media/filters/audio_renderer_impl.cc

   1 // Copyright (c) 2011 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 "media/filters/audio_renderer_impl.h"
   6
   7 #include <math.h>
   8
   9 #include "base/logging.h"
  10 #include "media/base/filter_host.h"
  11 #include "media/audio/audio_manager.h"
  12
  13 namespace media {
  14
  15 // We'll try to fill 4096 samples per buffer, which is roughly ~92ms of audio
  16 // data for a 44.1kHz audio source.
  17 static const size_t kSamplesPerBuffer = 8*1024;
  18
  19 AudioRendererImpl::AudioRendererImpl()
  20     : AudioRendererBase(),
  21       stream_(NULL),
  22       bytes_per_second_(0) {
  23 }
  24
  25 AudioRendererImpl::~AudioRendererImpl() {
  26   // Close down the audio device.
  27   if (stream_) {
  28     stream_->Stop();
  29     stream_->Close();
  30   }
  31 }
  32
  33 void AudioRendererImpl::SetPlaybackRate(float rate) {
  34   // TODO(fbarchard): limit rate to reasonable values
  35   AudioRendererBase::SetPlaybackRate(rate);
  36
  37   static bool started = false;
  38   if (rate > 0.0f && !started && stream_)
  39     stream_->Start(this);
  40 }
  41
  42 void AudioRendererImpl::SetVolume(float volume) {
  43   if (stream_)
  44     stream_->SetVolume(volume);
  45 }
  46
  47 uint32 AudioRendererImpl::OnMoreData(
  48     AudioOutputStream* stream, uint8* dest, uint32 len,
  49     AudioBuffersState buffers_state) {
  50   // TODO(scherkus): handle end of stream.
  51   if (!stream_)
  52     return 0;
  53
  54   // TODO(fbarchard): Waveout_output_win.h should handle zero length buffers
  55   //                  without clicking.
  56   uint32 pending_bytes = static_cast<uint32>(ceil(buffers_state.total_bytes() *
  57                                                   GetPlaybackRate()));
  58   base::TimeDelta delay = base::TimeDelta::FromMicroseconds(
  59       base::Time::kMicrosecondsPerSecond * pending_bytes /
  60       bytes_per_second_);
  61   bool buffers_empty = buffers_state.pending_bytes == 0;
  62   return FillBuffer(dest, len, delay, buffers_empty);
  63 }
  64
  65 void AudioRendererImpl::OnClose(AudioOutputStream* stream) {
  66   // TODO(scherkus): implement OnClose.
  67   NOTIMPLEMENTED();
  68 }
  69
  70 void AudioRendererImpl::OnError(AudioOutputStream* stream, int code) {
  71   // TODO(scherkus): implement OnError.
  72   NOTIMPLEMENTED();
  73 }
  74
  75 bool AudioRendererImpl::OnInitialize(const AudioDecoderConfig& config) {
  76   AudioParameters params(config);
  77   params.samples_per_packet = kSamplesPerBuffer;
  78
  79   bytes_per_second_ = params.GetBytesPerSecond();
  80
  81   // Create our audio stream.
  82   stream_ = AudioManager::GetAudioManager()->MakeAudioOutputStream(params);
  83   if (!stream_)
  84     return false;
  85
  86   if (!stream_->Open()) {
  87     stream_->Close();
  88     stream_ = NULL;
  89   }
  90   return true;
  91 }
  92
  93 void AudioRendererImpl::OnStop() {
  94   if (stream_)
  95     stream_->Stop();
  96 }
  97
  98 }  // namespace media