audio_coding: remove "main" directory

This is the last piece of the old directory layout of the modules.

Duplicated header files are left in audio_coding/main/include until
downstream code is updated to the new location. They have pragma
warnings added to them and identical header guards as the new headers to avoid breaking things.

BUG=webrtc:5095
TESTED=Passing compile-trybots with --clobber flag:
git cl try --clobber --bot=win_compile_rel --bot=linux_compile_rel --bot=android_compile_rel --bot=mac_compile_rel --bot=ios_rel --bot=linux_gn_rel --bot=win_x64_gn_rel --bot=mac_x64_gn_rel --bot=android_gn_rel -m tryserver.webrtc
NOTRY=True
NOPRESUBMIT=True

Review URL: https://codereview.webrtc.org/1481493004

Cr-Commit-Position: refs/heads/master@{#10803}
diff --git a/webrtc/modules/audio_coding/acm2/acm_receiver.cc b/webrtc/modules/audio_coding/acm2/acm_receiver.cc
new file mode 100644
index 0000000..036877c
--- /dev/null
+++ b/webrtc/modules/audio_coding/acm2/acm_receiver.cc
@@ -0,0 +1,540 @@
+/*
+ *  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/acm2/acm_receiver.h"
+
+#include <stdlib.h>  // malloc
+
+#include <algorithm>  // sort
+#include <vector>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/format_macros.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/common_types.h"
+#include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
+#include "webrtc/modules/audio_coding/acm2/acm_resampler.h"
+#include "webrtc/modules/audio_coding/acm2/call_statistics.h"
+#include "webrtc/modules/audio_coding/neteq/include/neteq.h"
+#include "webrtc/system_wrappers/include/clock.h"
+#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
+#include "webrtc/system_wrappers/include/tick_util.h"
+#include "webrtc/system_wrappers/include/trace.h"
+
+namespace webrtc {
+
+namespace acm2 {
+
+namespace {
+
+// |vad_activity_| field of |audio_frame| is set to |previous_audio_activity_|
+// before the call to this function.
+void SetAudioFrameActivityAndType(bool vad_enabled,
+                                  NetEqOutputType type,
+                                  AudioFrame* audio_frame) {
+  if (vad_enabled) {
+    switch (type) {
+      case kOutputNormal: {
+        audio_frame->vad_activity_ = AudioFrame::kVadActive;
+        audio_frame->speech_type_ = AudioFrame::kNormalSpeech;
+        break;
+      }
+      case kOutputVADPassive: {
+        audio_frame->vad_activity_ = AudioFrame::kVadPassive;
+        audio_frame->speech_type_ = AudioFrame::kNormalSpeech;
+        break;
+      }
+      case kOutputCNG: {
+        audio_frame->vad_activity_ = AudioFrame::kVadPassive;
+        audio_frame->speech_type_ = AudioFrame::kCNG;
+        break;
+      }
+      case kOutputPLC: {
+        // Don't change |audio_frame->vad_activity_|, it should be the same as
+        // |previous_audio_activity_|.
+        audio_frame->speech_type_ = AudioFrame::kPLC;
+        break;
+      }
+      case kOutputPLCtoCNG: {
+        audio_frame->vad_activity_ = AudioFrame::kVadPassive;
+        audio_frame->speech_type_ = AudioFrame::kPLCCNG;
+        break;
+      }
+      default:
+        assert(false);
+    }
+  } else {
+    // Always return kVadUnknown when receive VAD is inactive
+    audio_frame->vad_activity_ = AudioFrame::kVadUnknown;
+    switch (type) {
+      case kOutputNormal: {
+        audio_frame->speech_type_ = AudioFrame::kNormalSpeech;
+        break;
+      }
+      case kOutputCNG: {
+        audio_frame->speech_type_ = AudioFrame::kCNG;
+        break;
+      }
+      case kOutputPLC: {
+        audio_frame->speech_type_ = AudioFrame::kPLC;
+        break;
+      }
+      case kOutputPLCtoCNG: {
+        audio_frame->speech_type_ = AudioFrame::kPLCCNG;
+        break;
+      }
+      case kOutputVADPassive: {
+        // Normally, we should no get any VAD decision if post-decoding VAD is
+        // not active. However, if post-decoding VAD has been active then
+        // disabled, we might be here for couple of frames.
