media/audio/virtual_audio_input_stream.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/audio/virtual_audio_input_stream.h"
   6
   7 #include <algorithm>
   8 #include <utility>
   9
  10 #include "base/bind.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "media/audio/virtual_audio_output_stream.h"
  13
  14 namespace media {
  15
  16 // LoopbackAudioConverter works similar to AudioConverter and converts input
  17 // streams to different audio parameters. Then, the LoopbackAudioConverter can
  18 // be used as an input to another AudioConverter. This allows us to
  19 // use converted audio from AudioOutputStreams as input to an AudioConverter.
  20 // For example, this allows converting multiple streams into a common format and
  21 // using the converted audio as input to another AudioConverter (i.e. a mixer).
  22 class LoopbackAudioConverter : public AudioConverter::InputCallback {
  23  public:
  24   LoopbackAudioConverter(const AudioParameters& input_params,
  25                          const AudioParameters& output_params)
  26       : audio_converter_(input_params, output_params, false) {}
  27
  28   virtual ~LoopbackAudioConverter() {}
  29
  30   void AddInput(AudioConverter::InputCallback* input) {
  31     audio_converter_.AddInput(input);
  32   }
  33
  34   void RemoveInput(AudioConverter::InputCallback* input) {
  35     audio_converter_.RemoveInput(input);
  36   }
  37
  38  private:
  39   virtual double ProvideInput(AudioBus* audio_bus,
  40                               base::TimeDelta buffer_delay) OVERRIDE {
  41     audio_converter_.Convert(audio_bus);
  42     return 1.0;
  43   }
  44
  45   AudioConverter audio_converter_;
  46
  47   DISALLOW_COPY_AND_ASSIGN(LoopbackAudioConverter);
  48 };
  49
  50 VirtualAudioInputStream::VirtualAudioInputStream(
  51     const AudioParameters& params,
  52     const scoped_refptr<base::SingleThreadTaskRunner>& worker_task_runner,
  53     const AfterCloseCallback& after_close_cb)
  54     : worker_task_runner_(worker_task_runner),
  55       after_close_cb_(after_close_cb),
  56       callback_(NULL),
  57       buffer_(new uint8[params.GetBytesPerBuffer()]),
  58       params_(params),
  59       mixer_(params_, params_, false),
  60       num_attached_output_streams_(0),
  61       fake_consumer_(worker_task_runner_, params_) {
  62   DCHECK(params_.IsValid());
  63   DCHECK(worker_task_runner_.get());
  64
  65   // VAIS can be constructed on any thread, but will DCHECK that all
  66   // AudioInputStream methods are called from the same thread.
  67   thread_checker_.DetachFromThread();
  68 }
  69
  70 VirtualAudioInputStream::~VirtualAudioInputStream() {
  71   DCHECK(!callback_);
  72
  73   // Sanity-check: Contract for Add/RemoveOutputStream() requires that all
  74   // output streams be removed before VirtualAudioInputStream is destroyed.
  75   DCHECK_EQ(0, num_attached_output_streams_);
  76
  77   for (AudioConvertersMap::iterator it = converters_.begin();
  78        it != converters_.end(); ++it) {
  79     delete it->second;
  80   }
  81 }
  82
  83 bool VirtualAudioInputStream::Open() {
  84   DCHECK(thread_checker_.CalledOnValidThread());
  85   memset(buffer_.get(), 0, params_.GetBytesPerBuffer());
  86   return true;
  87 }
  88
  89 void VirtualAudioInputStream::Start(AudioInputCallback* callback) {
  90   DCHECK(thread_checker_.CalledOnValidThread());
  91   callback_ = callback;
  92   fake_consumer_.Start(base::Bind(
  93       &VirtualAudioInputStream::PumpAudio, base::Unretained(this)));
  94 }
  95
  96 void VirtualAudioInputStream::Stop() {
  97   DCHECK(thread_checker_.CalledOnValidThread());
  98   fake_consumer_.Stop();
  99   callback_ = NULL;
 100 }
 101
 102 void VirtualAudioInputStream::AddOutputStream(
 103     VirtualAudioOutputStream* stream, const AudioParameters& output_params) {
 104   DCHECK(thread_checker_.CalledOnValidThread());
 105
 106   base::AutoLock scoped_lock(converter_network_lock_);
 107
 108   AudioConvertersMap::iterator converter = converters_.find(output_params);
 109   if (converter == converters_.end()) {
 110     std::pair<AudioConvertersMap::iterator, bool> result = converters_.insert(
 111         std::make_pair(output_params,
 112                        new LoopbackAudioConverter(output_params, params_)));
 113     converter = result.first;
 114
 115     // Add to main mixer if we just added a new AudioTransform.
 116     mixer_.AddInput(converter->second);
 117   }
 118   converter->second->AddInput(stream);
 119   ++num_attached_output_streams_;
 120 }
 121
 122 void VirtualAudioInputStream::RemoveOutputStream(
 123     VirtualAudioOutputStream* stream, const AudioParameters& output_params) {
 124   DCHECK(thread_checker_.CalledOnValidThread());
 125
 126   base::AutoLock scoped_lock(converter_network_lock_);
 127
 128   DCHECK(converters_.find(output_params) != converters_.end());
 129   converters_[output_params]->RemoveInput(stream);
 130
 131   --num_attached_output_streams_;
 132   DCHECK_LE(0, num_attached_output_streams_);
 133 }
 134
 135 void VirtualAudioInputStream::PumpAudio(AudioBus* audio_bus) {
 136   DCHECK(worker_task_runner_->BelongsToCurrentThread());
 137
 138   {
 139     base::AutoLock scoped_lock(converter_network_lock_);
 140     mixer_.Convert(audio_bus);
 141   }
 142   audio_bus->ToInterleaved(params_.frames_per_buffer(),
 143                            params_.bits_per_sample() / 8,
 144                            buffer_.get());
 145   callback_->OnData(this,
 146                     buffer_.get(),
 147                     params_.GetBytesPerBuffer(),
 148                     params_.GetBytesPerBuffer(),
 149                     1.0);
 150 }
 151
 152 void VirtualAudioInputStream::Close() {
 153   DCHECK(thread_checker_.CalledOnValidThread());
 154
 155   Stop();  // Make sure callback_ is no longer being used.
 156
 157   // If a non-null AfterCloseCallback was provided to the constructor, invoke it
 158   // here.  The callback is moved to a stack-local first since |this| could be
 159   // destroyed during Run().
 160   if (!after_close_cb_.is_null()) {
 161     const AfterCloseCallback cb = after_close_cb_;
 162     after_close_cb_.Reset();
 163     cb.Run(this);
 164   }
 165 }
 166
 167 double VirtualAudioInputStream::GetMaxVolume() {
 168   return 1.0;
 169 }
 170
 171 void VirtualAudioInputStream::SetVolume(double volume) {}
 172
 173 double VirtualAudioInputStream::GetVolume() {
 174   return 1.0;
 175 }
 176
 177 void VirtualAudioInputStream::SetAutomaticGainControl(bool enabled) {}
 178
 179 bool VirtualAudioInputStream::GetAutomaticGainControl() {
 180   return false;
 181 }
 182
 183 }  // namespace media