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/logging.h"
   9 #include "media/base/audio_renderer_mixer.h"
  10
  11 namespace media {
  12
  13 AudioRendererMixerInput::AudioRendererMixerInput(
  14     const GetMixerCB& get_mixer_cb, const RemoveMixerCB& remove_mixer_cb)
  15     : playing_(false),
  16       initialized_(false),
  17       volume_(1.0f),
  18       get_mixer_cb_(get_mixer_cb),
  19       remove_mixer_cb_(remove_mixer_cb),
  20       mixer_(NULL),
  21       callback_(NULL),
  22       error_cb_(base::Bind(
  23           &AudioRendererMixerInput::OnRenderError, base::Unretained(this))) {
  24 }
  25
  26 AudioRendererMixerInput::~AudioRendererMixerInput() {
  27   // Mixer is no longer safe to use after |remove_mixer_cb_| has been called.
  28   if (initialized_)
  29     remove_mixer_cb_.Run(params_);
  30 }
  31
  32 void AudioRendererMixerInput::Initialize(
  33     const AudioParameters& params,
  34     AudioRendererSink::RenderCallback* callback) {
  35   DCHECK(!initialized_);
  36   params_ = params;
  37   mixer_ = get_mixer_cb_.Run(params_);
  38   callback_ = callback;
  39   initialized_ = true;
  40 }
  41
  42 void AudioRendererMixerInput::Start() {
  43   DCHECK(initialized_);
  44   DCHECK(!playing_);
  45 }
  46
  47 void AudioRendererMixerInput::Stop() {
  48   // Stop() may be called at any time, if Pause() hasn't been called we need to
  49   // remove our mixer input before shutdown.
  50   if (!playing_)
  51     return;
  52
  53   mixer_->RemoveMixerInput(this);
  54   playing_ = false;
  55 }
  56
  57 void AudioRendererMixerInput::Play() {
  58   DCHECK(initialized_);
  59
  60   if (playing_)
  61     return;
  62
  63   mixer_->AddMixerInput(this, error_cb_);
  64   playing_ = true;
  65 }
  66
  67 void AudioRendererMixerInput::Pause() {
  68   DCHECK(initialized_);
  69
  70   if (!playing_)
  71     return;
  72
  73   mixer_->RemoveMixerInput(this);
  74   playing_ = false;
  75 }
  76
  77 bool AudioRendererMixerInput::SetVolume(double volume) {
  78   volume_ = volume;
  79   return true;
  80 }
  81
  82 double AudioRendererMixerInput::ProvideInput(AudioBus* audio_bus,
  83                                              base::TimeDelta buffer_delay) {
  84   int frames_filled = callback_->Render(
  85       audio_bus, static_cast<int>(buffer_delay.InMillisecondsF() + 0.5));
  86
  87   // AudioConverter expects unfilled frames to be zeroed.
  88   if (frames_filled < audio_bus->frames()) {
  89     audio_bus->ZeroFramesPartial(
  90         frames_filled, audio_bus->frames() - frames_filled);
  91   }
  92
  93   return frames_filled > 0 ? volume_ : 0;
  94 }
  95
  96 void AudioRendererMixerInput::OnRenderError() {
  97   callback_->OnRenderError();
  98 }
  99
 100 }  // namespace media