+        audio_frame->speech_type_ = AudioFrame::kNormalSpeech;
+        LOG(WARNING) << "Post-decoding VAD is disabled but output is "
+            << "labeled VAD-passive";
+        break;
+      }
+      default:
+        assert(false);
+    }
+  }
+}
+
+// Is the given codec a CNG codec?
+// TODO(kwiberg): Move to RentACodec.
+bool IsCng(int codec_id) {
+  auto i = RentACodec::CodecIdFromIndex(codec_id);
+  return (i && (*i == RentACodec::CodecId::kCNNB ||
+                *i == RentACodec::CodecId::kCNWB ||
+                *i == RentACodec::CodecId::kCNSWB ||
+                *i == RentACodec::CodecId::kCNFB));
+}
+
+}  // namespace
+
+AcmReceiver::AcmReceiver(const AudioCodingModule::Config& config)
+    : crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),
+      id_(config.id),
+      last_audio_decoder_(nullptr),
+      previous_audio_activity_(AudioFrame::kVadPassive),
+      audio_buffer_(new int16_t[AudioFrame::kMaxDataSizeSamples]),
+      last_audio_buffer_(new int16_t[AudioFrame::kMaxDataSizeSamples]),
+      neteq_(NetEq::Create(config.neteq_config)),
+      vad_enabled_(config.neteq_config.enable_post_decode_vad),
+      clock_(config.clock),
+      resampled_last_output_frame_(true) {
+  assert(clock_);
+  memset(audio_buffer_.get(), 0, AudioFrame::kMaxDataSizeSamples);
+  memset(last_audio_buffer_.get(), 0, AudioFrame::kMaxDataSizeSamples);
+}
+
+AcmReceiver::~AcmReceiver() {
+  delete neteq_;
+}
+
+int AcmReceiver::SetMinimumDelay(int delay_ms) {
+  if (neteq_->SetMinimumDelay(delay_ms))
+    return 0;
+  LOG(LERROR) << "AcmReceiver::SetExtraDelay " << delay_ms;
+  return -1;
+}
+
+int AcmReceiver::SetMaximumDelay(int delay_ms) {
+  if (neteq_->SetMaximumDelay(delay_ms))
+    return 0;
+  LOG(LERROR) << "AcmReceiver::SetExtraDelay " << delay_ms;
+  return -1;
+}
+
+int AcmReceiver::LeastRequiredDelayMs() const {
+  return neteq_->LeastRequiredDelayMs();
+}
+
+rtc::Optional<int> AcmReceiver::last_packet_sample_rate_hz() const {
+  CriticalSectionScoped lock(crit_sect_.get());
+  return last_packet_sample_rate_hz_;
+}
+
+int AcmReceiver::last_output_sample_rate_hz() const {
+  return neteq_->last_output_sample_rate_hz();
+}
+
+int AcmReceiver::InsertPacket(const WebRtcRTPHeader& rtp_header,
+                              rtc::ArrayView<const uint8_t> incoming_payload) {
+  uint32_t receive_timestamp = 0;
+  const RTPHeader* header = &rtp_header.header;  // Just a shorthand.
+
+  {
+    CriticalSectionScoped lock(crit_sect_.get());
+
+    const Decoder* decoder = RtpHeaderToDecoder(*header, incoming_payload[0]);
+    if (!decoder) {
+      LOG_F(LS_ERROR) << "Payload-type "
+                      << static_cast<int>(header->payloadType)
+                      << " is not registered.";
+      return -1;
+    }
+    const int sample_rate_hz = [&decoder] {
+      const auto ci = RentACodec::CodecIdFromIndex(decoder->acm_codec_id);
+      return ci ? RentACodec::CodecInstById(*ci)->plfreq : -1;
+    }();
+    receive_timestamp = NowInTimestamp(sample_rate_hz);
+
+    // If this is a CNG while the audio codec is not mono, skip pushing in
+    // packets into NetEq.
