audio_manager_base.h revision 0529e5d033099cbfc42635f6f6183833b09dff6e 
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_AUDIO_MANAGER_BASE_H_
6#define MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
7
8#include <string>
9#include <utility>
10
11#include "base/compiler_specific.h"
12#include "base/memory/scoped_ptr.h"
13#include "base/memory/scoped_vector.h"
14#include "base/observer_list.h"
15#include "base/threading/thread.h"
16#include "media/audio/audio_manager.h"
17
18#include "media/audio/audio_output_dispatcher.h"
19
20#if defined(OS_WIN)
21#include "base/win/scoped_com_initializer.h"
22#endif
23
24namespace media {
25
26class AudioOutputDispatcher;
27
28// AudioManagerBase provides AudioManager functions common for all platforms.
29class MEDIA_EXPORT AudioManagerBase : public AudioManager {
30 public:
31  // TODO(sergeyu): The constants below belong to AudioManager interface, not
32  // to the base implementation.
33
34  // Name of the generic "default" device.
35  static const char kDefaultDeviceName[];
36  // Unique Id of the generic "default" device.
37  static const char kDefaultDeviceId[];
38
39  // Input device ID used to capture the default system playback stream. When
40  // this device ID is passed to MakeAudioInputStream() the returned
41  // AudioInputStream will be capturing audio currently being played on the
42  // default playback device. At the moment this feature is supported only on
43  // some platforms. AudioInputStream::Intialize() will return an error on
44  // platforms that don't support it. GetInputStreamParameters() must be used
45  // to get the parameters of the loopback device before creating a loopback
46  // stream, otherwise stream initialization may fail.
47  static const char kLoopbackInputDeviceId[];
48
49  virtual ~AudioManagerBase();
50
51  virtual scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() OVERRIDE;
52  virtual scoped_refptr<base::SingleThreadTaskRunner> GetWorkerTaskRunner()
53      OVERRIDE;
54
55  virtual base::string16 GetAudioInputDeviceModel() OVERRIDE;
56
57  virtual void ShowAudioInputSettings() OVERRIDE;
58
59  virtual void GetAudioInputDeviceNames(
60      AudioDeviceNames* device_names) OVERRIDE;
61
62  virtual void GetAudioOutputDeviceNames(
63      AudioDeviceNames* device_names) OVERRIDE;
64
65  virtual AudioOutputStream* MakeAudioOutputStream(
66      const AudioParameters& params,
67      const std::string& device_id) OVERRIDE;
68
69  virtual AudioInputStream* MakeAudioInputStream(
70      const AudioParameters& params, const std::string& device_id) OVERRIDE;
71
72  virtual AudioOutputStream* MakeAudioOutputStreamProxy(
73      const AudioParameters& params,
74      const std::string& device_id) OVERRIDE;
75
76  // Called internally by the audio stream when it has been closed.
77  virtual void ReleaseOutputStream(AudioOutputStream* stream);
78  virtual void ReleaseInputStream(AudioInputStream* stream);
79
80  // Creates the output stream for the |AUDIO_PCM_LINEAR| format. The legacy
81  // name is also from |AUDIO_PCM_LINEAR|.
82  virtual AudioOutputStream* MakeLinearOutputStream(
83      const AudioParameters& params) = 0;
84
85  // Creates the output stream for the |AUDIO_PCM_LOW_LATENCY| format.
86  virtual AudioOutputStream* MakeLowLatencyOutputStream(
87      const AudioParameters& params,
88      const std::string& device_id) = 0;
89
90  // Creates the input stream for the |AUDIO_PCM_LINEAR| format. The legacy
91  // name is also from |AUDIO_PCM_LINEAR|.
92  virtual AudioInputStream* MakeLinearInputStream(
93      const AudioParameters& params, const std::string& device_id) = 0;
94
95  // Creates the input stream for the |AUDIO_PCM_LOW_LATENCY| format.
