media/audio/audio_manager_base.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_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
  24 namespace media {
  25
  26 class AudioOutputDispatcher;
  27
  28 // AudioManagerBase provides AudioManager functions common for all platforms.
  29 class 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_