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_worker.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   ~VirtualAudioInputStream() override;
  48
  49   // AudioInputStream:
  50   bool Open() override;
  51   void Start(AudioInputCallback* callback) override;
  52   void Stop() override;
  53   void Close() override;
  54   double GetMaxVolume() override;
  55   void SetVolume(double volume) override;
  56   double GetVolume() override;
  57   bool SetAutomaticGainControl(bool enabled) override;
  58   bool GetAutomaticGainControl() override;
  59   bool IsMuted() override;
  60
  61   // Attaches a VirtualAudioOutputStream to be used as input. This
  62   // VirtualAudioInputStream must outlive all attached streams, so any attached
  63   // stream must be closed (which causes a detach) before
  64   // VirtualAudioInputStream is destroyed.
  65   virtual void AddOutputStream(VirtualAudioOutputStream* stream,
  66                                const AudioParameters& output_params);
  67
  68   // Detaches a VirtualAudioOutputStream and removes it as input.
  69   virtual void RemoveOutputStream(VirtualAudioOutputStream* stream,
  70                                   const AudioParameters& output_params);
  71
  72  private:
  73   friend class VirtualAudioInputStreamTest;
  74
  75   typedef std::map<AudioParameters, LoopbackAudioConverter*> AudioConvertersMap;
  76
  77   // Pulls audio data from all attached VirtualAudioOutputStreams, mixes and
  78   // converts the streams into one, and pushes the result to |callback_|.
  79   // Invoked on the worker thread.
  80   void PumpAudio();
  81
  82   const scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner_;
  83
  84   AfterCloseCallback after_close_cb_;
  85
  86   AudioInputCallback* callback_;
  87
  88   // Non-const for testing.
  89   scoped_ptr<uint8[]> buffer_;
  90   AudioParameters params_;
  91
  92   // Guards concurrent access to the converter network: converters_, mixer_, and
  93   // num_attached_output_streams_.
  94   base::Lock converter_network_lock_;
  95
  96   // AudioConverters associated with the attached VirtualAudioOutputStreams,
  97   // partitioned by common AudioParameters.
  98   AudioConvertersMap converters_;
  99
 100   // AudioConverter that takes all the audio converters and mixes them into one
 101   // final audio stream.
 102   AudioConverter mixer_;
 103
 104   // Number of currently attached VirtualAudioOutputStreams.
 105   int num_attached_output_streams_;
 106
 107   // Handles callback timing for consumption of audio data.
 108   FakeAudioWorker fake_worker_;
 109
 110   scoped_ptr<AudioBus> audio_bus_;
 111
 112   base::ThreadChecker thread_checker_;
 113
 114   DISALLOW_COPY_AND_ASSIGN(VirtualAudioInputStream);
 115 };
 116
 117 }  // namespace media
 118
 119 #endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_