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/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