/*
* Copyright (C) 2010 Google Inc. All rights reserved.
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* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
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* 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
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#ifndef FFTConvolver_h
#define FFTConvolver_h
#include "platform/audio/AudioArray.h"
#include "platform/audio/FFTFrame.h"
namespace WebCore {
class PLATFORM_EXPORT FFTConvolver {
public:
// fftSize must be a power of two
FFTConvolver(size_t fftSize);
// For now, with multiple calls to Process(), framesToProcess MUST add up EXACTLY to fftSize / 2
//
// FIXME: Later, we can do more sophisticated buffering to relax this requirement...
//
// The input to output latency is equal to fftSize / 2
//
// Processing in-place is allowed...
void process(FFTFrame* fftKernel, const float* sourceP, float* destP, size_t framesToProcess);
void reset();
size_t fftSize() const { return m_frame.fftSize(); }
private:
FFTFrame m_frame;
// Buffer input until we get fftSize / 2 samples then do an FFT
size_t m_readWriteIndex;
AudioFloatArray m_inputBuffer;
// Stores output which we read a little at a time
AudioFloatArray m_outputBuffer;
// Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the 1st half of the next one
AudioFloatArray m_lastOverlapBuffer;
};
} // namespace WebCore
#endif // FFTConvolver_h