database;
+  // Tell the mock decoder database to return DecoderInfo structs with different
+  // codec types.
+  // Use scoped pointers to avoid having to delete them later.
+  // (Sample rate is set to 8000 Hz, but does not matter.)
+  scoped_ptr<DecoderDatabase::DecoderInfo> info(
+      new DecoderDatabase::DecoderInfo(decoder_type_, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(kPayloadType))
+      .WillRepeatedly(Return(info.get()));
+
+  PayloadSplitter splitter;
+  EXPECT_EQ(0, splitter.SplitAudio(&packet_list, decoder_database));
+  // The payloads are expected to be split as follows:
+  // 10 ms -> 10 ms
+  // 20 ms -> 20 ms
+  // 30 ms -> 30 ms
+  // 40 ms -> 20 + 20 ms
+  // 50 ms -> 25 + 25 ms
+  // 60 ms -> 30 + 30 ms
+  int expected_size_ms[] = {10, 20, 30, 20, 20, 25, 25, 30, 30};
+  int expected_payload_value[] = {10, 20, 30, 40, 40, 50, 50, 60, 60};
+  int expected_timestamp_offset_ms[] = {0, 0, 0, 0, 20, 0, 25, 0, 30};
+  size_t expected_num_packets =
+      sizeof(expected_size_ms) / sizeof(expected_size_ms[0]);
+  EXPECT_EQ(expected_num_packets, packet_list.size());
+
+  PacketList::iterator it = packet_list.begin();
+  int i = 0;
+  while (it != packet_list.end()) {
+    int length_bytes = expected_size_ms[i] * bytes_per_ms_;
+    uint32_t expected_timestamp = kBaseTimestamp +
+        expected_timestamp_offset_ms[i] * samples_per_ms_;
+    VerifyPacket((*it), length_bytes, kPayloadType, kSequenceNumber,
+                 expected_timestamp, expected_payload_value[i]);
+    delete [] (*it)->payload;
+    delete (*it);
+    it = packet_list.erase(it);
+    ++i;
+  }
+
+  // The destructor is called when decoder_database goes out of scope.
+  EXPECT_CALL(decoder_database, Die());
+}
+
+INSTANTIATE_TEST_CASE_P(
+    PayloadSplitter, SplitBySamplesTest,
+    ::testing::Values(kDecoderPCMu, kDecoderPCMa, kDecoderPCMu_2ch,
+                      kDecoderPCMa_2ch, kDecoderG722, kDecoderPCM16B,
+                      kDecoderPCM16Bwb, kDecoderPCM16Bswb32kHz,
+                      kDecoderPCM16Bswb48kHz, kDecoderPCM16B_2ch,
+                      kDecoderPCM16Bwb_2ch, kDecoderPCM16Bswb32kHz_2ch,
+                      kDecoderPCM16Bswb48kHz_2ch, kDecoderPCM16B_5ch));
+
+
+class SplitIlbcTest : public ::testing::TestWithParam<std::pair<int, int> > {
+ protected:
+  virtual void SetUp() {
+    const std::pair<int, int> parameters = GetParam();
+    num_frames_ = parameters.first;
+    frame_length_ms_ = parameters.second;
+    frame_length_bytes_ = (frame_length_ms_ == 20) ? 38 : 50;
+  }
+  size_t num_frames_;
+  int frame_length_ms_;
+  int frame_length_bytes_;
+};
+
+// Test splitting sample-based payloads.
+TEST_P(SplitIlbcTest, NumFrames) {
+  PacketList packet_list;
+  static const uint8_t kPayloadType = 17;  // Just a random number.
+  const int frame_length_samples = frame_length_ms_ * 8;
+  int payload_length_bytes = frame_length_bytes_ * num_frames_;
+  Packet* packet = CreatePacket(kPayloadType, payload_length_bytes, 0);
+  // Fill payload with increasing integers {0, 1, 2, ...}.
+  for (int i = 0; i < packet->payload_length; ++i) {
+    packet->payload[i] = static_cast<uint8_t>(i);
+  }
+  packet_list.push_back(packet);
+
+  MockDecoderDatabase decoder_database;
+  // Tell the mock decoder database to return DecoderInfo structs with different
+  // codec types.
+  // Use scoped pointers to avoid having to delete them later.
+  scoped_ptr<DecoderDatabase::DecoderInfo> info(
+      new DecoderDatabase::DecoderInfo(kDecoderILBC, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(kPayloadType))
+      .WillRepeatedly(Return(info.get()));
+
+  PayloadSplitter splitter;
+  EXPECT_EQ(0, splitter.SplitAudio(&packet_list, decoder_database));
+  EXPECT_EQ(num_frames_, packet_list.size());
+
+  PacketList::iterator it = packet_list.begin();
+  int frame_num = 0;
+  uint8_t payload_value = 0;
+  while (it != packet_list.end()) {
+    Packet* packet = (*it);
+    EXPECT_EQ(kBaseTimestamp + frame_length_samples * frame_num,
+              packet->header.timestamp);
+    EXPECT_EQ(frame_length_bytes_, packet->payload_length);
+    EXPECT_EQ(kPayloadType, packet->header.payloadType);
+    EXPECT_EQ(kSequenceNumber, packet->header.sequenceNumber);
+    EXPECT_EQ(true, packet->primary);
+    ASSERT_FALSE(packet->payload == NULL);
+    for (int i = 0; i < packet->payload_length; ++i) {
+      EXPECT_EQ(payload_value, packet->payload[i]);
+      ++payload_value;
+    }
+    delete [] (*it)->payload;
+    delete (*it);
+    it = packet_list.erase(it);
+    ++frame_num;
+  }
+
+  // The destructor is called when decoder_database goes out of scope.
+  EXPECT_CALL(decoder_database, Die());
+}
+
+// Test 1 through 5 frames of 20 and 30 ms size.
+// Also test the maximum number of frames in one packet for 20 and 30 ms.
+// The maximum is defined by the largest payload length that can be uniquely
+// resolved to a frame size of either 38 bytes (20 ms) or 50 bytes (30 ms).
+INSTANTIATE_TEST_CASE_P(
+    PayloadSplitter, SplitIlbcTest,
+    ::testing::Values(std::pair<int, int>(1, 20),  // 1 frame, 20 ms.
+                      std::pair<int, int>(2, 20),  // 2 frames, 20 ms.
+                      std::pair<int, int>(3, 20),  // And so on.
+                      std::pair<int, int>(4, 20),
+                      std::pair<int, int>(5, 20),
+                      std::pair<int, int>(24, 20),
+                      std::pair<int, int>(1, 30),
+                      std::pair<int, int>(2, 30),
+                      std::pair<int, int>(3, 30),
+                      std::pair<int, int>(4, 30),
+                      std::pair<int, int>(5, 30),
+                      std::pair<int, int>(18, 30)));
+
+// Test too large payload size.
+TEST(IlbcPayloadSplitter, TooLargePayload) {
+  PacketList packet_list;
+  static const uint8_t kPayloadType = 17;  // Just a random number.
+  int kPayloadLengthBytes = 950;
+  Packet* packet = CreatePacket(kPayloadType, kPayloadLengthBytes, 0);
+  packet_list.push_back(packet);
+
+  MockDecoderDatabase decoder_database;
+  scoped_ptr<DecoderDatabase::DecoderInfo> info(
+      new DecoderDatabase::DecoderInfo(kDecoderILBC, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(kPayloadType))
+      .WillRepeatedly(Return(info.get()));
+
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kTooLargePayload,
+            splitter.SplitAudio(&packet_list, decoder_database));
+  EXPECT_EQ(1u, packet_list.size());
+
+  // Delete the packets and payloads to avoid having the test leak memory.
+  PacketList::iterator it = packet_list.begin();
+  while (it != packet_list.end()) {
+    delete [] (*it)->payload;
+    delete (*it);
+    it = packet_list.erase(it);
+  }
+
+  // The destructor is called when decoder_database goes out of scope.
+  EXPECT_CALL(decoder_database, Die());
+}
+
+// Payload not an integer number of frames.
+TEST(IlbcPayloadSplitter, UnevenPayload) {
+  PacketList packet_list;
+  static const uint8_t kPayloadType = 17;  // Just a random number.
+  int kPayloadLengthBytes = 39;  // Not an even number of frames.
+  Packet* packet = CreatePacket(kPayloadType, kPayloadLengthBytes, 0);
+  packet_list.push_back(packet);
+
+  MockDecoderDatabase decoder_database;
+  scoped_ptr<DecoderDatabase::DecoderInfo> info(
+      new DecoderDatabase::DecoderInfo(kDecoderILBC, 8000, NULL, false));
+  EXPECT_CALL(decoder_database, GetDecoderInfo(kPayloadType))
+      .WillRepeatedly(Return(info.get()));
+
+  PayloadSplitter splitter;
+  EXPECT_EQ(PayloadSplitter::kFrameSplitError,
+            splitter.SplitAudio(&packet_list, decoder_database));
+  EXPECT_EQ(1u, packet_list.size());
+
+  // Delete the packets and payloads to avoid having the test leak memory.
+  PacketList::iterator it = packet_list.begin();
+  while (it != packet_list.end()) {
+    delete [] (*it)->payload;
+    delete (*it);
+    it = packet_list.erase(it);
+  }
+
+  // The destructor is called when decoder_database goes out of scope.
+  EXPECT_CALL(decoder_database, Die());
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/post_decode_vad.cc b/webrtc/modules/audio_coding/neteq4/post_decode_vad.cc
new file mode 100644
index 0000000..38917cb
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/post_decode_vad.cc
@@ -0,0 +1,82 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/post_decode_vad.h"
+
+namespace webrtc {
+
+void PostDecodeVad::Enable() {
+  if (!vad_instance_) {
+    // Create the instance.
+    if (WebRtcVad_Create(&vad_instance_) != 0) {
+      // Failed to create instance.
+      Disable();
+      return;
+    }
+  }
+  Init();
+  enabled_ = true;
+}
+
+void PostDecodeVad::Disable() {
+  enabled_ = false;
+  running_ = false;
+}
+
+void PostDecodeVad::Init() {
+  running_ = false;
+  if (vad_instance_) {
+    WebRtcVad_Init(vad_instance_);
+    WebRtcVad_set_mode(vad_instance_, kVadMode);
+    running_ = true;
+  }
+}
+
+void PostDecodeVad::Update(int16_t* signal, size_t length,
+                           AudioDecoder::SpeechType speech_type,
+                           bool sid_frame,
+                           int fs_hz) {
+  if (!vad_instance_ || !enabled_) {
+    return;
+  }
+
+  if (speech_type == AudioDecoder::kComfortNoise || sid_frame ||
+      fs_hz > 16000) {
+    // TODO(hlundin): Remove restriction on fs_hz.
+    running_ = false;
+    active_speech_ = true;
+    sid_interval_counter_ = 0;
+  } else if (!running_) {
+    ++sid_interval_counter_;
+  }
+
+  if (sid_interval_counter_ >= kVadAutoEnable) {
+    Init();
+  }
+
+  if (length > 0 && running_) {
+    size_t vad_sample_index = 0;
+    active_speech_ = false;
+    // Loop through frame sizes 30, 20, and 10 ms.
+    for (size_t vad_frame_size_ms = 30; vad_frame_size_ms >= 10;
+        vad_frame_size_ms -= 10) {
+      size_t vad_frame_size_samples = vad_frame_size_ms * fs_hz / 1000;
+      while (length - vad_sample_index >= vad_frame_size_samples) {
+        int vad_return = WebRtcVad_Process(vad_instance_, fs_hz,
+                                           &signal[vad_sample_index],
+                                           vad_frame_size_samples);
+        active_speech_ |= (vad_return == 1);
+        vad_sample_index += vad_frame_size_samples;
+      }
+    }
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/post_decode_vad.h b/webrtc/modules/audio_coding/neteq4/post_decode_vad.h
new file mode 100644
index 0000000..363838bf
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/post_decode_vad.h
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_POST_DECODE_VAD_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_POST_DECODE_VAD_H_
+
+#include <string>  // size_t
+
+#include "webrtc/common_audio/vad/include/webrtc_vad.h"
+#include "webrtc/common_types.h"  // NULL
+#include "webrtc/modules/audio_coding/neteq4/defines.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+class PostDecodeVad {
+ public:
+  PostDecodeVad()
+      : enabled_(false),
+        running_(false),
+        active_speech_(true),
+        sid_interval_counter_(0),
+        vad_instance_(NULL) {
+  }
+
+  virtual ~PostDecodeVad() {
+    if (vad_instance_) {
+      WebRtcVad_Free(vad_instance_);
+    }
+  }
+
+  // Enables post-decode VAD.
+  void Enable();
+
+  // Disables post-decode VAD.
+  void Disable();
+
+  // Initializes post-decode VAD.
+  void Init();
+
+  // Updates post-decode VAD with the audio data in |signal| having |length|
+  // samples. The data is of type |speech_type|, at the sample rate |fs_hz|.
+  void Update(int16_t* signal, size_t length,
+              AudioDecoder::SpeechType speech_type, bool sid_frame, int fs_hz);
+
+  // Accessors.
+  bool enabled() const { return enabled_; }
+  bool running() const { return running_; }
+  bool active_speech() const { return active_speech_; }
+
+ private:
+  static const int kVadMode = 0;  // Sets aggressiveness to "Normal".
+  // Number of Update() calls without CNG/SID before re-enabling VAD.
+  static const int kVadAutoEnable = 3000;
+
+  bool enabled_;
+  bool running_;
+  bool active_speech_;
+  int sid_interval_counter_;
+  ::VadInst* vad_instance_;
+
+  DISALLOW_COPY_AND_ASSIGN(PostDecodeVad);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_POST_DECODE_VAD_H_
diff --git a/webrtc/modules/audio_coding/neteq4/post_decode_vad_unittest.cc b/webrtc/modules/audio_coding/neteq4/post_decode_vad_unittest.cc
new file mode 100644
index 0000000..a4d9da8
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/post_decode_vad_unittest.cc
@@ -0,0 +1,25 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for PostDecodeVad class.
+
+#include "webrtc/modules/audio_coding/neteq4/post_decode_vad.h"
+
+#include "gtest/gtest.h"
+
+namespace webrtc {
+
+TEST(PostDecodeVad, CreateAndDestroy) {
+  PostDecodeVad vad;
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/preemptive_expand.cc b/webrtc/modules/audio_coding/neteq4/preemptive_expand.cc
new file mode 100644
index 0000000..9929078
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/preemptive_expand.cc
@@ -0,0 +1,100 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/preemptive_expand.h"
+
+#include <algorithm>  // min, max
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+
+namespace webrtc {
+
+PreemptiveExpand::ReturnCodes PreemptiveExpand::Process(
+    const int16_t* input,
+    int input_length,
+    int old_data_length,
+    AudioMultiVector<int16_t>* output,
+    int16_t* length_change_samples) {
+  old_data_length_per_channel_ = old_data_length;
+  // Input length must be (almost) 30 ms.
+  // Also, the new part must be at least |overlap_samples_| elements.
+  static const int k15ms = 120;  // 15 ms = 120 samples at 8 kHz sample rate.
+  if (num_channels_ == 0 ||
+      input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_ ||
+      old_data_length >= input_length / num_channels_ - overlap_samples_) {
+    // Length of input data too short to do preemptive expand. Simply move all
+    // data from input to output.
+    output->PushBackInterleaved(input, input_length);
+    return kError;
+  }
+  return TimeStretch::Process(input, input_length, output,
+                              length_change_samples);
+}
+
+void PreemptiveExpand::SetParametersForPassiveSpeech(int len,
+                                                     int16_t* best_correlation,
+                                                     int* peak_index) const {
+  // When the signal does not contain any active speech, the correlation does
+  // not matter. Simply set it to zero.
+  *best_correlation = 0;
+
+  // For low energy expansion, the new data can be less than 15 ms,
+  // but we must ensure that best_correlation is not larger than the length of
+  // the new data.
+  // but we must ensure that best_correlation is not larger than the new data.
+  *peak_index = std::min(*peak_index, len - old_data_length_per_channel_);
+}
+
+PreemptiveExpand::ReturnCodes PreemptiveExpand::CheckCriteriaAndStretch(
+    const WebRtc_Word16 *input, int input_length, size_t peak_index,
+    int16_t best_correlation, bool active_speech,
+    AudioMultiVector<int16_t>* output) const {
+  // Pre-calculate common multiplication with |fs_mult_|.
+  // 120 corresponds to 15 ms.
+  int fs_mult_120 = fs_mult_ * 120;
+  assert(old_data_length_per_channel_ >= 0);  // Make sure it's been set.
+  // Check for strong correlation (>0.9 in Q14) and at least 15 ms new data,
+  // or passive speech.
+  if (((best_correlation > kCorrelationThreshold) &&
+      (old_data_length_per_channel_ <= fs_mult_120)) ||
+      !active_speech) {
+    // Do accelerate operation by overlap add.
+
+    // Set length of the first part, not to be modified.
+    size_t unmodified_length = std::max(old_data_length_per_channel_,
+                                        fs_mult_120);
+    // Copy first part, including cross-fade region.
+    output->PushBackInterleaved(
+        input, (unmodified_length + peak_index) * num_channels_);
+    // Copy the last |peak_index| samples up to 15 ms to |temp_vector|.
+    AudioMultiVector<int16_t> temp_vector(num_channels_);
+    temp_vector.PushBackInterleaved(
+        &input[(unmodified_length - peak_index) * num_channels_],
+        peak_index * num_channels_);
+    // Cross-fade |temp_vector| onto the end of |output|.
+    output->CrossFade(temp_vector, peak_index);
+    // Copy the last unmodified part, 15 ms + pitch period until the end.
+    output->PushBackInterleaved(
+        &input[unmodified_length * num_channels_],
+        input_length - unmodified_length * num_channels_);
+
+    if (active_speech) {
+      return kSuccess;
+    } else {
+      return kSuccessLowEnergy;
+    }
+  } else {
+    // Accelerate not allowed. Simply move all data from decoded to outData.
+    output->PushBackInterleaved(input, input_length);
+    return kNoStretch;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/preemptive_expand.h b/webrtc/modules/audio_coding/neteq4/preemptive_expand.h
new file mode 100644
index 0000000..96a8511
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/preemptive_expand.h
@@ -0,0 +1,74 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PREEMPTIVE_EXPAND_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PREEMPTIVE_EXPAND_H_
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/modules/audio_coding/neteq4/time_stretch.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+
+// This class implements the PreemptiveExpand operation. Most of the work is
+// done in the base class TimeStretch, which is shared with the Accelerate
+// operation. In the PreemptiveExpand class, the operations that are specific to
+// PreemptiveExpand are implemented.
+class PreemptiveExpand : public TimeStretch {
+ public:
+  PreemptiveExpand(int sample_rate_hz, size_t num_channels,
+                   const BackgroundNoise& background_noise)
+      : TimeStretch(sample_rate_hz, num_channels, background_noise),
+        old_data_length_per_channel_(-1),
+        overlap_samples_(5 * sample_rate_hz / 8000) {
+  }
+
+  virtual ~PreemptiveExpand() {}
+
+  // This method performs the actual PreemptiveExpand operation. The samples are
+  // read from |input|, of length |input_length| elements, and are written to
+  // |output|. The number of samples added through time-stretching is
+  // is provided in the output |length_change_samples|. The method returns
+  // the outcome of the operation as an enumerator value.
+  ReturnCodes Process(const WebRtc_Word16 *pw16_decoded,
+                      int len,
+                      int oldDataLen,
+                      AudioMultiVector<int16_t>* output,
+                      int16_t* length_change_samples);
+
+ protected:
+  // Sets the parameters |best_correlation| and |peak_index| to suitable
+  // values when the signal contains no active speech.
+  virtual void SetParametersForPassiveSpeech(int len,
+                                             int16_t* w16_bestCorr,
+                                             int* w16_bestIndex) const;
+
+  // Checks the criteria for performing the time-stretching operation and,
+  // if possible, performs the time-stretching.
+  virtual ReturnCodes CheckCriteriaAndStretch(
+      const WebRtc_Word16 *pw16_decoded, int len, size_t w16_bestIndex,
+      int16_t w16_bestCorr, bool w16_VAD,
+      AudioMultiVector<int16_t>* output) const;
+
+ private:
+  int old_data_length_per_channel_;
+  int overlap_samples_;
+
+  DISALLOW_COPY_AND_ASSIGN(PreemptiveExpand);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_PREEMPTIVE_EXPAND_H_
diff --git a/webrtc/modules/audio_coding/neteq4/random_vector.cc b/webrtc/modules/audio_coding/neteq4/random_vector.cc
new file mode 100644
index 0000000..823909f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/random_vector.cc
@@ -0,0 +1,57 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+
+namespace webrtc {
+
+const int16_t RandomVector::kRandomTable[RandomVector::kRandomTableSize] = {
+    2680, 5532, 441, 5520, 16170, -5146, -1024, -8733, 3115, 9598, -10380,
+    -4959, -1280, -21716, 7133, -1522, 13458, -3902, 2789, -675, 3441, 5016,
+    -13599, -4003, -2739, 3922, -7209, 13352, -11617, -7241, 12905, -2314, 5426,
+    10121, -9702, 11207, -13542, 1373, 816, -5934, -12504, 4798, 1811, 4112,
+    -613, 201, -10367, -2960, -2419, 3442, 4299, -6116, -6092, 1552, -1650,
+    -480, -1237, 18720, -11858, -8303, -8212, 865, -2890, -16968, 12052, -5845,
+    -5912, 9777, -5665, -6294, 5426, -4737, -6335, 1652, 761, 3832, 641, -8552,
+    -9084, -5753, 8146, 12156, -4915, 15086, -1231, -1869, 11749, -9319, -6403,
+    11407, 6232, -1683, 24340, -11166, 4017, -10448, 3153, -2936, 6212, 2891,
+    -866, -404, -4807, -2324, -1917, -2388, -6470, -3895, -10300, 5323, -5403,
+    2205, 4640, 7022, -21186, -6244, -882, -10031, -3395, -12885, 7155, -5339,
+    5079, -2645, -9515, 6622, 14651, 15852, 359, 122, 8246, -3502, -6696, -3679,
+    -13535, -1409, -704, -7403, -4007, 1798, 279, -420, -12796, -14219, 1141,
+    3359, 11434, 7049, -6684, -7473, 14283, -4115, -9123, -8969, 4152, 4117,
+    13792, 5742, 16168, 8661, -1609, -6095, 1881, 14380, -5588, 6758, -6425,
+    -22969, -7269, 7031, 1119, -1611, -5850, -11281, 3559, -8952, -10146, -4667,
+    -16251, -1538, 2062, -1012, -13073, 227, -3142, -5265, 20, 5770, -7559,
+    4740, -4819, 992, -8208, -7130, -4652, 6725, 7369, -1036, 13144, -1588,
+    -5304, -2344, -449, -5705, -8894, 5205, -17904, -11188, -1022, 4852, 10101,
+    -5255, -4200, -752, 7941, -1543, 5959, 14719, 13346, 17045, -15605, -1678,
+    -1600, -9230, 68, 23348, 1172, 7750, 11212, -18227, 9956, 4161, 883, 3947,
+    4341, 1014, -4889, -2603, 1246, -5630, -3596, -870, -1298, 2784, -3317,
+    -6612, -20541, 4166, 4181, -8625, 3562, 12890, 4761, 3205, -12259, -8579 };
+
+void RandomVector::Reset() {
+  seed_ = 777;
+  seed_increment_ = 1;
+}
+
+void RandomVector::Generate(size_t length, int16_t* output) {
+  for (size_t i = 0; i < length; i++) {
+    seed_ += seed_increment_;
+    size_t position = seed_ & (kRandomTableSize - 1);
+    output[i] = kRandomTable[position];
+  }
+}
+
+void RandomVector::IncreaseSeedIncrement(int16_t increase_by) {
+  seed_increment_+= increase_by;
+  seed_increment_ &= kRandomTableSize - 1;
+}
+}
diff --git a/webrtc/modules/audio_coding/neteq4/random_vector.h b/webrtc/modules/audio_coding/neteq4/random_vector.h
new file mode 100644
index 0000000..a456b17
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/random_vector.h
@@ -0,0 +1,50 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_RANDOM_VECTOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_RANDOM_VECTOR_H_
+
+#include <cstring>  // size_t
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// This class generates pseudo-random samples.
+class RandomVector {
+ public:
+  static const int kRandomTableSize = 256;
+  static const int16_t kRandomTable[kRandomTableSize];
+
+  RandomVector()
+      : seed_(777),
+        seed_increment_(1) {
+  }
+
+  void Reset();
+
+  void Generate(size_t length, int16_t* output);
+
+  void IncreaseSeedIncrement(int16_t increase_by);
+
+  // Accessors and mutators.
+  int16_t seed_increment() { return seed_increment_; }
+  void set_seed_increment(int16_t value) { seed_increment_ = value; }
+
+ private:
+  uint32_t seed_;
+  int16_t seed_increment_;
+
+  DISALLOW_COPY_AND_ASSIGN(RandomVector);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_RANDOM_VECTOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/random_vector_unittest.cc b/webrtc/modules/audio_coding/neteq4/random_vector_unittest.cc
new file mode 100644
index 0000000..83193e2
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/random_vector_unittest.cc
@@ -0,0 +1,25 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for RandomVector class.
+
+#include "webrtc/modules/audio_coding/neteq4/random_vector.h"
+
+#include "gtest/gtest.h"
+
+namespace webrtc {
+
+TEST(RandomVector, CreateAndDestroy) {
+  RandomVector random_vector;
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/rtcp.cc b/webrtc/modules/audio_coding/neteq4/rtcp.cc
new file mode 100644
index 0000000..3572471
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/rtcp.cc
@@ -0,0 +1,95 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/rtcp.h"
+
+#include <string.h>
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/interface/module_common_types.h"
+
+namespace webrtc {
+
+void Rtcp::Init(uint16_t start_sequence_number) {
+  cycles_ = 0;
+  max_seq_no_ = start_sequence_number;
+  base_seq_no_ = start_sequence_number;
+  received_packets_ = 0;
+  received_packets_prior_ = 0;
+  expected_prior_ = 0;
+  jitter_ = 0;
+  transit_ = 0;
+}
+
+void Rtcp::Update(const RTPHeader& rtp_header, uint32_t receive_timestamp) {
+  // Update number of received packets, and largest packet number received.
+  received_packets_++;
+  int16_t sn_diff = rtp_header.sequenceNumber - max_seq_no_;
+  if (sn_diff >= 0) {
+    if (rtp_header.sequenceNumber < max_seq_no_) {
+      // Wrap-around detected.
+      cycles_++;
+    }
+    max_seq_no_ = rtp_header.sequenceNumber;
+  }
+
+  // Calculate jitter according to RFC 3550, and update previous timestamps.
+  // Note that the value in |jitter_| is in Q4.
+  if (received_packets_ > 1) {
+    int32_t ts_diff = receive_timestamp - (rtp_header.timestamp - transit_);
+    ts_diff = WEBRTC_SPL_ABS_W32(ts_diff);
+    int32_t jitter_diff = (ts_diff << 4) - jitter_;
+    // Calculate 15 * jitter_ / 16 + jitter_diff / 16 (with proper rounding).
+    jitter_ = jitter_ + ((jitter_diff + 8) >> 4);
+  }
+  transit_ = rtp_header.timestamp - receive_timestamp;
+}
+
+void Rtcp::GetStatistics(bool no_reset, RtcpStatistics* stats) {
+  // Extended highest sequence number received.
+  stats->extended_max = (static_cast<int>(cycles_) << 16) + max_seq_no_;
+
+  // Calculate expected number of packets and compare it with the number of
+  // packets that were actually received. The cumulative number of lost packets
+  // can be extracted.
+  uint32_t expected_packets = stats->extended_max - base_seq_no_ + 1;
+  if (received_packets_ == 0) {
+    // No packets received, assume none lost.
+    stats->cumulative_lost = 0;
+  } else if (expected_packets > received_packets_) {
+    stats->cumulative_lost = expected_packets - received_packets_;
+    if (stats->cumulative_lost > 0xFFFFFF) {
+      stats->cumulative_lost = 0xFFFFFF;
+    }
+  } else {
+    stats->cumulative_lost = 0;
+  }
+
+  // Fraction lost since last report.
+  uint32_t expected_since_last = expected_packets - expected_prior_;
+  uint32_t received_since_last = received_packets_ - received_packets_prior_;
+  if (!no_reset) {
+    expected_prior_ = expected_packets;
+    received_packets_prior_ = received_packets_;
+  }
+  int32_t lost = expected_since_last - received_since_last;
+  if (expected_since_last == 0 || lost <= 0 || received_packets_ == 0) {
+    stats->fraction_lost = 0;
+  } else {
+    stats->fraction_lost = (lost << 8) / expected_since_last;
+  }
+  if (stats->fraction_lost > 0xFF) {
+    stats->fraction_lost = 0xFF;
+  }
+
+  stats->jitter = jitter_ >> 4;  // Scaling from Q4.
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/rtcp.h b/webrtc/modules/audio_coding/neteq4/rtcp.h
new file mode 100644
index 0000000..00cbbd1
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/rtcp.h
@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_RTCP_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_RTCP_H_
+
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declaration.
+struct RTPHeader;
+
+class Rtcp {
+ public:
+  Rtcp() {
+    Init(0);
+  }
+
+  ~Rtcp() {}
+
+  // Resets the RTCP statistics, and sets the first received sequence number.
+  void Init(uint16_t start_sequence_number);
+
+  // Updates the RTCP statistics with a new received packet.
+  void Update(const RTPHeader& rtp_header, uint32_t receive_timestamp);
+
+  // Returns the current RTCP statistics. If |no_reset| is true, the statistics
+  // are not reset, otherwise they are.
+  void GetStatistics(bool no_reset, RtcpStatistics* stats);
+
+ private:
+  uint16_t cycles_;  // The number of wrap-arounds for the sequence number.
+  uint16_t max_seq_no_;  // The maximum sequence number received. Starts over
+                         // from 0 after wrap-around.
+  uint16_t base_seq_no_;  // The sequence number of the first received packet.
+  uint32_t received_packets_;  // The number of packets that have been received.
+  uint32_t received_packets_prior_;  // Number of packets received when last
+                                     // report was generated.
+  uint32_t expected_prior_;  // Expected number of packets, at the time of the
+                             // last report.
+  uint32_t jitter_;  // Current jitter value.
+  int32_t transit_;  // Clock difference for previous packet.
