1/*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef FFTConvolver_h
30#define FFTConvolver_h
31
32#include "AudioArray.h"
33#include "FFTFrame.h"
34
35namespace WebCore {
36
37class FFTConvolver {
38public:
39 // fftSize must be a power of two
40 FFTConvolver(size_t fftSize);
41
42 // For now, with multiple calls to Process(), framesToProcess MUST add up EXACTLY to fftSize / 2
43 //
44 // FIXME: Later, we can do more sophisticated buffering to relax this requirement...
45 //
46 // The input to output latency is equal to fftSize / 2
47 //
48 // Processing in-place is allowed...
49 void process(FFTFrame* fftKernel, const float* sourceP, float* destP, size_t framesToProcess);
50
51 void reset();
52
53 size_t fftSize() const { return m_frame.fftSize(); }
54
55private:
56 FFTFrame m_frame;
57
58 // Buffer input until we get fftSize / 2 samples then do an FFT
59 size_t m_readWriteIndex;
60 AudioFloatArray m_inputBuffer;
61
62 // Stores output which we read a little at a time
63 AudioFloatArray m_outputBuffer;
64
65 // Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the 1st half of the next one
66 AudioFloatArray m_lastOverlapBuffer;
67};
68
69} // namespace WebCore
70
71#endif // FFTConvolver_h
72