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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_OUTPUT_MAC_H_
#define MEDIA_AUDIO_MAC_AUDIO_OUTPUT_MAC_H_
#include <AudioToolbox/AudioFormat.h>
#include <AudioToolbox/AudioQueue.h>
#include <AudioUnit/AudioUnit.h>
#include "base/compiler_specific.h"
#include "base/synchronization/lock.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_parameters.h"
class AudioManagerMac;
// Implementation of AudioOuputStream for Mac OS X using the audio queue service
// present in OS 10.5 and later. Audioqueue is the successor to the SoundManager
// services but it is supported in 64 bits.
class PCMQueueOutAudioOutputStream : public AudioOutputStream {
public:
// The ctor takes all the usual parameters, plus |manager| which is the
// the audio manager who is creating this object.
PCMQueueOutAudioOutputStream(AudioManagerMac* manager,
const AudioParameters& params);
// The dtor is typically called by the AudioManager only and it is usually
// triggered by calling AudioOutputStream::Close().
virtual ~PCMQueueOutAudioOutputStream();
// Implementation of AudioOutputStream.
virtual bool Open() OVERRIDE;
virtual void Close() OVERRIDE;
virtual void Start(AudioSourceCallback* callback) OVERRIDE;
virtual void Stop() OVERRIDE;
virtual void SetVolume(double volume) OVERRIDE;
virtual void GetVolume(double* volume) OVERRIDE;
private:
// The audio is double buffered.
static const uint32 kNumBuffers = 2;
static const int kEmptyChannel = -1;
// Reorder PCM from source layout to device layout found in Core Audio.
template<class Format>
void SwizzleLayout(Format* b, uint32 filled);
// Check and move channels if surround sound layout needs adjusted.
bool CheckForAdjustedLayout(Channels input_channel, Channels output_channel);
// The OS calls back here when an audio buffer has been processed.
static void RenderCallback(void* p_this, AudioQueueRef queue,
AudioQueueBufferRef buffer);
// Called when an error occurs.
void HandleError(OSStatus err);
// Atomic operations for setting/getting the source callback.
void SetSource(AudioSourceCallback* source);
AudioSourceCallback* GetSource();
// Structure that holds the stream format details such as bitrate.
AudioStreamBasicDescription format_;
// Handle to the OS audio queue object.
AudioQueueRef audio_queue_;
// Array of pointers to the OS managed audio buffers.
AudioQueueBufferRef buffer_[kNumBuffers];
// Mutex for the |source_| to implment atomic set and get.
// It is important to NOT wait on any other locks while this is held.
base::Lock source_lock_;
// Pointer to the object that will provide the audio samples.
AudioSourceCallback* source_;
// Our creator, the audio manager needs to be notified when we close.
AudioManagerMac* manager_;
// Packet size in bytes.
uint32 packet_size_;
// Number of bytes for making a silence buffer.
int silence_bytes_;
// Volume level from 0 to 1.
float volume_;
// Number of bytes yet to be played in audio buffer.
uint32 pending_bytes_;
// Number of channels in the source audio.
int num_source_channels_;
// Source's channel layout for surround sound channels.
ChannelLayout source_layout_;
// Device's channel layout.
int core_channel_orderings_[CHANNELS_MAX];
// An array for remapping source to device channel layouts during a swizzle.
int channel_remap_[CHANNELS_MAX];
// Number of channels in device layout.
int num_core_channels_;
// A flag to determine if swizzle is needed from source to device layouts.
bool should_swizzle_;
// A flag to determine if downmix is needed from source to device layouts.
bool should_down_mix_;
DISALLOW_COPY_AND_ASSIGN(PCMQueueOutAudioOutputStream);
};
#endif // MEDIA_AUDIO_MAC_AUDIO_OUTPUT_MAC_H_
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