+
+  DISALLOW_COPY_AND_ASSIGN(Rtcp);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_RTCP_H_
diff --git a/webrtc/modules/audio_coding/neteq4/statistics_calculator.cc b/webrtc/modules/audio_coding/neteq4/statistics_calculator.cc
new file mode 100644
index 0000000..9355204
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/statistics_calculator.cc
@@ -0,0 +1,171 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/statistics_calculator.h"
+
+#include <assert.h>
+
+#include <cstring>  // memset
+
+#include "webrtc/modules/audio_coding/neteq4/decision_logic.h"
+#include "webrtc/modules/audio_coding/neteq4/delay_manager.h"
+
+namespace webrtc {
+
+StatisticsCalculator::StatisticsCalculator()
+    : preemptive_samples_(0),
+      accelerate_samples_(0),
+      added_zero_samples_(0),
+      expanded_voice_samples_(0),
+      expanded_noise_samples_(0),
+      discarded_packets_(0),
+      lost_timestamps_(0),
+      last_report_timestamp_(0),
+      len_waiting_times_(0),
+      next_waiting_time_index_(0) {
+  memset(waiting_times_, 0, kLenWaitingTimes * sizeof(waiting_times_[0]));
+}
+
+void StatisticsCalculator::Reset() {
+  preemptive_samples_ = 0;
+  accelerate_samples_ = 0;
+  added_zero_samples_ = 0;
+  expanded_voice_samples_ = 0;
+  expanded_noise_samples_ = 0;
+}
+
+void StatisticsCalculator::ResetMcu() {
+  discarded_packets_ = 0;
+  lost_timestamps_ = 0;
+  last_report_timestamp_ = 0;
+}
+
+void StatisticsCalculator::ResetWaitingTimeStatistics() {
+  memset(waiting_times_, 0, kLenWaitingTimes * sizeof(waiting_times_[0]));
+  len_waiting_times_ = 0;
+  next_waiting_time_index_ = 0;
+}
+
+void StatisticsCalculator::ExpandedVoiceSamples(int num_samples) {
+  expanded_voice_samples_ += num_samples;
+}
+
+void StatisticsCalculator::ExpandedNoiseSamples(int num_samples) {
+  expanded_noise_samples_ += num_samples;
+}
+
+void StatisticsCalculator::PreemptiveExpandedSamples(int num_samples) {
+  preemptive_samples_ += num_samples;
+}
+
+void StatisticsCalculator::AcceleratedSamples(int num_samples) {
+  accelerate_samples_ += num_samples;
+}
+
+void StatisticsCalculator::AddZeros(int num_samples) {
+  added_zero_samples_ += num_samples;
+}
+
+void StatisticsCalculator::PacketsDiscarded(int num_packets) {
+  discarded_packets_ += num_packets;
+}
+
+void StatisticsCalculator::LostSamples(int num_samples) {
+  lost_timestamps_ += num_samples;
+}
+
+void StatisticsCalculator::IncreaseCounter(int num_samples, int fs_hz) {
+  last_report_timestamp_ += num_samples;
+  if (last_report_timestamp_ >
+      static_cast<uint32_t>(fs_hz * kMaxReportPeriod)) {
+    lost_timestamps_ = 0;
+    last_report_timestamp_ = 0;
+    discarded_packets_ = 0;
+  }
+}
+
+void StatisticsCalculator::StoreWaitingTime(int waiting_time_ms) {
+  assert(next_waiting_time_index_ < kLenWaitingTimes);
+  waiting_times_[next_waiting_time_index_] = waiting_time_ms;
+  next_waiting_time_index_++;
+  if (next_waiting_time_index_ >= kLenWaitingTimes) {
+    next_waiting_time_index_ = 0;
+  }
+  if (len_waiting_times_ < kLenWaitingTimes) {
+    len_waiting_times_++;
+  }
+}
+
+void StatisticsCalculator::GetNetworkStatistics(
+    int fs_hz,
+    int num_samples_in_buffers,
+    int samples_per_packet,
+    const DelayManager& delay_manager,
+    const DecisionLogic& decision_logic,
+    NetEqNetworkStatistics *stats) {
+  if (fs_hz <= 0 || !stats) {
+    assert(false);
+    return;
+  }
+
+  stats->added_zero_samples = added_zero_samples_;
+  stats->current_buffer_size_ms = num_samples_in_buffers * 1000 / fs_hz;
+  const int ms_per_packet = decision_logic.packet_length_samples() /
+      (fs_hz / 1000);
+  stats->preferred_buffer_size_ms = (delay_manager.TargetLevel() >> 8) *
+      ms_per_packet;
+  stats->jitter_peaks_found = delay_manager.PeakFound();
+  stats->clockdrift_ppm = delay_manager.AverageIAT();
+
+  stats->packet_loss_rate = CalculateQ14Ratio(lost_timestamps_,
+                                              last_report_timestamp_);
+
+  const unsigned discarded_samples = discarded_packets_ * samples_per_packet;
+  stats->packet_discard_rate = CalculateQ14Ratio(discarded_samples,
+                                                 last_report_timestamp_);
+
+  stats->accelerate_rate = CalculateQ14Ratio(accelerate_samples_,
+                                             last_report_timestamp_);
+
+  stats->preemptive_rate = CalculateQ14Ratio(preemptive_samples_,
+                                             last_report_timestamp_);
+
+  stats->expand_rate = CalculateQ14Ratio(expanded_voice_samples_ +
+                                         expanded_noise_samples_,
+                                         last_report_timestamp_);
+
+  // Reset counters.
+  ResetMcu();
+  Reset();
+}
+
+void StatisticsCalculator::WaitingTimes(std::vector<int>* waiting_times) {
+  if (!waiting_times) {
+    return;
+  }
+  waiting_times->assign(waiting_times_, waiting_times_ + len_waiting_times_);
+  ResetWaitingTimeStatistics();
+}
+
+int StatisticsCalculator::CalculateQ14Ratio(uint32_t numerator,
+                                            uint32_t denominator) {
+  if (numerator == 0) {
+    return 0;
+  } else if (numerator < denominator) {
+    // Ratio must be smaller than 1 in Q14.
+    assert((numerator << 14) / denominator < (1 << 14));
+    return (numerator << 14) / denominator;
+  } else {
+    // Will not produce a ratio larger than 1, since this is probably an error.
+    return 1 << 14;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/statistics_calculator.h b/webrtc/modules/audio_coding/neteq4/statistics_calculator.h
new file mode 100644
index 0000000..25f8a14
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/statistics_calculator.h
@@ -0,0 +1,109 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_STATISTICS_CALCULATOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_STATISTICS_CALCULATOR_H_
+
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class DecisionLogic;
+class DelayManager;
+
+// This class handles various network statistics in NetEq.
+class StatisticsCalculator {
+ public:
+  StatisticsCalculator();
+
+  virtual ~StatisticsCalculator() {}
+
+  // Resets most of the counters.
+  void Reset();
+
+  // Resets the counters that are not handled by Reset().
+  void ResetMcu();
+
+  // Resets the waiting time statistics.
+  void ResetWaitingTimeStatistics();
+
+  // Reports that |num_samples| samples were produced through expansion, and
+  // that the expansion produced other than just noise samples.
+  void ExpandedVoiceSamples(int num_samples);
+
+  // Reports that |num_samples| samples were produced through expansion, and
+  // that the expansion produced only noise samples.
+  void ExpandedNoiseSamples(int num_samples);
+
+  // Reports that |num_samples| samples were produced through preemptive
+  // expansion.
+  void PreemptiveExpandedSamples(int num_samples);
+
+  // Reports that |num_samples| samples were removed through accelerate.
+  void AcceleratedSamples(int num_samples);
+
+  // Reports that |num_samples| zeros were inserted into the output.
+  void AddZeros(int num_samples);
+
+  // Reports that |num_packets| packets were discarded.
+  void PacketsDiscarded(int num_packets);
+
+  // Reports that |num_samples| were lost.
+  void LostSamples(int num_samples);
+
+  // Increases the report interval counter with |num_samples| at a sample rate
+  // of |fs_hz|.
+  void IncreaseCounter(int num_samples, int fs_hz);
+
+  // Stores new packet waiting time in waiting time statistics.
+  void StoreWaitingTime(int waiting_time_ms);
+
+  // Returns the current network statistics in |stats|. The current sample rate
+  // is |fs_hz|, the total number of samples in packet buffer and sync buffer
+  // yet to play out is |num_samples_in_buffers|, and the number of samples per
+  // packet is |samples_per_packet|.
+  void GetNetworkStatistics(int fs_hz,
+                            int num_samples_in_buffers,
+                            int samples_per_packet,
+                            const DelayManager& delay_manager,
+                            const DecisionLogic& decision_logic,
+                            NetEqNetworkStatistics *stats);
+
+  void WaitingTimes(std::vector<int>* waiting_times);
+
+ private:
+  static const int kMaxReportPeriod = 60;  // Seconds before auto-reset.
+  static const int kLenWaitingTimes = 100;
+
+  // Calculates numerator / denominator, and returns the value in Q14.
+  static int CalculateQ14Ratio(uint32_t numerator, uint32_t denominator);
+
+  uint32_t preemptive_samples_;
+  uint32_t accelerate_samples_;
+  int added_zero_samples_;
+  uint32_t expanded_voice_samples_;
+  uint32_t expanded_noise_samples_;
+  int discarded_packets_;
+  uint32_t lost_timestamps_;
+  uint32_t last_report_timestamp_;
+  int waiting_times_[kLenWaitingTimes];  // Used as a circular buffer.
+  int len_waiting_times_;
+  int next_waiting_time_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(StatisticsCalculator);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_STATISTICS_CALCULATOR_H_
diff --git a/webrtc/modules/audio_coding/neteq4/sync_buffer.cc b/webrtc/modules/audio_coding/neteq4/sync_buffer.cc
new file mode 100644
index 0000000..72fa16a
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/sync_buffer.cc
@@ -0,0 +1,107 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <assert.h>
+
+#include <algorithm>  // Access to min.
+
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+namespace webrtc {
+
+size_t SyncBuffer::FutureLength() const {
+  return Size() - next_index_;
+}
+
+void SyncBuffer::PushBack(const AudioMultiVector<int16_t>& append_this) {
+  size_t samples_added = append_this.Size();
+  AudioMultiVector<int16_t>::PushBack(append_this);
+  AudioMultiVector<int16_t>::PopFront(samples_added);
+  if (samples_added <= next_index_) {
+    next_index_ -= samples_added;
+  } else {
+    // This means that we are pushing out future data that was never used.
+//    assert(false);
+    // TODO(hlundin): This assert must be disabled to support 60 ms frames.
+    // This should not happen even for 60 ms frames, but it does. Investigate
+    // why.
+    next_index_ = 0;
+  }
+  dtmf_index_ -= std::min(dtmf_index_, samples_added);
+}
+
+void SyncBuffer::PushFrontZeros(size_t length) {
+  InsertZerosAtIndex(length, 0);
+}
+
+void SyncBuffer::InsertZerosAtIndex(size_t length, size_t position) {
+  position = std::min(position, Size());
+  length = std::min(length, Size() - position);
+  AudioMultiVector<int16_t>::PopBack(length);
+  for (size_t channel = 0; channel < Channels(); ++channel) {
+    channels_[channel]->InsertZerosAt(length, position);
+  }
+  if (next_index_ >= position) {
+    // We are moving the |next_index_| sample.
+    set_next_index(next_index_ + length);  // Overflow handled by subfunction.
+  }
+  if (dtmf_index_ > 0 && dtmf_index_ >= position) {
+    // We are moving the |dtmf_index_| sample.
+    set_dtmf_index(dtmf_index_ + length);  // Overflow handled by subfunction.
+  }
+}
+
+void SyncBuffer::ReplaceAtIndex(const AudioMultiVector<int16_t>& insert_this,
+                                size_t length,
+                                size_t position) {
+  position = std::min(position, Size());  // Cap |position| in the valid range.
+  length = std::min(length, Size() - position);
+  AudioMultiVector<int16_t>::OverwriteAt(insert_this, length, position);
+}
+
+void SyncBuffer::ReplaceAtIndex(const AudioMultiVector<int16_t>& insert_this,
+                                size_t position) {
+  ReplaceAtIndex(insert_this, insert_this.Size(), position);
+}
+
+size_t SyncBuffer::GetNextAudioInterleaved(size_t requested_len,
+                                           int16_t* output) {
+  if (!output) {
+    assert(false);
+    return 0;
+  }
+  size_t samples_to_read = std::min(FutureLength(), requested_len);
+  ReadInterleavedFromIndex(next_index_, samples_to_read, output);
+  next_index_ += samples_to_read;
+  return samples_to_read;
+}
+
+void SyncBuffer::IncreaseEndTimestamp(uint32_t increment) {
+  end_timestamp_ += increment;
+}
+
+void SyncBuffer::Flush() {
+  Zeros(Size());
+  next_index_ = Size();
+  end_timestamp_ = 0;
+  dtmf_index_ = 0;
+}
+
+void SyncBuffer::set_next_index(size_t value) {
+  // Cannot set |next_index_| larger than the size of the buffer.
+  next_index_ = std::min(value, Size());
+}
+
+void SyncBuffer::set_dtmf_index(size_t value) {
+  // Cannot set |dtmf_index_| larger than the size of the buffer.
+  dtmf_index_ = std::min(value, Size());
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/sync_buffer.h b/webrtc/modules/audio_coding/neteq4/sync_buffer.h
new file mode 100644
index 0000000..7add358
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/sync_buffer.h
@@ -0,0 +1,100 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_SYNC_BUFFER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_SYNC_BUFFER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+class SyncBuffer : public AudioMultiVector<int16_t> {
+ public:
+  SyncBuffer(size_t channels, size_t length)
+      : AudioMultiVector<int16_t>(channels, length),
+        next_index_(length),
+        end_timestamp_(0),
+        dtmf_index_(0) {}
+
+  virtual ~SyncBuffer() {}
+
+  // Returns the number of samples yet to play out form the buffer.
+  size_t FutureLength() const;
+
+  // Adds the contents of |append_this| to the back of the SyncBuffer. Removes
+  // the same number of samples from the beginning of the SyncBuffer, to
+  // maintain a constant buffer size. The |next_index_| is updated to reflect
+  // the move of the beginning of "future" data.
+  void PushBack(const AudioMultiVector<int16_t>& append_this);
+
+  // Adds |length| zeros to the beginning of each channel. Removes
+  // the same number of samples from the end of the SyncBuffer, to
+  // maintain a constant buffer size. The |next_index_| is updated to reflect
+  // the move of the beginning of "future" data.
+  // Note that this operation may delete future samples that are waiting to
+  // be played.
+  void PushFrontZeros(size_t length);
+
+  // Inserts |length| zeros into each channel at index |position|. The size of
+  // the SyncBuffer is kept constant, which means that the last |length|
+  // elements in each channel will be purged.
+  virtual void InsertZerosAtIndex(size_t length, size_t position);
+
+  // Overwrites each channel in this SyncBuffer with values taken from
+  // |insert_this|. The values are taken from the beginning of |insert_this| and
+  // are inserted starting at |position|. |length| values are written into each
+  // channel. The size of the SyncBuffer is kept constant. That is, if |length|
+  // and |position| are selected such that the new data would extend beyond the
+  // end of the current SyncBuffer, the buffer is not extended.
+  // The |next_index_| is not updated.
+  virtual void ReplaceAtIndex(const AudioMultiVector<int16_t>& insert_this,
+                              size_t length,
+                              size_t position);
+
+  // Same as the above method, but where all of |insert_this| is written (with
+  // the same constraints as above, that the SyncBuffer is not extended).
+  virtual void ReplaceAtIndex(const AudioMultiVector<int16_t>& insert_this,
+                              size_t position);
+
+  // Reads |requested_len| samples from each channel and writes them interleaved
+  // into |output|. The |next_index_| is updated to point to the sample to read
+  // next time.
+  size_t GetNextAudioInterleaved(size_t requested_len, int16_t* output);
+
+  // Adds |increment| to |end_timestamp_|.
+  void IncreaseEndTimestamp(uint32_t increment);
+
+  // Flushes the buffer. The buffer will contain only zeros after the flush, and
+  // |next_index_| will point to the end, like when the buffer was first
+  // created.
+  void Flush();
+
+  const AudioVector<int16_t>& Channel(size_t n) { return *channels_[n]; }
+
+  // Accessors and mutators.
+  size_t next_index() const { return next_index_; }
+  void set_next_index(size_t value);
+  uint32_t end_timestamp() const { return end_timestamp_; }
+  void set_end_timestamp(uint32_t value) { end_timestamp_ = value; }
+  size_t dtmf_index() const { return dtmf_index_; }
+  void set_dtmf_index(size_t value);
+
+ private:
+  size_t next_index_;
+  uint32_t end_timestamp_;  // The timestamp of the last sample in the buffer.
+  size_t dtmf_index_;  // Index to the first non-DTMF sample in the buffer.
+
+  DISALLOW_COPY_AND_ASSIGN(SyncBuffer);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_SYNC_BUFFER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/sync_buffer_unittest.cc b/webrtc/modules/audio_coding/neteq4/sync_buffer_unittest.cc
new file mode 100644
index 0000000..054e69a
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/sync_buffer_unittest.cc
@@ -0,0 +1,164 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/sync_buffer.h"
+
+#include "gtest/gtest.h"
+
+namespace webrtc {
+
+TEST(SyncBuffer, CreateAndDestroy) {
+  // Create a SyncBuffer with two channels and 10 samples each.
+  static const size_t kLen = 10;
+  static const size_t kChannels = 2;
+  SyncBuffer sync_buffer(kChannels, kLen);
+  EXPECT_EQ(kChannels, sync_buffer.Channels());
+  EXPECT_EQ(kLen, sync_buffer.Size());
+  // When the buffer is empty, the next index to play out is at the end.
+  EXPECT_EQ(kLen, sync_buffer.next_index());
+  // Verify that all elements are zero.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kLen; ++i) {
+      EXPECT_EQ(0, sync_buffer[channel][i]);
+    }
+  }
+}
+
+TEST(SyncBuffer, SetNextIndex) {
+  // Create a SyncBuffer with two channels and 100 samples each.
+  static const size_t kLen = 100;
+  static const size_t kChannels = 2;
+  SyncBuffer sync_buffer(kChannels, kLen);
+  sync_buffer.set_next_index(0);
+  EXPECT_EQ(0u, sync_buffer.next_index());
+  sync_buffer.set_next_index(kLen / 2);
+  EXPECT_EQ(kLen / 2, sync_buffer.next_index());
+  sync_buffer.set_next_index(kLen);
+  EXPECT_EQ(kLen, sync_buffer.next_index());
+  // Try to set larger than the buffer size; should cap at buffer size.
+  sync_buffer.set_next_index(kLen + 1);
+  EXPECT_EQ(kLen, sync_buffer.next_index());
+}
+
+TEST(SyncBuffer, PushBackAndFlush) {
+  // Create a SyncBuffer with two channels and 100 samples each.
+  static const size_t kLen = 100;
+  static const size_t kChannels = 2;
+  SyncBuffer sync_buffer(kChannels, kLen);
+  static const size_t kNewLen = 10;
+  AudioMultiVector<int16_t> new_data(kChannels, kNewLen);
+  // Populate |new_data|.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kNewLen; ++i) {
+      new_data[channel][i] = i;
+    }
+  }
+  // Push back |new_data| into |sync_buffer|. This operation should pop out
+  // data from the front of |sync_buffer|, so that the size of the buffer
+  // remains the same. The |next_index_| should also move with the same length.
+  sync_buffer.PushBack(new_data);
+  ASSERT_EQ(kLen, sync_buffer.Size());
+  // Verify that |next_index_| moved accordingly.
+  EXPECT_EQ(kLen - kNewLen, sync_buffer.next_index());
+  // Verify the new contents.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kNewLen; ++i) {
+      EXPECT_EQ(new_data[channel][i],
+                sync_buffer[channel][sync_buffer.next_index() + i]);
+    }
+  }
+
+  // Now flush the buffer, and verify that it is all zeros, and that next_index
+  // points to the end.
+  sync_buffer.Flush();
+  ASSERT_EQ(kLen, sync_buffer.Size());
+  EXPECT_EQ(kLen, sync_buffer.next_index());
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kLen; ++i) {
+      EXPECT_EQ(0, sync_buffer[channel][i]);
+    }
+  }
+}
+
+TEST(SyncBuffer, PushFrontZeros) {
+  // Create a SyncBuffer with two channels and 100 samples each.
+  static const size_t kLen = 100;
+  static const size_t kChannels = 2;
+  SyncBuffer sync_buffer(kChannels, kLen);
+  static const size_t kNewLen = 10;
+  AudioMultiVector<int16_t> new_data(kChannels, kNewLen);
+  // Populate |new_data|.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kNewLen; ++i) {
+      new_data[channel][i] = 1000 + i;
+    }
+  }
+  sync_buffer.PushBack(new_data);
+  EXPECT_EQ(kLen, sync_buffer.Size());
+
+  // Push |kNewLen| - 1 zeros into each channel in the front of the SyncBuffer.
+  sync_buffer.PushFrontZeros(kNewLen - 1);
+  EXPECT_EQ(kLen, sync_buffer.Size());  // Size should remain the same.
+  // Verify that |next_index_| moved accordingly. Should be at the end - 1.
+  EXPECT_EQ(kLen - 1, sync_buffer.next_index());
+  // Verify the zeros.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kNewLen - 1; ++i) {
+      EXPECT_EQ(0, sync_buffer[channel][i]);
+    }
+  }
+  // Verify that the correct data is at the end of the SyncBuffer.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    EXPECT_EQ(1000, sync_buffer[channel][sync_buffer.next_index()]);
+  }
+}
+
+TEST(SyncBuffer, GetNextAudioInterleaved) {
+  // Create a SyncBuffer with two channels and 100 samples each.
+  static const size_t kLen = 100;
+  static const size_t kChannels = 2;
+  SyncBuffer sync_buffer(kChannels, kLen);
+  static const size_t kNewLen = 10;
+  AudioMultiVector<int16_t> new_data(kChannels, kNewLen);
+  // Populate |new_data|.
+  for (size_t channel = 0; channel < kChannels; ++channel) {
+    for (size_t i = 0; i < kNewLen; ++i) {
+      new_data[channel][i] = i;
+    }
+  }
+  // Push back |new_data| into |sync_buffer|. This operation should pop out
+  // data from the front of |sync_buffer|, so that the size of the buffer
+  // remains the same. The |next_index_| should also move with the same length.
+  sync_buffer.PushBack(new_data);
+
+  // Read to interleaved output. Read in two batches, where each read operation
+  // should automatically update the |net_index_| in the SyncBuffer.
+  int16_t output[kChannels * kNewLen];
+  // Note that |samples_read| is the number of samples read from each channel.
+  // That is, the number of samples written to |output| is
+  // |samples_read| * |kChannels|.
+  size_t samples_read = sync_buffer.GetNextAudioInterleaved(kNewLen / 2,
+                                                            output);
+  samples_read +=
+      sync_buffer.GetNextAudioInterleaved(kNewLen / 2,
+                                          &output[samples_read * kChannels]);
+  EXPECT_EQ(kNewLen, samples_read);
+
+  // Verify the data.
+  int16_t* output_ptr = output;
+  for (size_t i = 0; i < kNewLen; ++i) {
+    for (size_t channel = 0; channel < kChannels; ++channel) {
+      EXPECT_EQ(new_data[channel][i], *output_ptr);
+      ++output_ptr;
+    }
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.cc b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.cc
new file mode 100644
index 0000000..b215bd3
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.cc
@@ -0,0 +1,193 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "NETEQTEST_DummyRTPpacket.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <netinet/in.h> // for htons, htonl, etc
+#endif
+
+int NETEQTEST_DummyRTPpacket::readFromFile(FILE *fp)
+{
+    if (!fp)
+    {
+        return -1;
+    }
+
+    WebRtc_UWord16 length, plen;
+    WebRtc_UWord32 offset;
+
+    if (fread(&length, 2, 1, fp) == 0)
+    {
+        reset();
+        return -2;
+    }
+    length = ntohs(length);
+
+    if (fread(&plen, 2, 1, fp) == 0)
+    {
+        reset();
+        return -1;
+    }
+    int packetLen = ntohs(plen);
+
+    if (fread(&offset, 4, 1, fp) == 0)
+    {
+        reset();
+        return -1;
+    }
+    // Store in local variable until we have passed the reset below.
+    WebRtc_UWord32 receiveTime = ntohl(offset);
+
+    // Use length here because a plen of 0 specifies rtcp.
+    length = (WebRtc_UWord16) (length - _kRDHeaderLen);
+
+    // check buffer size
+    if (_datagram && _memSize < length)
+    {
+        reset();
+    }
+
+    if (!_datagram)
+    {
+        _datagram = new WebRtc_UWord8[length];
+        _memSize = length;
+    }
+    memset(_datagram, 0, length);
+
+    if (length == 0)
+    {
+        _datagramLen = 0;
+        _rtpParsed = false;
+        return packetLen;
+    }
+
+    // Read basic header
+    if (fread((unsigned short *) _datagram, 1, _kBasicHeaderLen, fp)
+        != (size_t)_kBasicHeaderLen)
+    {
+        reset();
+        return -1;
+    }
+    _receiveTime = receiveTime;
+    _datagramLen = _kBasicHeaderLen;
+
+    // Parse the basic header
+    webrtc::WebRtcRTPHeader tempRTPinfo;
+    int P, X, CC;
+    parseBasicHeader(&tempRTPinfo, &P, &X, &CC);
+
+    // Check if we have to extend the header
+    if (X != 0 || CC != 0)
+    {
+        int newLen = _kBasicHeaderLen + CC * 4 + X * 4;
+        assert(_memSize >= newLen);
+
+        // Read extension from file
+        size_t readLen = newLen - _kBasicHeaderLen;
+        if (fread((unsigned short *) _datagram + _kBasicHeaderLen, 1, readLen,
+            fp) != readLen)
+        {
+            reset();
+            return -1;
+        }
+        _datagramLen = newLen;
+
+        if (X != 0)
+        {
+            int totHdrLen = calcHeaderLength(X, CC);
+            assert(_memSize >= totHdrLen);
+
+            // Read extension from file
+            size_t readLen = totHdrLen - newLen;
+            if (fread((unsigned short *) _datagram + newLen, 1, readLen, fp)
+                != readLen)
+            {
+                reset();
+                return -1;
+            }
+            _datagramLen = totHdrLen;
+        }
+    }
+    _datagramLen = length;
+
+    if (!_blockList.empty() && _blockList.count(payloadType()) > 0)
+    {
+        // discard this payload
+        return readFromFile(fp);
+    }
+
+    _rtpParsed = false;
+    return packetLen;
+
+}
+
+int NETEQTEST_DummyRTPpacket::writeToFile(FILE *fp)
+{
+    if (!fp)
+    {
+        return -1;
+    }
+
+    WebRtc_UWord16 length, plen;
+    WebRtc_UWord32 offset;
+
+    // length including RTPplay header
+    length = htons(_datagramLen + _kRDHeaderLen);
+    if (fwrite(&length, 2, 1, fp) != 1)
+    {
+        return -1;
+    }
+
+    // payload length
+    plen = htons(_datagramLen);
+    if (fwrite(&plen, 2, 1, fp) != 1)
+    {
+        return -1;
+    }
+
+    // offset (=receive time)
+    offset = htonl(_receiveTime);
+    if (fwrite(&offset, 4, 1, fp) != 1)
+    {
+        return -1;
+    }
+
+    // Figure out the length of the RTP header.
+    int headerLen;
+    if (_datagramLen == 0)
+    {
+        // No payload at all; we are done writing to file.
+        headerLen = 0;
+    }
+    else
+    {
+        parseHeader();
+        headerLen = _payloadPtr - _datagram;
+        assert(headerLen >= 0);
+    }
+
+    // write RTP header
+    if (fwrite((unsigned short *) _datagram, 1, headerLen, fp) !=
+        static_cast<size_t>(headerLen))
+    {
+        return -1;
+    }
+
+    return (headerLen + _kRDHeaderLen); // total number of bytes written
+
+}
+
diff --git a/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.h b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.h
new file mode 100644
index 0000000..ef74421
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.h
@@ -0,0 +1,23 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef NETEQTEST_DUMMYRTPPACKET_H
+#define NETEQTEST_DUMMYRTPPACKET_H
+
+#include "NETEQTEST_RTPpacket.h"
+
+class NETEQTEST_DummyRTPpacket : public NETEQTEST_RTPpacket
+{
+public:
+    virtual int readFromFile(FILE *fp);
+    virtual int writeToFile(FILE *fp);
+};
+
+#endif //NETEQTEST_DUMMYRTPPACKET_H
diff --git a/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.cc b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.cc
new file mode 100644
index 0000000..49c8bc9
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.cc
@@ -0,0 +1,870 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "NETEQTEST_RTPpacket.h"
+
+#include <assert.h>
+#include <stdlib.h>  // rand
+#include <string.h>
+
+#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <netinet/in.h> // for htons, htonl, etc
+#endif
+
+const int NETEQTEST_RTPpacket::_kRDHeaderLen = 8;
+const int NETEQTEST_RTPpacket::_kBasicHeaderLen = 12;
+
+NETEQTEST_RTPpacket::NETEQTEST_RTPpacket()
+:
+_datagram(NULL),
+_payloadPtr(NULL),
+_memSize(0),
+_datagramLen(-1),
+_payloadLen(0),
+_rtpParsed(false),
+_receiveTime(0),
+_lost(false)
+{
+    memset(&_rtpInfo, 0, sizeof(_rtpInfo));
+    _blockList.clear();
+}
+
+NETEQTEST_RTPpacket::~NETEQTEST_RTPpacket()
+{
+    if(_datagram)
+    {
+        delete [] _datagram;
+    }
+}
+
+void NETEQTEST_RTPpacket::reset()
+{
+    if(_datagram) {
+        delete [] _datagram;
+    }
+    _datagram = NULL;
+    _memSize = 0;
+    _datagramLen = -1;
+    _payloadLen = 0;
+    _payloadPtr = NULL;
+    _receiveTime = 0;
+    memset(&_rtpInfo, 0, sizeof(_rtpInfo));
+    _rtpParsed = false;
+
+}
+
+int NETEQTEST_RTPpacket::skipFileHeader(FILE *fp)
+{
+    if (!fp) {
+        return -1;
+    }
+
+    const int kFirstLineLength = 40;
+    char firstline[kFirstLineLength];
+    if (fgets(firstline, kFirstLineLength, fp) == NULL) {
+        return -1;
+    }
+    if (strncmp(firstline, "#!rtpplay", 9) == 0) {
+        if (strncmp(firstline, "#!rtpplay1.0", 12) != 0) {
+            return -1;
+        }
+    }
+    else if (strncmp(firstline, "#!RTPencode", 11) == 0) {
+        if (strncmp(firstline, "#!RTPencode1.0", 14) != 0) {
+            return -1;
+        }
+    }
+    else
+    {
+        return -1;
+    }
+
+    const int kRtpDumpHeaderSize = 4 + 4 + 4 + 2 + 2;
+    if (fseek(fp, kRtpDumpHeaderSize, SEEK_CUR) != 0)
+    {
+        return -1;
+    }
+    return 0;
+}
+
+int NETEQTEST_RTPpacket::readFromFile(FILE *fp)
+{
+    if(!fp)
+    {
+        return(-1);
+    }
+
+    WebRtc_UWord16 length, plen;
+    WebRtc_UWord32 offset;
+
+    if (fread(&length,2,1,fp)==0)
+    {
+        reset();
+        return(-2);
+    }
+    length = ntohs(length);
+
+    if (fread(&plen,2,1,fp)==0)
+    {
+        reset();
+        return(-1);
+    }
+    int packetLen = ntohs(plen);
+
+    if (fread(&offset,4,1,fp)==0)
+    {
+        reset();
+        return(-1);
+    }
+    WebRtc_UWord32 receiveTime = ntohl(offset); // store in local variable until we have passed the reset below
+
+    // Use length here because a plen of 0 specifies rtcp
+    length = (WebRtc_UWord16) (length - _kRDHeaderLen);
+
+    // check buffer size
+    if (_datagram && _memSize < length)
+    {
+        reset();
+    }
+
+    if (!_datagram)
+    {
+        _datagram = new WebRtc_UWord8[length];
+        _memSize = length;
+    }
+
+    if (fread((unsigned short *) _datagram,1,length,fp) != length)
+    {
+        reset();
+        return(-1);
+    }
+
+    _datagramLen = length;
+    _receiveTime = receiveTime;
+
+    if (!_blockList.empty() && _blockList.count(payloadType()) > 0)
+    {
+        // discard this payload
+        return(readFromFile(fp));
+    }
+
+    _rtpParsed = false;
+    return(packetLen);
+
+}
+
+
+int NETEQTEST_RTPpacket::readFixedFromFile(FILE *fp, size_t length)
+{
+    if (!fp)
+    {
+        return -1;
+    }
+
+    // check buffer size
+    if (_datagram && _memSize < static_cast<int>(length))
+    {
+        reset();
+    }
+
+    if (!_datagram)
+    {
+        _datagram = new WebRtc_UWord8[length];
+        _memSize = length;
+    }
+
+    if (fread(_datagram, 1, length, fp) != length)
+    {
+        reset();
+        return -1;
+    }
+
+    _datagramLen = length;
+    _receiveTime = 0;
+
+    if (!_blockList.empty() && _blockList.count(payloadType()) > 0)
+    {
+        // discard this payload
+        return readFromFile(fp);
+    }
+
+    _rtpParsed = false;
+    return length;
+
+}
+
+
+int NETEQTEST_RTPpacket::writeToFile(FILE *fp)
+{
+    if (!fp)
+    {
+        return -1;
+    }
+
+    WebRtc_UWord16 length, plen;
+    WebRtc_UWord32 offset;
+
+    // length including RTPplay header
+    length = htons(_datagramLen + _kRDHeaderLen);
+    if (fwrite(&length, 2, 1, fp) != 1)
+    {
+        return -1;
+    }
+
+    // payload length
+    plen = htons(_datagramLen);
+    if (fwrite(&plen, 2, 1, fp) != 1)
+    {
+        return -1;
+    }
+
+    // offset (=receive time)
+    offset = htonl(_receiveTime);
+    if (fwrite(&offset, 4, 1, fp) != 1)
+    {
+        return -1;
+    }
+
+
+    // write packet data
+    if (fwrite(_datagram, 1, _datagramLen, fp) !=
+            static_cast<size_t>(_datagramLen))
+    {
+        return -1;
+    }
+
+    return _datagramLen + _kRDHeaderLen; // total number of bytes written
+
+}
+
+
+void NETEQTEST_RTPpacket::blockPT(WebRtc_UWord8 pt)
+{
+    _blockList[pt] = true;
+}
+
+
+void NETEQTEST_RTPpacket::parseHeader()
+{
+    if (_rtpParsed)
+    {
+        // nothing to do
+        return;
+    }
+
+    if (_datagramLen < _kBasicHeaderLen)
+    {
+        // corrupt packet?
