audio_manager_base.h revision d0247b1b59f9c528cb6df88b4f2b9afaf80d181e 
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/synchronization/lock.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 base {
25class Thread;
26}
27
28namespace media {
29
30class AudioOutputDispatcher;
31
32// AudioManagerBase provides AudioManager functions common for all platforms.
33class MEDIA_EXPORT AudioManagerBase : public AudioManager {
34 public:
35  // TODO(sergeyu): The constants below belong to AudioManager interface, not
36  // to the base implementation.
37
38  // Name of the generic "default" device.
39  static const char kDefaultDeviceName[];
40  // Unique Id of the generic "default" device.
41  static const char kDefaultDeviceId[];
42
43  // Input device ID used to capture the default system playback stream. When
44  // this device ID is passed to MakeAudioInputStream() the returned
45  // AudioInputStream will be capturing audio currently being played on the
46  // default playback device. At the moment this feature is supported only on
47  // some platforms. AudioInputStream::Intialize() will return an error on
48  // platforms that don't support it. GetInputStreamParameters() must be used
49  // to get the parameters of the loopback device before creating a loopback
50  // stream, otherwise stream initialization may fail.
51  static const char kLoopbackInputDeviceId[];
52
53  virtual ~AudioManagerBase();
54
55  virtual scoped_refptr<base::MessageLoopProxy> GetMessageLoop() OVERRIDE;
56  virtual scoped_refptr<base::MessageLoopProxy> GetWorkerLoop() OVERRIDE;
57
58  virtual string16 GetAudioInputDeviceModel() OVERRIDE;
59
60  virtual void ShowAudioInputSettings() OVERRIDE;
61
62  virtual void GetAudioInputDeviceNames(
63      AudioDeviceNames* device_names) OVERRIDE;
64
65  virtual void GetAudioOutputDeviceNames(
66      AudioDeviceNames* device_names) OVERRIDE;
67
68  virtual AudioOutputStream* MakeAudioOutputStream(
69      const AudioParameters& params,
70      const std::string& device_id,
71      const std::string& input_device_id) OVERRIDE;
72
73  virtual AudioInputStream* MakeAudioInputStream(
74      const AudioParameters& params, const std::string& device_id) OVERRIDE;
75
76  virtual AudioOutputStream* MakeAudioOutputStreamProxy(
77      const AudioParameters& params,
78      const std::string& device_id,
79      const std::string& input_device_id) OVERRIDE;
80
81  // Called internally by the audio stream when it has been closed.
82  virtual void ReleaseOutputStream(AudioOutputStream* stream);
83  virtual void ReleaseInputStream(AudioInputStream* stream);
84
85  // Creates the output stream for the |AUDIO_PCM_LINEAR| format. The legacy
86  // name is also from |AUDIO_PCM_LINEAR|.
87  virtual AudioOutputStream* MakeLinearOutputStream(
88      const AudioParameters& params) = 0;
89
90  // Creates the output stream for the |AUDIO_PCM_LOW_LATENCY| format.
91  // |input_device_id| is used by unified IO to open the correct input device.
92  virtual AudioOutputStream* MakeLowLatencyOutputStream(
93      const AudioParameters& params,
94      const std::string& device_id,
95      const std::string& input_device_id) = 0;
96
97  // Creates the input stream for the |AUDIO_PCM_LINEAR| format. The legacy
98  // name is also from |AUDIO_PCM_LINEAR|.
99  virtual AudioInputStream* MakeLinearInputStream(
100      const AudioParameters& params, const std::string& device_id) = 0;
101
102  // Creates the input stream for the |AUDIO_PCM_LOW_LATENCY| format.
103  virtual AudioInputStream* MakeLowLatencyInputStream(
104      const AudioParameters& params, const std::string& device_id) = 0;
105
106  // Listeners will be notified on the AudioManager::GetMessageLoop() loop.
107  virtual void AddOutputDeviceChangeListener(
108      AudioDeviceListener* listener) OVERRIDE;
109  virtual void RemoveOutputDeviceChangeListener(
110      AudioDeviceListener* listener) OVERRIDE;
111
112  virtual AudioParameters GetDefaultOutputStreamParameters() OVERRIDE;
113  virtual AudioParameters GetOutputStreamParameters(
114      const std::string& device_id) OVERRIDE;
115
116  virtual AudioParameters GetInputStreamParameters(
117      const std::string& device_id) OVERRIDE;
118
119  virtual std::string GetAssociatedOutputDeviceID(
120      const std::string& input_device_id) OVERRIDE;
121
122 protected:
123  AudioManagerBase();
124
125
126  // Shuts down the audio thread and releases all the audio output dispatchers
127  // on the audio thread.  All audio streams should be freed before Shutdown()
128  // is called.  This must be called in the destructor of every AudioManagerBase
129  // implementation.
130  void Shutdown();
131
132  void SetMaxOutputStreamsAllowed(int max) { max_num_output_streams_ = max; }
133
134  // Called by each platform specific AudioManager to notify output state change
135  // listeners that a state change has occurred.  Must be called from the audio
136  // thread.
137  void NotifyAllOutputDeviceChangeListeners();
138
139  // Returns the preferred hardware audio output parameters for opening output
140  // streams. If the users inject a valid |input_params|, each AudioManager
141  // will decide if they should return the values from |input_params| or the
142  // default hardware values. If the |input_params| is invalid, it will return
143  // the default hardware audio parameters.
144  // If |output_device_id| is empty, the implementation must treat that as
145  // a request for the default output device.
146  virtual AudioParameters GetPreferredOutputStreamParameters(
147      const std::string& output_device_id,
148      const AudioParameters& input_params) = 0;
149
150  // Returns the ID of the default audio output device.
151  // Implementations that don't yet support this should return an empty string.
152  virtual std::string GetDefaultOutputDeviceID();
153
154  // Get number of input or output streams.
155  int input_stream_count() { return num_input_streams_; }
156  int output_stream_count() { return num_output_streams_; }
157
158 private:
159  struct DispatcherParams;
160  typedef ScopedVector<DispatcherParams> AudioOutputDispatchers;
161
162  class CompareByParams;
163
164  // Called by Shutdown().
165  void ShutdownOnAudioThread();
166
167  // Max number of open output streams, modified by
168  // SetMaxOutputStreamsAllowed().
169  int max_num_output_streams_;
170
171  // Max number of open input streams.
172  int max_num_input_streams_;
173
174  // Number of currently open output streams.
175  int num_output_streams_;
176
177  // Number of currently open input streams.
178  int num_input_streams_;
179
180  // Track output state change listeners.
181  ObserverList<AudioDeviceListener> output_listeners_;
182
183  // Thread used to interact with audio streams created by this audio manager.
184  scoped_ptr<base::Thread> audio_thread_;
185  mutable base::Lock audio_thread_lock_;
186
187  // The message loop of the audio thread this object runs on. Used for internal
188  // tasks which run on the audio thread even after Shutdown() has been started
189  // and GetMessageLoop() starts returning NULL.
190  scoped_refptr<base::MessageLoopProxy> message_loop_;
191
192  // Map of cached AudioOutputDispatcher instances.  Must only be touched
193  // from the audio thread (no locking).
194  AudioOutputDispatchers output_dispatchers_;
195
196  DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
197};
198
199}  // namespace media
200
201#endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_
202