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 "media/audio/audio_io.h"
  14 #include "media/audio/audio_parameters.h"
  15 #include "media/audio/fake_audio_consumer.h"
  16 #include "media/base/audio_converter.h"
  17
  18 namespace base {
  19 class MessageLoopProxy;
  20 }
  21
  22 namespace media {
  23
  24 class LoopbackAudioConverter;
  25 class VirtualAudioOutputStream;
  26
  27 // VirtualAudioInputStream converts and mixes audio from attached
  28 // VirtualAudioOutputStreams into a single stream. It will continuously render
  29 // audio until this VirtualAudioInputStream is stopped and closed.
  30 class MEDIA_EXPORT VirtualAudioInputStream : public AudioInputStream {
  31  public:
  32   // Callback invoked just after VirtualAudioInputStream is closed.
  33   typedef base::Callback<void(VirtualAudioInputStream* vais)>
  34       AfterCloseCallback;
  35
  36   // Construct a target for audio loopback which mixes multiple data streams
  37   // into a single stream having the given |params|.
  38   VirtualAudioInputStream(
  39       const AudioParameters& params,
  40       const scoped_refptr<base::MessageLoopProxy>& message_loop,
  41       const AfterCloseCallback& after_close_cb);
  42
  43   virtual ~VirtualAudioInputStream();
  44
  45   // AudioInputStream:
  46   virtual bool Open() OVERRIDE;
  47   virtual void Start(AudioInputCallback* callback) OVERRIDE;
  48   virtual void Stop() OVERRIDE;
  49   virtual void Close() OVERRIDE;
  50   virtual double GetMaxVolume() OVERRIDE;
  51   virtual void SetVolume(double volume) OVERRIDE;
  52   virtual double GetVolume() OVERRIDE;
  53   virtual void SetAutomaticGainControl(bool enabled) OVERRIDE;
  54   virtual bool GetAutomaticGainControl() OVERRIDE;
  55
  56   // Attaches a VirtualAudioOutputStream to be used as input. This
  57   // VirtualAudioInputStream must outlive all attached streams, so any attached
  58   // stream must be closed (which causes a detach) before
  59   // VirtualAudioInputStream is destroyed.
  60   virtual void AddOutputStream(VirtualAudioOutputStream* stream,
  61                                const AudioParameters& output_params);
  62
  63   // Detaches a VirtualAudioOutputStream and removes it as input.
  64   virtual void RemoveOutputStream(VirtualAudioOutputStream* stream,
  65                                   const AudioParameters& output_params);
  66
  67  private:
  68   friend class VirtualAudioInputStreamTest;
  69
  70   typedef std::map<AudioParameters, LoopbackAudioConverter*> AudioConvertersMap;
  71
  72   // When Start() is called on this class, we continuously schedule this
  73   // callback to render audio using any attached VirtualAudioOutputStreams until
  74   // Stop() is called.
  75   void ReadAudio(AudioBus* audio_bus);
  76
  77   const scoped_refptr<base::MessageLoopProxy> message_loop_;
  78
  79   AfterCloseCallback after_close_cb_;
  80
  81   AudioInputCallback* callback_;
  82
  83   // Non-const for testing.
  84   scoped_ptr<uint8[]> buffer_;
  85   AudioParameters params_;
  86
  87   // AudioConverters associated with the attached VirtualAudioOutputStreams,
  88   // partitioned by common AudioParameters.
  89   AudioConvertersMap converters_;
  90
  91   // AudioConverter that takes all the audio converters and mixes them into one
  92   // final audio stream.
  93   AudioConverter mixer_;
  94
  95   // Number of currently attached VirtualAudioOutputStreams.
  96   int num_attached_output_streams_;
  97
  98   // Handles callback timing for consumption of audio data.
  99   FakeAudioConsumer fake_consumer_;
 100
 101   DISALLOW_COPY_AND_ASSIGN(VirtualAudioInputStream);
 102 };
 103
 104 }  // namespace media
 105
 106 #endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_