+        return;
+    }
+
+    _payloadLen = parseRTPheader(&_payloadPtr);
+
+    _rtpParsed = true;
+
+    return;
+
+}
+
+void NETEQTEST_RTPpacket::parseHeader(webrtc::WebRtcRTPHeader* rtp_header) {
+  if (!_rtpParsed) {
+    parseHeader();
+  }
+  if (rtp_header) {
+    rtp_header->header.markerBit = _rtpInfo.header.markerBit;
+    rtp_header->header.payloadType = _rtpInfo.header.payloadType;
+    rtp_header->header.sequenceNumber = _rtpInfo.header.sequenceNumber;
+    rtp_header->header.timestamp = _rtpInfo.header.timestamp;
+    rtp_header->header.ssrc = _rtpInfo.header.ssrc;
+  }
+}
+
+const webrtc::WebRtcRTPHeader* NETEQTEST_RTPpacket::RTPinfo() const
+{
+    if (_rtpParsed)
+    {
+        return &_rtpInfo;
+    }
+    else
+    {
+        return NULL;
+    }
+}
+
+WebRtc_UWord8 * NETEQTEST_RTPpacket::datagram() const
+{
+    if (_datagramLen > 0)
+    {
+        return _datagram;
+    }
+    else
+    {
+        return NULL;
+    }
+}
+
+WebRtc_UWord8 * NETEQTEST_RTPpacket::payload() const
+{
+    if (_payloadLen > 0)
+    {
+        return _payloadPtr;
+    }
+    else
+    {
+        return NULL;
+    }
+}
+
+WebRtc_Word16 NETEQTEST_RTPpacket::payloadLen()
+{
+    parseHeader();
+    return _payloadLen;
+}
+
+WebRtc_Word16 NETEQTEST_RTPpacket::dataLen() const
+{
+    return _datagramLen;
+}
+
+bool NETEQTEST_RTPpacket::isParsed() const
+{
+    return _rtpParsed;
+}
+
+bool NETEQTEST_RTPpacket::isLost() const
+{
+    return _lost;
+}
+
+WebRtc_UWord8  NETEQTEST_RTPpacket::payloadType() const
+{
+    webrtc::WebRtcRTPHeader tempRTPinfo;
+
+    if(_datagram && _datagramLen >= _kBasicHeaderLen)
+    {
+        parseRTPheader(&tempRTPinfo);
+    }
+    else
+    {
+        return 0;
+    }
+
+    return tempRTPinfo.header.payloadType;
+}
+
+WebRtc_UWord16 NETEQTEST_RTPpacket::sequenceNumber() const
+{
+    webrtc::WebRtcRTPHeader tempRTPinfo;
+
+    if(_datagram && _datagramLen >= _kBasicHeaderLen)
+    {
+        parseRTPheader(&tempRTPinfo);
+    }
+    else
+    {
+        return 0;
+    }
+
+    return tempRTPinfo.header.sequenceNumber;
+}
+
+WebRtc_UWord32 NETEQTEST_RTPpacket::timeStamp() const
+{
+    webrtc::WebRtcRTPHeader tempRTPinfo;
+
+    if(_datagram && _datagramLen >= _kBasicHeaderLen)
+    {
+        parseRTPheader(&tempRTPinfo);
+    }
+    else
+    {
+        return 0;
+    }
+
+    return tempRTPinfo.header.timestamp;
+}
+
+WebRtc_UWord32 NETEQTEST_RTPpacket::SSRC() const
+{
+    webrtc::WebRtcRTPHeader tempRTPinfo;
+
+    if(_datagram && _datagramLen >= _kBasicHeaderLen)
+    {
+        parseRTPheader(&tempRTPinfo);
+    }
+    else
+    {
+        return 0;
+    }
+
+    return tempRTPinfo.header.ssrc;
+}
+
+WebRtc_UWord8  NETEQTEST_RTPpacket::markerBit() const
+{
+    webrtc::WebRtcRTPHeader tempRTPinfo;
+
+    if(_datagram && _datagramLen >= _kBasicHeaderLen)
+    {
+        parseRTPheader(&tempRTPinfo);
+    }
+    else
+    {
+        return 0;
+    }
+
+    return tempRTPinfo.header.markerBit;
+}
+
+
+
+int NETEQTEST_RTPpacket::setPayloadType(WebRtc_UWord8 pt)
+{
+
+    if (_datagramLen < 12)
+    {
+        return -1;
+    }
+
+    if (!_rtpParsed)
+    {
+        _rtpInfo.header.payloadType = pt;
+    }
+
+    _datagram[1]=(unsigned char)(pt & 0xFF);
+
+    return 0;
+
+}
+
+int NETEQTEST_RTPpacket::setSequenceNumber(WebRtc_UWord16 sn)
+{
+
+    if (_datagramLen < 12)
+    {
+        return -1;
+    }
+
+    if (!_rtpParsed)
+    {
+        _rtpInfo.header.sequenceNumber = sn;
+    }
+
+    _datagram[2]=(unsigned char)((sn>>8)&0xFF);
+    _datagram[3]=(unsigned char)((sn)&0xFF);
+
+    return 0;
+
+}
+
+int NETEQTEST_RTPpacket::setTimeStamp(WebRtc_UWord32 ts)
+{
+
+    if (_datagramLen < 12)
+    {
+        return -1;
+    }
+
+    if (!_rtpParsed)
+    {
+        _rtpInfo.header.timestamp = ts;
+    }
+
+    _datagram[4]=(unsigned char)((ts>>24)&0xFF);
+    _datagram[5]=(unsigned char)((ts>>16)&0xFF);
+    _datagram[6]=(unsigned char)((ts>>8)&0xFF);
+    _datagram[7]=(unsigned char)(ts & 0xFF);
+
+    return 0;
+
+}
+
+int NETEQTEST_RTPpacket::setSSRC(WebRtc_UWord32 ssrc)
+{
+
+    if (_datagramLen < 12)
+    {
+        return -1;
+    }
+
+    if (!_rtpParsed)
+    {
+        _rtpInfo.header.ssrc = ssrc;
+    }
+
+    _datagram[8]=(unsigned char)((ssrc>>24)&0xFF);
+    _datagram[9]=(unsigned char)((ssrc>>16)&0xFF);
+    _datagram[10]=(unsigned char)((ssrc>>8)&0xFF);
+    _datagram[11]=(unsigned char)(ssrc & 0xFF);
+
+    return 0;
+
+}
+
+int NETEQTEST_RTPpacket::setMarkerBit(WebRtc_UWord8 mb)
+{
+
+    if (_datagramLen < 12)
+    {
+        return -1;
+    }
+
+    if (_rtpParsed)
+    {
+        _rtpInfo.header.markerBit = mb;
+    }
+
+    if (mb)
+    {
+        _datagram[0] |= 0x01;
+    }
+    else
+    {
+        _datagram[0] &= 0xFE;
+    }
+
+    return 0;
+
+}
+
+int NETEQTEST_RTPpacket::setRTPheader(const webrtc::WebRtcRTPHeader* RTPinfo)
+{
+    if (_datagramLen < 12)
+    {
+        // this packet is not ok
+        return -1;
+    }
+
+    makeRTPheader(_datagram,
+        RTPinfo->header.payloadType,
+        RTPinfo->header.sequenceNumber,
+        RTPinfo->header.timestamp,
+        RTPinfo->header.ssrc,
+        RTPinfo->header.markerBit);
+
+    return 0;
+}
+
+
+int NETEQTEST_RTPpacket::splitStereo(NETEQTEST_RTPpacket* slaveRtp,
+                                     enum stereoModes mode)
+{
+    // if mono, do nothing
+    if (mode == stereoModeMono)
+    {
+        return 0;
+    }
+
+    // check that the RTP header info is parsed
+    parseHeader();
+
+    // start by copying the main rtp packet
+    *slaveRtp = *this;
+
+    if(_payloadLen == 0)
+    {
+        // do no more
+        return 0;
+    }
+
+    if(_payloadLen%2 != 0)
+    {
+        // length must be a factor of 2
+        return -1;
+    }
+
+    switch(mode)
+    {
+    case stereoModeSample1:
+        {
+            // sample based codec with 1-byte samples
+            splitStereoSample(slaveRtp, 1 /* 1 byte/sample */);
+            break;
+        }
+    case stereoModeSample2:
+        {
+            // sample based codec with 2-byte samples
+            splitStereoSample(slaveRtp, 2 /* 2 bytes/sample */);
+            break;
+        }
+    case stereoModeFrame:
+        {
+            // frame based codec
+            splitStereoFrame(slaveRtp);
+            break;
+        }
+    case stereoModeDuplicate:
+        {
+            // frame based codec, send the whole packet to both master and slave
+            splitStereoDouble(slaveRtp);
+            break;
+        }
+    case stereoModeMono:
+        {
+            assert(false);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+
+void NETEQTEST_RTPpacket::makeRTPheader(unsigned char* rtp_data, WebRtc_UWord8 payloadType, WebRtc_UWord16 seqNo, WebRtc_UWord32 timestamp, WebRtc_UWord32 ssrc, WebRtc_UWord8 markerBit) const
+{
+    rtp_data[0]=(unsigned char)0x80;
+    if (markerBit)
+    {
+        rtp_data[0] |= 0x01;
+    }
+    else
+    {
+        rtp_data[0] &= 0xFE;
+    }
+    rtp_data[1]=(unsigned char)(payloadType & 0xFF);
+    rtp_data[2]=(unsigned char)((seqNo>>8)&0xFF);
+    rtp_data[3]=(unsigned char)((seqNo)&0xFF);
+    rtp_data[4]=(unsigned char)((timestamp>>24)&0xFF);
+    rtp_data[5]=(unsigned char)((timestamp>>16)&0xFF);
+
+    rtp_data[6]=(unsigned char)((timestamp>>8)&0xFF);
+    rtp_data[7]=(unsigned char)(timestamp & 0xFF);
+
+    rtp_data[8]=(unsigned char)((ssrc>>24)&0xFF);
+    rtp_data[9]=(unsigned char)((ssrc>>16)&0xFF);
+
+    rtp_data[10]=(unsigned char)((ssrc>>8)&0xFF);
+    rtp_data[11]=(unsigned char)(ssrc & 0xFF);
+}
+
+WebRtc_UWord16
+    NETEQTEST_RTPpacket::parseRTPheader(webrtc::WebRtcRTPHeader* RTPinfo,
+                                        WebRtc_UWord8 **payloadPtr) const
+{
+    WebRtc_Word16 *rtp_data = (WebRtc_Word16 *) _datagram;
+    int i_P, i_X, i_CC;
+
+    assert(_datagramLen >= 12);
+    parseBasicHeader(RTPinfo, &i_P, &i_X, &i_CC);
+
+    int i_startPosition = calcHeaderLength(i_X, i_CC);
+
+    int i_padlength = calcPadLength(i_P);
+
+    if (payloadPtr)
+    {
+        *payloadPtr = (WebRtc_UWord8*) &rtp_data[i_startPosition >> 1];
+    }
+
+    return (WebRtc_UWord16) (_datagramLen - i_startPosition - i_padlength);
+}
+
+
+void NETEQTEST_RTPpacket::parseBasicHeader(webrtc::WebRtcRTPHeader* RTPinfo,
+                                           int *i_P, int *i_X, int *i_CC) const
+{
+    WebRtc_Word16 *rtp_data = (WebRtc_Word16 *) _datagram;
+    if (_datagramLen < 12)
+    {
+        assert(false);
+        return;
+    }
+
+    *i_P=(((WebRtc_UWord16)(rtp_data[0] & 0x20))>>5); /* Extract the P bit */
+    *i_X=(((WebRtc_UWord16)(rtp_data[0] & 0x10))>>4); /* Extract the X bit */
+    *i_CC=(WebRtc_UWord16)(rtp_data[0] & 0xF); /* Get the CC number  */
+    /* Get the marker bit */
+    RTPinfo->header.markerBit = (WebRtc_UWord8) ((rtp_data[0] >> 15) & 0x01);
+    /* Get the coder type */
+    RTPinfo->header.payloadType = (WebRtc_UWord8) ((rtp_data[0] >> 8) & 0x7F);
+    /* Get the packet number */
+    RTPinfo->header.sequenceNumber =
+        ((( ((WebRtc_UWord16)rtp_data[1]) >> 8) & 0xFF) |
+        ( ((WebRtc_UWord16)(rtp_data[1] & 0xFF)) << 8));
+    /* Get timestamp */
+    RTPinfo->header.timestamp = ((((WebRtc_UWord16)rtp_data[2]) & 0xFF) << 24) |
+        ((((WebRtc_UWord16)rtp_data[2]) & 0xFF00) << 8) |
+        ((((WebRtc_UWord16)rtp_data[3]) >> 8) & 0xFF) |
+        ((((WebRtc_UWord16)rtp_data[3]) & 0xFF) << 8);
+    /* Get the SSRC */
+    RTPinfo->header.ssrc = ((((WebRtc_UWord16)rtp_data[4]) & 0xFF) << 24) |
+        ((((WebRtc_UWord16)rtp_data[4]) & 0xFF00) << 8) |
+        ((((WebRtc_UWord16)rtp_data[5]) >> 8) & 0xFF) |
+        ((((WebRtc_UWord16)rtp_data[5]) & 0xFF) << 8);
+}
+
+int NETEQTEST_RTPpacket::calcHeaderLength(int i_X, int i_CC) const
+{
+    int i_extlength = 0;
+    WebRtc_Word16 *rtp_data = (WebRtc_Word16 *) _datagram;
+
+    if (i_X == 1)
+    {
+        // Extension header exists.
+        // Find out how many WebRtc_Word32 it consists of.
+        assert(_datagramLen > 2 * (7 + 2 * i_CC));
+        if (_datagramLen > 2 * (7 + 2 * i_CC))
+        {
+            i_extlength = (((((WebRtc_UWord16) rtp_data[7 + 2 * i_CC]) >> 8)
+                & 0xFF) | (((WebRtc_UWord16) (rtp_data[7 + 2 * i_CC] & 0xFF))
+                << 8)) + 1;
+        }
+    }
+
+    return 12 + 4 * i_extlength + 4 * i_CC;
+}
+
+int NETEQTEST_RTPpacket::calcPadLength(int i_P) const
+{
+    WebRtc_Word16 *rtp_data = (WebRtc_Word16 *) _datagram;
+    if (i_P == 1)
+    {
+        /* Padding exists. Find out how many bytes the padding consists of. */
+        if (_datagramLen & 0x1)
+        {
+            /* odd number of bytes => last byte in higher byte */
+            return rtp_data[_datagramLen >> 1] & 0xFF;
+        }
+        else
+        {
+            /* even number of bytes => last byte in lower byte */
+            return ((WebRtc_UWord16) rtp_data[(_datagramLen >> 1) - 1]) >> 8;
+        }
+    }
+    return 0;
+}
+
+void NETEQTEST_RTPpacket::splitStereoSample(NETEQTEST_RTPpacket* slaveRtp,
+                                            int stride)
+{
+    if(!_payloadPtr || !slaveRtp || !slaveRtp->_payloadPtr
+        || _payloadLen <= 0 || slaveRtp->_memSize < _memSize)
+    {
+        return;
+    }
+
+    WebRtc_UWord8 *readDataPtr = _payloadPtr;
+    WebRtc_UWord8 *writeDataPtr = _payloadPtr;
+    WebRtc_UWord8 *slaveData = slaveRtp->_payloadPtr;
+
+    while (readDataPtr - _payloadPtr < _payloadLen)
+    {
+        // master data
+        for (int ix = 0; ix < stride; ix++) {
+            *writeDataPtr = *readDataPtr;
+            writeDataPtr++;
+            readDataPtr++;
+        }
+
+        // slave data
+        for (int ix = 0; ix < stride; ix++) {
+            *slaveData = *readDataPtr;
+            slaveData++;
+            readDataPtr++;
+        }
+    }
+
+    _payloadLen /= 2;
+    slaveRtp->_payloadLen = _payloadLen;
+}
+
+
+void NETEQTEST_RTPpacket::splitStereoFrame(NETEQTEST_RTPpacket* slaveRtp)
+{
+    if(!_payloadPtr || !slaveRtp || !slaveRtp->_payloadPtr
+        || _payloadLen <= 0 || slaveRtp->_memSize < _memSize)
+    {
+        return;
+    }
+
+    memmove(slaveRtp->_payloadPtr, _payloadPtr + _payloadLen/2, _payloadLen/2);
+
+    _payloadLen /= 2;
+    slaveRtp->_payloadLen = _payloadLen;
+}
+void NETEQTEST_RTPpacket::splitStereoDouble(NETEQTEST_RTPpacket* slaveRtp)
+{
+    if(!_payloadPtr || !slaveRtp || !slaveRtp->_payloadPtr
+        || _payloadLen <= 0 || slaveRtp->_memSize < _memSize)
+    {
+        return;
+    }
+
+    memcpy(slaveRtp->_payloadPtr, _payloadPtr, _payloadLen);
+    slaveRtp->_payloadLen = _payloadLen;
+}
+
+// Get the RTP header for the RED payload indicated by argument index.
+// The first RED payload is index = 0.
+int NETEQTEST_RTPpacket::extractRED(int index, webrtc::WebRtcRTPHeader& red)
+{
+//
+//  0                   1                    2                   3
+//  0 1 2 3 4 5 6 7 8 9 0 1 2 3  4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |1|   block PT  |  timestamp offset         |   block length    |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |1|    ...                                                      |
+// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+// |0|   block PT  |
+// +-+-+-+-+-+-+-+-+
+//
+
+    parseHeader();
+
+    WebRtc_UWord8* ptr = payload();
+    WebRtc_UWord8* payloadEndPtr = ptr + payloadLen();
+    int num_encodings = 0;
+    int total_len = 0;
+
+    while ((ptr < payloadEndPtr) && (*ptr & 0x80))
+    {
+        int len = ((ptr[2] & 0x03) << 8) + ptr[3];
+        if (num_encodings == index)
+        {
+            // Header found.
+            red.header.payloadType = ptr[0] & 0x7F;
+            WebRtc_UWord32 offset = (ptr[1] << 6) + ((ptr[2] & 0xFC) >> 2);
+            red.header.sequenceNumber = sequenceNumber();
+            red.header.timestamp = timeStamp() - offset;
+            red.header.markerBit = markerBit();
+            red.header.ssrc = SSRC();
+            return len;
+        }
+        ++num_encodings;
+        total_len += len;
+        ptr += 4;
+    }
+    if ((ptr < payloadEndPtr) && (num_encodings == index))
+    {
+        // Last header.
+        red.header.payloadType = ptr[0] & 0x7F;
+        red.header.sequenceNumber = sequenceNumber();
+        red.header.timestamp = timeStamp();
+        red.header.markerBit = markerBit();
+        red.header.ssrc = SSRC();
+        ++ptr;
+        return payloadLen() - (ptr - payload()) - total_len;
+    }
+    return -1;
+}
+
+// Randomize the payload, not the RTP header.
+void NETEQTEST_RTPpacket::scramblePayload(void)
+{
+    parseHeader();
+
+    for (int i = 0; i < _payloadLen; ++i)
+    {
+        _payloadPtr[i] = static_cast<WebRtc_UWord8>(rand());
+    }
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h
new file mode 100644
index 0000000..1199d97
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h
@@ -0,0 +1,105 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef NETEQTEST_RTPPACKET_H
+#define NETEQTEST_RTPPACKET_H
+
+#include <map>
+#include <stdio.h>
+#include "webrtc/typedefs.h"
+#include "webrtc/modules/interface/module_common_types.h"
+
+enum stereoModes {
+    stereoModeMono,
+    stereoModeSample1,
+    stereoModeSample2,
+    stereoModeFrame,
+    stereoModeDuplicate
+};
+
+class NETEQTEST_RTPpacket
+{
+public:
+    NETEQTEST_RTPpacket();
+    bool operator !() const { return (dataLen() < 0); };
+    virtual ~NETEQTEST_RTPpacket();
+    void reset();
+    static int skipFileHeader(FILE *fp);
+    virtual int readFromFile(FILE *fp);
+    int readFixedFromFile(FILE *fp, size_t len);
+    virtual int writeToFile(FILE *fp);
+    void blockPT(WebRtc_UWord8 pt);
+    //WebRtc_Word16 payloadType();
+    void parseHeader();
+    void parseHeader(webrtc::WebRtcRTPHeader* rtp_header);
+    const webrtc::WebRtcRTPHeader* RTPinfo() const;
+    WebRtc_UWord8 * datagram() const;
+    WebRtc_UWord8 * payload() const;
+    WebRtc_Word16 payloadLen();
+    WebRtc_Word16 dataLen() const;
+    bool isParsed() const;
+    bool isLost() const;
+    WebRtc_UWord32 time() const { return _receiveTime; };
+
+    WebRtc_UWord8  payloadType() const;
+    WebRtc_UWord16 sequenceNumber() const;
+    WebRtc_UWord32 timeStamp() const;
+    WebRtc_UWord32 SSRC() const;
+    WebRtc_UWord8  markerBit() const;
+
+    int setPayloadType(WebRtc_UWord8 pt);
+    int setSequenceNumber(WebRtc_UWord16 sn);
+    int setTimeStamp(WebRtc_UWord32 ts);
+    int setSSRC(WebRtc_UWord32 ssrc);
+    int setMarkerBit(WebRtc_UWord8 mb);
+    void setTime(WebRtc_UWord32 receiveTime) { _receiveTime = receiveTime; };
+
+    int setRTPheader(const webrtc::WebRtcRTPHeader* RTPinfo);
+
+    int splitStereo(NETEQTEST_RTPpacket* slaveRtp, enum stereoModes mode);
+
+    int extractRED(int index, webrtc::WebRtcRTPHeader& red);
+
+    void scramblePayload(void);
+
+    WebRtc_UWord8 *       _datagram;
+    WebRtc_UWord8 *       _payloadPtr;
+    int                 _memSize;
+    WebRtc_Word16         _datagramLen;
+    WebRtc_Word16         _payloadLen;
+    webrtc::WebRtcRTPHeader _rtpInfo;
+    bool                _rtpParsed;
+    WebRtc_UWord32        _receiveTime;
+    bool                _lost;
+    std::map<WebRtc_UWord8, bool> _blockList;
+
+protected:
+    static const int _kRDHeaderLen;
+    static const int _kBasicHeaderLen;
+
+    void parseBasicHeader(webrtc::WebRtcRTPHeader* RTPinfo, int *i_P, int *i_X,
+                          int *i_CC) const;
+    int calcHeaderLength(int i_X, int i_CC) const;
+
+private:
+    void makeRTPheader(unsigned char* rtp_data, WebRtc_UWord8 payloadType,
+                       WebRtc_UWord16 seqNo, WebRtc_UWord32 timestamp,
+                       WebRtc_UWord32 ssrc, WebRtc_UWord8 markerBit) const;
+    WebRtc_UWord16 parseRTPheader(webrtc::WebRtcRTPHeader* RTPinfo,
+                                  WebRtc_UWord8 **payloadPtr = NULL) const;
+    WebRtc_UWord16 parseRTPheader(WebRtc_UWord8 **payloadPtr = NULL)
+        { return parseRTPheader(&_rtpInfo, payloadPtr);};
+    int calcPadLength(int i_P) const;
+    void splitStereoSample(NETEQTEST_RTPpacket* slaveRtp, int stride);
+    void splitStereoFrame(NETEQTEST_RTPpacket* slaveRtp);
+    void splitStereoDouble(NETEQTEST_RTPpacket* slaveRtp);
+};
+
+#endif //NETEQTEST_RTPPACKET_H
diff --git a/webrtc/modules/audio_coding/neteq4/test/PayloadTypes.h b/webrtc/modules/audio_coding/neteq4/test/PayloadTypes.h
new file mode 100644
index 0000000..f6cc3da
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/PayloadTypes.h
@@ -0,0 +1,77 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/* PayloadTypes.h */
+/* Used by NetEqRTPplay application */
+
+/* RTP defined codepoints */
+#define NETEQ_CODEC_PCMU_PT				0
+#define NETEQ_CODEC_GSMFR_PT			3
+#define NETEQ_CODEC_G723_PT				4
+#define NETEQ_CODEC_DVI4_PT				125 // 8 kHz version
+//#define NETEQ_CODEC_DVI4_16_PT			6  // 16 kHz version
+#define NETEQ_CODEC_PCMA_PT				8
+#define NETEQ_CODEC_G722_PT				9
+#define NETEQ_CODEC_CN_PT				13
+//#define NETEQ_CODEC_G728_PT				15
+//#define NETEQ_CODEC_DVI4_11_PT			16  // 11.025 kHz version
+//#define NETEQ_CODEC_DVI4_22_PT			17  // 22.050 kHz version
+#define NETEQ_CODEC_G729_PT				18
+
+/* Dynamic RTP codepoints as defined in VoiceEngine (file VEAPI.cpp) */
+#define NETEQ_CODEC_IPCMWB_PT			97
+#define NETEQ_CODEC_SPEEX8_PT			98
+#define NETEQ_CODEC_SPEEX16_PT			99
+#define NETEQ_CODEC_EG711U_PT			100
+#define NETEQ_CODEC_EG711A_PT			101
+#define NETEQ_CODEC_ILBC_PT				102
+#define NETEQ_CODEC_ISAC_PT				103
+#define NETEQ_CODEC_ISACLC_PT			119
+#define NETEQ_CODEC_ISACSWB_PT			104
+#define NETEQ_CODEC_AVT_PT				106
+#define NETEQ_CODEC_G722_1_16_PT		108
+#define NETEQ_CODEC_G722_1_24_PT		109
+#define NETEQ_CODEC_G722_1_32_PT		110
+#define NETEQ_CODEC_SC3_PT				111
+#define NETEQ_CODEC_AMR_PT				112
+#define NETEQ_CODEC_GSMEFR_PT			113
+//#define NETEQ_CODEC_ILBCRCU_PT			114
+#define NETEQ_CODEC_G726_16_PT			115
+#define NETEQ_CODEC_G726_24_PT			116
+#define NETEQ_CODEC_G726_32_PT			121
+#define NETEQ_CODEC_RED_PT				117
+#define NETEQ_CODEC_G726_40_PT			118
+//#define NETEQ_CODEC_ENERGY_PT			120
+#define NETEQ_CODEC_CN_WB_PT			105
+#define NETEQ_CODEC_CN_SWB_PT           126
+#define NETEQ_CODEC_G729_1_PT			107
+#define NETEQ_CODEC_G729D_PT			123
+#define NETEQ_CODEC_MELPE_PT			124
+#define NETEQ_CODEC_CELT32_PT     114
+
+/* Extra dynamic codepoints */
+#define NETEQ_CODEC_AMRWB_PT			120
+#define NETEQ_CODEC_PCM16B_PT			93
+#define NETEQ_CODEC_PCM16B_WB_PT		94
+#define NETEQ_CODEC_PCM16B_SWB32KHZ_PT	95
+#define NETEQ_CODEC_PCM16B_SWB48KHZ_PT	96
+#define NETEQ_CODEC_MPEG4AAC_PT			122
+
+
+/* Not default in VoiceEngine */
+#define NETEQ_CODEC_G722_1C_24_PT		84
+#define NETEQ_CODEC_G722_1C_32_PT		85
+#define NETEQ_CODEC_G722_1C_48_PT		86
+
+#define NETEQ_CODEC_SILK_8_PT			80
+#define NETEQ_CODEC_SILK_12_PT			81
+#define NETEQ_CODEC_SILK_16_PT			82
+#define NETEQ_CODEC_SILK_24_PT			83
+
diff --git a/webrtc/modules/audio_coding/neteq4/test/RTPanalyze.cc b/webrtc/modules/audio_coding/neteq4/test/RTPanalyze.cc
new file mode 100644
index 0000000..8df47dd
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/RTPanalyze.cc
@@ -0,0 +1,72 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.h"
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h"
+
+//#define WEBRTC_DUMMY_RTP
+
+enum {
+  kRedPayloadType = 127
+};
+
+int main(int argc, char* argv[]) {
+  FILE* in_file = fopen(argv[1], "rb");
+  if (!in_file) {
+    printf("Cannot open input file %s\n", argv[1]);
+    return -1;
+  }
+  printf("Input file: %s\n", argv[1]);
+
+  FILE* out_file = fopen(argv[2], "wt");
+  if (!out_file) {
+    printf("Cannot open output file %s\n", argv[2]);
+    return -1;
+  }
+  printf("Output file: %s\n\n", argv[2]);
+
+  // Print file header.
+  fprintf(out_file, "SeqNo  TimeStamp   SendTime  Size    PT  M\n");
+
+  // Read file header.
+  NETEQTEST_RTPpacket::skipFileHeader(in_file);
+#ifdef WEBRTC_DUMMY_RTP
+  NETEQTEST_DummyRTPpacket packet;
+#else
+  NETEQTEST_RTPpacket packet;
+#endif
+
+  while (packet.readFromFile(in_file) >= 0) {
+    // Write packet data to file.