+    if (IsCng(decoder->acm_codec_id) && last_audio_decoder_ &&
+        last_audio_decoder_->channels > 1)
+        return 0;
+    if (!IsCng(decoder->acm_codec_id) &&
+        decoder->acm_codec_id !=
+            *RentACodec::CodecIndexFromId(RentACodec::CodecId::kAVT)) {
+      last_audio_decoder_ = decoder;
+      last_packet_sample_rate_hz_ = rtc::Optional<int>(decoder->sample_rate_hz);
+    }
+
+  }  // |crit_sect_| is released.
+
+  if (neteq_->InsertPacket(rtp_header, incoming_payload, receive_timestamp) <
+      0) {
+    LOG(LERROR) << "AcmReceiver::InsertPacket "
+                << static_cast<int>(header->payloadType)
+                << " Failed to insert packet";
+    return -1;
+  }
+  return 0;
+}
+
+int AcmReceiver::GetAudio(int desired_freq_hz, AudioFrame* audio_frame) {
+  enum NetEqOutputType type;
+  size_t samples_per_channel;
+  int num_channels;
+
+  // Accessing members, take the lock.
+  CriticalSectionScoped lock(crit_sect_.get());
+
+  // Always write the output to |audio_buffer_| first.
+  if (neteq_->GetAudio(AudioFrame::kMaxDataSizeSamples,
+                       audio_buffer_.get(),
+                       &samples_per_channel,
+                       &num_channels,
+                       &type) != NetEq::kOK) {
+    LOG(LERROR) << "AcmReceiver::GetAudio - NetEq Failed.";
+    return -1;
+  }
+
+  const int current_sample_rate_hz = neteq_->last_output_sample_rate_hz();
+
+  // Update if resampling is required.
+  const bool need_resampling =
+      (desired_freq_hz != -1) && (current_sample_rate_hz != desired_freq_hz);
+
+  if (need_resampling && !resampled_last_output_frame_) {
+    // Prime the resampler with the last frame.
+    int16_t temp_output[AudioFrame::kMaxDataSizeSamples];
+    int samples_per_channel_int = resampler_.Resample10Msec(
+        last_audio_buffer_.get(), current_sample_rate_hz, desired_freq_hz,
+        num_channels, AudioFrame::kMaxDataSizeSamples, temp_output);
+    if (samples_per_channel_int < 0) {
+      LOG(LERROR) << "AcmReceiver::GetAudio - "
+                     "Resampling last_audio_buffer_ failed.";
+      return -1;
+    }
+    samples_per_channel = static_cast<size_t>(samples_per_channel_int);
+  }
+
+  // The audio in |audio_buffer_| is tansferred to |audio_frame_| below, either
+  // through resampling, or through straight memcpy.
+  // TODO(henrik.lundin) Glitches in the output may appear if the output rate
+  // from NetEq changes. See WebRTC issue 3923.
+  if (need_resampling) {
+    int samples_per_channel_int = resampler_.Resample10Msec(
+        audio_buffer_.get(), current_sample_rate_hz, desired_freq_hz,
+        num_channels, AudioFrame::kMaxDataSizeSamples, audio_frame->data_);
+    if (samples_per_channel_int < 0) {
+      LOG(LERROR) << "AcmReceiver::GetAudio - Resampling audio_buffer_ failed.";
+      return -1;
+    }
+    samples_per_channel = static_cast<size_t>(samples_per_channel_int);
+    resampled_last_output_frame_ = true;
+  } else {
+    resampled_last_output_frame_ = false;
+    // We might end up here ONLY if codec is changed.
+    memcpy(audio_frame->data_,
+           audio_buffer_.get(),
+           samples_per_channel * num_channels * sizeof(int16_t));
+  }
+
+  // Swap buffers, so that the current audio is stored in |last_audio_buffer_|
+  // for next time.
