media/base/audio_renderer_mixer_input.cc

   1 // Copyright (c) 2012 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/base/audio_renderer_mixer_input.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/logging.h"
  10 #include "media/base/audio_renderer_mixer.h"
  11
  12 namespace media {
  13
  14 AudioRendererMixerInput::AudioRendererMixerInput(
  15     const GetMixerCB& get_mixer_cb, const RemoveMixerCB& remove_mixer_cb)
  16     : playing_(false),
  17       initialized_(false),
  18       volume_(1.0f),
  19       get_mixer_cb_(get_mixer_cb),
  20       remove_mixer_cb_(remove_mixer_cb),
  21       mixer_(NULL),
  22       callback_(NULL),
  23       error_cb_(base::Bind(
  24           &AudioRendererMixerInput::OnRenderError, base::Unretained(this))) {
  25 }
  26
  27 AudioRendererMixerInput::~AudioRendererMixerInput() {
  28   DCHECK(!playing_);
  29   DCHECK(!mixer_);
  30 }
  31
  32 void AudioRendererMixerInput::Initialize(
  33     const AudioParameters& params,
  34     AudioRendererSink::RenderCallback* callback) {
  35   DCHECK(callback);
  36   DCHECK(!initialized_);
  37
  38   params_ = params;
  39   callback_ = callback;
  40   initialized_ = true;
  41 }
  42
  43 void AudioRendererMixerInput::Start() {
  44   DCHECK(initialized_);
  45   DCHECK(!playing_);
  46   DCHECK(!mixer_);
  47   mixer_ = get_mixer_cb_.Run(params_);
  48
  49   // Note: OnRenderError() may be called immediately after this call returns.
  50   mixer_->AddErrorCallback(error_cb_);
  51 }
  52
  53 void AudioRendererMixerInput::Stop() {
  54   // Stop() may be called at any time, if Pause() hasn't been called we need to
  55   // remove our mixer input before shutdown.
  56   if (playing_) {
  57     mixer_->RemoveMixerInput(this);
  58     playing_ = false;
  59   }
  60
  61   if (mixer_) {
  62     // TODO(dalecurtis): This is required so that |callback_| isn't called after
  63     // Stop() by an error event since it may outlive this ref-counted object. We
  64     // should instead have sane ownership semantics: http://crbug.com/151051
  65     mixer_->RemoveErrorCallback(error_cb_);
  66     remove_mixer_cb_.Run(params_);
  67     mixer_ = NULL;
  68   }
  69 }
  70
  71 void AudioRendererMixerInput::Play() {
  72   DCHECK(initialized_);
  73   DCHECK(mixer_);
  74
  75   if (playing_)
  76     return;
  77
  78   mixer_->AddMixerInput(this);
  79   playing_ = true;
  80 }
  81
  82 void AudioRendererMixerInput::Pause() {
  83   DCHECK(initialized_);
  84   DCHECK(mixer_);
  85
  86   if (!playing_)
  87     return;
  88
  89   mixer_->RemoveMixerInput(this);
  90   playing_ = false;
  91 }
  92
  93 bool AudioRendererMixerInput::SetVolume(double volume) {
  94   volume_ = volume;
  95   return true;
  96 }
  97
  98 OutputDevice* AudioRendererMixerInput::GetOutputDevice() {
  99   DVLOG(1) << __FUNCTION__;
 100   return mixer_->GetOutputDevice();
 101 }
 102
 103 double AudioRendererMixerInput::ProvideInput(AudioBus* audio_bus,
 104                                              base::TimeDelta buffer_delay) {
 105   int frames_filled = callback_->Render(
 106       audio_bus, static_cast<int>(buffer_delay.InMillisecondsF() + 0.5));
 107
 108   // AudioConverter expects unfilled frames to be zeroed.
 109   if (frames_filled < audio_bus->frames()) {
 110     audio_bus->ZeroFramesPartial(
 111         frames_filled, audio_bus->frames() - frames_filled);
 112   }
 113
 114   return frames_filled > 0 ? volume_ : 0;
 115 }
 116
 117 void AudioRendererMixerInput::OnRenderError() {
 118   callback_->OnRenderError();
 119 }
 120
 121 }  // namespace media