+    fprintf(out_file, "%5u %10u %10u %5i %5i %2i\n",
+            packet.sequenceNumber(), packet.timeStamp(), packet.time(),
+            packet.dataLen(), packet.payloadType(), packet.markerBit());
+    if (packet.payloadType() == kRedPayloadType) {
+      webrtc::WebRtcRTPHeader red_header;
+      int len;
+      int red_index = 0;
+      while ((len = packet.extractRED(red_index++, red_header)) >= 0) {
+        fprintf(out_file, "* %5u %10u %10u %5i %5i\n",
+                red_header.header.sequenceNumber, red_header.header.timestamp,
+                packet.time(), len, red_header.header.payloadType);
+      }
+      assert(red_index > 1);  // We must get at least one payload.
+    }
+  }
+
+  fclose(in_file);
+  fclose(out_file);
+
+  return 0;
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/RTPcat.cc b/webrtc/modules/audio_coding/neteq4/test/RTPcat.cc
new file mode 100644
index 0000000..87189cf
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/RTPcat.cc
@@ -0,0 +1,75 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <stdio.h>
+
+#include <algorithm>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h"
+
+#define FIRSTLINELEN 40
+
+int main(int argc, char* argv[]) {
+  if (argc < 3) {
+    printf("Usage: RTPcat in1.rtp int2.rtp [...] out.rtp\n");
+    exit(1);
+  }
+
+  FILE* in_file = fopen(argv[1], "rb");
+  if (!in_file) {
+    printf("Cannot open input file %s\n", argv[1]);
+    return -1;
+  }
+
+  FILE* out_file = fopen(argv[argc - 1], "wb");  // Last parameter is out file.
+  if (!out_file) {
+    printf("Cannot open output file %s\n", argv[argc - 1]);
+    return -1;
+  }
+  printf("Output RTP file: %s\n\n", argv[argc - 1]);
+
+  // Read file header and write directly to output file.
+  char firstline[FIRSTLINELEN];
+  const unsigned int kRtpDumpHeaderSize = 4 + 4 + 4 + 2 + 2;
+  EXPECT_TRUE(fgets(firstline, FIRSTLINELEN, in_file) != NULL);
+  EXPECT_GT(fputs(firstline, out_file), 0);
+  EXPECT_EQ(kRtpDumpHeaderSize, fread(firstline, 1, kRtpDumpHeaderSize,
+                                      in_file));
+  EXPECT_EQ(kRtpDumpHeaderSize, fwrite(firstline, 1, kRtpDumpHeaderSize,
+                                       out_file));
+
+  // Close input file and re-open it later (easier to write the loop below).
+  fclose(in_file);
+
+  for (int i = 1; i < argc - 1; i++) {
+    in_file = fopen(argv[i], "rb");
+    if (!in_file) {
+      printf("Cannot open input file %s\n", argv[i]);
+      return -1;
+    }
+    printf("Input RTP file: %s\n", argv[i]);
+
+    NETEQTEST_RTPpacket::skipFileHeader(in_file);
+    NETEQTEST_RTPpacket packet;
+    int pack_len = packet.readFromFile(in_file);
+    if (pack_len < 0) {
+      exit(1);
+    }
+    while (pack_len >= 0) {
+      packet.writeToFile(out_file);
+      pack_len = packet.readFromFile(in_file);
+    }
+    fclose(in_file);
+  }
+  fclose(out_file);
+  return 0;
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/RTPchange.cc b/webrtc/modules/audio_coding/neteq4/test/RTPchange.cc
new file mode 100644
index 0000000..30bee86
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/RTPchange.cc
@@ -0,0 +1,133 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <stdio.h>
+
+#include <algorithm>
+#include <vector>
+
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.h"
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h"
+
+#define FIRSTLINELEN 40
+//#define WEBRTC_DUMMY_RTP
+
+static bool pktCmp(NETEQTEST_RTPpacket *a, NETEQTEST_RTPpacket *b) {
+  return (a->time() < b->time());
+}
+
+int main(int argc, char* argv[]) {
+  FILE* in_file = fopen(argv[1], "rb");
+  if (!in_file) {
+    printf("Cannot open input file %s\n", argv[1]);
+    return -1;
+  }
+  printf("Input RTP file: %s\n", argv[1]);
+
+  FILE* stat_file = fopen(argv[2], "rt");
+  if (!stat_file) {
+    printf("Cannot open timing file %s\n", argv[2]);
+    return -1;
+  }
+  printf("Timing file: %s\n", argv[2]);
+
+  FILE* out_file = fopen(argv[3], "wb");
+  if (!out_file) {
+    printf("Cannot open output file %s\n", argv[3]);
+    return -1;
+  }
+  printf("Output RTP file: %s\n\n", argv[3]);
+
+  // Read all statistics and insert into map.
+  // Read first line.
+  char temp_str[100];
+  if (fgets(temp_str, 100, stat_file) == NULL) {
+    printf("Failed to read timing file %s\n", argv[2]);
+    return -1;
+  }
+  // Define map.
+  std::map<std::pair<uint16_t, uint32_t>, uint32_t> packet_stats;
+  uint16_t seq_no;
+  uint32_t ts;
+  uint32_t send_time;
+
+  while (fscanf(stat_file,
+                "%hu %u %u %*i %*i\n", &seq_no, &ts, &send_time) == 3) {
+    std::pair<uint16_t, uint32_t>
+        temp_pair = std::pair<uint16_t, uint32_t>(seq_no, ts);
+
+    packet_stats[temp_pair] = send_time;
+  }
+
+  fclose(stat_file);
+
+  // Read file header and write directly to output file.
+  char first_line[FIRSTLINELEN];
+  if (fgets(first_line, FIRSTLINELEN, in_file) == NULL) {
+    printf("Failed to read first line of input file %s\n", argv[1]);
+    return -1;
+  }
+  fputs(first_line, out_file);
+  // start_sec + start_usec + source + port + padding
+  const unsigned int kRtpDumpHeaderSize = 4 + 4 + 4 + 2 + 2;
+  if (fread(first_line, 1, kRtpDumpHeaderSize, in_file)
+      != kRtpDumpHeaderSize) {
+    printf("Failed to read RTP dump header from input file %s\n", argv[1]);
+    return -1;
+  }
+  if (fwrite(first_line, 1, kRtpDumpHeaderSize, out_file)
+      != kRtpDumpHeaderSize) {
+    printf("Failed to write RTP dump header to output file %s\n", argv[3]);
+    return -1;
+  }
+
+  std::vector<NETEQTEST_RTPpacket *> packet_vec;
+
+  while (1) {
+    // Insert in vector.
+#ifdef WEBRTC_DUMMY_RTP
+    NETEQTEST_RTPpacket *new_packet = new NETEQTEST_DummyRTPpacket();
+#else
+    NETEQTEST_RTPpacket *new_packet = new NETEQTEST_RTPpacket();
+#endif
+    if (new_packet->readFromFile(in_file) < 0) {
+      // End of file.
+      break;
+    }
+
+    // Look for new send time in statistics vector.
+    std::pair<uint16_t, uint32_t> temp_pair =
+        std::pair<uint16_t, uint32_t>(new_packet->sequenceNumber(),
+                                      new_packet->timeStamp());
+
+    uint32_t new_send_time = packet_stats[temp_pair];
+    new_packet->setTime(new_send_time);  // Set new send time.
+    packet_vec.push_back(new_packet);  // Insert in vector.
+  }
+
+  // Sort the vector according to send times.
+  std::sort(packet_vec.begin(), packet_vec.end(), pktCmp);
+
+  std::vector<NETEQTEST_RTPpacket *>::iterator it;
+  for (it = packet_vec.begin(); it != packet_vec.end(); it++) {
+    // Write to out file.
+    if ((*it)->writeToFile(out_file) < 0) {
+      printf("Error writing to file\n");
+      return -1;
+    }
+    // Delete packet.
+    delete *it;
+  }
+
+  fclose(in_file);
+  fclose(out_file);
+
+  return 0;
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/RTPencode.cc b/webrtc/modules/audio_coding/neteq4/test/RTPencode.cc
new file mode 100644
index 0000000..c79d5db
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/RTPencode.cc
@@ -0,0 +1,1826 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+//TODO(hlundin): Reformat file to meet style guide.
+
+/* header includes */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef WIN32
+#include <winsock2.h>
+#endif
+#ifdef WEBRTC_LINUX
+#include <netinet/in.h>
+#endif
+
+#include <cassert>
+
+#include "webrtc/typedefs.h"
+// needed for NetEqDecoder
+#include "webrtc/modules/audio_coding/neteq4/interface/audio_decoder.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+
+/************************/
+/* Define payload types */
+/************************/
+
+#include "PayloadTypes.h"
+
+
+
+/*********************/
+/* Misc. definitions */
+/*********************/
+
+#define STOPSENDTIME 3000
+#define RESTARTSENDTIME 0 //162500
+#define FIRSTLINELEN 40
+#define CHECK_NOT_NULL(a) if((a)==0){printf("\n %s \n line: %d \nerror at %s\n",__FILE__,__LINE__,#a );return(-1);}
+
+//#define MULTIPLE_SAME_TIMESTAMP
+#define REPEAT_PACKET_DISTANCE 17
+#define REPEAT_PACKET_COUNT 1  // number of extra packets to send
+
+//#define INSERT_OLD_PACKETS
+#define OLD_PACKET 5 // how many seconds too old should the packet be?
+
+//#define TIMESTAMP_WRAPAROUND
+
+//#define RANDOM_DATA
+//#define RANDOM_PAYLOAD_DATA
+#define RANDOM_SEED 10
+
+//#define INSERT_DTMF_PACKETS
+//#define NO_DTMF_OVERDUB
+#define DTMF_PACKET_INTERVAL 2000
+#define DTMF_DURATION 500
+
+#define STEREO_MODE_FRAME 0
+#define STEREO_MODE_SAMPLE_1 1 //1 octet per sample
+#define STEREO_MODE_SAMPLE_2 2 //2 octets per sample
+
+/*************************/
+/* Function declarations */
+/*************************/
+
+void NetEQTest_GetCodec_and_PT(char * name, webrtc::NetEqDecoder *codec, int *PT, int frameLen, int *fs, int *bitrate, int *useRed);
+int NetEQTest_init_coders(webrtc::NetEqDecoder coder, int enc_frameSize, int bitrate, int sampfreq , int vad, int numChannels);
+void defineCodecs(webrtc::NetEqDecoder *usedCodec, int *noOfCodecs );
+int NetEQTest_free_coders(webrtc::NetEqDecoder coder, int numChannels);
+int NetEQTest_encode(int coder, WebRtc_Word16 *indata, int frameLen, unsigned char * encoded,int sampleRate , int * vad, int useVAD, int bitrate, int numChannels);
+void makeRTPheader(unsigned char* rtp_data, int payloadType, int seqNo, WebRtc_UWord32 timestamp, WebRtc_UWord32 ssrc);
+int makeRedundantHeader(unsigned char* rtp_data, int *payloadType, int numPayloads, WebRtc_UWord32 *timestamp, WebRtc_UWord16 *blockLen,
+                        int seqNo, WebRtc_UWord32 ssrc);
+int makeDTMFpayload(unsigned char* payload_data, int Event, int End, int Volume, int Duration);
+void stereoDeInterleave(WebRtc_Word16* audioSamples, int numSamples);
+void stereoInterleave(unsigned char* data, int dataLen, int stride);
+
+/*********************/
+/* Codec definitions */
+/*********************/
+
+#include "webrtc_vad.h"
+
+#if ((defined CODEC_PCM16B)||(defined NETEQ_ARBITRARY_CODEC))
+	#include "pcm16b.h"
+#endif
+#ifdef CODEC_G711
+	#include "g711_interface.h"
+#endif
+#ifdef CODEC_G729
+	#include "G729Interface.h"
+#endif
+#ifdef CODEC_G729_1
+	#include "G729_1Interface.h"
+#endif
+#ifdef CODEC_AMR
+	#include "AMRInterface.h"
+	#include "AMRCreation.h"
+#endif
+#ifdef CODEC_AMRWB
+	#include "AMRWBInterface.h"
+	#include "AMRWBCreation.h"
+#endif
+#ifdef CODEC_ILBC
+	#include "ilbc.h"
+#endif
+#if (defined CODEC_ISAC || defined CODEC_ISAC_SWB) 
+	#include "isac.h"
+#endif
+#ifdef NETEQ_ISACFIX_CODEC
+	#include "isacfix.h"
+	#ifdef CODEC_ISAC
+		#error Cannot have both ISAC and ISACfix defined. Please de-select one in the beginning of RTPencode.cpp
+	#endif
+#endif
+#ifdef CODEC_G722
+	#include "g722_interface.h"
+#endif
+#ifdef CODEC_G722_1_24
+	#include "G722_1Interface.h"
+#endif
+#ifdef CODEC_G722_1_32
+	#include "G722_1Interface.h"
+#endif
+#ifdef CODEC_G722_1_16
+	#include "G722_1Interface.h"
+#endif
+#ifdef CODEC_G722_1C_24
+	#include "G722_1Interface.h"
+#endif
+#ifdef CODEC_G722_1C_32
+	#include "G722_1Interface.h"
+#endif
+#ifdef CODEC_G722_1C_48
+	#include "G722_1Interface.h"
+#endif
+#ifdef CODEC_G726
+    #include "G726Creation.h"
+    #include "G726Interface.h"
+#endif
+#ifdef CODEC_GSMFR
+	#include "GSMFRInterface.h"
+	#include "GSMFRCreation.h"
+#endif
+#if (defined(CODEC_CNGCODEC8) || defined(CODEC_CNGCODEC16) || \
+    defined(CODEC_CNGCODEC32) || defined(CODEC_CNGCODEC48))
+  #include "webrtc_cng.h"
+#endif
+#if ((defined CODEC_SPEEX_8)||(defined CODEC_SPEEX_16))
+	#include "SpeexInterface.h"
+#endif
+#ifdef CODEC_CELT_32
+#include "celt_interface.h"
+#endif
+
+
+/***********************************/
+/* Global codec instance variables */
+/***********************************/
+
+WebRtcVadInst *VAD_inst[2];
+
+#ifdef CODEC_G722
+    G722EncInst *g722EncState[2];
+#endif
+
+#ifdef CODEC_G722_1_24
+	G722_1_24_encinst_t *G722_1_24enc_inst[2];
+#endif
+#ifdef CODEC_G722_1_32
+	G722_1_32_encinst_t *G722_1_32enc_inst[2];
+#endif
+#ifdef CODEC_G722_1_16
+	G722_1_16_encinst_t *G722_1_16enc_inst[2];
+#endif
+#ifdef CODEC_G722_1C_24
+	G722_1C_24_encinst_t *G722_1C_24enc_inst[2];
+#endif
+#ifdef CODEC_G722_1C_32
+	G722_1C_32_encinst_t *G722_1C_32enc_inst[2];
+#endif
+#ifdef CODEC_G722_1C_48
+	G722_1C_48_encinst_t *G722_1C_48enc_inst[2];
+#endif
+#ifdef CODEC_G726
+    G726_encinst_t *G726enc_inst[2];
+#endif
+#ifdef CODEC_G729
+	G729_encinst_t *G729enc_inst[2];
+#endif
+#ifdef CODEC_G729_1
+	G729_1_inst_t *G729_1_inst[2];
+#endif
+#ifdef CODEC_AMR
+	AMR_encinst_t *AMRenc_inst[2];
+	WebRtc_Word16		  AMR_bitrate;
+#endif
+#ifdef CODEC_AMRWB
+	AMRWB_encinst_t *AMRWBenc_inst[2];
+	WebRtc_Word16		  AMRWB_bitrate;
+#endif
+#ifdef CODEC_ILBC
+	iLBC_encinst_t *iLBCenc_inst[2];
+#endif
+#ifdef CODEC_ISAC
+	ISACStruct *ISAC_inst[2];
+#endif
+#ifdef NETEQ_ISACFIX_CODEC
+	ISACFIX_MainStruct *ISAC_inst[2];
+#endif
+#ifdef CODEC_ISAC_SWB
+	ISACStruct *ISACSWB_inst[2];
+#endif
+#ifdef CODEC_GSMFR
+	GSMFR_encinst_t *GSMFRenc_inst[2];
+#endif
+#if (defined(CODEC_CNGCODEC8) || defined(CODEC_CNGCODEC16) || \
+    defined(CODEC_CNGCODEC32) || defined(CODEC_CNGCODEC48))
+	CNG_enc_inst *CNGenc_inst[2];
+#endif
+#ifdef CODEC_SPEEX_8
+	SPEEX_encinst_t *SPEEX8enc_inst[2];
+#endif
+#ifdef CODEC_SPEEX_16
+	SPEEX_encinst_t *SPEEX16enc_inst[2];
+#endif
+#ifdef CODEC_CELT_32
+  CELT_encinst_t *CELT32enc_inst[2];
+#endif
+#ifdef CODEC_G711
+    void *G711state[2]={NULL, NULL};
+#endif
+
+
+int main(int argc, char* argv[])
+{
+	int packet_size, fs;
+	webrtc::NetEqDecoder usedCodec;
+	int payloadType;
+	int bitrate = 0;
+	int useVAD, vad;
+    int useRed=0;
+	int len, enc_len;
+	WebRtc_Word16 org_data[4000];
+	unsigned char rtp_data[8000];
+	WebRtc_Word16 seqNo=0xFFF;
+	WebRtc_UWord32 ssrc=1235412312;
+	WebRtc_UWord32 timestamp=0xAC1245;
+        WebRtc_UWord16 length, plen;
+	WebRtc_UWord32 offset;
+	double sendtime = 0;
+    int red_PT[2] = {0};
+    WebRtc_UWord32 red_TS[2] = {0};
+    WebRtc_UWord16 red_len[2] = {0};
+    int RTPheaderLen=12;
+	unsigned char red_data[8000];
+#ifdef INSERT_OLD_PACKETS
+	WebRtc_UWord16 old_length, old_plen;
+	int old_enc_len;
+	int first_old_packet=1;
+	unsigned char old_rtp_data[8000];
+	int packet_age=0;
+#endif
+#ifdef INSERT_DTMF_PACKETS
+	int NTone = 1;
+	int DTMFfirst = 1;
+	WebRtc_UWord32 DTMFtimestamp;
+    bool dtmfSent = false;
+#endif
+    bool usingStereo = false;
+    int stereoMode = 0;
+    int numChannels = 1;
+
+	/* check number of parameters */
+	if ((argc != 6) && (argc != 7)) {
+		/* print help text and exit */
+		printf("Application to encode speech into an RTP stream.\n");
+		printf("The program reads a PCM file and encodes is using the specified codec.\n");
+		printf("The coded speech is packetized in RTP packest and written to the output file.\n");
+		printf("The format of the RTP stream file is simlilar to that of rtpplay,\n");
+		printf("but with the receive time euqal to 0 for all packets.\n");
+		printf("Usage:\n\n");
+		printf("%s PCMfile RTPfile frameLen codec useVAD bitrate\n", argv[0]);
+		printf("where:\n");
+
+		printf("PCMfile      : PCM speech input file\n\n");
+
+		printf("RTPfile      : RTP stream output file\n\n");
+
+		printf("frameLen     : 80...960...  Number of samples per packet (limit depends on codec)\n\n");
+
+		printf("codecName\n");
+#ifdef CODEC_PCM16B
+		printf("             : pcm16b       16 bit PCM (8kHz)\n");
+#endif
+#ifdef CODEC_PCM16B_WB
+		printf("             : pcm16b_wb   16 bit PCM (16kHz)\n");
+#endif
+#ifdef CODEC_PCM16B_32KHZ
+		printf("             : pcm16b_swb32 16 bit PCM (32kHz)\n");
+#endif
+#ifdef CODEC_PCM16B_48KHZ
+		printf("             : pcm16b_swb48 16 bit PCM (48kHz)\n");
+#endif
+#ifdef CODEC_G711
+		printf("             : pcma         g711 A-law (8kHz)\n");
+#endif
+#ifdef CODEC_G711
+		printf("             : pcmu         g711 u-law (8kHz)\n");
+#endif
+#ifdef CODEC_G729
+		printf("             : g729         G729 (8kHz and 8kbps) CELP (One-Three frame(s)/packet)\n");
+#endif
+#ifdef CODEC_G729_1
+		printf("             : g729.1       G729.1 (16kHz) variable rate (8--32 kbps)\n");
+#endif
+#ifdef CODEC_G722_1_16
+		printf("             : g722.1_16    G722.1 coder (16kHz) (g722.1 with 16kbps)\n");
+#endif
+#ifdef CODEC_G722_1_24
+		printf("             : g722.1_24    G722.1 coder (16kHz) (the 24kbps version)\n");
+#endif
+#ifdef CODEC_G722_1_32
+		printf("             : g722.1_32    G722.1 coder (16kHz) (the 32kbps version)\n");
+#endif
+#ifdef CODEC_G722_1C_24
+		printf("             : g722.1C_24    G722.1 C coder (32kHz) (the 24kbps version)\n");
+#endif
+#ifdef CODEC_G722_1C_32
+		printf("             : g722.1C_32    G722.1 C coder (32kHz) (the 32kbps version)\n");
+#endif
+#ifdef CODEC_G722_1C_48
+		printf("             : g722.1C_48    G722.1 C coder (32kHz) (the 48kbps)\n");
+#endif
+
+#ifdef CODEC_G726
+        printf("             : g726_16      G726 coder (8kHz) 16kbps\n");
+        printf("             : g726_24      G726 coder (8kHz) 24kbps\n");
+        printf("             : g726_32      G726 coder (8kHz) 32kbps\n");
+        printf("             : g726_40      G726 coder (8kHz) 40kbps\n");
+#endif
+#ifdef CODEC_AMR
+		printf("             : AMRXk        Adaptive Multi Rate CELP codec (8kHz)\n");
+		printf("                            X = 4.75, 5.15, 5.9, 6.7, 7.4, 7.95, 10.2 or 12.2\n");
+#endif
+#ifdef CODEC_AMRWB
+		printf("             : AMRwbXk      Adaptive Multi Rate Wideband CELP codec (16kHz)\n");
+		printf("                            X = 7, 9, 12, 14, 16, 18, 20, 23 or 24\n");
+#endif
+#ifdef CODEC_ILBC
+		printf("             : ilbc         iLBC codec (8kHz and 13.8kbps)\n");
+#endif
+#ifdef CODEC_ISAC
+		printf("             : isac         iSAC (16kHz and 32.0 kbps). To set rate specify a rate parameter as last parameter\n");
+#endif
+#ifdef CODEC_ISAC_SWB
+		printf("             : isacswb       iSAC SWB (32kHz and 32.0-52.0 kbps). To set rate specify a rate parameter as last parameter\n");
+#endif
+#ifdef CODEC_GSMFR
+		printf("             : gsmfr        GSM FR codec (8kHz and 13kbps)\n");
+#endif
+#ifdef CODEC_G722
+		printf("             : g722         g722 coder (16kHz) (the 64kbps version)\n");
+#endif
+#ifdef CODEC_SPEEX_8
+		printf("             : speex8       speex coder (8 kHz)\n");
+#endif
+#ifdef CODEC_SPEEX_16
+		printf("             : speex16      speex coder (16 kHz)\n");
+#endif
+#ifdef CODEC_CELT_32
+    printf("             : celt32       celt coder (32 kHz)\n");
+#endif
+#ifdef CODEC_RED
+#ifdef CODEC_G711
+		printf("             : red_pcm      Redundancy RTP packet with 2*G711A frames\n");
+#endif
+#ifdef CODEC_ISAC
+		printf("             : red_isac     Redundancy RTP packet with 2*iSAC frames\n");
+#endif
+#endif
+        printf("\n");
+
+#if (defined(CODEC_CNGCODEC8) || defined(CODEC_CNGCODEC16) || \
+    defined(CODEC_CNGCODEC32) || defined(CODEC_CNGCODEC48))
+		printf("useVAD       : 0 Voice Activity Detection is switched off\n");
+		printf("             : 1 Voice Activity Detection is switched on\n\n");
+#else
+		printf("useVAD       : 0 Voice Activity Detection switched off (on not supported)\n\n");
+#endif
+		printf("bitrate      : Codec bitrate in bps (only applies to vbr codecs)\n\n");
+
+		return(0);
+	}
+
+	FILE* in_file=fopen(argv[1],"rb");
+	CHECK_NOT_NULL(in_file);
+	printf("Input file: %s\n",argv[1]);
+	FILE* out_file=fopen(argv[2],"wb");
+	CHECK_NOT_NULL(out_file);
+	printf("Output file: %s\n\n",argv[2]);
+	packet_size=atoi(argv[3]);
+	CHECK_NOT_NULL(packet_size);
+	printf("Packet size: %i\n",packet_size);
+
+    // check for stereo
+    if(argv[4][strlen(argv[4])-1] == '*') {
+        // use stereo
+        usingStereo = true;
+        numChannels = 2;
+        argv[4][strlen(argv[4])-1] = '\0';
+    }
+
+	NetEQTest_GetCodec_and_PT(argv[4], &usedCodec, &payloadType, packet_size, &fs, &bitrate, &useRed);
+
+    if(useRed) {
+        RTPheaderLen = 12 + 4 + 1; /* standard RTP = 12; 4 bytes per redundant payload, except last one which is 1 byte */
+    }
+
+	useVAD=atoi(argv[5]);
+#if !(defined(CODEC_CNGCODEC8) || defined(CODEC_CNGCODEC16) || \
+    defined(CODEC_CNGCODEC32) || defined(CODEC_CNGCODEC48))
+	if (useVAD!=0) {
+		printf("Error: this simulation does not support VAD/DTX/CNG\n");
+	}
+#endif
+	
+    // check stereo type
+    if(usingStereo)
+    {
+        switch(usedCodec) 
+        {
+            // sample based codecs 
+        case webrtc::kDecoderPCMu:
+        case webrtc::kDecoderPCMa:
+        case webrtc::kDecoderG722:
+            {
+                // 1 octet per sample
+                stereoMode = STEREO_MODE_SAMPLE_1;
+                break;
+            }
+        case webrtc::kDecoderPCM16B:
+        case webrtc::kDecoderPCM16Bwb:
+        case webrtc::kDecoderPCM16Bswb32kHz:
+        case webrtc::kDecoderPCM16Bswb48kHz:
+            {
+                // 2 octets per sample
+                stereoMode = STEREO_MODE_SAMPLE_2;
+                break;
+            }
+
+            // fixed-rate frame codecs (with internal VAD)
+        default:
+            {
+                printf("Cannot use codec %s as stereo codec\n", argv[4]);
+                exit(0);
+            }
+        }
+    }
+
+	if ((usedCodec == webrtc::kDecoderISAC) || (usedCodec == webrtc::kDecoderISACswb))
+    {
+        if (argc != 7)
+        {
+            if (usedCodec == webrtc::kDecoderISAC)
+            {
+                bitrate = 32000;
+                printf(
+                    "Running iSAC at default bitrate of 32000 bps (to specify explicitly add the bps as last parameter)\n");
+            }
+            else // (usedCodec==webrtc::kDecoderISACswb)
+            {
+                bitrate = 56000;
+                printf(
+                    "Running iSAC at default bitrate of 56000 bps (to specify explicitly add the bps as last parameter)\n");
+            }
+        }
+        else
+        {
+            bitrate = atoi(argv[6]);
+            if (usedCodec == webrtc::kDecoderISAC)
+            {
+                if ((bitrate < 10000) || (bitrate > 32000))
+                {
+                    printf(
+                        "Error: iSAC bitrate must be between 10000 and 32000 bps (%i is invalid)\n",
+                        bitrate);
+                    exit(0);
+                }
+                printf("Running iSAC at bitrate of %i bps\n", bitrate);
+            }
+            else // (usedCodec==webrtc::kDecoderISACswb)
+            {
+                if ((bitrate < 32000) || (bitrate > 56000))
+                {
+                    printf(
+                        "Error: iSAC SWB bitrate must be between 32000 and 56000 bps (%i is invalid)\n",
+                        bitrate);
+                    exit(0);
+                }
+            }
+        }
+    }
+    else
+    {
+        if (argc == 7)
+        {
+            printf(
+                "Error: Bitrate parameter can only be specified for iSAC, G.723, and G.729.1\n");
+            exit(0);
+        }
+    }
+	
+    if(useRed) {
+        printf("Redundancy engaged. ");
+    }
+	printf("Used codec: %i\n",usedCodec);
+	printf("Payload type: %i\n",payloadType);
+	
+	NetEQTest_init_coders(usedCodec, packet_size, bitrate, fs, useVAD, numChannels);
+
+	/* write file header */
+	//fprintf(out_file, "#!RTPencode%s\n", "1.0");
+	fprintf(out_file, "#!rtpplay%s \n", "1.0"); // this is the string that rtpplay needs
+	WebRtc_UWord32 dummy_variable = 0; // should be converted to network endian format, but does not matter when 0
+        if (fwrite(&dummy_variable, 4, 1, out_file) != 1) {
+          return -1;
+        }
+        if (fwrite(&dummy_variable, 4, 1, out_file) != 1) {
+          return -1;
+        }
+        if (fwrite(&dummy_variable, 4, 1, out_file) != 1) {
+          return -1;
+        }
+        if (fwrite(&dummy_variable, 2, 1, out_file) != 1) {
+          return -1;
+        }
+        if (fwrite(&dummy_variable, 2, 1, out_file) != 1) {
+          return -1;
+        }
+
+#ifdef TIMESTAMP_WRAPAROUND
+	timestamp = 0xFFFFFFFF - fs*10; /* should give wrap-around in 10 seconds */
+#endif
+#if defined(RANDOM_DATA) | defined(RANDOM_PAYLOAD_DATA)
+	srand(RANDOM_SEED);
+#endif
+
+    /* if redundancy is used, the first redundant payload is zero length */
+    red_len[0] = 0;
+
+	/* read first frame */
+	len=fread(org_data,2,packet_size * numChannels,in_file) / numChannels;
+
+    /* de-interleave if stereo */
+    if ( usingStereo )
+    {
+        stereoDeInterleave(org_data, len * numChannels);
+    }
+
+	while (len==packet_size) {
+
+#ifdef INSERT_DTMF_PACKETS
+        dtmfSent = false;
+
+        if ( sendtime >= NTone * DTMF_PACKET_INTERVAL ) {
+            if ( sendtime < NTone * DTMF_PACKET_INTERVAL + DTMF_DURATION ) {
+                // tone has not ended
+                if (DTMFfirst==1) {
+                    DTMFtimestamp = timestamp; // save this timestamp
+                    DTMFfirst=0;
+                }
+                makeRTPheader(rtp_data, NETEQ_CODEC_AVT_PT, seqNo,DTMFtimestamp, ssrc);
+                enc_len = makeDTMFpayload(&rtp_data[12], NTone % 12, 0, 4, (int) (sendtime - NTone * DTMF_PACKET_INTERVAL)*(fs/1000) + len);
+            }
+            else {
+                // tone has ended
+                makeRTPheader(rtp_data, NETEQ_CODEC_AVT_PT, seqNo,DTMFtimestamp, ssrc);
+                enc_len = makeDTMFpayload(&rtp_data[12], NTone % 12, 1, 4, DTMF_DURATION*(fs/1000));
+                NTone++;
+                DTMFfirst=1;
+            }
+
+            /* write RTP packet to file */
+            length = htons(12 + enc_len + 8);
+            plen = htons(12 + enc_len);
+            offset = (WebRtc_UWord32) sendtime; //(timestamp/(fs/1000));
+            offset = htonl(offset);
+            if (fwrite(&length, 2, 1, out_file) != 1) {
+              return -1;
+            }
+            if (fwrite(&plen, 2, 1, out_file) != 1) {
+              return -1;
+            }
+            if (fwrite(&offset, 4, 1, out_file) != 1) {
+              return -1;
+            }
+            if (fwrite(rtp_data, 12 + enc_len, 1, out_file) != 1) {
+              return -1;
+            }
+
+            dtmfSent = true;
+        }
+#endif
+
+#ifdef NO_DTMF_OVERDUB
+        /* If DTMF is sent, we should not send any speech packets during the same time */
+        if (dtmfSent) {
+            enc_len = 0;
+        }
+        else {
+#endif
+		/* encode frame */
+		enc_len=NetEQTest_encode(usedCodec, org_data, packet_size, &rtp_data[12] ,fs,&vad, useVAD, bitrate, numChannels);
+		if (enc_len==-1) {
+			printf("Error encoding frame\n");
+			exit(0);
+		}
+
+        if ( usingStereo &&
+            stereoMode != STEREO_MODE_FRAME &&
+            vad == 1 )
+        {
+            // interleave the encoded payload for sample-based codecs (not for CNG)
+            stereoInterleave(&rtp_data[12], enc_len, stereoMode);
+        }
+#ifdef NO_DTMF_OVERDUB
+        }
+#endif
+		
+		if (enc_len > 0 && (sendtime <= STOPSENDTIME || sendtime > RESTARTSENDTIME)) {
+            if(useRed) {
+                if(red_len[0] > 0) {
+                    memmove(&rtp_data[RTPheaderLen+red_len[0]], &rtp_data[12], enc_len);
+                    memcpy(&rtp_data[RTPheaderLen], red_data, red_len[0]);
+
+                    red_len[1] = enc_len;
+                    red_TS[1] = timestamp;
+                    if(vad)
+                        red_PT[1] = payloadType;
+                    else
+                        red_PT[1] = NETEQ_CODEC_CN_PT;
+
+                    makeRedundantHeader(rtp_data, red_PT, 2, red_TS, red_len, seqNo++, ssrc);
+
+
+                    enc_len += red_len[0] + RTPheaderLen - 12;
+                }
+                else { // do not use redundancy payload for this packet, i.e., only last payload
+                    memmove(&rtp_data[RTPheaderLen-4], &rtp_data[12], enc_len);
+                    //memcpy(&rtp_data[RTPheaderLen], red_data, red_len[0]);
+
+                    red_len[1] = enc_len;
+                    red_TS[1] = timestamp;
+                    if(vad)
+                        red_PT[1] = payloadType;
+                    else
+                        red_PT[1] = NETEQ_CODEC_CN_PT;
+
+                    makeRedundantHeader(rtp_data, red_PT, 2, red_TS, red_len, seqNo++, ssrc);
+
+
+                    enc_len += red_len[0] + RTPheaderLen - 4 - 12; // 4 is length of redundancy header (not used)
+                }
+            }
+            else {
+                
+                /* make RTP header */
+                if (vad) // regular speech data
+                    makeRTPheader(rtp_data, payloadType, seqNo++,timestamp, ssrc);
+                else // CNG data
+                    makeRTPheader(rtp_data, NETEQ_CODEC_CN_PT, seqNo++,timestamp, ssrc);