+  audio_buffer_.swap(last_audio_buffer_);
+
+  audio_frame->num_channels_ = num_channels;
+  audio_frame->samples_per_channel_ = samples_per_channel;
+  audio_frame->sample_rate_hz_ = static_cast<int>(samples_per_channel * 100);
+
+  // Should set |vad_activity| before calling SetAudioFrameActivityAndType().
+  audio_frame->vad_activity_ = previous_audio_activity_;
+  SetAudioFrameActivityAndType(vad_enabled_, type, audio_frame);
+  previous_audio_activity_ = audio_frame->vad_activity_;
+  call_stats_.DecodedByNetEq(audio_frame->speech_type_);
+
+  // Computes the RTP timestamp of the first sample in |audio_frame| from
+  // |GetPlayoutTimestamp|, which is the timestamp of the last sample of
+  // |audio_frame|.
+  uint32_t playout_timestamp = 0;
+  if (GetPlayoutTimestamp(&playout_timestamp)) {
+    audio_frame->timestamp_ = playout_timestamp -
+        static_cast<uint32_t>(audio_frame->samples_per_channel_);
+  } else {
+    // Remain 0 until we have a valid |playout_timestamp|.
+    audio_frame->timestamp_ = 0;
+  }
+
+  return 0;
+}
+
+int32_t AcmReceiver::AddCodec(int acm_codec_id,
+                              uint8_t payload_type,
+                              int channels,
+                              int sample_rate_hz,
+                              AudioDecoder* audio_decoder) {
+  const auto neteq_decoder = [acm_codec_id, channels]() -> NetEqDecoder {
+    if (acm_codec_id == -1)
+      return NetEqDecoder::kDecoderArbitrary;  // External decoder.
+    const rtc::Optional<RentACodec::CodecId> cid =
+        RentACodec::CodecIdFromIndex(acm_codec_id);
+    RTC_DCHECK(cid) << "Invalid codec index: " << acm_codec_id;
+    const rtc::Optional<NetEqDecoder> ned =
+        RentACodec::NetEqDecoderFromCodecId(*cid, channels);
+    RTC_DCHECK(ned) << "Invalid codec ID: " << static_cast<int>(*cid);
+    return *ned;
+  }();
+
+  CriticalSectionScoped lock(crit_sect_.get());
+
+  // The corresponding NetEq decoder ID.
+  // If this codec has been registered before.
+  auto it = decoders_.find(payload_type);
+  if (it != decoders_.end()) {
+    const Decoder& decoder = it->second;
+    if (acm_codec_id != -1 && decoder.acm_codec_id == acm_codec_id &&
+        decoder.channels == channels &&
+        decoder.sample_rate_hz == sample_rate_hz) {
+      // Re-registering the same codec. Do nothing and return.
+      return 0;
+    }
+
+    // Changing codec. First unregister the old codec, then register the new
+    // one.
+    if (neteq_->RemovePayloadType(payload_type) != NetEq::kOK) {
+      LOG(LERROR) << "Cannot remove payload " << static_cast<int>(payload_type);
+      return -1;
+    }
+
+    decoders_.erase(it);
+  }
+
+  int ret_val;
+  if (!audio_decoder) {
+    ret_val = neteq_->RegisterPayloadType(neteq_decoder, payload_type);
+  } else {
+    ret_val = neteq_->RegisterExternalDecoder(audio_decoder, neteq_decoder,
+                                              payload_type, sample_rate_hz);
+  }
+  if (ret_val != NetEq::kOK) {
+    LOG(LERROR) << "AcmReceiver::AddCodec " << acm_codec_id
+                << static_cast<int>(payload_type)
+                << " channels: " << channels;
+    return -1;
+  }
+
+  Decoder decoder;
+  decoder.acm_codec_id = acm_codec_id;
+  decoder.payload_type = payload_type;
+  decoder.channels = channels;
+  decoder.sample_rate_hz = sample_rate_hz;
+  decoders_[payload_type] = decoder;
+  return 0;
+}
+
+void AcmReceiver::EnableVad() {
+  neteq_->EnableVad();
+  CriticalSectionScoped lock(crit_sect_.get());
+  vad_enabled_ = true;
+}
+
+void AcmReceiver::DisableVad() {
+  neteq_->DisableVad();
+  CriticalSectionScoped lock(crit_sect_.get());
+  vad_enabled_ = false;
+}
+
+void AcmReceiver::FlushBuffers() {
+  neteq_->FlushBuffers();
+}
+
+// If failed in removing one of the codecs, this method continues to remove as
+// many as it can.
