virtual_audio_input_stream.h revision eb525c5499e34cc9c4b825d6d9e75bb07cc06ace 
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
20namespace base {
21class MessageLoopProxy;
22}
23
24namespace media {
25
26class LoopbackAudioConverter;
27class 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.
32class 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_loop| is the loop
40  // on which AudioInputCallback methods are called and may or may not be the
41  // single thread that invokes the AudioInputStream methods.
42  VirtualAudioInputStream(
43      const AudioParameters& params,
44      const scoped_refptr<base::MessageLoopProxy>& worker_loop,
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::MessageLoopProxy> worker_loop_;
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_
117