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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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 AudioBufferSourceNode_h
#define AudioBufferSourceNode_h
#include "AudioBuffer.h"
#include "AudioBus.h"
#include "AudioGain.h"
#include "AudioPannerNode.h"
#include "AudioResampler.h"
#include "AudioSourceNode.h"
#include "AudioSourceProvider.h"
#include <wtf/PassRefPtr.h>
#include <wtf/RefPtr.h>
#include <wtf/Threading.h>
namespace WebCore {
class AudioContext;
// AudioBufferSourceNode is an AudioNode representing an audio source from an in-memory audio asset represented by an AudioBuffer.
// It generally will be used for short sounds which require a high degree of scheduling flexibility (can playback in rhythmically perfect ways).
class AudioBufferSourceNode : public AudioSourceNode, public AudioSourceProvider {
public:
static PassRefPtr<AudioBufferSourceNode> create(AudioContext*, double sampleRate);
virtual ~AudioBufferSourceNode();
// AudioNode
virtual void process(size_t framesToProcess);
virtual void reset();
// AudioSourceProvider
// When process() is called, the resampler calls provideInput (in the audio thread) to gets its input stream.
virtual void provideInput(AudioBus*, size_t numberOfFrames);
// setBuffer() is called on the main thread. This is the buffer we use for playback.
void setBuffer(AudioBuffer*);
AudioBuffer* buffer() { return m_buffer.get(); }
// numberOfChannels() returns the number of output channels. This value equals the number of channels from the buffer.
// If a new buffer is set with a different number of channels, then this value will dynamically change.
unsigned numberOfChannels();
// Play-state
// noteOn(), noteGrainOn(), and noteOff() must all be called from the main thread.
void noteOn(double when);
void noteGrainOn(double when, double grainOffset, double grainDuration);
void noteOff(double when);
bool looping() const { return m_isLooping; }
void setLooping(bool looping) { m_isLooping = looping; }
AudioGain* gain() { return m_gain.get(); }
AudioParam* playbackRate() { return m_playbackRate.get(); }
// If a panner node is set, then we can incorporate doppler shift into the playback pitch rate.
void setPannerNode(PassRefPtr<AudioPannerNode> pannerNode) { m_pannerNode = pannerNode; }
private:
AudioBufferSourceNode(AudioContext*, double sampleRate);
// m_buffer holds the sample data which this node outputs.
RefPtr<AudioBuffer> m_buffer;
// Used for the "gain" and "playbackRate" attributes.
RefPtr<AudioGain> m_gain;
RefPtr<AudioParam> m_playbackRate;
// m_isPlaying is set to true when noteOn() or noteGrainOn() is called.
bool m_isPlaying;
// If m_isLooping is false, then this node will be done playing and become inactive after it reaches the end of the sample data in the buffer.
// If true, it will wrap around to the start of the buffer each time it reaches the end.
bool m_isLooping;
// This node is considered finished when it reaches the end of the buffer's sample data after noteOn() has been called.
// This will only be set to true if m_isLooping == false.
bool m_hasFinished;
// m_startTime is the time to start playing based on the context's timeline (0.0 or a time less than the context's current time means "now").
double m_startTime; // in seconds
// m_schedulingFrameDelay is the sample-accurate scheduling offset.
// It's used so that we start rendering audio samples at a very precise point in time.
// It will only be a non-zero value the very first render quantum that we render from the buffer.
int m_schedulingFrameDelay;
// m_readIndex is a sample-frame index into our buffer representing the current playback position.
unsigned m_readIndex;
// Granular playback
bool m_isGrain;
double m_grainOffset; // in seconds
double m_grainDuration; // in seconds
int m_grainFrameCount; // keeps track of which frame in the grain we're currently rendering
// totalPitchRate() returns the instantaneous pitch rate (non-time preserving).
// It incorporates the base pitch rate, any sample-rate conversion factor from the buffer, and any doppler shift from an associated panner node.
double totalPitchRate();
// m_resampler performs the pitch rate changes to the buffer playback.
AudioResampler m_resampler;
// m_lastGain provides continuity when we dynamically adjust the gain.
double m_lastGain;
// We optionally keep track of a panner node which has a doppler shift that is incorporated into the pitch rate.
RefPtr<AudioPannerNode> m_pannerNode;
// This synchronizes process() with setBuffer() which can cause dynamic channel count changes.
mutable Mutex m_processLock;
// Reads the next framesToProcess sample-frames from the AudioBuffer into destinationBus.
// A grain envelope will be applied if m_isGrain is set to true.
void readFromBuffer(AudioBus* destinationBus, size_t framesToProcess);
// readFromBufferWithGrainEnvelope() is a low-level blitter which reads from the AudioBuffer and applies a grain envelope.
void readFromBufferWithGrainEnvelope(float* sourceL, float* sourceR, float* destinationL, float* destinationR, size_t framesToProcess);
};
} // namespace WebCore
#endif // AudioBufferSourceNode_h
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