+int AcmReceiver::RemoveAllCodecs() {
+  int ret_val = 0;
+  CriticalSectionScoped lock(crit_sect_.get());
+  for (auto it = decoders_.begin(); it != decoders_.end(); ) {
+    auto cur = it;
+    ++it;  // it will be valid even if we erase cur
+    if (neteq_->RemovePayloadType(cur->second.payload_type) == 0) {
+      decoders_.erase(cur);
+    } else {
+      LOG_F(LS_ERROR) << "Cannot remove payload "
+                      << static_cast<int>(cur->second.payload_type);
+      ret_val = -1;
+    }
+  }
+
+  // No codec is registered, invalidate last audio decoder.
+  last_audio_decoder_ = nullptr;
+  last_packet_sample_rate_hz_ = rtc::Optional<int>();
+  return ret_val;
+}
+
+int AcmReceiver::RemoveCodec(uint8_t payload_type) {
+  CriticalSectionScoped lock(crit_sect_.get());
+  auto it = decoders_.find(payload_type);
+  if (it == decoders_.end()) {  // Such a payload-type is not registered.
+    return 0;
+  }
+  if (neteq_->RemovePayloadType(payload_type) != NetEq::kOK) {
+    LOG(LERROR) << "AcmReceiver::RemoveCodec" << static_cast<int>(payload_type);
+    return -1;
+  }
+  if (last_audio_decoder_ == &it->second) {
+    last_audio_decoder_ = nullptr;
+    last_packet_sample_rate_hz_ = rtc::Optional<int>();
+  }
+  decoders_.erase(it);
+  return 0;
+}
+
+void AcmReceiver::set_id(int id) {
+  CriticalSectionScoped lock(crit_sect_.get());
+  id_ = id;
+}
+
+bool AcmReceiver::GetPlayoutTimestamp(uint32_t* timestamp) {
+  return neteq_->GetPlayoutTimestamp(timestamp);
+}
+
+int AcmReceiver::LastAudioCodec(CodecInst* codec) const {
+  CriticalSectionScoped lock(crit_sect_.get());
+  if (!last_audio_decoder_) {
+    return -1;
+  }
+  *codec = *RentACodec::CodecInstById(
+      *RentACodec::CodecIdFromIndex(last_audio_decoder_->acm_codec_id));
+  codec->pltype = last_audio_decoder_->payload_type;
+  codec->channels = last_audio_decoder_->channels;
+  codec->plfreq = last_audio_decoder_->sample_rate_hz;
+  return 0;
+}
+
+void AcmReceiver::GetNetworkStatistics(NetworkStatistics* acm_stat) {
+  NetEqNetworkStatistics neteq_stat;
+  // NetEq function always returns zero, so we don't check the return value.
