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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 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
* 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 FFTConvolver_h
#define FFTConvolver_h
#include "platform/audio/AudioArray.h"
#include "platform/audio/FFTFrame.h"
#include "wtf/Allocator.h"
#include "wtf/Noncopyable.h"
namespace blink {
class PLATFORM_EXPORT FFTConvolver {
USING_FAST_MALLOC(FFTConvolver);
WTF_MAKE_NONCOPYABLE(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 blink
#endif // FFTConvolver_h
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