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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
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_FFT_CONVOLVER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_FFT_CONVOLVER_H_
#include "base/macros.h"
#include "third_party/blink/renderer/platform/audio/audio_array.h"
#include "third_party/blink/renderer/platform/audio/fft_frame.h"
#include "third_party/blink/renderer/platform/wtf/allocator.h"
namespace blink {
class PLATFORM_EXPORT FFTConvolver {
USING_FAST_MALLOC(FFTConvolver);
public:
// fftSize must be a power of two
FFTConvolver(size_t fft_size);
// 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(const FFTFrame* fft_kernel,
const float* source_p,
float* dest_p,
uint32_t frames_to_process);
void Reset();
size_t FftSize() const { return frame_.FftSize(); }
private:
FFTFrame frame_;
// Buffer input until we get fftSize / 2 samples then do an FFT
size_t read_write_index_;
AudioFloatArray input_buffer_;
// Stores output which we read a little at a time
AudioFloatArray output_buffer_;
// Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the
// 1st half of the next one
AudioFloatArray last_overlap_buffer_;
DISALLOW_COPY_AND_ASSIGN(FFTConvolver);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_FFT_CONVOLVER_H_