+  neteq_->NetworkStatistics(&neteq_stat);
+
+  acm_stat->currentBufferSize = neteq_stat.current_buffer_size_ms;
+  acm_stat->preferredBufferSize = neteq_stat.preferred_buffer_size_ms;
+  acm_stat->jitterPeaksFound = neteq_stat.jitter_peaks_found ? true : false;
+  acm_stat->currentPacketLossRate = neteq_stat.packet_loss_rate;
+  acm_stat->currentDiscardRate = neteq_stat.packet_discard_rate;
+  acm_stat->currentExpandRate = neteq_stat.expand_rate;
+  acm_stat->currentSpeechExpandRate = neteq_stat.speech_expand_rate;
+  acm_stat->currentPreemptiveRate = neteq_stat.preemptive_rate;
+  acm_stat->currentAccelerateRate = neteq_stat.accelerate_rate;
+  acm_stat->currentSecondaryDecodedRate = neteq_stat.secondary_decoded_rate;
+  acm_stat->clockDriftPPM = neteq_stat.clockdrift_ppm;
+  acm_stat->addedSamples = neteq_stat.added_zero_samples;
+  acm_stat->meanWaitingTimeMs = neteq_stat.mean_waiting_time_ms;
+  acm_stat->medianWaitingTimeMs = neteq_stat.median_waiting_time_ms;
+  acm_stat->minWaitingTimeMs = neteq_stat.min_waiting_time_ms;
+  acm_stat->maxWaitingTimeMs = neteq_stat.max_waiting_time_ms;
+}
+
+int AcmReceiver::DecoderByPayloadType(uint8_t payload_type,
+                                      CodecInst* codec) const {
+  CriticalSectionScoped lock(crit_sect_.get());
+  auto it = decoders_.find(payload_type);
+  if (it == decoders_.end()) {
+    LOG(LERROR) << "AcmReceiver::DecoderByPayloadType "
+                << static_cast<int>(payload_type);
+    return -1;
+  }
+  const Decoder& decoder = it->second;
+  *codec = *RentACodec::CodecInstById(
+      *RentACodec::CodecIdFromIndex(decoder.acm_codec_id));
+  codec->pltype = decoder.payload_type;
+  codec->channels = decoder.channels;
+  codec->plfreq = decoder.sample_rate_hz;
+  return 0;
+}
+
+int AcmReceiver::EnableNack(size_t max_nack_list_size) {
+  neteq_->EnableNack(max_nack_list_size);
+  return 0;
+}
+
+void AcmReceiver::DisableNack() {
+  neteq_->DisableNack();
+}
+
+std::vector<uint16_t> AcmReceiver::GetNackList(
+    int64_t round_trip_time_ms) const {
+  return neteq_->GetNackList(round_trip_time_ms);
+}
+
+void AcmReceiver::ResetInitialDelay() {
+  neteq_->SetMinimumDelay(0);
+  // TODO(turajs): Should NetEq Buffer be flushed?
+}
+
+const AcmReceiver::Decoder* AcmReceiver::RtpHeaderToDecoder(
+    const RTPHeader& rtp_header,
+    uint8_t payload_type) const {
+  auto it = decoders_.find(rtp_header.payloadType);
+  const auto red_index =
+      RentACodec::CodecIndexFromId(RentACodec::CodecId::kRED);
+  if (red_index &&  // This ensures that RED is defined in WebRTC.
+      it != decoders_.end() && it->second.acm_codec_id == *red_index) {
+    // This is a RED packet, get the payload of the audio codec.
+    it = decoders_.find(payload_type & 0x7F);
+  }
+
+  // Check if the payload is registered.
+  return it != decoders_.end() ? &it->second : nullptr;
+}
+
+uint32_t AcmReceiver::NowInTimestamp(int decoder_sampling_rate) const {
+  // Down-cast the time to (32-6)-bit since we only care about
+  // the least significant bits. (32-6) bits cover 2^(32-6) = 67108864 ms.
+  // We masked 6 most significant bits of 32-bit so there is no overflow in
+  // the conversion from milliseconds to timestamp.
+  const uint32_t now_in_ms = static_cast<uint32_t>(
+      clock_->TimeInMilliseconds() & 0x03ffffff);
+  return static_cast<uint32_t>(
+      (decoder_sampling_rate / 1000) * now_in_ms);
+}
+
+void AcmReceiver::GetDecodingCallStatistics(
+    AudioDecodingCallStats* stats) const {
+  CriticalSectionScoped lock(crit_sect_.get());
+  *stats = call_stats_.GetDecodingStatistics();
+}
+
+}  // namespace acm2
+
+}  // namespace webrtc