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   // Unique Id of the generic default communications device (where supported).
  39   static const char kCommunicationsDeviceId[];
  40   // Name of the generic default communications device (where supported).
  41   static const char kCommunicationsDeviceName[];
  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   ~AudioManagerBase() override;
  54
  55   // AudioManager:
  56   scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() override;
  57   scoped_refptr<base::SingleThreadTaskRunner> GetWorkerTaskRunner() override;
  58   base::string16 GetAudioInputDeviceModel() override;
  59   void ShowAudioInputSettings() override;
  60   void GetAudioInputDeviceNames(AudioDeviceNames* device_names) override;
  61   void GetAudioOutputDeviceNames(AudioDeviceNames* device_names) override;
  62   AudioOutputStream* MakeAudioOutputStream(
  63       const AudioParameters& params,
  64       const std::string& device_id) override;
  65   AudioInputStream* MakeAudioInputStream(const AudioParameters& params,
  66                                          const std::string& device_id) override;
  67   AudioOutputStream* MakeAudioOutputStreamProxy(
  68       const AudioParameters& params,
  69       const std::string& device_id) override;
  70
  71   // Listeners will be notified on the GetTaskRunner() task runner.
  72   void AddOutputDeviceChangeListener(AudioDeviceListener* listener) override;
  73   void RemoveOutputDeviceChangeListener(AudioDeviceListener* listener) override;
  74
  75   AudioParameters GetDefaultOutputStreamParameters() override;
  76   AudioParameters GetOutputStreamParameters(
  77       const std::string& device_id) override;
  78   AudioParameters GetInputStreamParameters(
  79       const std::string& device_id) override;
  80   std::string GetAssociatedOutputDeviceID(
  81       const std::string& input_device_id) override;
  82   scoped_ptr<AudioLog> CreateAudioLog(
  83       AudioLogFactory::AudioComponent component) override;
  84   void SetHasKeyboardMic() override;
  85
  86   // AudioManagerBase:
  87
  88   // Called internally by the audio stream when it has been closed.
  89   virtual void ReleaseOutputStream(AudioOutputStream* stream);
  90   virtual void ReleaseInputStream(AudioInputStream* stream);
  91
  92   // Creates the output stream for the |AUDIO_PCM_LINEAR| format. The legacy
  93   // name is also from |AUDIO_PCM_LINEAR|.
  94   virtual AudioOutputStream* MakeLinearOutputStream(
  95       const AudioParameters& params) = 0;
  96
  97   // Creates the output stream for the |AUDIO_PCM_LOW_LATENCY| format.
  98   virtual AudioOutputStream* MakeLowLatencyOutputStream(
  99       const AudioParameters& params,
 100       const std::string& device_id) = 0;
 101
 102   // Creates the input stream for the |AUDIO_PCM_LINEAR| format. The legacy
 103   // name is also from |AUDIO_PCM_LINEAR|.
 104   virtual AudioInputStream* MakeLinearInputStream(
 105       const AudioParameters& params, const std::string& device_id) = 0;
 106
 107   // Creates the input stream for the |AUDIO_PCM_LOW_LATENCY| format.
 108   virtual AudioInputStream* MakeLowLatencyInputStream(
 109       const AudioParameters& params, const std::string& device_id) = 0;
 110
 111   // Get number of input or output streams.
 112   int input_stream_count() const { return num_input_streams_; }
 113   int output_stream_count() const { return num_output_streams_; }
 114
 115  protected:
 116   AudioManagerBase(AudioLogFactory* audio_log_factory);
 117
 118   // Shuts down the audio thread and releases all the audio output dispatchers
 119   // on the audio thread.  All audio streams should be freed before Shutdown()
 120   // is called.  This must be called in the destructor of every AudioManagerBase
 121   // implementation.
 122   void Shutdown();
 123
 124   void SetMaxOutputStreamsAllowed(int max) { max_num_output_streams_ = max; }
 125
 126   // Called by each platform specific AudioManager to notify output state change
 127   // listeners that a state change has occurred.  Must be called from the audio
 128   // thread.
 129   void NotifyAllOutputDeviceChangeListeners();
 130
 131   // Returns user buffer size as specified on the command line or 0 if no buffer
 132   // size has been specified.
 133   int GetUserBufferSize();
 134
 135   // Returns the preferred hardware audio output parameters for opening output
 136   // streams. If the users inject a valid |input_params|, each AudioManager
 137   // will decide if they should return the values from |input_params| or the
 138   // default hardware values. If the |input_params| is invalid, it will return
 139   // the default hardware audio parameters.
 140   // If |output_device_id| is empty, the implementation must treat that as
 141   // a request for the default output device.
 142   virtual AudioParameters GetPreferredOutputStreamParameters(
 143       const std::string& output_device_id,
 144       const AudioParameters& input_params) = 0;
 145
 146   // Returns the ID of the default audio output device.
 147   // Implementations that don't yet support this should return an empty string.
 148   virtual std::string GetDefaultOutputDeviceID();
 149
 150  private:
 151   struct DispatcherParams;
 152   typedef ScopedVector<DispatcherParams> AudioOutputDispatchers;
 153
 154   class CompareByParams;
 155
 156   // Called by Shutdown().
 157   void ShutdownOnAudioThread();
 158
 159   // Max number of open output streams, modified by
 160   // SetMaxOutputStreamsAllowed().
 161   int max_num_output_streams_;
 162
 163   // Max number of open input streams.
 164   int max_num_input_streams_;
 165
 166   // Number of currently open output streams.
 167   int num_output_streams_;
 168
 169   // Number of currently open input streams.
 170   int num_input_streams_;
 171
 172   // Track output state change listeners.
 173   base::ObserverList<AudioDeviceListener> output_listeners_;
 174
 175   // Thread used to interact with audio streams created by this audio manager.
 176   base::Thread audio_thread_;
 177
 178   // The task runner of the audio thread this object runs on. Used for internal
 179   // tasks which run on the audio thread even after Shutdown() has been started
 180   // and GetTaskRunner() starts returning NULL.
 181   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 182
 183   // Map of cached AudioOutputDispatcher instances.  Must only be touched
 184   // from the audio thread (no locking).
 185   AudioOutputDispatchers output_dispatchers_;
 186
 187   // Proxy for creating AudioLog objects.
 188   AudioLogFactory* const audio_log_factory_;
 189
 190   DISALLOW_COPY_AND_ASSIGN(AudioManagerBase);
 191 };
 192
 193 }  // namespace media
 194
 195 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_BASE_H_