+                
+            }
+#ifdef MULTIPLE_SAME_TIMESTAMP
+			int mult_pack=0;
+			do {
+#endif //MULTIPLE_SAME_TIMESTAMP
+			/* write RTP packet to file */
+                          length = htons(12 + enc_len + 8);
+                          plen = htons(12 + enc_len);
+                          offset = (WebRtc_UWord32) sendtime;
+                          //(timestamp/(fs/1000));
+                          offset = htonl(offset);
+                          if (fwrite(&length, 2, 1, out_file) != 1) {
+                            return -1;
+                          }
+                          if (fwrite(&plen, 2, 1, out_file) != 1) {
+                            return -1;
+                          }
+                          if (fwrite(&offset, 4, 1, out_file) != 1) {
+                            return -1;
+                          }
+#ifdef RANDOM_DATA
+			for (int k=0; k<12+enc_len; k++) {
+				rtp_data[k] = rand() + rand();
+			}
+#endif
+#ifdef RANDOM_PAYLOAD_DATA
+			for (int k=12; k<12+enc_len; k++) {
+				rtp_data[k] = rand() + rand();
+			}
+#endif
+                        if (fwrite(rtp_data, 12 + enc_len, 1, out_file) != 1) {
+                          return -1;
+                        }
+#ifdef MULTIPLE_SAME_TIMESTAMP
+			} while ( (seqNo%REPEAT_PACKET_DISTANCE == 0) && (mult_pack++ < REPEAT_PACKET_COUNT) );
+#endif //MULTIPLE_SAME_TIMESTAMP
+
+#ifdef INSERT_OLD_PACKETS
+			if (packet_age >= OLD_PACKET*fs) {
+				if (!first_old_packet) {
+                                  // send the old packet
+                                  if (fwrite(&old_length, 2, 1,
+                                             out_file) != 1) {
+                                    return -1;
+                                  }
+                                  if (fwrite(&old_plen, 2, 1,
+                                             out_file) != 1) {
+                                    return -1;
+                                  }
+                                  if (fwrite(&offset, 4, 1,
+                                             out_file) != 1) {
+                                    return -1;
+                                  }
+                                  if (fwrite(old_rtp_data, 12 + old_enc_len,
+                                             1, out_file) != 1) {
+                                    return -1;
+                                  }
+				}
+				// store current packet as old
+				old_length=length;
+				old_plen=plen;
+				memcpy(old_rtp_data,rtp_data,12+enc_len);
+				old_enc_len=enc_len;
+				first_old_packet=0;
+				packet_age=0;
+
+			}
+			packet_age += packet_size;
+#endif
+			
+            if(useRed) {
+                /* move data to redundancy store */
+#ifdef CODEC_ISAC
+                if(usedCodec==webrtc::kDecoderISAC)
+                {
+                    assert(!usingStereo); // Cannot handle stereo yet
+                    red_len[0] = WebRtcIsac_GetRedPayload(ISAC_inst[0], (WebRtc_Word16*)red_data);
+                }
+                else
+                {
+#endif
+                    memcpy(red_data, &rtp_data[RTPheaderLen+red_len[0]], enc_len);
+                    red_len[0]=red_len[1];
+#ifdef CODEC_ISAC
+                }
+#endif
+                red_TS[0]=red_TS[1];
+                red_PT[0]=red_PT[1];
+            }
+            
+		}
+
+		/* read next frame */
+        len=fread(org_data,2,packet_size * numChannels,in_file) / numChannels;
+        /* de-interleave if stereo */
+        if ( usingStereo )
+        {
+            stereoDeInterleave(org_data, len * numChannels);
+        }
+
+        if (payloadType==NETEQ_CODEC_G722_PT)
+            timestamp+=len>>1;
+        else
+            timestamp+=len;
+
+		sendtime += (double) len/(fs/1000);
+	}
+	
+	NetEQTest_free_coders(usedCodec, numChannels);
+	fclose(in_file);
+	fclose(out_file);
+    printf("Done!\n");
+
+	return(0);
+}
+
+
+
+
+/****************/
+/* Subfunctions */
+/****************/
+
+void NetEQTest_GetCodec_and_PT(char * name, webrtc::NetEqDecoder *codec, int *PT, int frameLen, int *fs, int *bitrate, int *useRed) {
+
+	*bitrate = 0; /* Default bitrate setting */
+    *useRed = 0; /* Default no redundancy */
+
+	if(!strcmp(name,"pcmu")){
+		*codec=webrtc::kDecoderPCMu;
+		*PT=NETEQ_CODEC_PCMU_PT;
+		*fs=8000;
+	}
+	else if(!strcmp(name,"pcma")){
+		*codec=webrtc::kDecoderPCMa;
+		*PT=NETEQ_CODEC_PCMA_PT;
+		*fs=8000;
+	}
+	else if(!strcmp(name,"pcm16b")){
+		*codec=webrtc::kDecoderPCM16B;
+		*PT=NETEQ_CODEC_PCM16B_PT;
+		*fs=8000;
+	}
+	else if(!strcmp(name,"pcm16b_wb")){
+		*codec=webrtc::kDecoderPCM16Bwb;
+		*PT=NETEQ_CODEC_PCM16B_WB_PT;
+		*fs=16000;
+	}
+	else if(!strcmp(name,"pcm16b_swb32")){
+		*codec=webrtc::kDecoderPCM16Bswb32kHz;
+		*PT=NETEQ_CODEC_PCM16B_SWB32KHZ_PT;
+		*fs=32000;
+	}
+	else if(!strcmp(name,"pcm16b_swb48")){
+		*codec=webrtc::kDecoderPCM16Bswb48kHz;
+		*PT=NETEQ_CODEC_PCM16B_SWB48KHZ_PT;
+		*fs=48000;
+	}
+	else if(!strcmp(name,"g722")){
+		*codec=webrtc::kDecoderG722;
+		*PT=NETEQ_CODEC_G722_PT;
+		*fs=16000;
+	}
+	else if((!strcmp(name,"ilbc"))&&((frameLen%240==0)||(frameLen%160==0))){
+		*fs=8000;
+		*codec=webrtc::kDecoderILBC;
+		*PT=NETEQ_CODEC_ILBC_PT;
+	}
+	else if(!strcmp(name,"isac")){
+		*fs=16000;
+		*codec=webrtc::kDecoderISAC;
+		*PT=NETEQ_CODEC_ISAC_PT;
+	}
+    else if(!strcmp(name,"isacswb")){
+		*fs=32000;
+		*codec=webrtc::kDecoderISACswb;
+		*PT=NETEQ_CODEC_ISACSWB_PT;
+	}
+  else if(!strcmp(name,"celt32")){
+    *fs=32000;
+    *codec=webrtc::kDecoderCELT_32;
+    *PT=NETEQ_CODEC_CELT32_PT;
+  }
+    else if(!strcmp(name,"red_pcm")){
+		*codec=webrtc::kDecoderPCMa;
+		*PT=NETEQ_CODEC_PCMA_PT; /* this will be the PT for the sub-headers */
+		*fs=8000;
+        *useRed = 1;
+	} else if(!strcmp(name,"red_isac")){
+		*codec=webrtc::kDecoderISAC;
+		*PT=NETEQ_CODEC_ISAC_PT; /* this will be the PT for the sub-headers */
+		*fs=16000;
+        *useRed = 1;
+    } else {
+		printf("Error: Not a supported codec (%s)\n", name);
+		exit(0);
+	}
+
+}
+
+
+
+
+int NetEQTest_init_coders(webrtc::NetEqDecoder coder, int enc_frameSize, int bitrate, int sampfreq , int vad, int numChannels){
+	
+	int ok=0;
+	
+    for (int k = 0; k < numChannels; k++) 
+    {
+        ok=WebRtcVad_Create(&VAD_inst[k]);
+        if (ok!=0) {
+            printf("Error: Couldn't allocate memory for VAD instance\n");
+            exit(0);
+        }
+        ok=WebRtcVad_Init(VAD_inst[k]);
+        if (ok==-1) {
+            printf("Error: Initialization of VAD struct failed\n");	
+            exit(0); 
+        }
+
+
+#if (defined(CODEC_CNGCODEC8) || defined(CODEC_CNGCODEC16) || \
+    defined(CODEC_CNGCODEC32) || defined(CODEC_CNGCODEC48))
+        ok=WebRtcCng_CreateEnc(&CNGenc_inst[k]);
+        if (ok!=0) {
+            printf("Error: Couldn't allocate memory for CNG encoding instance\n");
+            exit(0);
+        }
+        if(sampfreq <= 16000) {
+            ok=WebRtcCng_InitEnc(CNGenc_inst[k],sampfreq, 200, 5);
+            if (ok==-1) {
+                printf("Error: Initialization of CNG struct failed. Error code %d\n", 
+                    WebRtcCng_GetErrorCodeEnc(CNGenc_inst[k]));	
+                exit(0); 
+            }
+        }
+#endif
+
+        switch (coder) {
+#ifdef CODEC_PCM16B
+    case webrtc::kDecoderPCM16B :
+#endif
+#ifdef CODEC_PCM16B_WB
+    case webrtc::kDecoderPCM16Bwb :
+#endif
+#ifdef CODEC_PCM16B_32KHZ
+    case webrtc::kDecoderPCM16Bswb32kHz :
+#endif
+#ifdef CODEC_PCM16B_48KHZ
+    case webrtc::kDecoderPCM16Bswb48kHz :
+#endif
+#ifdef CODEC_G711
+    case webrtc::kDecoderPCMu :
+    case webrtc::kDecoderPCMa :
+#endif
+        // do nothing
+        break;
+#ifdef CODEC_G729
+    case webrtc::kDecoderG729:
+        if (sampfreq==8000) {
+            if ((enc_frameSize==80)||(enc_frameSize==160)||(enc_frameSize==240)||(enc_frameSize==320)||(enc_frameSize==400)||(enc_frameSize==480)) {
+                ok=WebRtcG729_CreateEnc(&G729enc_inst[k]);
+                if (ok!=0) {
+                    printf("Error: Couldn't allocate memory for G729 encoding instance\n");
+                    exit(0);
+                }
+            } else {
+                printf("\nError: g729 only supports 10, 20, 30, 40, 50 or 60 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG729_EncoderInit(G729enc_inst[k], vad);
+            if ((vad==1)&&(enc_frameSize!=80)) {
+                printf("\nError - This simulation only supports VAD for G729 at 10ms packets (not %dms)\n", (enc_frameSize>>3));
+            }
+        } else {
+            printf("\nError - g729 is only developed for 8kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G729_1
+    case webrtc::kDecoderG729_1:
+        if (sampfreq==16000) {
+            if ((enc_frameSize==320)||(enc_frameSize==640)||(enc_frameSize==960)
+                ) {
+                    ok=WebRtcG7291_Create(&G729_1_inst[k]);
+                    if (ok!=0) {
+                        printf("Error: Couldn't allocate memory for G.729.1 codec instance\n");
+                        exit(0);
+                    }
+                } else {
+                    printf("\nError: G.729.1 only supports 20, 40 or 60 ms!!\n\n");
+                    exit(0);
+                }
+                if (!(((bitrate >= 12000) && (bitrate <= 32000) && (bitrate%2000 == 0)) || (bitrate == 8000))) {
+                    /* must be 8, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, or 32 kbps */
+                    printf("\nError: G.729.1 bitrate must be 8000 or 12000--32000 in steps of 2000 bps\n");
+                    exit(0);
+                }
+                WebRtcG7291_EncoderInit(G729_1_inst[k], bitrate, 0 /* flag8kHz*/, 0 /*flagG729mode*/);
+        } else {
+            printf("\nError - G.729.1 input is always 16 kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_SPEEX_8
+    case webrtc::kDecoderSPEEX_8 :
+        if (sampfreq==8000) {
+            if ((enc_frameSize==160)||(enc_frameSize==320)||(enc_frameSize==480)) {
+                ok=WebRtcSpeex_CreateEnc(&SPEEX8enc_inst[k], sampfreq);
+                if (ok!=0) {
+                    printf("Error: Couldn't allocate memory for Speex encoding instance\n");
+                    exit(0);
+                }
+            } else {
+                printf("\nError: Speex only supports 20, 40, and 60 ms!!\n\n");
+                exit(0);
+            }
+            if ((vad==1)&&(enc_frameSize!=160)) {
+                printf("\nError - This simulation only supports VAD for Speex at 20ms packets (not %dms)\n", (enc_frameSize>>3));
+                vad=0;
+            }
+            ok=WebRtcSpeex_EncoderInit(SPEEX8enc_inst[k], 0/*vbr*/, 3 /*complexity*/, vad);
+            if (ok!=0) exit(0);
+        } else {
+            printf("\nError - Speex8 called with sample frequency other than 8 kHz.\n\n");
+        }
+        break;
+#endif
+#ifdef CODEC_SPEEX_16
+    case webrtc::kDecoderSPEEX_16 :
+        if (sampfreq==16000) {
+            if ((enc_frameSize==320)||(enc_frameSize==640)||(enc_frameSize==960)) {
+                ok=WebRtcSpeex_CreateEnc(&SPEEX16enc_inst[k], sampfreq);
+                if (ok!=0) {
+                    printf("Error: Couldn't allocate memory for Speex encoding instance\n");
+                    exit(0);
+                }
+            } else {
+                printf("\nError: Speex only supports 20, 40, and 60 ms!!\n\n");
+                exit(0);
+            }
+            if ((vad==1)&&(enc_frameSize!=320)) {
+                printf("\nError - This simulation only supports VAD for Speex at 20ms packets (not %dms)\n", (enc_frameSize>>4));
+                vad=0;
+            }
+            ok=WebRtcSpeex_EncoderInit(SPEEX16enc_inst[k], 0/*vbr*/, 3 /*complexity*/, vad);
+            if (ok!=0) exit(0);
+        } else {
+            printf("\nError - Speex16 called with sample frequency other than 16 kHz.\n\n");
+        }
+        break;
+#endif
+#ifdef CODEC_CELT_32
+    case webrtc::kDecoderCELT_32 :
+        if (sampfreq==32000) {
+            if (enc_frameSize==320) {
+                ok=WebRtcCelt_CreateEnc(&CELT32enc_inst[k], 1 /*mono*/);
+                if (ok!=0) {
+                    printf("Error: Couldn't allocate memory for Celt encoding instance\n");
+                    exit(0);
+                }
+            } else {
+                printf("\nError: Celt only supports 10 ms!!\n\n");
+                exit(0);
+            }
+            ok=WebRtcCelt_EncoderInit(CELT32enc_inst[k],  1 /*mono*/, 48000 /*bitrate*/);
+            if (ok!=0) exit(0);
+        } else {
+          printf("\nError - Celt32 called with sample frequency other than 32 kHz.\n\n");
+        }
+        break;
+#endif
+
+#ifdef CODEC_G722_1_16
+    case webrtc::kDecoderG722_1_16 :
+        if (sampfreq==16000) {
+            ok=WebRtcG7221_CreateEnc16(&G722_1_16enc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for G.722.1 instance\n");
+                exit(0);
+            }
+            if (enc_frameSize==320) {				
+            } else {
+                printf("\nError: G722.1 only supports 20 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG7221_EncoderInit16((G722_1_16_encinst_t*)G722_1_16enc_inst[k]);
+        } else {
+            printf("\nError - G722.1 is only developed for 16kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G722_1_24
+    case webrtc::kDecoderG722_1_24 :
+        if (sampfreq==16000) {
+            ok=WebRtcG7221_CreateEnc24(&G722_1_24enc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for G.722.1 instance\n");
+                exit(0);
+            }
+            if (enc_frameSize==320) {
+            } else {
+                printf("\nError: G722.1 only supports 20 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG7221_EncoderInit24((G722_1_24_encinst_t*)G722_1_24enc_inst[k]);
+        } else {
+            printf("\nError - G722.1 is only developed for 16kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G722_1_32
+    case webrtc::kDecoderG722_1_32 :
+        if (sampfreq==16000) {
+            ok=WebRtcG7221_CreateEnc32(&G722_1_32enc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for G.722.1 instance\n");
+                exit(0);
+            }
+            if (enc_frameSize==320) {
+            } else {
+                printf("\nError: G722.1 only supports 20 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG7221_EncoderInit32((G722_1_32_encinst_t*)G722_1_32enc_inst[k]);
+        } else {
+            printf("\nError - G722.1 is only developed for 16kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G722_1C_24
+    case webrtc::kDecoderG722_1C_24 :
+        if (sampfreq==32000) {
+            ok=WebRtcG7221C_CreateEnc24(&G722_1C_24enc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for G.722.1C instance\n");
+                exit(0);
+            }
+            if (enc_frameSize==640) {
+            } else {
+                printf("\nError: G722.1 C only supports 20 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG7221C_EncoderInit24((G722_1C_24_encinst_t*)G722_1C_24enc_inst[k]);
+        } else {
+            printf("\nError - G722.1 C is only developed for 32kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G722_1C_32
+    case webrtc::kDecoderG722_1C_32 :
+        if (sampfreq==32000) {
+            ok=WebRtcG7221C_CreateEnc32(&G722_1C_32enc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for G.722.1C instance\n");
+                exit(0);
+            }
+            if (enc_frameSize==640) {
+            } else {
+                printf("\nError: G722.1 C only supports 20 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG7221C_EncoderInit32((G722_1C_32_encinst_t*)G722_1C_32enc_inst[k]);
+        } else {
+            printf("\nError - G722.1 C is only developed for 32kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G722_1C_48
+    case webrtc::kDecoderG722_1C_48 :
+        if (sampfreq==32000) {
+            ok=WebRtcG7221C_CreateEnc48(&G722_1C_48enc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for G.722.1C instance\n");
+                exit(0);
+            }
+            if (enc_frameSize==640) {
+            } else {
+                printf("\nError: G722.1 C only supports 20 ms!!\n\n");
+                exit(0);
+            }
+            WebRtcG7221C_EncoderInit48((G722_1C_48_encinst_t*)G722_1C_48enc_inst[k]);
+        } else {
+            printf("\nError - G722.1 C is only developed for 32kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_G722
+    case webrtc::kDecoderG722 :
+        if (sampfreq==16000) {
+            if (enc_frameSize%2==0) {				
+            } else {
+                printf("\nError - g722 frames must have an even number of enc_frameSize\n");
+                exit(0);
+            }
+            WebRtcG722_CreateEncoder(&g722EncState[k]);
+            WebRtcG722_EncoderInit(g722EncState[k]);
+        } else {
+            printf("\nError - g722 is only developed for 16kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_AMR
+    case webrtc::kDecoderAMR :
+        if (sampfreq==8000) {
+            ok=WebRtcAmr_CreateEnc(&AMRenc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for AMR encoding instance\n");
+                exit(0);
+            }if ((enc_frameSize==160)||(enc_frameSize==320)||(enc_frameSize==480)) {				
+            } else {
+                printf("\nError - AMR must have a multiple of 160 enc_frameSize\n");
+                exit(0);
+            }
+            WebRtcAmr_EncoderInit(AMRenc_inst[k], vad);
+            WebRtcAmr_EncodeBitmode(AMRenc_inst[k], AMRBandwidthEfficient);
+            AMR_bitrate = bitrate;
+        } else {
+            printf("\nError - AMR is only developed for 8kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_AMRWB
+    case webrtc::kDecoderAMRWB :
+        if (sampfreq==16000) {
+            ok=WebRtcAmrWb_CreateEnc(&AMRWBenc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for AMRWB encoding instance\n");
+                exit(0);
+            }
+            if (((enc_frameSize/320)<0)||((enc_frameSize/320)>3)||((enc_frameSize%320)!=0)) {
+                printf("\nError - AMRwb must have frameSize of 20, 40 or 60ms\n");
+                exit(0);
+            }
+            WebRtcAmrWb_EncoderInit(AMRWBenc_inst[k], vad);
+            if (bitrate==7000) {
+                AMRWB_bitrate = AMRWB_MODE_7k;
+            } else if (bitrate==9000) {
+                AMRWB_bitrate = AMRWB_MODE_9k;
+            } else if (bitrate==12000) {
+                AMRWB_bitrate = AMRWB_MODE_12k;
+            } else if (bitrate==14000) {
+                AMRWB_bitrate = AMRWB_MODE_14k;
+            } else if (bitrate==16000) {
+                AMRWB_bitrate = AMRWB_MODE_16k;
+            } else if (bitrate==18000) {
+                AMRWB_bitrate = AMRWB_MODE_18k;
+            } else if (bitrate==20000) {
+                AMRWB_bitrate = AMRWB_MODE_20k;
+            } else if (bitrate==23000) {
+                AMRWB_bitrate = AMRWB_MODE_23k;
+            } else if (bitrate==24000) {
+                AMRWB_bitrate = AMRWB_MODE_24k;
+            }
+            WebRtcAmrWb_EncodeBitmode(AMRWBenc_inst[k], AMRBandwidthEfficient);
+
+        } else {
+            printf("\nError - AMRwb is only developed for 16kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_ILBC
+    case webrtc::kDecoderILBC :
+        if (sampfreq==8000) {
+            ok=WebRtcIlbcfix_EncoderCreate(&iLBCenc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for iLBC encoding instance\n");
+                exit(0);
+            }
+            if ((enc_frameSize==160)||(enc_frameSize==240)||(enc_frameSize==320)||(enc_frameSize==480)) {				
+            } else {
+                printf("\nError - iLBC only supports 160, 240, 320 and 480 enc_frameSize (20, 30, 40 and 60 ms)\n");
+                exit(0);
+            }
+            if ((enc_frameSize==160)||(enc_frameSize==320)) {
+                /* 20 ms version */
+                WebRtcIlbcfix_EncoderInit(iLBCenc_inst[k], 20);
+            } else {
+                /* 30 ms version */
+                WebRtcIlbcfix_EncoderInit(iLBCenc_inst[k], 30);
+            }
+        } else {
+            printf("\nError - iLBC is only developed for 8kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_ISAC
+    case webrtc::kDecoderISAC:
+        if (sampfreq==16000) {
+            ok=WebRtcIsac_Create(&ISAC_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for iSAC instance\n");
+                exit(0);
+            }if ((enc_frameSize==480)||(enc_frameSize==960)) {
+            } else {
+                printf("\nError - iSAC only supports frameSize (30 and 60 ms)\n");
+                exit(0);
+            }
+            WebRtcIsac_EncoderInit(ISAC_inst[k],1);
+            if ((bitrate<10000)||(bitrate>32000)) {
+                printf("\nError - iSAC bitrate has to be between 10000 and 32000 bps (not %i)\n", bitrate);
+                exit(0);
+            }
+            WebRtcIsac_Control(ISAC_inst[k], bitrate, enc_frameSize>>4);
+        } else {
+            printf("\nError - iSAC only supports 480 or 960 enc_frameSize (30 or 60 ms)\n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef NETEQ_ISACFIX_CODEC
+    case webrtc::kDecoderISAC:
+        if (sampfreq==16000) {
+            ok=WebRtcIsacfix_Create(&ISAC_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for iSAC instance\n");
+                exit(0);
+            }if ((enc_frameSize==480)||(enc_frameSize==960)) {
+            } else {
+                printf("\nError - iSAC only supports frameSize (30 and 60 ms)\n");
+                exit(0);
+            }
+            WebRtcIsacfix_EncoderInit(ISAC_inst[k],1);
+            if ((bitrate<10000)||(bitrate>32000)) {
+                printf("\nError - iSAC bitrate has to be between 10000 and 32000 bps (not %i)\n", bitrate);
+                exit(0);
+            }
+            WebRtcIsacfix_Control(ISAC_inst[k], bitrate, enc_frameSize>>4);
+        } else {
+            printf("\nError - iSAC only supports 480 or 960 enc_frameSize (30 or 60 ms)\n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_ISAC_SWB
+    case webrtc::kDecoderISACswb:
+        if (sampfreq==32000) {
+            ok=WebRtcIsac_Create(&ISACSWB_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for iSAC SWB instance\n");
+                exit(0);
+            }if (enc_frameSize==960) {
+            } else {
+                printf("\nError - iSAC SWB only supports frameSize 30 ms\n");
+                exit(0);
+            }
+            ok = WebRtcIsac_SetEncSampRate(ISACSWB_inst[k], 32000);
+            if (ok!=0) {
+                printf("Error: Couldn't set sample rate for iSAC SWB instance\n");
+                exit(0);
+            }
+            WebRtcIsac_EncoderInit(ISACSWB_inst[k],1);
+            if ((bitrate<32000)||(bitrate>56000)) {
+                printf("\nError - iSAC SWB bitrate has to be between 32000 and 56000 bps (not %i)\n", bitrate);
+                exit(0);
+            }
+            WebRtcIsac_Control(ISACSWB_inst[k], bitrate, enc_frameSize>>5);
+        } else {
+            printf("\nError - iSAC SWB only supports 960 enc_frameSize (30 ms)\n");
+            exit(0);
+        }
+        break;
+#endif
+#ifdef CODEC_GSMFR
+    case webrtc::kDecoderGSMFR:
+        if (sampfreq==8000) {
+            ok=WebRtcGSMFR_CreateEnc(&GSMFRenc_inst[k]);
+            if (ok!=0) {
+                printf("Error: Couldn't allocate memory for GSM FR encoding instance\n");
+                exit(0);
+            }
+            if ((enc_frameSize==160)||(enc_frameSize==320)||(enc_frameSize==480)) {			
+            } else {
+                printf("\nError - GSM FR must have a multiple of 160 enc_frameSize\n");
+                exit(0);
+            }
+            WebRtcGSMFR_EncoderInit(GSMFRenc_inst[k], 0);
+        } else {
+            printf("\nError - GSM FR is only developed for 8kHz \n");
+            exit(0);
+        }
+        break;
+#endif
+    default :
+        printf("Error: unknown codec in call to NetEQTest_init_coders.\n");
+        exit(0);
+        break;
+        }
+
+        if (ok != 0) {
+            return(ok);
+        }
+    } // end for
+
+    return(0);
+}			
+
+
+
+
+int NetEQTest_free_coders(webrtc::NetEqDecoder coder, int numChannels) {
+
+    for (int k = 0; k < numChannels; k++)
+    {
+        WebRtcVad_Free(VAD_inst[k]);
+#if (defined(CODEC_CNGCODEC8) || defined(CODEC_CNGCODEC16) || \
+    defined(CODEC_CNGCODEC32) || defined(CODEC_CNGCODEC48))
+        WebRtcCng_FreeEnc(CNGenc_inst[k]);
+#endif
+
+        switch (coder) 
+        {
+#ifdef CODEC_PCM16B
+        case webrtc::kDecoderPCM16B :
+#endif
+#ifdef CODEC_PCM16B_WB
+        case webrtc::kDecoderPCM16Bwb :
+#endif
+#ifdef CODEC_PCM16B_32KHZ
+        case webrtc::kDecoderPCM16Bswb32kHz :
+#endif
+#ifdef CODEC_PCM16B_48KHZ
+        case webrtc::kDecoderPCM16Bswb48kHz :
+#endif
+#ifdef CODEC_G711
+        case webrtc::kDecoderPCMu :
+        case webrtc::kDecoderPCMa :
+#endif
+            // do nothing
+            break;
+#ifdef CODEC_G729
+        case webrtc::kDecoderG729:
+            WebRtcG729_FreeEnc(G729enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G729_1
+        case webrtc::kDecoderG729_1:
+            WebRtcG7291_Free(G729_1_inst[k]);
+            break;
+#endif
+#ifdef CODEC_SPEEX_8
+        case webrtc::kDecoderSPEEX_8 :
+            WebRtcSpeex_FreeEnc(SPEEX8enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_SPEEX_16
+        case webrtc::kDecoderSPEEX_16 :
+            WebRtcSpeex_FreeEnc(SPEEX16enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_CELT_32
+        case webrtc::kDecoderCELT_32 :
+            WebRtcCelt_FreeEnc(CELT32enc_inst[k]);
+            break;
+#endif
+
+#ifdef CODEC_G722_1_16
+        case webrtc::kDecoderG722_1_16 :
+            WebRtcG7221_FreeEnc16(G722_1_16enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G722_1_24
+        case webrtc::kDecoderG722_1_24 :
+            WebRtcG7221_FreeEnc24(G722_1_24enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G722_1_32
+        case webrtc::kDecoderG722_1_32 :
+            WebRtcG7221_FreeEnc32(G722_1_32enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G722_1C_24
+        case webrtc::kDecoderG722_1C_24 :
+            WebRtcG7221C_FreeEnc24(G722_1C_24enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G722_1C_32
+        case webrtc::kDecoderG722_1C_32 :
+            WebRtcG7221C_FreeEnc32(G722_1C_32enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G722_1C_48
+        case webrtc::kDecoderG722_1C_48 :
+            WebRtcG7221C_FreeEnc48(G722_1C_48enc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_G722
+        case webrtc::kDecoderG722 :
+            WebRtcG722_FreeEncoder(g722EncState[k]);
+            break;
+#endif
+#ifdef CODEC_AMR
+        case webrtc::kDecoderAMR :
+            WebRtcAmr_FreeEnc(AMRenc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_AMRWB
+        case webrtc::kDecoderAMRWB :
+            WebRtcAmrWb_FreeEnc(AMRWBenc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_ILBC
+        case webrtc::kDecoderILBC :
+            WebRtcIlbcfix_EncoderFree(iLBCenc_inst[k]);
+            break;
+#endif
+#ifdef CODEC_ISAC
+        case webrtc::kDecoderISAC:
+            WebRtcIsac_Free(ISAC_inst[k]);
+            break;
+#endif
+#ifdef NETEQ_ISACFIX_CODEC
+        case webrtc::kDecoderISAC:
+            WebRtcIsacfix_Free(ISAC_inst[k]);
+            break;
+#endif
+#ifdef CODEC_ISAC_SWB
+        case webrtc::kDecoderISACswb:
+            WebRtcIsac_Free(ISACSWB_inst[k]);
+            break;
+#endif
+#ifdef CODEC_GSMFR
+        case webrtc::kDecoderGSMFR:
+            WebRtcGSMFR_FreeEnc(GSMFRenc_inst[k]);
+            break;
+#endif
+        default :
+            printf("Error: unknown codec in call to NetEQTest_init_coders.\n");
+            exit(0);
+            break;
+        }
+    }
+
+	return(0);
+}
+
+
+
+
+
+
+int NetEQTest_encode(int coder, WebRtc_Word16 *indata, int frameLen, unsigned char * encoded,int sampleRate , 
+						  int * vad, int useVAD, int bitrate, int numChannels){
+
+	short cdlen = 0;
+	WebRtc_Word16 *tempdata;
+	static int first_cng=1;
+	WebRtc_Word16 tempLen;
+
+	*vad =1;
+
+    // check VAD first
+	if(useVAD)
+    {
+        *vad = 0;
+
+        for (int k = 0; k < numChannels; k++)
+        {
+            tempLen = frameLen;
+            tempdata = &indata[k*frameLen];
+            int localVad=0;
+            /* Partition the signal and test each chunk for VAD.
