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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef AudioDestination_h
#define AudioDestination_h
#include "AudioBus.h"
#include "AudioIOCallback.h"
#include <memory>
#include <wtf/AbstractRefCounted.h>
#include <wtf/CompletionHandler.h>
#include <wtf/Lock.h>
#include <wtf/MediaTime.h>
#include <wtf/ThreadSafeRefCounted.h>
#include <wtf/text/WTFString.h>
namespace WebCore {
// AudioDestination is an abstraction for audio hardware I/O.
// The audio hardware periodically calls the AudioIOCallback render() method asking it to render/output the next render quantum of audio.
// It optionally will pass in local/live audio input when it calls render().
class AudioDestination : public AbstractRefCounted {
public:
// Pass in (numberOfInputChannels > 0) if live/local audio input is desired.
// Port-specific device identification information for live/local input streams can be passed in the inputDeviceId.
WEBCORE_EXPORT static Ref<AudioDestination> create(AudioIOCallback&, const String& inputDeviceId, unsigned numberOfInputChannels, unsigned numberOfOutputChannels, float sampleRate);
virtual ~AudioDestination() = default;
void clearCallback();
virtual void start(Function<void(Function<void()>&&)>&& dispatchToRenderThread, CompletionHandler<void(bool)>&& = [](bool) { }) = 0;
virtual void stop(CompletionHandler<void(bool)>&& = [](bool) { }) = 0;
virtual bool isPlaying() = 0;
// Sample-rate conversion may happen in AudioDestination to the hardware sample-rate
virtual float sampleRate() const { return m_sampleRate; }
WEBCORE_EXPORT static float hardwareSampleRate();
virtual unsigned framesPerBuffer() const = 0;
virtual WTF::MediaTime outputLatency() const { return MediaTime::zeroTime(); }
// maxChannelCount() returns the total number of output channels of the audio hardware.
// A value of 0 indicates that the number of channels cannot be configured and
// that only stereo (2-channel) destinations can be created.
// The numberOfOutputChannels parameter of AudioDestination::create() is allowed to
// be a value: 1 <= numberOfOutputChannels <= maxChannelCount(),
// or if maxChannelCount() equals 0, then numberOfOutputChannels must be 2.
static unsigned long maxChannelCount();
void callRenderCallback(AudioBus* sourceBus, AudioBus* destinationBus, size_t framesToProcess, const AudioIOPosition& outputPosition);
protected:
explicit AudioDestination(AudioIOCallback&, float sampleRate);
Lock m_callbackLock;
AudioIOCallback* m_callback WTF_GUARDED_BY_LOCK(m_callbackLock) { nullptr };
private:
const float m_sampleRate;
};
inline AudioDestination::AudioDestination(AudioIOCallback& callback, float sampleRate)
: m_sampleRate(sampleRate)
{
Locker locker { m_callbackLock };
m_callback = &callback;
}
inline void AudioDestination::clearCallback()
{
Locker locker { m_callbackLock };
m_callback = nullptr;
}
inline void AudioDestination::callRenderCallback(AudioBus* sourceBus, AudioBus* destinationBus, size_t framesToProcess, const AudioIOPosition& outputPosition)
{
if (m_callbackLock.tryLock()) {
Locker locker { AdoptLock, m_callbackLock };
if (m_callback) {
m_callback->render(sourceBus, destinationBus, framesToProcess, outputPosition);
return;
}
}
destinationBus->zero();
}
} // namespace WebCore
#endif // AudioDestination_h
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