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 #include "config.h" 30 31 #if ENABLE(WEB_AUDIO) 32 33 #include "FFTConvolver.h" 34 35 #include "VectorMath.h" 36 37 namespace WebCore { 38 39 using namespace VectorMath; 40 41 FFTConvolver::FFTConvolver(size_t fftSize) 42 : m_frame(fftSize) 43 , m_readWriteIndex(0) 44 , m_inputBuffer(fftSize) // 2nd half of buffer is always zeroed 45 , m_outputBuffer(fftSize) 46 , m_lastOverlapBuffer(fftSize / 2) 47 { 48 } 49 50 void FFTConvolver::process(FFTFrame* fftKernel, float* sourceP, float* destP, size_t framesToProcess) 51 { 52 // FIXME: make so framesToProcess is not required to fit evenly into fftSize/2 53 54 // Copy samples to input buffer (note contraint above!) 55 float* inputP = m_inputBuffer.data(); 56 57 // Sanity check 58 bool isCopyGood1 = sourceP && inputP && m_readWriteIndex + framesToProcess <= m_inputBuffer.size(); 59 ASSERT(isCopyGood1); 60 if (!isCopyGood1) 61 return; 62 63 memcpy(inputP + m_readWriteIndex, sourceP, sizeof(float) * framesToProcess); 64 65 // Copy samples from output buffer 66 float* outputP = m_outputBuffer.data(); 67 68 // Sanity check 69 bool isCopyGood2 = destP && outputP && m_readWriteIndex + framesToProcess <= m_outputBuffer.size(); 70 ASSERT(isCopyGood2); 71 if (!isCopyGood2) 72 return; 73 74 memcpy(destP, outputP + m_readWriteIndex, sizeof(float) * framesToProcess); 75 m_readWriteIndex += framesToProcess; 76 77 78 // Check if it's time to perform the next FFT 79 size_t halfSize = fftSize() / 2; 80 if (m_readWriteIndex == halfSize) { 81 // The input buffer is now filled (get frequency-domain version) 82 m_frame.doFFT(m_inputBuffer.data()); 83 m_frame.multiply(*fftKernel); 84 m_frame.doInverseFFT(m_outputBuffer.data()); 85 86 // Overlap-add 1st half from previous time 87 vadd(m_outputBuffer.data(), 1, m_lastOverlapBuffer.data(), 1, m_outputBuffer.data(), 1, halfSize); 88 89 // Finally, save 2nd half of result 90 bool isCopyGood3 = m_outputBuffer.size() == 2 * halfSize && m_lastOverlapBuffer.size() == halfSize; 91 ASSERT(isCopyGood3); 92 if (!isCopyGood3) 93 return; 94 95 memcpy(m_lastOverlapBuffer.data(), m_outputBuffer.data() + halfSize, sizeof(float) * halfSize); 96 97 // Reset index back to start for next time 98 m_readWriteIndex = 0; 99 } 100 } 101 102 void FFTConvolver::reset() 103 { 104 m_lastOverlapBuffer.zero(); 105 m_readWriteIndex = 0; 106 } 107 108 } // namespace WebCore 109 110 #endif // ENABLE(WEB_AUDIO) 111