+            All chunks must be VAD=0 to produce a total VAD=0. */
+            while (tempLen >= 10*sampleRate/1000) {
+                if ((tempLen % 30*sampleRate/1000) == 0) { // tempLen is multiple of 30ms
+                    localVad |= WebRtcVad_Process(VAD_inst[k] ,sampleRate, tempdata, 30*sampleRate/1000);
+                    tempdata += 30*sampleRate/1000;
+                    tempLen -= 30*sampleRate/1000;
+                }
+                else if (tempLen >= 20*sampleRate/1000) { // tempLen >= 20ms
+                    localVad |= WebRtcVad_Process(VAD_inst[k] ,sampleRate, tempdata, 20*sampleRate/1000);
+                    tempdata += 20*sampleRate/1000;
+                    tempLen -= 20*sampleRate/1000;
+                }
+                else { // use 10ms
+                    localVad |= WebRtcVad_Process(VAD_inst[k] ,sampleRate, tempdata, 10*sampleRate/1000);
+                    tempdata += 10*sampleRate/1000;
+                    tempLen -= 10*sampleRate/1000;
+                }
+            }
+
+            // aggregate all VAD decisions over all channels
+            *vad |= localVad;
+        }
+
+        if(!*vad){
+            // all channels are silent
+            cdlen = 0;
+            for (int k = 0; k < numChannels; k++)
+            {
+                WebRtcCng_Encode(CNGenc_inst[k],&indata[k*frameLen], (frameLen <= 640 ? frameLen : 640) /* max 640 */,
+                    encoded,&tempLen,first_cng);
+                encoded += tempLen;
+                cdlen += tempLen;
+            }
+            *vad=0;
+            first_cng=0;
+            return(cdlen);
+        }
+	}
+
+
+    // loop over all channels
+    int totalLen = 0;
+
+    for (int k = 0; k < numChannels; k++)
+    {
+        /* Encode with the selected coder type */
+        if (coder==webrtc::kDecoderPCMu) { /*g711 u-law */
+#ifdef CODEC_G711
+            cdlen = WebRtcG711_EncodeU(G711state[k], indata, frameLen, (WebRtc_Word16*) encoded);
+#endif
+        }  
+        else if (coder==webrtc::kDecoderPCMa) { /*g711 A-law */
+#ifdef CODEC_G711
+            cdlen = WebRtcG711_EncodeA(G711state[k], indata, frameLen, (WebRtc_Word16*) encoded);
+        }
+#endif
+#ifdef CODEC_PCM16B
+        else if ((coder==webrtc::kDecoderPCM16B)||(coder==webrtc::kDecoderPCM16Bwb)||
+            (coder==webrtc::kDecoderPCM16Bswb32kHz)||(coder==webrtc::kDecoderPCM16Bswb48kHz)) { /*pcm16b (8kHz, 16kHz, 32kHz or 48kHz) */
+                cdlen = WebRtcPcm16b_EncodeW16(indata, frameLen, (WebRtc_Word16*) encoded);
+            }
+#endif
+#ifdef CODEC_G722
+        else if (coder==webrtc::kDecoderG722) { /*g722 */
+            cdlen=WebRtcG722_Encode(g722EncState[k], indata, frameLen, (WebRtc_Word16*)encoded);
+            cdlen=frameLen>>1;
+        }
+#endif
+#ifdef CODEC_ILBC
+        else if (coder==webrtc::kDecoderILBC) { /*iLBC */
+            cdlen=WebRtcIlbcfix_Encode(iLBCenc_inst[k], indata,frameLen,(WebRtc_Word16*)encoded);
+        }
+#endif
+#if (defined(CODEC_ISAC) || defined(NETEQ_ISACFIX_CODEC)) // TODO(hlundin): remove all NETEQ_ISACFIX_CODEC
+        else if (coder==webrtc::kDecoderISAC) { /*iSAC */
+            int noOfCalls=0;
+            cdlen=0;
+            while (cdlen<=0) {
+#ifdef CODEC_ISAC /* floating point */
+                cdlen=WebRtcIsac_Encode(ISAC_inst[k],&indata[noOfCalls*160],(WebRtc_Word16*)encoded);
+#else /* fixed point */
+                cdlen=WebRtcIsacfix_Encode(ISAC_inst[k],&indata[noOfCalls*160],(WebRtc_Word16*)encoded);
+#endif
+                noOfCalls++;
+            }
+        }
+#endif
+#ifdef CODEC_ISAC_SWB
+        else if (coder==webrtc::kDecoderISACswb) { /* iSAC SWB */
+            int noOfCalls=0;
+            cdlen=0;
+            while (cdlen<=0) {
+                cdlen=WebRtcIsac_Encode(ISACSWB_inst[k],&indata[noOfCalls*320],(WebRtc_Word16*)encoded);
+                noOfCalls++;
+            }
+        }
+#endif
+#ifdef CODEC_CELT_32
+        else if (coder==webrtc::kDecoderCELT_32) { /* Celt */
+            int encodedLen = 0;
+            cdlen = 0;
+            while (cdlen <= 0) {
+                cdlen = WebRtcCelt_Encode(CELT32enc_inst[k], &indata[encodedLen], encoded);
+                encodedLen += 10*32; /* 10 ms */
+            }
+            if( (encodedLen != frameLen) || cdlen < 0) {
+                printf("Error encoding Celt frame!\n");
+                exit(0);
+            }
+        }
+#endif
+
+        indata += frameLen;
+        encoded += cdlen;
+        totalLen += cdlen;
+
+    } // end for
+
+	first_cng=1;
+	return(totalLen);
+}
+
+
+
+void makeRTPheader(unsigned char* rtp_data, int payloadType, int seqNo, WebRtc_UWord32 timestamp, WebRtc_UWord32 ssrc){
+			
+			rtp_data[0]=(unsigned char)0x80;
+			rtp_data[1]=(unsigned char)(payloadType & 0xFF);
+			rtp_data[2]=(unsigned char)((seqNo>>8)&0xFF);
+			rtp_data[3]=(unsigned char)((seqNo)&0xFF);
+			rtp_data[4]=(unsigned char)((timestamp>>24)&0xFF);
+			rtp_data[5]=(unsigned char)((timestamp>>16)&0xFF);
+
+			rtp_data[6]=(unsigned char)((timestamp>>8)&0xFF); 
+			rtp_data[7]=(unsigned char)(timestamp & 0xFF);
+
+			rtp_data[8]=(unsigned char)((ssrc>>24)&0xFF);
+			rtp_data[9]=(unsigned char)((ssrc>>16)&0xFF);
+
+			rtp_data[10]=(unsigned char)((ssrc>>8)&0xFF);
+			rtp_data[11]=(unsigned char)(ssrc & 0xFF);
+}
+
+
+int makeRedundantHeader(unsigned char* rtp_data, int *payloadType, int numPayloads, WebRtc_UWord32 *timestamp, WebRtc_UWord16 *blockLen,
+                        int seqNo, WebRtc_UWord32 ssrc)
+{
+
+    int i;
+    unsigned char *rtpPointer;
+    WebRtc_UWord16 offset;
+
+    /* first create "standard" RTP header */
+    makeRTPheader(rtp_data, NETEQ_CODEC_RED_PT, seqNo, timestamp[numPayloads-1], ssrc);
+
+    rtpPointer = &rtp_data[12];
+
+    /* add one sub-header for each redundant payload (not the primary) */
+    for(i=0; i<numPayloads-1; i++) {                                            /* |0 1 2 3 4 5 6 7| */
+        if(blockLen[i] > 0) {
+            offset = (WebRtc_UWord16) (timestamp[numPayloads-1] - timestamp[i]);
+
+            rtpPointer[0] = (unsigned char) ( 0x80 | (0x7F & payloadType[i]) ); /* |F|   block PT  | */
+            rtpPointer[1] = (unsigned char) ((offset >> 6) & 0xFF);             /* |  timestamp-   | */
+            rtpPointer[2] = (unsigned char) ( ((offset & 0x3F)<<2) |
+                ( (blockLen[i]>>8) & 0x03 ) );                                  /* | -offset   |bl-| */
+            rtpPointer[3] = (unsigned char) ( blockLen[i] & 0xFF );             /* | -ock length   | */
+
+            rtpPointer += 4;
+        }
+    }
+
+    /* last sub-header */
+    rtpPointer[0]= (unsigned char) (0x00 | (0x7F&payloadType[numPayloads-1]));/* |F|   block PT  | */
+    rtpPointer += 1;
+
+    return(rtpPointer - rtp_data); /* length of header in bytes */
+}
+
+
+
+int makeDTMFpayload(unsigned char* payload_data, int Event, int End, int Volume, int Duration) {
+	unsigned char E,R,V;
+	R=0;
+	V=(unsigned char)Volume;
+	if (End==0) {
+		E = 0x00;
+	} else {
+		E = 0x80;
+	}
+	payload_data[0]=(unsigned char)Event;
+	payload_data[1]=(unsigned char)(E|R|V);
+	//Duration equals 8 times time_ms, default is 8000 Hz.
+	payload_data[2]=(unsigned char)((Duration>>8)&0xFF);
+	payload_data[3]=(unsigned char)(Duration&0xFF);
+	return(4);
+}
+
+void stereoDeInterleave(WebRtc_Word16* audioSamples, int numSamples)
+{
+
+    WebRtc_Word16 *tempVec;
+    WebRtc_Word16 *readPtr, *writeL, *writeR;
+
+    if (numSamples <= 0)
+        return;
+
+    tempVec = (WebRtc_Word16 *) malloc(sizeof(WebRtc_Word16) * numSamples);
+    if (tempVec == NULL) {
+        printf("Error allocating memory\n");
+        exit(0);
+    }
+
+    memcpy(tempVec, audioSamples, numSamples*sizeof(WebRtc_Word16));
+
+    writeL = audioSamples;
+    writeR = &audioSamples[numSamples/2];
+    readPtr = tempVec;
+
+    for (int k = 0; k < numSamples; k += 2)
+    {
+        *writeL = *readPtr;
+        readPtr++;
+        *writeR = *readPtr;
+        readPtr++;
+        writeL++;
+        writeR++;
+    }
+
+    free(tempVec);
+
+}
+
+
+void stereoInterleave(unsigned char* data, int dataLen, int stride)
+{
+
+    unsigned char *ptrL, *ptrR;
+    unsigned char temp[10];
+
+    if (stride > 10)
+    {
+        exit(0);
+    }
+
+    if (dataLen%1 != 0)
+    {
+        // must be even number of samples
+        printf("Error: cannot interleave odd sample number\n");
+        exit(0);
+    }
+
+    ptrL = data + stride;
+    ptrR = &data[dataLen/2];
+
+    while (ptrL < ptrR) {
+        // copy from right pointer to temp
+        memcpy(temp, ptrR, stride);
+
+        // shift data between pointers
+        memmove(ptrL + stride, ptrL, ptrR - ptrL);
+
+        // copy from temp to left pointer
+        memcpy(ptrL, temp, stride);
+
+        // advance pointers
+        ptrL += stride*2;
+        ptrR += stride;
+    }
+
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/RTPjitter.cc b/webrtc/modules/audio_coding/neteq4/test/RTPjitter.cc
new file mode 100644
index 0000000..77b29ec
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/RTPjitter.cc
@@ -0,0 +1,202 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+//TODO(hlundin): Reformat file to meet style guide.
+
+/* header includes */
+#include <float.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef WIN32
+#include <winsock2.h>
+#include <io.h>
+#endif
+#ifdef WEBRTC_LINUX
+#include <netinet/in.h>
+#endif
+
+#include <cassert>
+
+#include "gtest/gtest.h"
+#include "webrtc/typedefs.h"
+
+/*********************/
+/* Misc. definitions */
+/*********************/
+
+#define FIRSTLINELEN 40
+#define CHECK_NOT_NULL(a) if((a)==NULL){fprintf(stderr,"\n %s \n line: %d \nerror at %s\n",__FILE__,__LINE__,#a );return(-1);}
+
+struct arr_time {
+	float time;
+	WebRtc_UWord32 ix;
+};
+
+int filelen(FILE *fid)
+{
+  fpos_t cur_pos;
+  int len;
+
+  if (!fid || fgetpos(fid, &cur_pos)) {
+    return(-1);
+  }
+
+  fseek(fid, 0, SEEK_END);
+  len = ftell(fid);
+
+  fsetpos(fid, &cur_pos);
+
+  return (len);
+}
+
+int compare_arr_time(const void *x, const void *y);
+
+int main(int argc, char* argv[])
+{
+	unsigned int	dat_len, rtp_len, Npack, k;
+	arr_time		*time_vec;
+	char			firstline[FIRSTLINELEN];
+	unsigned char	*rtp_vec = NULL, **packet_ptr, *temp_packet;
+	const unsigned int kRtpDumpHeaderSize = 4 + 4 + 4 + 2 + 2;
+	WebRtc_UWord16			len;
+	WebRtc_UWord32			*offset;
+
+/* check number of parameters */
+	if (argc != 4) {
+		/* print help text and exit */
+		printf("Apply jitter on RTP stream.\n");
+		printf("The program reads an RTP stream and packet timing from two files.\n");
+		printf("The RTP stream is modified to have the same jitter as described in the timing files.\n");
+		printf("The format of the RTP stream file should be the same as for rtpplay,\n");
+		printf("and can be obtained e.g., from Ethereal by using\n");
+		printf("Statistics -> RTP -> Show All Streams -> [select a stream] -> Save As\n\n");
+		printf("Usage:\n\n");
+		printf("%s RTP_infile dat_file RTP_outfile\n", argv[0]);
+		printf("where:\n");
+
+		printf("RTP_infile       : RTP stream input file\n\n");
+
+		printf("dat_file         : file with packet arrival times in ms\n\n");
+
+		printf("RTP_outfile      : RTP stream output file\n\n");
+
+		return(0);
+	}
+
+	FILE* in_file=fopen(argv[1],"rb");
+	CHECK_NOT_NULL(in_file);
+	printf("Input file: %s\n",argv[1]);
+	FILE* dat_file=fopen(argv[2],"rb");
+	CHECK_NOT_NULL(dat_file);
+	printf("Dat-file: %s\n",argv[2]);
+	FILE* out_file=fopen(argv[3],"wb");
+	CHECK_NOT_NULL(out_file);
+	printf("Output file: %s\n\n",argv[3]);
+	
+	time_vec = (arr_time *) malloc(sizeof(arr_time)*(filelen(dat_file)/sizeof(float)) + 1000); // add 1000 bytes to avoid (rare) strange error
+	if (time_vec==NULL) {
+		fprintf(stderr, "Error: could not allocate memory for reading dat file\n");
+		goto closing;
+	}
+
+	dat_len=0;
+	while(fread(&(time_vec[dat_len].time),sizeof(float),1,dat_file)>0) {
+		time_vec[dat_len].ix=dat_len;
+		dat_len++;
+	}
+	
+	qsort(time_vec,dat_len,sizeof(arr_time),compare_arr_time);
+
+
+	rtp_vec = (unsigned char *) malloc(sizeof(unsigned char)*filelen(in_file));
+	if (rtp_vec==NULL) {
+		fprintf(stderr,"Error: could not allocate memory for reading rtp file\n");
+		goto closing;
+	}
+
+	// read file header and write directly to output file
+	EXPECT_TRUE(fgets(firstline, FIRSTLINELEN, in_file) != NULL);
+	EXPECT_GT(fputs(firstline, out_file), 0);
+	EXPECT_EQ(kRtpDumpHeaderSize, fread(firstline, 1, kRtpDumpHeaderSize,
+	                                    in_file));
+	EXPECT_EQ(kRtpDumpHeaderSize, fwrite(firstline, 1, kRtpDumpHeaderSize,
+	                                     out_file));
+
+	// read all RTP packets into vector
+	rtp_len=0;
+	Npack=0;
+	len=(WebRtc_UWord16) fread(&rtp_vec[rtp_len], sizeof(unsigned char), 2, in_file); // read length of first packet
+	while(len==2) {
+		len = ntohs(*((WebRtc_UWord16 *)(rtp_vec + rtp_len)));
+		rtp_len += 2;
+		if(fread(&rtp_vec[rtp_len], sizeof(unsigned char), len-2, in_file)!=(unsigned) (len-2)) {
+			fprintf(stderr,"Error: currupt packet length\n");
+			goto closing;
+		}
+		rtp_len += len-2;
+		Npack++;
+		len=(WebRtc_UWord16) fread(&rtp_vec[rtp_len], sizeof(unsigned char), 2, in_file); // read length of next packet
+	}
+
+	packet_ptr = (unsigned char **) malloc(Npack*sizeof(unsigned char*));
+
+	packet_ptr[0]=rtp_vec;
+	k=1;
+	while(k<Npack) {
+		len = ntohs(*((WebRtc_UWord16 *) packet_ptr[k-1]));
+		packet_ptr[k]=packet_ptr[k-1]+len;
+		k++;
+	}
+
+	for(k=0; k<dat_len && k<Npack; k++) {
+		if(time_vec[k].time < FLT_MAX && time_vec[k].ix < Npack){ 
+			temp_packet = packet_ptr[time_vec[k].ix];
+			offset = (WebRtc_UWord32 *) (temp_packet+4);
+			if ( time_vec[k].time >= 0 ) {
+				*offset = htonl((WebRtc_UWord32) time_vec[k].time);
+			}
+			else {
+				*offset = htonl((WebRtc_UWord32) 0);
+				fprintf(stderr, "Warning: negative receive time in dat file transformed to 0.\n");
+			}
+
+			// write packet to file
+                        if (fwrite(temp_packet, sizeof(unsigned char),
+                                   ntohs(*((WebRtc_UWord16*) temp_packet)),
+                                   out_file) !=
+                            ntohs(*((WebRtc_UWord16*) temp_packet))) {
+                          return -1;
+                        }
+		}
+	}
+
+
+closing:
+	free(time_vec);
+	free(rtp_vec);
+	fclose(in_file);
+	fclose(dat_file);
+	fclose(out_file);
+
+	return(0);
+}
+
+
+
+int compare_arr_time(const void *xp, const void *yp) {
+
+	if(((arr_time *)xp)->time == ((arr_time *)yp)->time)
+		return(0);
+	else if(((arr_time *)xp)->time > ((arr_time *)yp)->time)
+		return(1);
+
+	return(-1);
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/RTPtimeshift.cc b/webrtc/modules/audio_coding/neteq4/test/RTPtimeshift.cc
new file mode 100644
index 0000000..dc7ff9f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/RTPtimeshift.cc
@@ -0,0 +1,97 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <algorithm>
+#include <stdio.h>
+#include <vector>
+
+#include "NETEQTEST_RTPpacket.h"
+#include "gtest/gtest.h"
+
+/*********************/
+/* Misc. definitions */
+/*********************/
+
+#define FIRSTLINELEN 40
+
+
+int main(int argc, char* argv[])
+{
+    if(argc < 4 || argc > 6)
+    {
+        printf("Usage: RTPtimeshift in.rtp out.rtp newStartTS [newStartSN [newStartArrTime]]\n");
+        exit(1);
+    }
+
+	FILE *inFile=fopen(argv[1],"rb");
+	if (!inFile)
+    {
+        printf("Cannot open input file %s\n", argv[1]);
+        return(-1);
+    }
+    printf("Input RTP file: %s\n",argv[1]);
+
+	FILE *outFile=fopen(argv[2],"wb");
+	if (!outFile)
+    {
+        printf("Cannot open output file %s\n", argv[2]);
+        return(-1);
+    }
+	printf("Output RTP file: %s\n\n",argv[2]);
+
+    // read file header and write directly to output file
+	const unsigned int kRtpDumpHeaderSize = 4 + 4 + 4 + 2 + 2;
+	char firstline[FIRSTLINELEN];
+	EXPECT_TRUE(fgets(firstline, FIRSTLINELEN, inFile) != NULL);
+	EXPECT_GT(fputs(firstline, outFile), 0);
+	EXPECT_EQ(kRtpDumpHeaderSize,
+	          fread(firstline, 1, kRtpDumpHeaderSize, inFile));
+	EXPECT_EQ(kRtpDumpHeaderSize,
+	          fwrite(firstline, 1, kRtpDumpHeaderSize, outFile));
+	NETEQTEST_RTPpacket packet;
+	int packLen = packet.readFromFile(inFile);
+	if (packLen < 0)
+	{
+	    exit(1);
+	}
+
+    // get new start TS and start SeqNo from arguments
+	WebRtc_UWord32 TSdiff = atoi(argv[3]) - packet.timeStamp();
+	WebRtc_UWord16 SNdiff = 0;
+	WebRtc_UWord32 ATdiff = 0;
+    if (argc > 4)
+    {
+        if (argv[4] >= 0)
+            SNdiff = atoi(argv[4]) - packet.sequenceNumber();
+        if (argc > 5)
+        {
+            if (argv[5] >= 0)
+                ATdiff = atoi(argv[5]) - packet.time();
+        }
+    }
+
+    while (packLen >= 0)
+    {
+        
+        packet.setTimeStamp(packet.timeStamp() + TSdiff);
+        packet.setSequenceNumber(packet.sequenceNumber() + SNdiff);
+        packet.setTime(packet.time() + ATdiff);
+
+        packet.writeToFile(outFile);
+
+        packLen = packet.readFromFile(inFile);
+
+    }
+
+    fclose(inFile);
+    fclose(outFile);
+
+    return 0;
+}
diff --git a/webrtc/modules/audio_coding/neteq4/test/delay_tool/parse_delay_file.m b/webrtc/modules/audio_coding/neteq4/test/delay_tool/parse_delay_file.m
new file mode 100644
index 0000000..77b394f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/delay_tool/parse_delay_file.m
@@ -0,0 +1,191 @@
+function outStruct = parse_delay_file(file)
+
+fid = fopen(file, 'rb');
+if fid == -1
+    error('Cannot open file %s', file);
+end
+
+textline = fgetl(fid);
+if ~strncmp(textline, '#!NetEQ_Delay_Logging', 21)
+    error('Wrong file format');
+end
+
+ver = sscanf(textline, '#!NetEQ_Delay_Logging%d.%d');
+if ~all(ver == [2; 0])
+    error('Wrong version of delay logging function')
+end
+
+
+start_pos = ftell(fid);
+fseek(fid, -12, 'eof');
+textline = fgetl(fid);
+if ~strncmp(textline, 'End of file', 21)
+    error('File ending is not correct. Seems like the simulation ended abnormally.');
+end
+
+fseek(fid,-12-4, 'eof');
+Npackets = fread(fid, 1, 'int32');
+fseek(fid, start_pos, 'bof');
+
+rtpts = zeros(Npackets, 1);
+seqno = zeros(Npackets, 1);
+pt = zeros(Npackets, 1);
+plen = zeros(Npackets, 1);
+recin_t = nan*ones(Npackets, 1);
+decode_t = nan*ones(Npackets, 1);
+playout_delay = zeros(Npackets, 1);
+optbuf = zeros(Npackets, 1);
+
+fs_ix = 1;
+clock = 0;
+ts_ix = 1;
+ended = 0;
+late_packets = 0;
+fs_now = 8000;
+last_decode_k = 0;
+tot_expand = 0;
+tot_accelerate = 0;
+tot_preemptive = 0;
+
+while not(ended)
+    signal = fread(fid, 1, '*int32');
+    
+    switch signal
+        case 3 % NETEQ_DELAY_LOGGING_SIGNAL_CLOCK
+            clock = fread(fid, 1, '*float32');
+            
+            % keep on reading batches of M until the signal is no longer "3"
+            % read int32 + float32 in one go
+            % this is to save execution time
+            temp = [3; 0];
+            M = 120;
+            while all(temp(1,:) == 3)
+                fp = ftell(fid);
+                temp = fread(fid, [2 M], '*int32');
+            end
+            
+            % back up to last clock event
+            fseek(fid, fp - ftell(fid) + ...
+                (find(temp(1,:) ~= 3, 1 ) - 2) * 2 * 4 + 4, 'cof');
+            % read the last clock value
+            clock = fread(fid, 1, '*float32');
+            
+        case 1 % NETEQ_DELAY_LOGGING_SIGNAL_RECIN
+            temp_ts = fread(fid, 1, 'uint32');
+            
+            if late_packets > 0
+                temp_ix = ts_ix - 1;
+                while (temp_ix >= 1) && (rtpts(temp_ix) ~= temp_ts)
+                    % TODO(hlundin): use matlab vector search instead?
+                    temp_ix = temp_ix - 1;
+                end
+                
+                if temp_ix >= 1
+                    % the ts was found in the vector
+                    late_packets = late_packets - 1;
+                else
+                    temp_ix = ts_ix;
+                    ts_ix = ts_ix + 1;
+                end
+            else
+                temp_ix = ts_ix;
+                ts_ix = ts_ix + 1;
+            end
+            
+            rtpts(temp_ix) = temp_ts;
+            seqno(temp_ix) = fread(fid, 1, 'uint16');
+            pt(temp_ix) = fread(fid, 1, 'int32');
+            plen(temp_ix) = fread(fid, 1, 'int16');
+            recin_t(temp_ix) = clock;
+            
+        case 2 % NETEQ_DELAY_LOGGING_SIGNAL_FLUSH
+            % do nothing
+            
+        case 4 % NETEQ_DELAY_LOGGING_SIGNAL_EOF
+            ended = 1;
+            
+        case 5 % NETEQ_DELAY_LOGGING_SIGNAL_DECODE
+            last_decode_ts = fread(fid, 1, 'uint32');
+            temp_delay = fread(fid, 1, 'uint16');
+            
+            k = find(rtpts(1:(ts_ix - 1))==last_decode_ts,1,'last');
+            if ~isempty(k)
+                decode_t(k) = clock;
+                playout_delay(k) = temp_delay + ...
+                    5 *  fs_now / 8000; % add overlap length
+                last_decode_k = k;
+            end
+            
+        case 6 % NETEQ_DELAY_LOGGING_SIGNAL_CHANGE_FS
+            fsvec(fs_ix) = fread(fid, 1, 'uint16');
+            fschange_ts(fs_ix) = last_decode_ts;
+            fs_now = fsvec(fs_ix);
+            fs_ix = fs_ix + 1;
+            
+        case 7 % NETEQ_DELAY_LOGGING_SIGNAL_MERGE_INFO
+            playout_delay(last_decode_k) = playout_delay(last_decode_k) ...
+                + fread(fid, 1, 'int32');
+            
+        case 8 % NETEQ_DELAY_LOGGING_SIGNAL_EXPAND_INFO
+            temp = fread(fid, 1, 'int32');
+            if last_decode_k ~= 0
+                tot_expand = tot_expand + temp / (fs_now / 1000);
+            end                
+            
+        case 9 % NETEQ_DELAY_LOGGING_SIGNAL_ACCELERATE_INFO
+            temp = fread(fid, 1, 'int32');
+            if last_decode_k ~= 0
+                tot_accelerate = tot_accelerate + temp / (fs_now / 1000);
+            end                
+
+        case 10 % NETEQ_DELAY_LOGGING_SIGNAL_PREEMPTIVE_INFO
+            temp = fread(fid, 1, 'int32');
+            if last_decode_k ~= 0
+                tot_preemptive = tot_preemptive + temp / (fs_now / 1000);
+            end                
+            
+        case 11 % NETEQ_DELAY_LOGGING_SIGNAL_OPTBUF
+            optbuf(last_decode_k) = fread(fid, 1, 'int32');
+            
+        case 12 % NETEQ_DELAY_LOGGING_SIGNAL_DECODE_ONE_DESC
+            last_decode_ts = fread(fid, 1, 'uint32');
+            k = ts_ix - 1;
+            
+            while (k >= 1) && (rtpts(k) ~= last_decode_ts)
+                % TODO(hlundin): use matlab vector search instead?
+                k = k - 1;
+            end
+            
+            if k < 1
+                % packet not received yet
+                k = ts_ix;
+                rtpts(ts_ix) = last_decode_ts;
+                late_packets = late_packets + 1;
+            end
+            
+            decode_t(k) = clock;
+            playout_delay(k) = fread(fid, 1, 'uint16') + ...
+                5 *  fs_now / 8000; % add overlap length
+            last_decode_k = k;
+             
+    end
+    
+end
+
+
+fclose(fid);
+
+outStruct = struct(...
+    'ts', rtpts, ...
+    'sn', seqno, ...
+    'pt', pt,...
+    'plen', plen,...
+    'arrival', recin_t,...
+    'decode', decode_t,...
+    'fs', fsvec(:),...
+    'fschange_ts', fschange_ts(:),...
+    'playout_delay', playout_delay,...
+    'tot_expand', tot_expand,...
+    'tot_accelerate', tot_accelerate,...
+    'tot_preemptive', tot_preemptive,...
