media/audio/mac/audio_unified_mac.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_MAC_AUDIO_UNIFIED_MAC_H_
   6 #define MEDIA_AUDIO_MAC_AUDIO_UNIFIED_MAC_H_
   7
   8 #include <CoreAudio/CoreAudio.h>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "media/audio/audio_io.h"
  12 #include "media/audio/audio_parameters.h"
  13
  14 namespace media {
  15
  16 class AudioManagerMac;
  17
  18 // Implementation of AudioOutputStream for Mac OS X using the
  19 // CoreAudio AudioHardware API suitable for low-latency unified audio I/O
  20 // when using devices which support *both* input and output
  21 // in the same driver.  This is the case with professional
  22 // USB and Firewire devices.
  23 //
  24 // Please note that it's required to first get the native sample-rate of the
  25 // default output device and use that sample-rate when creating this object.
  26 class AudioHardwareUnifiedStream : public AudioOutputStream {
  27  public:
  28   // The ctor takes all the usual parameters, plus |manager| which is the
  29   // the audio manager who is creating this object.
  30   AudioHardwareUnifiedStream(AudioManagerMac* manager,
  31                              const AudioParameters& params);
  32   // The dtor is typically called by the AudioManager only and it is usually
  33   // triggered by calling AudioOutputStream::Close().
  34   virtual ~AudioHardwareUnifiedStream();
  35
  36   // Implementation of AudioOutputStream.
  37   virtual bool Open() OVERRIDE;
  38   virtual void Close() OVERRIDE;
  39   virtual void Start(AudioSourceCallback* callback) OVERRIDE;
  40   virtual void Stop() OVERRIDE;
  41   virtual void SetVolume(double volume) OVERRIDE;
  42   virtual void GetVolume(double* volume) OVERRIDE;
  43
  44   int input_channels() const { return input_channels_; }
  45   int output_channels() const { return output_channels_; }
  46
  47  private:
  48   OSStatus Render(AudioDeviceID device,
  49                   const AudioTimeStamp* now,
  50                   const AudioBufferList* input_data,
  51                   const AudioTimeStamp* input_time,
  52                   AudioBufferList* output_data,
  53                   const AudioTimeStamp* output_time);
  54
  55   static OSStatus RenderProc(AudioDeviceID device,
  56                              const AudioTimeStamp* now,
  57                              const AudioBufferList* input_data,
  58                              const AudioTimeStamp* input_time,
  59                              AudioBufferList* output_data,
  60                              const AudioTimeStamp* output_time,
  61                              void* user_data);
  62
  63   // Our creator, the audio manager needs to be notified when we close.
  64   AudioManagerMac* manager_;
  65
  66   // Pointer to the object that will provide the audio samples.
  67   AudioSourceCallback* source_;
  68
  69   // Structure that holds the stream format details such as bitrate.
  70   AudioStreamBasicDescription format_;
  71
  72   // Hardware buffer size.
  73   int number_of_frames_;
  74
  75   // Number of audio channels provided to the client via OnMoreIOData().
  76   int client_input_channels_;
  77
  78   // Volume level from 0 to 1.
  79   float volume_;
  80
  81   // Number of input and output channels queried from the hardware.
  82   int input_channels_;
  83   int output_channels_;
  84   int input_channels_per_frame_;
  85   int output_channels_per_frame_;
  86
  87   AudioDeviceIOProcID io_proc_id_;
  88   AudioDeviceID device_;
  89   bool is_playing_;
  90
  91   // Intermediate buffers used with call to OnMoreIOData().
  92   scoped_ptr<AudioBus> input_bus_;
  93   scoped_ptr<AudioBus> output_bus_;
  94
  95   DISALLOW_COPY_AND_ASSIGN(AudioHardwareUnifiedStream);
  96 };
  97
  98 }  // namespace media
  99
 100 #endif  // MEDIA_AUDIO_MAC_AUDIO_UNIFIED_MAC_H_