content/renderer/media/audio_renderer_mixer_manager.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 "content/renderer/media/audio_renderer_mixer_manager.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "content/renderer/media/audio_device_factory.h"
  10 #include "media/audio/audio_output_device.h"
  11 #include "media/base/audio_hardware_config.h"
  12 #include "media/base/audio_renderer_mixer.h"
  13 #include "media/base/audio_renderer_mixer_input.h"
  14
  15 namespace content {
  16
  17 AudioRendererMixerManager::AudioRendererMixerManager(
  18     media::AudioHardwareConfig* hardware_config)
  19     : hardware_config_(hardware_config),
  20       sink_for_testing_(NULL) {
  21 }
  22
  23 AudioRendererMixerManager::~AudioRendererMixerManager() {
  24   // References to AudioRendererMixers may be owned by garbage collected
  25   // objects.  During process shutdown they may be leaked, so, transitively,
  26   // |mixers_| may leak (i.e., may be non-empty at this time) as well.
  27 }
  28
  29 media::AudioRendererMixerInput* AudioRendererMixerManager::CreateInput(
  30     int source_render_frame_id) {
  31   return new media::AudioRendererMixerInput(
  32       base::Bind(&AudioRendererMixerManager::GetMixer, base::Unretained(this),
  33                  source_render_frame_id),
  34       base::Bind(&AudioRendererMixerManager::RemoveMixer,
  35                  base::Unretained(this), source_render_frame_id));
  36 }
  37
  38 void AudioRendererMixerManager::SetAudioRendererSinkForTesting(
  39     media::AudioRendererSink* sink) {
  40   sink_for_testing_ = sink;
  41 }
  42
  43 media::AudioRendererMixer* AudioRendererMixerManager::GetMixer(
  44     int source_render_frame_id,
  45     const media::AudioParameters& params) {
  46   // Effects are not passed through to output creation, so ensure none are set.
  47   DCHECK_EQ(params.effects(), media::AudioParameters::NO_EFFECTS);
  48
  49   const MixerKey key(source_render_frame_id, params);
  50   base::AutoLock auto_lock(mixers_lock_);
  51
  52   AudioRendererMixerMap::iterator it = mixers_.find(key);
  53   if (it != mixers_.end()) {
  54     it->second.ref_count++;
  55     return it->second.mixer;
  56   }
  57
  58   // On ChromeOS we can rely on the playback device to handle resampling, so
  59   // don't waste cycles on it here.
  60 #if defined(OS_CHROMEOS)
  61   int sample_rate = params.sample_rate();
  62 #else
  63   int sample_rate = hardware_config_->GetOutputSampleRate();
  64 #endif
  65
  66   // Create output parameters based on the audio hardware configuration for
  67   // passing on to the output sink.  Force to 16-bit output for now since we
  68   // know that works everywhere; ChromeOS does not support other bit depths.
  69   media::AudioParameters output_params(
  70       media::AudioParameters::AUDIO_PCM_LOW_LATENCY, params.channel_layout(),
  71       sample_rate, 16, hardware_config_->GetHighLatencyBufferSize());
  72
  73   // If we've created invalid output parameters, simply pass on the input params
  74   // and let the browser side handle automatic fallback.
  75   if (!output_params.IsValid())
  76     output_params = params;
  77
  78   media::AudioRendererMixer* mixer;
  79   if (sink_for_testing_) {
  80     mixer = new media::AudioRendererMixer(
  81         params, output_params, sink_for_testing_);
  82   } else {
  83     mixer = new media::AudioRendererMixer(
  84         params, output_params,
  85         AudioDeviceFactory::NewOutputDevice(source_render_frame_id));
  86   }
  87
  88   AudioRendererMixerReference mixer_reference = { mixer, 1 };
  89   mixers_[key] = mixer_reference;
  90   return mixer;
  91 }
  92
  93 void AudioRendererMixerManager::RemoveMixer(
  94     int source_render_frame_id,
  95     const media::AudioParameters& params) {
  96   const MixerKey key(source_render_frame_id, params);
  97   base::AutoLock auto_lock(mixers_lock_);
  98
  99   AudioRendererMixerMap::iterator it = mixers_.find(key);
 100   DCHECK(it != mixers_.end());
 101
 102   // Only remove the mixer if AudioRendererMixerManager is the last owner.
 103   it->second.ref_count--;
 104   if (it->second.ref_count == 0) {
 105     delete it->second.mixer;
 106     mixers_.erase(it);
 107   }
 108 }
 109
 110 }  // namespace content