+    'optbuf', optbuf);
diff --git a/webrtc/modules/audio_coding/neteq4/test/delay_tool/plot_neteq_delay.m b/webrtc/modules/audio_coding/neteq4/test/delay_tool/plot_neteq_delay.m
new file mode 100644
index 0000000..bc1c85a
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/delay_tool/plot_neteq_delay.m
@@ -0,0 +1,187 @@
+function [delay_struct, delayvalues] = plot_neteq_delay(delayfile, varargin)
+
+% InfoStruct = plot_neteq_delay(delayfile)
+% InfoStruct = plot_neteq_delay(delayfile, 'skipdelay', skip_seconds)
+%
+% Henrik Lundin, 2006-11-17
+% Henrik Lundin, 2011-05-17
+%
+
+try
+    s = parse_delay_file(delayfile);
+catch
+    error(lasterr);
+end
+
+delayskip=0;
+noplot=0;
+arg_ptr=1;
+delaypoints=[];
+
+s.sn=unwrap_seqno(s.sn);
+
+while arg_ptr+1 <= nargin
+    switch lower(varargin{arg_ptr})
+    case {'skipdelay', 'delayskip'}
+        % skip a number of seconds in the beginning when calculating delays
+        delayskip = varargin{arg_ptr+1};
+        arg_ptr = arg_ptr + 2;
+    case 'noplot'
+        noplot=1;
+        arg_ptr = arg_ptr + 1;
+    case {'get_delay', 'getdelay'}
+        % return a vector of delay values for the points in the given vector
+        delaypoints = varargin{arg_ptr+1};
+        arg_ptr = arg_ptr + 2;
+    otherwise
+        warning('Unknown switch %s\n', varargin{arg_ptr});
+        arg_ptr = arg_ptr + 1;
+    end
+end
+
+% find lost frames that were covered by one-descriptor decoding
+one_desc_ix=find(isnan(s.arrival));
+for k=1:length(one_desc_ix)
+    ix=find(s.ts==max(s.ts(s.ts(one_desc_ix(k))>s.ts)));
+    s.sn(one_desc_ix(k))=s.sn(ix)+1;
+    s.pt(one_desc_ix(k))=s.pt(ix);
+    s.arrival(one_desc_ix(k))=s.arrival(ix)+s.decode(one_desc_ix(k))-s.decode(ix);
+end
+
+% remove duplicate received frames that were never decoded (RED codec)
+if length(unique(s.ts(isfinite(s.ts)))) < length(s.ts(isfinite(s.ts)))
+    ix=find(isfinite(s.decode));
+    s.sn=s.sn(ix);
+    s.ts=s.ts(ix);
+    s.arrival=s.arrival(ix);
+    s.playout_delay=s.playout_delay(ix);
+    s.pt=s.pt(ix);
+    s.optbuf=s.optbuf(ix);
+    plen=plen(ix);
+    s.decode=s.decode(ix);
+end
+
+% find non-unique sequence numbers
+[~,un_ix]=unique(s.sn);
+nonun_ix=setdiff(1:length(s.sn),un_ix);
+if ~isempty(nonun_ix)
+    warning('RTP sequence numbers are in error');
+end
+            
+% sort vectors
+[s.sn,sort_ix]=sort(s.sn);
+s.ts=s.ts(sort_ix);
+s.arrival=s.arrival(sort_ix);
+s.decode=s.decode(sort_ix);
+s.playout_delay=s.playout_delay(sort_ix);
+s.pt=s.pt(sort_ix);
+
+send_t=s.ts-s.ts(1);
+if length(s.fs)<1
+    warning('No info about sample rate found in file. Using default 8000.');
+    s.fs(1)=8000;
+    s.fschange_ts(1)=min(s.ts);
+elseif s.fschange_ts(1)>min(s.ts)
+    s.fschange_ts(1)=min(s.ts);
+end
+
+end_ix=length(send_t);
+for k=length(s.fs):-1:1
+    start_ix=find(s.ts==s.fschange_ts(k));
+    send_t(start_ix:end_ix)=send_t(start_ix:end_ix)/s.fs(k)*1000;
+    s.playout_delay(start_ix:end_ix)=s.playout_delay(start_ix:end_ix)/s.fs(k)*1000;
+    s.optbuf(start_ix:end_ix)=s.optbuf(start_ix:end_ix)/s.fs(k)*1000;
+    end_ix=start_ix-1;
+end
+
+tot_time=max(send_t)-min(send_t);
+
+seq_ix=s.sn-min(s.sn)+1;
+send_t=send_t+max(min(s.arrival-send_t),0);
+
+plot_send_t=nan*ones(max(seq_ix),1);
+plot_send_t(seq_ix)=send_t;
+plot_nw_delay=nan*ones(max(seq_ix),1);
+plot_nw_delay(seq_ix)=s.arrival-send_t;
+
+cng_ix=find(s.pt~=13); % find those packets that are not CNG/SID
+    
+if noplot==0
+    h=plot(plot_send_t/1000,plot_nw_delay);
+    set(h,'color',0.75*[1 1 1]);
+    hold on
+    if any(s.optbuf~=0)
+        peak_ix=find(s.optbuf(cng_ix)<0); % peak mode is labeled with negative values
+        no_peak_ix=find(s.optbuf(cng_ix)>0); %setdiff(1:length(cng_ix),peak_ix);
+        h1=plot(send_t(cng_ix(peak_ix))/1000,...
+            s.arrival(cng_ix(peak_ix))+abs(s.optbuf(cng_ix(peak_ix)))-send_t(cng_ix(peak_ix)),...
+            'r.');
+        h2=plot(send_t(cng_ix(no_peak_ix))/1000,...
+            s.arrival(cng_ix(no_peak_ix))+abs(s.optbuf(cng_ix(no_peak_ix)))-send_t(cng_ix(no_peak_ix)),...
+            'g.');
+        set([h1, h2],'markersize',1)
+    end
+    %h=plot(send_t(seq_ix)/1000,s.decode+s.playout_delay-send_t(seq_ix));
+    h=plot(send_t(cng_ix)/1000,s.decode(cng_ix)+s.playout_delay(cng_ix)-send_t(cng_ix));
+    set(h,'linew',1.5);
+    hold off
+    ax1=axis;
+    axis tight
+    ax2=axis;
+    axis([ax2(1:3) ax1(4)])
+end
+
+
+% calculate delays and other parameters
+
+delayskip_ix = find(send_t-send_t(1)>=delayskip*1000, 1 );
+
+use_ix = intersect(cng_ix,... % use those that are not CNG/SID frames...
+    intersect(find(isfinite(s.decode)),... % ... that did arrive ...
+    (delayskip_ix:length(s.decode))')); % ... and are sent after delayskip seconds
+
+mean_delay = mean(s.decode(use_ix)+s.playout_delay(use_ix)-send_t(use_ix));
+neteq_delay = mean(s.decode(use_ix)+s.playout_delay(use_ix)-s.arrival(use_ix));
+
+Npack=max(s.sn(delayskip_ix:end))-min(s.sn(delayskip_ix:end))+1;
+nw_lossrate=(Npack-length(s.sn(delayskip_ix:end)))/Npack;
+neteq_lossrate=(length(s.sn(delayskip_ix:end))-length(use_ix))/Npack;
+
+delay_struct=struct('mean_delay',mean_delay,'neteq_delay',neteq_delay,...
+    'nw_lossrate',nw_lossrate,'neteq_lossrate',neteq_lossrate,...
+    'tot_expand',round(s.tot_expand),'tot_accelerate',round(s.tot_accelerate),...
+    'tot_preemptive',round(s.tot_preemptive),'tot_time',tot_time,...
+    'filename',delayfile,'units','ms','fs',unique(s.fs));
+    
+if not(isempty(delaypoints))
+    delayvalues=interp1(send_t(cng_ix),...
+        s.decode(cng_ix)+s.playout_delay(cng_ix)-send_t(cng_ix),...
+        delaypoints,'nearest',NaN);
+else
+    delayvalues=[];
+end
+
+
+
+% SUBFUNCTIONS %
+
+function y=unwrap_seqno(x)
+
+jumps=find(abs((diff(x)-1))>65000);
+
+while ~isempty(jumps)
+    n=jumps(1);
+    if x(n+1)-x(n) < 0
+        % negative jump
+        x(n+1:end)=x(n+1:end)+65536;
+    else
+        % positive jump
+        x(n+1:end)=x(n+1:end)-65536;
+    end
+    
+    jumps=find(abs((diff(x(n+1:end))-1))>65000);
+end
+
+y=x;
+
+return;
diff --git a/webrtc/modules/audio_coding/neteq4/test/rtp_to_text.cc b/webrtc/modules/audio_coding/neteq4/test/rtp_to_text.cc
new file mode 100644
index 0000000..1112d79
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/test/rtp_to_text.cc
@@ -0,0 +1,124 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/*
+ * Parses an rtpdump file and outputs a text table parsable by parseLog.m.
+ * The output file will have .txt appended to the specified base name.
+ * $ rtp_to_text [-d] <input_rtp_file> <output_base_name>
+ *
+ * -d   RTP headers only
+ *
+ */
+
+#include "data_log.h"
+#include "NETEQTEST_DummyRTPpacket.h"
+#include "NETEQTEST_RTPpacket.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+/*********************/
+/* Misc. definitions */
+/*********************/
+
+#define FIRSTLINELEN 40
+
+using ::webrtc::DataLog;
+
+int main(int argc, char* argv[])
+{
+    int arg_count = 1;
+    NETEQTEST_RTPpacket* packet;
+
+    if (argc < 3)
+    {
+      printf("Usage: %s [-d] <input_rtp_file> <output_base_name>\n", argv[0]);
+      return -1;
+    }
+
+    // Parse dummy option
+    if (argc >= 3 && strcmp(argv[arg_count], "-d") == 0)
+    {
+        packet = new NETEQTEST_DummyRTPpacket;
+        ++arg_count;
+    }
+    else
+    {
+        packet = new NETEQTEST_RTPpacket;
+    }
+
+    std::string input_filename = argv[arg_count++];
+    std::string table_name = argv[arg_count];
+
+    std::cout << "Input file: " << input_filename << std::endl;
+    std::cout << "Output file: " << table_name << ".txt" << std::endl;
+
+    FILE *inFile=fopen(input_filename.c_str(),"rb");
+    if (!inFile)
+    {
+        std::cout << "Cannot open input file " << input_filename << std::endl;
+        return -1;
+    }
+
+    // Set up the DataLog and define the table
+    DataLog::CreateLog();
+    if (DataLog::AddTable(table_name) < 0)
+    {
+        std::cout << "Error adding table " << table_name << ".txt" << std::endl;
+        return -1;
+    }
+
+    DataLog::AddColumn(table_name, "seq", 1);
+    DataLog::AddColumn(table_name, "ssrc", 1);
+    DataLog::AddColumn(table_name, "payload type", 1);
+    DataLog::AddColumn(table_name, "length", 1);
+    DataLog::AddColumn(table_name, "timestamp", 1);
+    DataLog::AddColumn(table_name, "marker bit", 1);
+    DataLog::AddColumn(table_name, "arrival", 1);
+
+    // read file header
+    char firstline[FIRSTLINELEN];
+    if (fgets(firstline, FIRSTLINELEN, inFile) == NULL)
+    {
+        std::cout << "Error reading file " << input_filename << std::endl;
+        return -1;
+    }
+
+    // start_sec + start_usec + source + port + padding
+    if (fread(firstline, 4+4+4+2+2, 1, inFile) != 1)
+    {
+        std::cout << "Error reading file " << input_filename << std::endl;
+        return -1;
+    }
+
+    while (packet->readFromFile(inFile) >= 0)
+    {
+        // write packet headers to
+        DataLog::InsertCell(table_name, "seq", packet->sequenceNumber());
+        DataLog::InsertCell(table_name, "ssrc", packet->SSRC());
+        DataLog::InsertCell(table_name, "payload type", packet->payloadType());
+        DataLog::InsertCell(table_name, "length", packet->dataLen());
+        DataLog::InsertCell(table_name, "timestamp", packet->timeStamp());
+        DataLog::InsertCell(table_name, "marker bit", packet->markerBit());
+        DataLog::InsertCell(table_name, "arrival", packet->time());
+        DataLog::NextRow(table_name);
+        return -1;
+    }
+
+    DataLog::ReturnLog();
+
+    fclose(inFile);
+
+    return 0;
+}
diff --git a/webrtc/modules/audio_coding/neteq4/time_stretch.cc b/webrtc/modules/audio_coding/neteq4/time_stretch.cc
new file mode 100644
index 0000000..7b63ac3
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/time_stretch.cc
@@ -0,0 +1,217 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/time_stretch.h"
+
+#include <algorithm>  // min, max
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+#include "webrtc/modules/audio_coding/neteq4/dsp_helper.h"
+#include "webrtc/system_wrappers/interface/scoped_ptr.h"
+
+namespace webrtc {
+
+TimeStretch::ReturnCodes TimeStretch::Process(
+    const int16_t* input,
+    size_t input_len,
+    AudioMultiVector<int16_t>* output,
+    int16_t* length_change_samples) {
+
+  // Pre-calculate common multiplication with |fs_mult_|.
+  int fs_mult_120 = fs_mult_ * 120;  // Corresponds to 15 ms.
+
+  const int16_t* signal;
+  scoped_array<int16_t> signal_array;
+  size_t signal_len;
+  if (num_channels_ == 1) {
+    signal = input;
+    signal_len = input_len;
+  } else {
+    // We want |signal| to be only the first channel of |input|, which is
+    // interleaved. Thus, we take the first sample, skip forward |num_channels|
+    // samples, and continue like that.
+    signal_len = input_len / num_channels_;
+    signal_array.reset(new int16_t[signal_len]);
+    signal = signal_array.get();
+    size_t j = master_channel_;
+    for (size_t i = 0; i < signal_len; ++i) {
+      signal_array[i] = input[j];
+      j += num_channels_;
+    }
+  }
+
+  // Find maximum absolute value of input signal.
+  max_input_value_ = WebRtcSpl_MaxAbsValueW16(signal, signal_len);
+
+  // Downsample to 4 kHz sample rate and calculate auto-correlation.
+  DspHelper::DownsampleTo4kHz(signal, signal_len, kDownsampledLen,
+                              sample_rate_hz_, true /* compensate delay*/,
+                              downsampled_input_);
+  AutoCorrelation();
+
+  // Find the strongest correlation peak.
+  static const int kNumPeaks = 1;
+  int peak_index;
+  int16_t peak_value;
+  DspHelper::PeakDetection(auto_correlation_, kCorrelationLen, kNumPeaks,
+                           fs_mult_, &peak_index, &peak_value);
+  // Assert that |peak_index| stays within boundaries.
+  assert(peak_index >= 0);
+  assert(peak_index <= (2 * kCorrelationLen - 1) * fs_mult_);
+
+  // Compensate peak_index for displaced starting position. The displacement
+  // happens in AutoCorrelation(). Here, |kMinLag| is in the down-sampled 4 kHz
+  // domain, while the |peak_index| is in the original sample rate; hence, the
+  // multiplication by fs_mult_ * 2.
+  peak_index += kMinLag * fs_mult_ * 2;
+  // Assert that |peak_index| stays within boundaries.
+  assert(peak_index >= 20 * fs_mult_);
+  assert(peak_index <= 20 * fs_mult_ + (2 * kCorrelationLen - 1) * fs_mult_);
+
+  // Calculate scaling to ensure that |peak_index| samples can be square-summed
+  // without overflowing.
+  int scaling = 31 - WebRtcSpl_NormW32(max_input_value_ * max_input_value_) -
+      WebRtcSpl_NormW32(peak_index);
+  scaling = std::max(0, scaling);
+
+  // |vec1| starts at 15 ms minus one pitch period.
+  const int16_t* vec1 = &signal[fs_mult_120 - peak_index];
+  // |vec2| start at 15 ms.
+  const int16_t* vec2 = &signal[fs_mult_120];
+  // Calculate energies for |vec1| and |vec2|, assuming they both contain
+  // |peak_index| samples.
+  int32_t vec1_energy =
+      WebRtcSpl_DotProductWithScale(vec1, vec1, peak_index, scaling);
+  int32_t vec2_energy =
+      WebRtcSpl_DotProductWithScale(vec2, vec2, peak_index, scaling);
+
+  // Calculate cross-correlation between |vec1| and |vec2|.
+  int32_t cross_corr =
+      WebRtcSpl_DotProductWithScale(vec1, vec2, peak_index, scaling);
+
+  // Check if the signal seems to be active speech or not (simple VAD).
+  bool active_speech = SpeechDetection(vec1_energy, vec2_energy, peak_index,
+                                       scaling);
+
+  int16_t best_correlation;
+  if (!active_speech) {
+    SetParametersForPassiveSpeech(signal_len, &best_correlation, &peak_index);
+  } else {
+    // Calculate correlation:
+    // cross_corr / sqrt(vec1_energy * vec2_energy).
+
+    // Start with calculating scale values.
+    int energy1_scale = std::max(0, 16 - WebRtcSpl_NormW32(vec1_energy));
+    int energy2_scale = std::max(0, 16 - WebRtcSpl_NormW32(vec2_energy));
+
+    // Make sure total scaling is even (to simplify scale factor after sqrt).
+    if ((energy1_scale + energy2_scale) & 1) {
+      // The sum is odd.
+      energy1_scale += 1;
+    }
+
+    // Scale energies to int16_t.
+    int16_t vec1_energy_int16 =
+        static_cast<int16_t>(vec1_energy >> energy1_scale);
+    int16_t vec2_energy_int16 =
+        static_cast<int16_t>(vec2_energy >> energy2_scale);
+
+    // Calculate square-root of energy product.
+    int16_t sqrt_energy_prod = WebRtcSpl_SqrtFloor(vec1_energy_int16 *
+                                                   vec2_energy_int16);
+
+    // Calculate cross_corr / sqrt(en1*en2) in Q14.
+    int temp_scale = 14 - (energy1_scale + energy2_scale) / 2;
+    cross_corr = WEBRTC_SPL_SHIFT_W32(cross_corr, temp_scale);
+    cross_corr = std::max(0, cross_corr);  // Don't use if negative.
+    best_correlation = WebRtcSpl_DivW32W16(cross_corr, sqrt_energy_prod);
+    // Make sure |best_correlation| is no larger than 1 in Q14.
+    best_correlation = std::min(static_cast<int16_t>(16384), best_correlation);
+  }
+
+
+  // Check accelerate criteria and stretch the signal.
+  ReturnCodes return_value = CheckCriteriaAndStretch(input, input_len,
+                                                     peak_index,
+                                                     best_correlation,
+                                                     active_speech, output);
+  switch (return_value) {
+    case kSuccess:
+      *length_change_samples = peak_index;
+      break;
+    case kSuccessLowEnergy:
+      *length_change_samples = peak_index;
+      break;
+    case kNoStretch:
+    case kError:
+      *length_change_samples = 0;
+      break;
+  }
+  return return_value;
+}
+
+void TimeStretch::AutoCorrelation() {
+  // Set scaling factor for cross correlation to protect against overflow.
+  int scaling = kLogCorrelationLen - WebRtcSpl_NormW32(
+      max_input_value_ * max_input_value_);
+  scaling = std::max(0, scaling);
+
+  // Calculate correlation from lag kMinLag to lag kMaxLag in 4 kHz domain.
+  int32_t auto_corr[kCorrelationLen];
+  WebRtcSpl_CrossCorrelation(auto_corr, &downsampled_input_[kMaxLag],
+                             &downsampled_input_[kMaxLag - kMinLag],
+                             kCorrelationLen, kMaxLag - kMinLag, scaling, -1);
+
+  // Normalize correlation to 14 bits and write to |auto_correlation_|.
+  int32_t max_corr = WebRtcSpl_MaxAbsValueW32(auto_corr, kCorrelationLen);
+  scaling = std::max(0, 17 - WebRtcSpl_NormW32(max_corr));
+  WebRtcSpl_VectorBitShiftW32ToW16(auto_correlation_, kCorrelationLen,
+                                   auto_corr, scaling);
+}
+
+bool TimeStretch::SpeechDetection(int32_t vec1_energy, int32_t vec2_energy,
+                                  int peak_index, int scaling) const {
+  // Check if the signal seems to be active speech or not (simple VAD).
+  // If (vec1_energy + vec2_energy) / (2 * peak_index) <=
+  // 8 * background_noise_energy, then we say that the signal contains no
+  // active speech.
+  // Rewrite the inequality as:
+  // (vec1_energy + vec2_energy) / 16 <= peak_index * background_noise_energy.
+  // The two sides of the inequality will be denoted |left_side| and
+  // |right_side|.
+  int32_t left_side = (vec1_energy + vec2_energy) / 16;
+  int32_t right_side;
+  if (background_noise_.initialized()) {
+    right_side = background_noise_.Energy(master_channel_);
+  } else {
+    // If noise parameters have not been estimated, use a fixed threshold.
+    right_side = 75000;
+  }
+  int right_scale = 16 - WebRtcSpl_NormW32(right_side);
+  right_scale = std::max(0, right_scale);
+  left_side = left_side >> right_scale;
+  right_side = peak_index * (right_side >> right_scale);
+
+  // Scale |left_side| properly before comparing with |right_side|.
+  // (|scaling| is the scale factor before energy calculation, thus the scale
+  // factor for the energy is 2 * scaling.)
+  if (WebRtcSpl_NormW32(left_side) < 2 * scaling) {
+    // Cannot scale only |left_side|, must scale |right_side| too.
+    int temp_scale = WebRtcSpl_NormW32(left_side);
+    left_side = left_side << temp_scale;
+    right_side = right_side >> (2 * scaling - temp_scale);
+  } else {
+    left_side = left_side << 2 * scaling;
+  }
+  return left_side > right_side;
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/time_stretch.h b/webrtc/modules/audio_coding/neteq4/time_stretch.h
new file mode 100644
index 0000000..e701e26
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/time_stretch.h
@@ -0,0 +1,112 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TIME_STRETCH_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TIME_STRETCH_H_
+
+#include <assert.h>
+
+#include <cstring>  // memset, size_t
+
+#include "webrtc/modules/audio_coding/neteq4/audio_multi_vector.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declarations.
+class BackgroundNoise;
+
+// This is the base class for Accelerate and PreemptiveExpand. This class
+// cannot be instantiated, but must be used through either of the derived
+// classes.
+class TimeStretch {
+ public:
+  enum ReturnCodes {
+    kSuccess = 0,
+    kSuccessLowEnergy = 1,
+    kNoStretch = 2,
+    kError = -1
+  };
+
+  TimeStretch(int sample_rate_hz, size_t num_channels,
+              const BackgroundNoise& background_noise)
+      : sample_rate_hz_(sample_rate_hz),
+        fs_mult_(sample_rate_hz / 8000),
+        num_channels_(num_channels),
+        master_channel_(0),  // First channel is master.
+        background_noise_(background_noise),
+        max_input_value_(0) {
+    assert(sample_rate_hz_ == 8000 ||
+           sample_rate_hz_ == 16000 ||
+           sample_rate_hz_ == 32000 ||
+           sample_rate_hz_ == 48000);
+    assert(num_channels_ > 0);
+    assert(static_cast<int>(master_channel_) < num_channels_);
+    memset(auto_correlation_, 0, sizeof(auto_correlation_));
+  }
+
+  virtual ~TimeStretch() {}
+
+  // This method performs the processing common to both Accelerate and
+  // PreemptiveExpand.
+  ReturnCodes Process(const int16_t* input,
+                      size_t input_len,
+                      AudioMultiVector<int16_t>* output,
+                      int16_t* length_change_samples);
+
+ protected:
+  // Sets the parameters |best_correlation| and |peak_index| to suitable
+  // values when the signal contains no active speech. This method must be
+  // implemented by the sub-classes.
+  virtual void SetParametersForPassiveSpeech(int input_length,
+                                             int16_t* best_correlation,
+                                             int* peak_index) const = 0;
+
+  // Checks the criteria for performing the time-stretching operation and,
+  // if possible, performs the time-stretching. This method must be implemented
+  // by the sub-classes.
+  virtual ReturnCodes CheckCriteriaAndStretch(
+      const int16_t* input, int input_length, size_t peak_index,
+      int16_t best_correlation, bool active_speech,
+      AudioMultiVector<int16_t>* output) const = 0;
+
+  static const int kCorrelationLen = 50;
+  static const int kLogCorrelationLen = 6;  // >= log2(kCorrelationLen).
+  static const int kMinLag = 10;
+  static const int kMaxLag = 60;
+  static const int kDownsampledLen = kCorrelationLen + kMaxLag;
+  static const int kCorrelationThreshold = 14746;  // 0.9 in Q14.
+
+  const int sample_rate_hz_;
+  const int fs_mult_;  // Sample rate multiplier = sample_rate_hz_ / 8000.
+  const int num_channels_;
+  const size_t master_channel_;
+  const BackgroundNoise& background_noise_;
+  int16_t max_input_value_;
+  int16_t downsampled_input_[kDownsampledLen];
+  // Adding 1 to the size of |auto_correlation_| because of how it is used
+  // by the peak-detection algorithm.
+  int16_t auto_correlation_[kCorrelationLen + 1];
+
+ private:
+  // Calculates the auto-correlation of |downsampled_input_| and writes the
+  // result to |auto_correlation_|.
+  void AutoCorrelation();
+
+  // Performs a simple voice-activity detection based on the input parameters.
+  bool SpeechDetection(int32_t vec1_energy, int32_t vec2_energy,
+                       int peak_index, int scaling) const;
+
+  DISALLOW_COPY_AND_ASSIGN(TimeStretch);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TIME_STRETCH_H_
diff --git a/webrtc/modules/audio_coding/neteq4/time_stretch_unittest.cc b/webrtc/modules/audio_coding/neteq4/time_stretch_unittest.cc
new file mode 100644
index 0000000..cf8131f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/time_stretch_unittest.cc
@@ -0,0 +1,31 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Unit tests for Accelerate and PreemptiveExpand classes.
+
+#include "webrtc/modules/audio_coding/neteq4/accelerate.h"
+#include "webrtc/modules/audio_coding/neteq4/preemptive_expand.h"
+
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/background_noise.h"
+
+namespace webrtc {
+
+TEST(TimeStretch, CreateAndDestroy) {
+  int sample_rate = 8000;
+  size_t num_channels = 1;
+  BackgroundNoise bgn(num_channels);
+  Accelerate accelerate(sample_rate, num_channels, bgn);
+  PreemptiveExpand preemptive_expand(sample_rate, num_channels, bgn);
+}
+
+// TODO(hlundin): Write more tests.
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/timestamp_scaler.cc b/webrtc/modules/audio_coding/neteq4/timestamp_scaler.cc
new file mode 100644
index 0000000..6bb22d5
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/timestamp_scaler.cc
@@ -0,0 +1,109 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/timestamp_scaler.h"
+
+#include "webrtc/modules/audio_coding/neteq4/decoder_database.h"
+#include "webrtc/system_wrappers/interface/logging.h"
+
+namespace webrtc {
+
+void TimestampScaler::ToInternal(Packet* packet) {
+  if (!packet) {
+    return;
+  }
+  packet->header.timestamp = ToInternal(packet->header.timestamp,
+                                        packet->header.payloadType);
+}
+
+void TimestampScaler::ToInternal(PacketList* packet_list) {
+  PacketList::iterator it;
+  for (it = packet_list->begin(); it != packet_list->end(); ++it) {
+    ToInternal(*it);
+  }
+}
+
+uint32_t TimestampScaler::ToInternal(uint32_t external_timestamp,
+                                     uint8_t rtp_payload_type) {
+  const DecoderDatabase::DecoderInfo* info =
+      decoder_database_.GetDecoderInfo(rtp_payload_type);
+  if (!info) {
+    // Payload type is unknown. Do not scale.
+    return external_timestamp;
+  }
+  switch (info->codec_type) {
+    case kDecoderG722:
+    case kDecoderG722_2ch: {
+      // Use timestamp scaling with factor 2 (two output samples per RTP
+      // timestamp).
+      numerator_ = 2;
+      denominator_ = 1;
+      break;
+    }
+    case kDecoderOpus:
+    case kDecoderOpus_2ch:
+    case kDecoderCNGswb48kHz: {
+      // Use timestamp scaling with factor 2/3 (32 kHz sample rate, but RTP
+      // timestamps run on 48 kHz).
+      // TODO(tlegrand): Remove scaling for kDecoderCNGswb48kHz once ACM has
+      // full 48 kHz support.
+      numerator_ = 2;
+      denominator_ = 3;
+    }
+    case kDecoderAVT:
+    case kDecoderCNGnb:
+    case kDecoderCNGwb:
+    case kDecoderCNGswb32kHz: {
+      // Do not change the timestamp scaling settings for DTMF or CNG.
+      break;
+    }
+    default: {
+      // Do not use timestamp scaling for any other codec.
+      numerator_ = 1;
+      denominator_ = 1;
+      break;
+    }
+  }
+
+  if (!(numerator_ == 1 && denominator_ == 1)) {
+    // We have a scale factor != 1.
+    if (!first_packet_received_) {
+      external_ref_ = external_timestamp;
+      internal_ref_ = external_timestamp;
+      first_packet_received_ = true;
+    }
+    int32_t external_diff = external_timestamp - external_ref_;
+    assert(denominator_ > 0);  // Should not be possible.
+    external_ref_ = external_timestamp;
+    internal_ref_ += (external_diff * numerator_) / denominator_;
+    LOG(LS_VERBOSE) << "Converting timestamp: " << external_timestamp <<
+        " -> " << internal_ref_;
+    return internal_ref_;
+  } else {
+    // No scaling.
+    return external_timestamp;
+  }
+}
+
+
+uint32_t TimestampScaler::ToExternal(uint32_t internal_timestamp) const {
+  if (!first_packet_received_ || (numerator_ == 1 && denominator_ == 1)) {
+    // Not initialized, or scale factor is 1.
+    return internal_timestamp;
+  } else {
+    int32_t internal_diff = internal_timestamp - internal_ref_;
+    assert(numerator_ > 0);  // Should not be possible.
+    // Do not update references in this method.
+    // Switch |denominator_| and |numerator_| to convert the other way.
+    return external_ref_ + (internal_diff * denominator_) / numerator_;
+  }
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/timestamp_scaler.h b/webrtc/modules/audio_coding/neteq4/timestamp_scaler.h
new file mode 100644
index 0000000..e165076
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/timestamp_scaler.h
@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TIMESTAMP_SCALER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TIMESTAMP_SCALER_H_
+
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declaration.
+class DecoderDatabase;
+
+// This class scales timestamps for codecs that need timestamp scaling.
+// This is done for codecs where one RTP timestamp does not correspond to
+// one sample.
+class TimestampScaler {
+ public:
+  explicit TimestampScaler(const DecoderDatabase& decoder_database)
+      : first_packet_received_(false),
+        numerator_(1),
+        denominator_(1),
+        external_ref_(0),
+        internal_ref_(0),
+        decoder_database_(decoder_database) {}
+
+  virtual ~TimestampScaler() {}
+
+  // Start over.
+  virtual void Reset() { first_packet_received_ = false; }
+
+  // Scale the timestamp in |packet| from external to internal.
+  virtual void ToInternal(Packet* packet);
+
+  // Scale the timestamp for all packets in |packet_list| from external to
+  // internal.
+  virtual void ToInternal(PacketList* packet_list);
+
+  // Returns the internal equivalent of |external_timestamp|, given the
+  // RTP payload type |rtp_payload_type|.
+  virtual uint32_t ToInternal(uint32_t external_timestamp,
+                              uint8_t rtp_payload_type);
+
+  // Scales back to external timestamp. This is the inverse of ToInternal().
+  virtual uint32_t ToExternal(uint32_t internal_timestamp) const;
+
+ private:
+  bool first_packet_received_;
+  int numerator_;
+  int denominator_;
+  uint32_t external_ref_;
+  uint32_t internal_ref_;
+  const DecoderDatabase& decoder_database_;
+
+  DISALLOW_COPY_AND_ASSIGN(TimestampScaler);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TIMESTAMP_SCALER_H_
diff --git a/webrtc/modules/audio_coding/neteq4/timestamp_scaler_unittest.cc b/webrtc/modules/audio_coding/neteq4/timestamp_scaler_unittest.cc
new file mode 100644
index 0000000..ecbed98
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/timestamp_scaler_unittest.cc
@@ -0,0 +1,271 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/timestamp_scaler.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "webrtc/modules/audio_coding/neteq4/mock/mock_decoder_database.h"
+#include "webrtc/modules/audio_coding/neteq4/packet.h"
+
+using ::testing::Return;
+using ::testing::ReturnNull;
+using ::testing::_;
+
+namespace webrtc {
+
+TEST(TimestampScaler, TestNoScaling) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderPCMu;  // Does not use scaled timestamps.
