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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_OUTPUT_MAC_H_
#define MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_OUTPUT_MAC_H_
#include <AudioUnit/AudioUnit.h>
#include "media/audio/audio_io.h"
#include "media/audio/audio_parameters.h"
class AudioManagerMac;
// Implementation of AudioOuputStream for Mac OS X using the
// default output Audio Unit present in OS 10.4 and later.
// The default output Audio Unit is for low-latency audio I/O.
class AUAudioOutputStream : public AudioOutputStream {
public:
// The ctor takes all the usual parameters, plus |manager| which is the
// the audio manager who is creating this object.
AUAudioOutputStream(AudioManagerMac* manager,
AudioParameters params);
// The dtor is typically called by the AudioManager only and it is usually
// triggered by calling AudioOutputStream::Close().
virtual ~AUAudioOutputStream();
// Implementation of AudioOutputStream.
virtual bool Open();
virtual void Close();
virtual void Start(AudioSourceCallback* callback);
virtual void Stop();
virtual void SetVolume(double volume);
virtual void GetVolume(double* volume);
static double HardwareSampleRate();
private:
// DefaultOutputUnit callback.
static OSStatus InputProc(void* user_data,
AudioUnitRenderActionFlags* flags,
const AudioTimeStamp* time_stamp,
UInt32 bus_number,
UInt32 number_of_frames,
AudioBufferList* io_data);
OSStatus Render(UInt32 number_of_frames, AudioBufferList* io_data);
// Sets up the stream format for the default output Audio Unit.
bool Configure();
// Our creator, the audio manager needs to be notified when we close.
AudioManagerMac* manager_;
size_t number_of_frames_;
// Pointer to the object that will provide the audio samples.
AudioSourceCallback* source_;
// Structure that holds the stream format details such as bitrate.
AudioStreamBasicDescription format_;
// The default output Audio Unit which talks to the audio hardware.
AudioUnit output_unit_;
// Volume level from 0 to 1.
float volume_;
DISALLOW_COPY_AND_ASSIGN(AUAudioOutputStream);
};
#endif // MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_OUTPUT_MAC_H_
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