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/cancelable_callback.h"
  12 #include "base/gtest_prod_util.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "media/audio/audio_io.h"
  15 #include "media/audio/audio_manager_base.h"
  16 #include "media/audio/audio_parameters.h"
  17 #include "media/base/audio_converter.h"
  18
  19 namespace media {
  20
  21 class LoopbackAudioConverter;
  22 class VirtualAudioOutputStream;
  23
  24 // VirtualAudioInputStream converts and mixes audio from attached
  25 // VirtualAudioOutputStreams into a single stream. It will continuously render
  26 // audio until this VirtualAudioInputStream is stopped and closed.
  27 class MEDIA_EXPORT VirtualAudioInputStream : public AudioInputStream {
  28  public:
  29   static VirtualAudioInputStream* MakeStream(
  30       AudioManagerBase* manager,
  31       const AudioParameters& params,
  32       base::MessageLoopProxy* message_loop);
  33
  34   virtual ~VirtualAudioInputStream();
  35
  36   // AudioInputStream:
  37   virtual bool Open() OVERRIDE;
  38   virtual void Start(AudioInputCallback* callback) OVERRIDE;
  39   virtual void Stop() OVERRIDE;
  40   virtual void Close() OVERRIDE;
  41   virtual double GetMaxVolume() OVERRIDE;
  42   virtual void SetVolume(double volume) OVERRIDE;
  43   virtual double GetVolume() OVERRIDE;
  44   virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
  45   virtual bool GetAutomaticGainControl() OVERRIDE;
  46
  47   // Attaches a VirtualAudioOutputStream to be used as input. This
  48   // VirtualAudioInputStream must outlive all attached streams, so any attached
  49   // stream must be closed (which causes a detach) before
  50   // VirtualAudioInputStream is destroyed.
  51   virtual void AddOutputStream(VirtualAudioOutputStream* stream,
  52                                const AudioParameters& output_params);
  53
  54   // Detaches a VirtualAudioOutputStream and removes it as input.
  55   virtual void RemoveOutputStream(VirtualAudioOutputStream* stream,
  56                                   const AudioParameters& output_params);
  57
  58  protected:
  59   friend class VirtualAudioInputStreamTest;
  60   FRIEND_TEST_ALL_PREFIXES(AudioOutputControllerTest,
  61                            VirtualStreamsTriggerDeviceChange);
  62
  63   typedef std::map<AudioParameters, LoopbackAudioConverter*> AudioConvertersMap;
  64
  65   VirtualAudioInputStream(AudioManagerBase* manager,
  66                           const AudioParameters& params,
  67                           base::MessageLoopProxy* message_loop);
  68
  69   // When Start() is called on this class, we continuously schedule this
  70   // callback to render audio using any attached VirtualAudioOutputStreams until
  71   // Stop() is called.
  72   void ReadAudio();
  73
  74   AudioManagerBase* audio_manager_;
  75   base::MessageLoopProxy* message_loop_;
  76   AudioInputCallback* callback_;
  77
  78   // Non-const for testing.
  79   base::TimeDelta buffer_duration_ms_;
  80   scoped_array<uint8> buffer_;
  81   AudioParameters params_;
  82   scoped_ptr<AudioBus> audio_bus_;
  83   base::CancelableClosure on_more_data_cb_;
  84
  85   // AudioConverters associated with the attached VirtualAudioOutputStreams,
  86   // partitioned by common AudioParameters.
  87   AudioConvertersMap converters_;
  88
  89   // AudioConverter that takes all the audio converters and mixes them into one
  90   // final audio stream.
  91   AudioConverter mixer_;
  92
  93   // Number of currently attached VirtualAudioOutputStreams.
  94   int num_attached_outputs_streams_;
  95
  96   DISALLOW_COPY_AND_ASSIGN(VirtualAudioInputStream);
  97 };
  98
  99 }  // namespace media
 100
 101 #endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_