+  static const uint8_t kRtpPayloadType = 0;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  for (uint32_t timestamp = 0xFFFFFFFF - 5; timestamp != 5; ++timestamp) {
+    // Scale to internal timestamp.
+    EXPECT_EQ(timestamp, scaler.ToInternal(timestamp, kRtpPayloadType));
+    // Scale back.
+    EXPECT_EQ(timestamp, scaler.ToExternal(timestamp));
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+TEST(TimestampScaler, TestNoScalingLargeStep) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderPCMu;  // Does not use scaled timestamps.
+  static const uint8_t kRtpPayloadType = 0;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  static const uint32_t kStep = 160;
+  uint32_t start_timestamp = 0;
+  // |external_timestamp| will be a large positive value.
+  start_timestamp = start_timestamp - 5 * kStep;
+  for (uint32_t timestamp = start_timestamp; timestamp != 5 * kStep;
+      timestamp += kStep) {
+    // Scale to internal timestamp.
+    EXPECT_EQ(timestamp, scaler.ToInternal(timestamp, kRtpPayloadType));
+    // Scale back.
+    EXPECT_EQ(timestamp, scaler.ToExternal(timestamp));
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+TEST(TimestampScaler, TestG722) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderG722;  // Uses a factor 2 scaling.
+  static const uint8_t kRtpPayloadType = 17;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  uint32_t external_timestamp = 0xFFFFFFFF - 5;
+  uint32_t internal_timestamp = external_timestamp;
+  for (; external_timestamp != 5; ++external_timestamp) {
+    // Scale to internal timestamp.
+    EXPECT_EQ(internal_timestamp,
+              scaler.ToInternal(external_timestamp, kRtpPayloadType));
+    // Scale back.
+    EXPECT_EQ(external_timestamp, scaler.ToExternal(internal_timestamp));
+    internal_timestamp += 2;
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+TEST(TimestampScaler, TestG722LargeStep) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderG722;  // Uses a factor 2 scaling.
+  static const uint8_t kRtpPayloadType = 17;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  static const uint32_t kStep = 320;
+  uint32_t external_timestamp = 0;
+  // |external_timestamp| will be a large positive value.
+  external_timestamp = external_timestamp - 5 * kStep;
+  uint32_t internal_timestamp = external_timestamp;
+  for (; external_timestamp != 5 * kStep; external_timestamp += kStep) {
+    // Scale to internal timestamp.
+    EXPECT_EQ(internal_timestamp,
+              scaler.ToInternal(external_timestamp, kRtpPayloadType));
+    // Scale back.
+    EXPECT_EQ(external_timestamp, scaler.ToExternal(internal_timestamp));
+    // Internal timestamp should be incremented with twice the step.
+    internal_timestamp += 2 * kStep;
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+TEST(TimestampScaler, TestG722WithCng) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info_g722, info_cng;
+  info_g722.codec_type = kDecoderG722;  // Uses a factor 2 scaling.
+  info_cng.codec_type = kDecoderCNGwb;
+  static const uint8_t kRtpPayloadTypeG722 = 17;
+  static const uint8_t kRtpPayloadTypeCng = 13;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadTypeG722))
+      .WillRepeatedly(Return(&info_g722));
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadTypeCng))
+      .WillRepeatedly(Return(&info_cng));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  uint32_t external_timestamp = 0xFFFFFFFF - 5;
+  uint32_t internal_timestamp = external_timestamp;
+  bool next_is_cng = false;
+  for (; external_timestamp != 5; ++external_timestamp) {
+    // Alternate between G.722 and CNG every other packet.
+    if (next_is_cng) {
+      // Scale to internal timestamp.
+      EXPECT_EQ(internal_timestamp,
+                scaler.ToInternal(external_timestamp, kRtpPayloadTypeCng));
+      next_is_cng = false;
+    } else {
+      // Scale to internal timestamp.
+      EXPECT_EQ(internal_timestamp,
+                scaler.ToInternal(external_timestamp, kRtpPayloadTypeG722));
+      next_is_cng = true;
+    }
+    // Scale back.
+    EXPECT_EQ(external_timestamp, scaler.ToExternal(internal_timestamp));
+    internal_timestamp += 2;
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+// Make sure that the method ToInternal(Packet* packet) is wired up correctly.
+// Since it is simply calling the other ToInternal method, we are not doing
+// as many tests here.
+TEST(TimestampScaler, TestG722Packet) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderG722;  // Does uses a factor 2 scaling.
+  static const uint8_t kRtpPayloadType = 17;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  uint32_t external_timestamp = 0xFFFFFFFF - 5;
+  uint32_t internal_timestamp = external_timestamp;
+  Packet packet;
+  packet.header.payloadType = kRtpPayloadType;
+  for (; external_timestamp != 5; ++external_timestamp) {
+    packet.header.timestamp = external_timestamp;
+    // Scale to internal timestamp.
+    scaler.ToInternal(&packet);
+    EXPECT_EQ(internal_timestamp, packet.header.timestamp);
+    internal_timestamp += 2;
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+// Make sure that the method ToInternal(PacketList* packet_list) is wired up
+// correctly. Since it is simply calling the ToInternal(Packet* packet) method,
+// we are not doing as many tests here.
+TEST(TimestampScaler, TestG722PacketList) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderG722;  // Uses a factor 2 scaling.
+  static const uint8_t kRtpPayloadType = 17;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  uint32_t external_timestamp = 0xFFFFFFFF - 5;
+  uint32_t internal_timestamp = external_timestamp;
+  Packet packet1;
+  packet1.header.payloadType = kRtpPayloadType;
+  packet1.header.timestamp = external_timestamp;
+  Packet packet2;
+  packet2.header.payloadType = kRtpPayloadType;
+  packet2.header.timestamp = external_timestamp + 10;
+  PacketList packet_list;
+  packet_list.push_back(&packet1);
+  packet_list.push_back(&packet2);
+
+  scaler.ToInternal(&packet_list);
+  EXPECT_EQ(internal_timestamp, packet1.header.timestamp);
+  EXPECT_EQ(internal_timestamp + 20, packet2.header.timestamp);
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+TEST(TimestampScaler, TestG722Reset) {
+  MockDecoderDatabase db;
+  DecoderDatabase::DecoderInfo info;
+  info.codec_type = kDecoderG722;  // Uses a factor 2 scaling.
+  static const uint8_t kRtpPayloadType = 17;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillRepeatedly(Return(&info));
+
+  TimestampScaler scaler(db);
+  // Test both sides of the timestamp wrap-around.
+  uint32_t external_timestamp = 0xFFFFFFFF - 5;
+  uint32_t internal_timestamp = external_timestamp;
+  for (; external_timestamp != 5; ++external_timestamp) {
+    // Scale to internal timestamp.
+    EXPECT_EQ(internal_timestamp,
+              scaler.ToInternal(external_timestamp, kRtpPayloadType));
+    // Scale back.
+    EXPECT_EQ(external_timestamp, scaler.ToExternal(internal_timestamp));
+    internal_timestamp += 2;
+  }
+  // Reset the scaler. After this, we expect the internal and external to start
+  // over at the same value again.
+  scaler.Reset();
+  internal_timestamp = external_timestamp;
+  for (; external_timestamp != 15; ++external_timestamp) {
+    // Scale to internal timestamp.
+    EXPECT_EQ(internal_timestamp,
+              scaler.ToInternal(external_timestamp, kRtpPayloadType));
+    // Scale back.
+    EXPECT_EQ(external_timestamp, scaler.ToExternal(internal_timestamp));
+    internal_timestamp += 2;
+  }
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+TEST(TimestampScaler, Failures) {
+  static const uint8_t kRtpPayloadType = 17;
+  MockDecoderDatabase db;
+  EXPECT_CALL(db, GetDecoderInfo(kRtpPayloadType))
+      .WillOnce(ReturnNull());  // Return NULL to indicate unknown payload type.
+
+  TimestampScaler scaler(db);
+  uint32_t timestamp = 4711;  // Some number.
+  EXPECT_EQ(timestamp, scaler.ToInternal(timestamp, kRtpPayloadType));
+
+  Packet* packet = NULL;
+  scaler.ToInternal(packet);  // Should not crash. That's all we can test.
+
+  EXPECT_CALL(db, Die());  // Called when database object is deleted.
+}
+
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/tools/input_audio_file.cc b/webrtc/modules/audio_coding/neteq4/tools/input_audio_file.cc
new file mode 100644
index 0000000..40b3f92
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/tools/input_audio_file.cc
@@ -0,0 +1,45 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/audio_coding/neteq4/tools/input_audio_file.h"
+
+namespace webrtc {
+namespace test {
+
+bool InputAudioFile::Read(size_t samples, int16_t* destination) {
+  if (!fp_) {
+    return false;
+  }
+  size_t bytes_read = fread(destination, sizeof(int16_t), samples, fp_);
+  if (bytes_read < samples) {
+    // Rewind and read the missing sampels.
+    rewind(fp_);
+    size_t missing_samples = samples - bytes_read;
+    if (fread(destination, sizeof(int16_t), missing_samples, fp_) <
+        missing_samples) {
+      // Could not read enough even after rewinding the file.
+      return false;
+    }
+  }
+  return true;
+}
+
+void InputAudioFile::DuplicateInterleaved(const int16_t* source, size_t samples,
+                                          size_t channels,
+                                          int16_t* destination) {
+  for (size_t i = 0; i < samples; ++i) {
+    for (size_t j = 0; j < channels; ++j) {
+      destination[i * channels + j] = source[i];
+    }
+  }
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/tools/input_audio_file.h b/webrtc/modules/audio_coding/neteq4/tools/input_audio_file.h
new file mode 100644
index 0000000..35d0d1f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/tools/input_audio_file.h
@@ -0,0 +1,54 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TOOLS_INPUT_AUDIO_FILE_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TOOLS_INPUT_AUDIO_FILE_H_
+
+#include <cstdio>
+#include <string>
+
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+namespace test {
+
+// Class for handling a looping input audio file.
+class InputAudioFile {
+ public:
+  explicit InputAudioFile(const std::string file_name) {
+    fp_ = fopen(file_name.c_str(), "rb");
+  }
+
+  virtual ~InputAudioFile() {
+    fclose(fp_);
+  }
+
+  // Reads |samples| elements from source file to |destination|. Returns true
+  // if the read was successful, otherwise false. If the file end is reached,
+  // the file is rewound and reading continues from the beginning.
+  // The output |destination| must have the capacity to hold |samples| elements.
+  bool Read(size_t samples, int16_t* destination);
+
+  // Creates a multi-channel signal from a mono signal. Each sample is repeated
+  // |channels| times to create an interleaved multi-channel signal where all
+  // channels are identical. The output |destination| must have the capacity to
+  // hold samples * channels elements.
+  static void DuplicateInterleaved(const int16_t* source, size_t samples,
+                                   size_t channels, int16_t* destination);
+
+ private:
+  FILE* fp_;
+  DISALLOW_COPY_AND_ASSIGN(InputAudioFile);
+};
+
+}  // namespace test
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TOOLS_INPUT_AUDIO_FILE_H_
diff --git a/webrtc/modules/audio_coding/neteq4/tools/neteq_rtpplay.cc b/webrtc/modules/audio_coding/neteq4/tools/neteq_rtpplay.cc
new file mode 100644
index 0000000..1c8a870
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/tools/neteq_rtpplay.cc
@@ -0,0 +1,423 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <algorithm>
+#include <cassert>
+#include <cstdio>
+#include <iostream>
+#include <string>
+
+#include "google/gflags.h"
+#include "webrtc/modules/audio_coding/neteq4/interface/neteq.h"
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_RTPpacket.h"
+#include "webrtc/modules/audio_coding/neteq4/test/NETEQTEST_DummyRTPpacket.h"
+#include "webrtc/modules/interface/module_common_types.h"
+#include "webrtc/system_wrappers/interface/trace.h"
+#include "webrtc/test/testsupport/fileutils.h"
+#include "webrtc/typedefs.h"
+
+using webrtc::NetEq;
+using webrtc::WebRtcRTPHeader;
+
+// Flag validators.
+static bool ValidatePayloadType(const char* flagname, int32_t value) {
+  if (value >= 0 && value <= 127)  // Value is ok.
+    return true;
+  printf("Invalid value for --%s: %d\n", flagname, static_cast<int>(value));
+  return false;
+}
+
+// Define command line flags.
+DEFINE_int32(pcmu, 0, "RTP payload type for PCM-u");
+static const bool pcmu_dummy =
+    google::RegisterFlagValidator(&FLAGS_pcmu, &ValidatePayloadType);
+DEFINE_int32(pcma, 8, "RTP payload type for PCM-a");
+static const bool pcma_dummy =
+    google::RegisterFlagValidator(&FLAGS_pcma, &ValidatePayloadType);
+DEFINE_int32(ilbc, 102, "RTP payload type for iLBC");
+static const bool ilbc_dummy =
+    google::RegisterFlagValidator(&FLAGS_ilbc, &ValidatePayloadType);
+DEFINE_int32(isac, 103, "RTP payload type for iSAC");
+static const bool isac_dummy =
+    google::RegisterFlagValidator(&FLAGS_isac, &ValidatePayloadType);
+DEFINE_int32(isac_swb, 104, "RTP payload type for iSAC-swb (32 kHz)");
+static const bool isac_swb_dummy =
+    google::RegisterFlagValidator(&FLAGS_isac_swb, &ValidatePayloadType);
+DEFINE_int32(pcm16b, 93, "RTP payload type for PCM16b-nb (8 kHz)");
+static const bool pcm16b_dummy =
+    google::RegisterFlagValidator(&FLAGS_pcm16b, &ValidatePayloadType);
+DEFINE_int32(pcm16b_wb, 94, "RTP payload type for PCM16b-wb (16 kHz)");
+static const bool pcm16b_wb_dummy =
+    google::RegisterFlagValidator(&FLAGS_pcm16b_wb, &ValidatePayloadType);
+DEFINE_int32(pcm16b_swb32, 95, "RTP payload type for PCM16b-swb32 (32 kHz)");
+static const bool pcm16b_swb32_dummy =
+    google::RegisterFlagValidator(&FLAGS_pcm16b_swb32, &ValidatePayloadType);
+DEFINE_int32(pcm16b_swb48, 96, "RTP payload type for PCM16b-swb48 (48 kHz)");
+static const bool pcm16b_swb48_dummy =
+    google::RegisterFlagValidator(&FLAGS_pcm16b_swb48, &ValidatePayloadType);
+DEFINE_int32(g722, 9, "RTP payload type for G.722");
+static const bool g722_dummy =
+    google::RegisterFlagValidator(&FLAGS_g722, &ValidatePayloadType);
+DEFINE_int32(avt, 106, "RTP payload type for AVT/DTMF");
+static const bool avt_dummy =
+    google::RegisterFlagValidator(&FLAGS_avt, &ValidatePayloadType);
+DEFINE_int32(red, 117, "RTP payload type for redundant audio (RED)");
+static const bool red_dummy =
+    google::RegisterFlagValidator(&FLAGS_red, &ValidatePayloadType);
+DEFINE_int32(cn_nb, 13, "RTP payload type for comfort noise (8 kHz)");
+static const bool cn_nb_dummy =
+    google::RegisterFlagValidator(&FLAGS_cn_nb, &ValidatePayloadType);
+DEFINE_int32(cn_wb, 98, "RTP payload type for comfort noise (16 kHz)");
+static const bool cn_wb_dummy =
+    google::RegisterFlagValidator(&FLAGS_cn_wb, &ValidatePayloadType);
+DEFINE_int32(cn_swb32, 99, "RTP payload type for comfort noise (32 kHz)");
+static const bool cn_swb32_dummy =
+    google::RegisterFlagValidator(&FLAGS_cn_swb32, &ValidatePayloadType);
+DEFINE_int32(cn_swb48, 100, "RTP payload type for comfort noise (48 kHz)");
+static const bool cn_swb48_dummy =
+    google::RegisterFlagValidator(&FLAGS_cn_swb48, &ValidatePayloadType);
+DEFINE_bool(codec_map, false, "Prints the mapping between RTP payload type and "
+    "codec");
+DEFINE_bool(dummy_rtp, false, "The input file contains ""dummy"" RTP data, "
+            "i.e., only headers");
+
+// Declaring helper functions (defined further down in this file).
+std::string CodecName(webrtc::NetEqDecoder codec);
+void RegisterPayloadTypes(NetEq* neteq);
+void PrintCodecMapping();
+
+int main(int argc, char* argv[]) {
+  static const int kMaxChannels = 5;
+  static const int kMaxSamplesPerMs = 48000 / 1000;
+  static const int kOutputBlockSizeMs = 10;
+
+  std::string program_name = argv[0];
+  std::string usage = "Tool for decoding an RTP dump file using NetEq.\n"
+      "Run " + program_name + " --helpshort for usage.\n"
+      "Example usage:\n" + program_name +
+      " input.rtp output.pcm\n";
+  google::SetUsageMessage(usage);
+  google::ParseCommandLineFlags(&argc, &argv, true);
+
+  if (FLAGS_codec_map) {
+    PrintCodecMapping();
+  }
+
+  if (argc != 3) {
+    if (FLAGS_codec_map) {
+      // We have already printed the codec map. Just end the program.
+      return 0;
+    }
+    // Print usage information.
+    std::cout << google::ProgramUsage();
+    return 0;
+  }
+
+  FILE* in_file = fopen(argv[1], "rb");
+  if (!in_file) {
+    std::cerr << "Cannot open input file " << argv[1] << std::endl;
+    exit(1);
+  }
+  std::cout << "Input file: " << argv[1] << std::endl;
+
+  FILE* out_file = fopen(argv[2], "wb");
+  if (!in_file) {
+    std::cerr << "Cannot open output file " << argv[2] << std::endl;
+    exit(1);
+  }
+  std::cout << "Output file: " << argv[2] << std::endl;
+
+  // Read RTP file header.
+  if (NETEQTEST_RTPpacket::skipFileHeader(in_file) != 0) {
+    std::cerr << "Wrong format in RTP file" << std::endl;
+    exit(1);
+  }
+
+  // Enable tracing.
+  webrtc::Trace::CreateTrace();
+  webrtc::Trace::SetTraceFile((webrtc::test::OutputPath() +
+      "neteq_trace.txt").c_str());
+  webrtc::Trace::SetLevelFilter(webrtc::kTraceAll);
+
+  // Initialize NetEq instance.
+  int sample_rate_hz = 16000;
+  NetEq* neteq = NetEq::Create(sample_rate_hz);
+  RegisterPayloadTypes(neteq);
+  neteq->EnableDtmf();
+
+  // Read first packet.
+  NETEQTEST_RTPpacket *rtp;
+  if (!FLAGS_dummy_rtp) {
+    rtp = new NETEQTEST_RTPpacket();
+  } else {
+    rtp = new NETEQTEST_DummyRTPpacket();
+  }
+  rtp->readFromFile(in_file);
+  if (!rtp) {
+    std::cout  << "Warning: RTP file is empty" << std::endl;
+  }
+
+  // This is the main simulation loop.
+  int time_now_ms = rtp->time();  // Start immediately with the first packet.
+  int next_input_time_ms = rtp->time();
+  int next_output_time_ms = time_now_ms;
+  if (time_now_ms % kOutputBlockSizeMs != 0) {
+    // Make sure that next_output_time_ms is rounded up to the next multiple
+    // of kOutputBlockSizeMs. (Legacy bit-exactness.)
+    next_output_time_ms +=
+        kOutputBlockSizeMs - time_now_ms % kOutputBlockSizeMs;
+  }
+  while (rtp->dataLen() >= 0) {
+    // Check if it is time to insert packet.
+    while (time_now_ms >= next_input_time_ms && rtp->dataLen() >= 0) {
+      if (rtp->dataLen() > 0) {
+        // Parse RTP header.
+        WebRtcRTPHeader rtp_header;
+        rtp->parseHeader(&rtp_header);
+        int error = neteq->InsertPacket(rtp_header, rtp->payload(),
+                                         rtp->payloadLen(),
+                                         rtp->time() * sample_rate_hz / 1000);
+        if (error != NetEq::kOK) {
+          std::cerr << "InsertPacket returned error code " <<
+              neteq->LastError() << std::endl;
+        }
+      }
+      // Get next packet from file.
+      rtp->readFromFile(in_file);
+      next_input_time_ms = rtp->time();
+    }
+
+    // Check if it is time to get output audio.
+    if (time_now_ms >= next_output_time_ms) {
+      static const int kOutDataLen = kOutputBlockSizeMs * kMaxSamplesPerMs *
+          kMaxChannels;
+      int16_t out_data[kOutDataLen];
+      int num_channels;
+      int samples_per_channel;
+      int error = neteq->GetAudio(kOutDataLen, out_data, &samples_per_channel,
+                                   &num_channels, NULL);
+      if (error != NetEq::kOK) {
+        std::cerr << "GetAudio returned error code " <<
+            neteq->LastError() << std::endl;
+      } else {
+        // Calculate sample rate from output size.
+        sample_rate_hz = 1000 * samples_per_channel / kOutputBlockSizeMs;
+      }
+
+      // Write to file.
+      size_t write_len = samples_per_channel * num_channels;
+      if (fwrite(out_data, sizeof(out_data[0]), write_len, out_file) !=
+          write_len) {
+        std::cerr << "Error while writing to file" << std::endl;
+        webrtc::Trace::ReturnTrace();
+        exit(1);
+      }
+      next_output_time_ms += kOutputBlockSizeMs;
+    }
+    // Advance time to next event.
+    time_now_ms = std::min(next_input_time_ms, next_output_time_ms);
+  }
+
+  std::cout << "Simulation done" << std::endl;
+
+  fclose(in_file);
+  fclose(out_file);
+  delete neteq;
+  webrtc::Trace::ReturnTrace();
+  return 0;
+}
+
+
+// Help functions.
+
+// Maps a codec type to a printable name string.
+std::string CodecName(webrtc::NetEqDecoder codec) {
+  switch (codec) {
+    case webrtc::kDecoderPCMu:
+      return "PCM-u";
+    case webrtc::kDecoderPCMa:
+      return "PCM-a";
+    case webrtc::kDecoderILBC:
+      return "iLBC";
+    case webrtc::kDecoderISAC:
+      return "iSAC";
+    case webrtc::kDecoderISACswb:
+      return "iSAC-swb (32 kHz)";
+    case webrtc::kDecoderPCM16B:
+      return "PCM16b-nb (8 kHz)";
+    case webrtc::kDecoderPCM16Bwb:
+      return "PCM16b-wb (16 kHz)";
+    case webrtc::kDecoderPCM16Bswb32kHz:
+      return "PCM16b-swb32 (32 kHz)";
+    case webrtc::kDecoderPCM16Bswb48kHz:
+      return "PCM16b-swb48 (48 kHz)";
+    case webrtc::kDecoderG722:
+      return "G.722";
+    case webrtc::kDecoderRED:
+      return "redundant audio (RED)";
+    case webrtc::kDecoderAVT:
+      return "AVT/DTMF";
+    case webrtc::kDecoderCNGnb:
+      return "comfort noise (8 kHz)";
+    case webrtc::kDecoderCNGwb:
+      return "comfort noise (16 kHz)";
+    case webrtc::kDecoderCNGswb32kHz:
+      return "comfort noise (32 kHz)";
+    case webrtc::kDecoderCNGswb48kHz:
+      return "comfort noise (48 kHz)";
+    default:
+      assert(false);
+      return "undefined";
+  }
+}
+
+// Registers all decoders in |neteq|.
+void RegisterPayloadTypes(NetEq* neteq) {
+  assert(neteq);
+  int error;
+  error = neteq->RegisterPayloadType(webrtc::kDecoderPCMu, FLAGS_pcmu);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_pcmu <<
+        " as " << CodecName(webrtc::kDecoderPCMu).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderPCMa, FLAGS_pcma);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_pcma <<
+        " as " << CodecName(webrtc::kDecoderPCMa).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderILBC, FLAGS_ilbc);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_ilbc <<
+        " as " << CodecName(webrtc::kDecoderILBC).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderISAC, FLAGS_isac);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_isac <<
+        " as " << CodecName(webrtc::kDecoderISAC).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderISACswb, FLAGS_isac_swb);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_isac_swb <<
+        " as " << CodecName(webrtc::kDecoderISACswb).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderPCM16B, FLAGS_pcm16b);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_pcm16b <<
+        " as " << CodecName(webrtc::kDecoderPCM16B).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderPCM16Bwb,
+                                      FLAGS_pcm16b_wb);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_pcm16b_wb <<
+        " as " << CodecName(webrtc::kDecoderPCM16Bwb).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderPCM16Bswb32kHz,
+                                      FLAGS_pcm16b_swb32);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_pcm16b_swb32 <<
+        " as " << CodecName(webrtc::kDecoderPCM16Bswb32kHz).c_str() <<
+        std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderPCM16Bswb48kHz,
+                                      FLAGS_pcm16b_swb48);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_pcm16b_swb48 <<
+        " as " << CodecName(webrtc::kDecoderPCM16Bswb48kHz).c_str() <<
+        std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderG722, FLAGS_g722);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_g722 <<
+        " as " << CodecName(webrtc::kDecoderG722).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderAVT, FLAGS_avt);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_avt <<
+        " as " << CodecName(webrtc::kDecoderAVT).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderRED, FLAGS_red);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_red <<
+        " as " << CodecName(webrtc::kDecoderRED).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderCNGnb, FLAGS_cn_nb);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_cn_nb <<
+        " as " << CodecName(webrtc::kDecoderCNGnb).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderCNGwb, FLAGS_cn_wb);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_cn_wb <<
+        " as " << CodecName(webrtc::kDecoderCNGwb).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderCNGswb32kHz,
+                                      FLAGS_cn_swb32);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_cn_swb32 <<
+        " as " << CodecName(webrtc::kDecoderCNGswb32kHz).c_str() << std::endl;
+    exit(1);
+  }
+  error = neteq->RegisterPayloadType(webrtc::kDecoderCNGswb48kHz,
+                                     FLAGS_cn_swb48);
+  if (error) {
+    std::cerr << "Cannot register payload type " << FLAGS_cn_swb48 <<
+        " as " << CodecName(webrtc::kDecoderCNGswb48kHz).c_str() << std::endl;
+    exit(1);
+  }
+}
+
+void PrintCodecMapping() {
+  std::cout << CodecName(webrtc::kDecoderPCMu).c_str() << ": " << FLAGS_pcmu <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderPCMa).c_str() << ": " << FLAGS_pcma <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderILBC).c_str() << ": " << FLAGS_ilbc <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderISAC).c_str() << ": " << FLAGS_isac <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderISACswb).c_str() << ": " <<
+      FLAGS_isac_swb << std::endl;
+  std::cout << CodecName(webrtc::kDecoderPCM16B).c_str() << ": " <<
+      FLAGS_pcm16b << std::endl;
+  std::cout << CodecName(webrtc::kDecoderPCM16Bwb).c_str() << ": " <<
+      FLAGS_pcm16b_wb << std::endl;
+  std::cout << CodecName(webrtc::kDecoderPCM16Bswb32kHz).c_str() << ": " <<
+      FLAGS_pcm16b_swb32 << std::endl;
+  std::cout << CodecName(webrtc::kDecoderPCM16Bswb48kHz).c_str() << ": " <<
+      FLAGS_pcm16b_swb48 << std::endl;
+  std::cout << CodecName(webrtc::kDecoderG722).c_str() << ": " << FLAGS_g722 <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderAVT).c_str() << ": " << FLAGS_avt <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderRED).c_str() << ": " << FLAGS_red <<
+      std::endl;
+  std::cout << CodecName(webrtc::kDecoderCNGnb).c_str() << ": " <<
+      FLAGS_cn_nb << std::endl;
+  std::cout << CodecName(webrtc::kDecoderCNGwb).c_str() << ": " <<
+      FLAGS_cn_wb << std::endl;
+  std::cout << CodecName(webrtc::kDecoderCNGswb32kHz).c_str() << ": " <<
+      FLAGS_cn_swb32 << std::endl;
+  std::cout << CodecName(webrtc::kDecoderCNGswb48kHz).c_str() << ": " <<
+      FLAGS_cn_swb48 << std::endl;
+}
diff --git a/webrtc/modules/audio_coding/neteq4/tools/rtp_generator.cc b/webrtc/modules/audio_coding/neteq4/tools/rtp_generator.cc
new file mode 100644
index 0000000..0ea28fb
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/tools/rtp_generator.cc
@@ -0,0 +1,41 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <assert.h>
+
+#include "webrtc/modules/audio_coding/neteq4/tools/rtp_generator.h"
+
+namespace webrtc {
+namespace test {
+
+uint32_t RtpGenerator::GetRtpHeader(uint8_t payload_type,
+                                    size_t payload_length_samples,
+                                    WebRtcRTPHeader* rtp_header) {
+  assert(rtp_header);
+  if (!rtp_header) {
+    return 0;
+  }
+  rtp_header->header.sequenceNumber = seq_number_++;
+  rtp_header->header.timestamp = timestamp_;
+  timestamp_ += payload_length_samples;
+  rtp_header->header.payloadType = payload_type;
+  rtp_header->header.markerBit = false;
+  rtp_header->header.ssrc = ssrc_;
+  rtp_header->header.numCSRCs = 0;
+  rtp_header->frameType = kAudioFrameSpeech;
+
+  uint32_t this_send_time = next_send_time_ms_;
+  assert(samples_per_ms_ > 0);
+  next_send_time_ms_ += payload_length_samples / samples_per_ms_;
+  return this_send_time;
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/neteq4/tools/rtp_generator.h b/webrtc/modules/audio_coding/neteq4/tools/rtp_generator.h
new file mode 100644
index 0000000..a2f885f
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq4/tools/rtp_generator.h
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TOOLS_RTP_GENERATOR_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TOOLS_RTP_GENERATOR_H_
+
+#include "webrtc/modules/interface/module_common_types.h"
+#include "webrtc/system_wrappers/interface/constructor_magic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+namespace test {
+
+// Class for generating RTP headers.
+class RtpGenerator {
+ public:
+  RtpGenerator(int samples_per_ms,
+               uint16_t start_seq_number = 0,
+               uint32_t start_timestamp = 0,
+               uint32_t start_send_time_ms = 0,
+               uint32_t ssrc = 0x12345678)
+      : seq_number_(start_seq_number),
+        timestamp_(start_timestamp),
+        next_send_time_ms_(start_send_time_ms),
+        ssrc_(ssrc),
+        samples_per_ms_(samples_per_ms) {
+  }
+
+  // Writes the next RTP header to |rtp_header|, which will be of type
+  // |payload_type|. Returns the send time for this packet (in ms). The value of
+  // |payload_length_samples| determines the send time for the next packet.
+  uint32_t GetRtpHeader(uint8_t payload_type, size_t payload_length_samples,
+                        WebRtcRTPHeader* rtp_header);
+
+ private:
+  uint16_t seq_number_;
+  uint32_t timestamp_;
+  uint32_t next_send_time_ms_;
+  const uint32_t ssrc_;
+  const int samples_per_ms_;
+  DISALLOW_COPY_AND_ASSIGN(RtpGenerator);
+};
+
+}  // namespace test
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ4_TOOLS_RTP_GENERATOR_H_