media/audio/virtual_audio_input_stream.h

   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 #ifndef MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_
   6 #define MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_
   7
   8 #include <map>
   9 #include <set>
  10
  11 #include "base/gtest_prod_util.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/synchronization/lock.h"
  14 #include "base/threading/thread_checker.h"
  15 #include "media/audio/audio_io.h"
  16 #include "media/audio/audio_parameters.h"
  17 #include "media/audio/fake_audio_consumer.h"
  18 #include "media/base/audio_converter.h"
  19
  20 namespace base {
  21 class SingleThreadTaskRunner;
  22 }
  23
  24 namespace media {
  25
  26 class LoopbackAudioConverter;
  27 class VirtualAudioOutputStream;
  28
  29 // VirtualAudioInputStream converts and mixes audio from attached
  30 // VirtualAudioOutputStreams into a single stream. It will continuously render
  31 // audio until this VirtualAudioInputStream is stopped and closed.
  32 class MEDIA_EXPORT VirtualAudioInputStream : public AudioInputStream {
  33  public:
  34   // Callback invoked just after VirtualAudioInputStream is closed.
  35   typedef base::Callback<void(VirtualAudioInputStream* vais)>
  36       AfterCloseCallback;
  37
  38   // Construct a target for audio loopback which mixes multiple data streams
  39   // into a single stream having the given |params|.  |worker_task_runner| is
  40   // the task runner on which AudioInputCallback methods are called and may or
  41   // may not be the single thread that invokes the AudioInputStream methods.
  42   VirtualAudioInputStream(
  43       const AudioParameters& params,
  44       const scoped_refptr<base::SingleThreadTaskRunner>& worker_task_runner,
  45       const AfterCloseCallback& after_close_cb);
  46
  47   virtual ~VirtualAudioInputStream();
  48
  49   // AudioInputStream:
  50   virtual bool Open() OVERRIDE;
  51   virtual void Start(AudioInputCallback* callback) OVERRIDE;
  52   virtual void Stop() OVERRIDE;
  53   virtual void Close() OVERRIDE;
  54   virtual double GetMaxVolume() OVERRIDE;
  55   virtual void SetVolume(double volume) OVERRIDE;
  56   virtual double GetVolume() OVERRIDE;
  57   virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
  58   virtual bool GetAutomaticGainControl() OVERRIDE;
  59
  60   // Attaches a VirtualAudioOutputStream to be used as input. This
  61   // VirtualAudioInputStream must outlive all attached streams, so any attached
  62   // stream must be closed (which causes a detach) before
  63   // VirtualAudioInputStream is destroyed.
  64   virtual void AddOutputStream(VirtualAudioOutputStream* stream,
  65                                const AudioParameters& output_params);
  66
  67   // Detaches a VirtualAudioOutputStream and removes it as input.
  68   virtual void RemoveOutputStream(VirtualAudioOutputStream* stream,
  69                                   const AudioParameters& output_params);
  70
  71  private:
  72   friend class VirtualAudioInputStreamTest;
  73
  74   typedef std::map<AudioParameters, LoopbackAudioConverter*> AudioConvertersMap;
  75
  76   // Pulls audio data from all attached VirtualAudioOutputStreams, mixes and
  77   // converts the streams into one, and pushes the result to |callback_|.
  78   // Invoked on the worker thread.
  79   void PumpAudio(AudioBus* audio_bus);
  80
  81   const scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner_;
  82
  83   AfterCloseCallback after_close_cb_;
  84
  85   AudioInputCallback* callback_;
  86
  87   // Non-const for testing.
  88   scoped_ptr<uint8[]> buffer_;
  89   AudioParameters params_;
  90
  91   // Guards concurrent access to the converter network: converters_, mixer_, and
  92   // num_attached_output_streams_.
  93   base::Lock converter_network_lock_;
  94
  95   // AudioConverters associated with the attached VirtualAudioOutputStreams,
  96   // partitioned by common AudioParameters.
  97   AudioConvertersMap converters_;
  98
  99   // AudioConverter that takes all the audio converters and mixes them into one
 100   // final audio stream.
 101   AudioConverter mixer_;
 102
 103   // Number of currently attached VirtualAudioOutputStreams.
 104   int num_attached_output_streams_;
 105
 106   // Handles callback timing for consumption of audio data.
 107   FakeAudioConsumer fake_consumer_;
 108
 109   base::ThreadChecker thread_checker_;
 110
 111   DISALLOW_COPY_AND_ASSIGN(VirtualAudioInputStream);
 112 };
 113
 114 }  // namespace media
 115
 116 #endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_