src/media/cast/audio_receiver/audio_decoder.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/logging.h"
   6 #include "media/cast/audio_receiver/audio_decoder.h"
   7
   8 #include "third_party/webrtc/modules/audio_coding/main/interface/audio_coding_module.h"
   9 #include "third_party/webrtc/modules/interface/module_common_types.h"
  10
  11 namespace media {
  12 namespace cast {
  13
  14 AudioDecoder::AudioDecoder(const AudioReceiverConfig& audio_config)
  15     : audio_decoder_(webrtc::AudioCodingModule::Create(0)),
  16       have_received_packets_(false) {
  17   audio_decoder_->InitializeReceiver();
  18
  19   webrtc::CodecInst receive_codec;
  20   switch (audio_config.codec) {
  21     case kPcm16:
  22       receive_codec.pltype = audio_config.rtp_payload_type;
  23       strncpy(receive_codec.plname, "L16", 4);
  24       receive_codec.plfreq = audio_config.frequency;
  25       receive_codec.pacsize = -1;
  26       receive_codec.channels = audio_config.channels;
  27       receive_codec.rate = -1;
  28       break;
  29     case kOpus:
  30       receive_codec.pltype = audio_config.rtp_payload_type;
  31       strncpy(receive_codec.plname, "opus", 5);
  32       receive_codec.plfreq = audio_config.frequency;
  33       receive_codec.pacsize = -1;
  34       receive_codec.channels = audio_config.channels;
  35       receive_codec.rate = -1;
  36       break;
  37     case kExternalAudio:
  38       DCHECK(false) << "Codec must be specified for audio decoder";
  39       break;
  40   }
  41   if (audio_decoder_->RegisterReceiveCodec(receive_codec) != 0) {
  42     DCHECK(false) << "Failed to register receive codec";
  43   }
  44
  45   audio_decoder_->SetMaximumPlayoutDelay(audio_config.rtp_max_delay_ms);
  46   audio_decoder_->SetPlayoutMode(webrtc::streaming);
  47 }
  48
  49 AudioDecoder::~AudioDecoder() {}
  50
  51 bool AudioDecoder::GetRawAudioFrame(int number_of_10ms_blocks,
  52                                     int desired_frequency,
  53                                     PcmAudioFrame* audio_frame,
  54                                     uint32* rtp_timestamp) {
  55   if (!have_received_packets_) return false;
  56
  57   audio_frame->samples.clear();
  58
  59   for (int i = 0; i < number_of_10ms_blocks; ++i) {
  60     webrtc::AudioFrame webrtc_audio_frame;
  61     if (0 != audio_decoder_->PlayoutData10Ms(desired_frequency,
  62                                              &webrtc_audio_frame)) {
  63       return false;
  64     }
  65     if (webrtc_audio_frame.speech_type_ == webrtc::AudioFrame::kPLCCNG ||
  66         webrtc_audio_frame.speech_type_ == webrtc::AudioFrame::kUndefined) {
  67       // We are only interested in real decoded audio.
  68       return false;
  69     }
  70     audio_frame->frequency = webrtc_audio_frame.sample_rate_hz_;
  71     audio_frame->channels = webrtc_audio_frame.num_channels_;
  72
  73     if (i == 0) {
  74       // Use the timestamp from the first 10ms block.
  75       if (0 != audio_decoder_->PlayoutTimestamp(rtp_timestamp)) {
  76         return false;
  77       }
  78     }
  79     int samples_per_10ms = webrtc_audio_frame.samples_per_channel_;
  80
  81     audio_frame->samples.insert(
  82         audio_frame->samples.end(),
  83         &webrtc_audio_frame.data_[0],
  84         &webrtc_audio_frame.data_[samples_per_10ms * audio_frame->channels]);
  85   }
  86   return true;
  87 }
  88
  89 void AudioDecoder::IncomingParsedRtpPacket(const uint8* payload_data,
  90                                            size_t payload_size,
  91                                            const RtpCastHeader& rtp_header) {
  92   DCHECK_LE(payload_size, kIpPacketSize);
  93   audio_decoder_->IncomingPacket(payload_data, static_cast<int32>(payload_size),
  94                                  rtp_header.webrtc);
  95   have_received_packets_ = true;
  96 }
  97
  98 }  // namespace cast
  99 }  // namespace media