96  virtual AudioInputStream* MakeLowLatencyInputStream(
97      const AudioParameters& params, const std::string& device_id) = 0;
98
99  // Listeners will be notified on the GetTaskRunner() task runner.
100  virtual void AddOutputDeviceChangeListener(
101      AudioDeviceListener* listener) OVERRIDE;
102  virtual void RemoveOutputDeviceChangeListener(
103      AudioDeviceListener* listener) OVERRIDE;
104
105  virtual AudioParameters GetDefaultOutputStreamParameters() OVERRIDE;
106  virtual AudioParameters GetOutputStreamParameters(
107      const std::string& device_id) OVERRIDE;
108
109  virtual AudioParameters GetInputStreamParameters(
110      const std::string& device_id) OVERRIDE;
111
112  virtual std::string GetAssociatedOutputDeviceID(
113      const std::string& input_device_id) OVERRIDE;
114
115  virtual scoped_ptr<AudioLog> CreateAudioLog(
116      AudioLogFactory::AudioComponent component) OVERRIDE;
117
118  // Get number of input or output streams.
119  int input_stream_count() const { return num_input_streams_; }
120  int output_stream_count() const { return num_output_streams_; }
121
122 protected:
123  AudioManagerBase(AudioLogFactory* audio_log_factory);
124
125  // Shuts down the audio thread and releases all the audio output dispatchers
126  // on the audio thread.  All audio streams should be freed before Shutdown()
127  // is called.  This must be called in the destructor of every AudioManagerBase
128  // implementation.
129  void Shutdown();
130
131  void SetMaxOutputStreamsAllowed(int max) { max_num_output_streams_ = max; }
132
133  // Called by each platform specific AudioManager to notify output state change
134  // listeners that a state change has occurred.  Must be called from the audio
135  // thread.
136  void NotifyAllOutputDeviceChangeListeners();
137
138  // Returns user buffer size as specified on the command line or 0 if no buffer
139  // size has been specified.
140  int GetUserBufferSize();
141
142  // Returns the preferred hardware audio output parameters for opening output
143  // streams. If the users inject a valid |input_params|, each AudioManager
144  // will decide if they should return the values from |input_params| or the
145  // default hardware values. If the |input_params| is invalid, it will return
146  // the default hardware audio parameters.
147  // If |output_device_id| is empty, the implementation must treat that as
148  // a request for the default output device.
149  virtual AudioParameters GetPreferredOutputStreamParameters(
150      const std::string& output_device_id,
151      const AudioParameters& input_params) = 0;
152
153  // Returns the ID of the default audio output device.
154  // Implementations that don't yet support this should return an empty string.
155  virtual std::string GetDefaultOutputDeviceID();
156
157 private:
158  struct DispatcherParams;
159  typedef ScopedVector<DispatcherParams> AudioOutputDispatchers;
160
161  class CompareByParams;
162
163  // Called by Shutdown().
164  void ShutdownOnAudioThread();
165
166  // Max number of open output streams, modified by
167  // SetMaxOutputStreamsAllowed().
168  int max_num_output_streams_;
169
170  // Max number of open input streams.
171  int max_num_input_streams_;
172
173  // Number of currently open output streams.
174  int num_output_streams_;
175
176  // Number of currently open input streams.
177  int num_input_streams_;
178
179  // Track output state change listeners.
180  ObserverList<AudioDeviceListener> output_listeners_;
181
182  // Thread used to interact with audio streams created by this audio manager.
183  base::Thread audio_thread_;
184
185  // The task runner of the audio thread this object runs on. Used for internal
186  // tasks which run on the audio thread even after Shutdown() has been started
187  // and GetTaskRunner() starts returning NULL.
188  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
189
190  // Map of cached AudioOutputDispatcher instances.  Must only be touched
191  // from the audio thread (no locking).
192  AudioOutputDispatchers output_dispatchers_;
193
194  // Proxy for creating AudioLog objects.
195  AudioLogFactory* const audio_log_factory_;
196
197  DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
198};
199
200}  // namespace media
201
202#endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
203