virtual_audio_input_stream.h revision ab8f6f0bd665d3c1ff476eb06c58c42630e462d4 
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 SingleThreadTaskRunner;
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_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  virtual 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(AudioBus* audio_bus);
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  FakeAudioConsumer fake_consumer_;
109
110  base::ThreadChecker thread_checker_;
111
112  DISALLOW_COPY_AND_ASSIGN(VirtualAudioInputStream);
113};
114
115}  // namespace media
116
117#endif  // MEDIA_AUDIO_VIRTUAL_AUDIO_INPUT_STREAM_H_
118