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 Computer, 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 35 namespace WebCore { 36 37 class FFTConvolver { 38 public: 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, float* sourceP, float* destP, size_t framesToProcess); 50 51 void reset(); 52 fftSize()53 size_t fftSize() const { return m_frame.fftSize(); } 54 55 private: 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