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      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_
    101