AudioBuffer.h   [plain text]

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * 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 Computer, 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
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 */

#ifndef AudioBuffer_h
#define AudioBuffer_h

#include <wtf/Float32Array.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>
#include <wtf/Vector.h>

namespace WebCore {

class AudioBus;
    
class AudioBuffer : public RefCounted<AudioBuffer> {
public:   
    static PassRefPtr<AudioBuffer> create(unsigned numberOfChannels, size_t numberOfFrames, double sampleRate);

    // Returns 0 if data is not a valid audio file.
    static PassRefPtr<AudioBuffer> createFromAudioFileData(const void* data, size_t dataSize, bool mixToMono, double sampleRate);

    // Format
    size_t length() const { return m_length; }
    double duration() const { return length() / sampleRate(); }
    double sampleRate() const { return m_sampleRate; }

    // Channel data access
    unsigned numberOfChannels() const { return m_channels.size(); }
    Float32Array* getChannelData(unsigned channelIndex);
    void zero();

    // Scalar gain
    double gain() const { return m_gain; }
    void setGain(double gain) { m_gain = gain; }

    // Because an AudioBuffer has a JavaScript wrapper, which will be garbage collected, it may take awhile for this object to be deleted.
    // releaseMemory() can be called when the AudioContext goes away, so we can release the memory earlier than when the garbage collection happens.
    // Careful! Only call this when the page unloads, after the AudioContext is no longer processing.
    void releaseMemory();
    
protected:
    AudioBuffer(unsigned numberOfChannels, size_t numberOfFrames, double sampleRate);
    AudioBuffer(AudioBus* bus);

    double m_gain; // scalar gain
    double m_sampleRate;
    size_t m_length;

    Vector<RefPtr<Float32Array> > m_channels;
};

} // namespace WebCore

#endif // AudioBuffer_h