/* * 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 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. */ #include "config.h" #if ENABLE(WEB_AUDIO) #include "FFTConvolver.h" #include "VectorMath.h" namespace WebCore { using namespace VectorMath; FFTConvolver::FFTConvolver(size_t fftSize) : m_frame(fftSize) , m_readWriteIndex(0) , m_inputBuffer(fftSize) // 2nd half of buffer is always zeroed , m_outputBuffer(fftSize) , m_lastOverlapBuffer(fftSize / 2) { } void FFTConvolver::process(FFTFrame* fftKernel, const float* sourceP, float* destP, size_t framesToProcess) { size_t halfSize = fftSize() / 2; // framesToProcess must be an exact multiple of halfSize, // or halfSize is a multiple of framesToProcess when halfSize > framesToProcess. bool isGood = !(halfSize % framesToProcess && framesToProcess % halfSize); ASSERT(isGood); if (!isGood) return; size_t numberOfDivisions = halfSize <= framesToProcess ? (framesToProcess / halfSize) : 1; size_t divisionSize = numberOfDivisions == 1 ? framesToProcess : halfSize; for (size_t i = 0; i < numberOfDivisions; ++i, sourceP += divisionSize, destP += divisionSize) { // Copy samples to input buffer (note contraint above!) float* inputP = m_inputBuffer.data(); // Sanity check bool isCopyGood1 = sourceP && inputP && m_readWriteIndex + divisionSize <= m_inputBuffer.size(); ASSERT(isCopyGood1); if (!isCopyGood1) return; memcpy(inputP + m_readWriteIndex, sourceP, sizeof(float) * divisionSize); // Copy samples from output buffer float* outputP = m_outputBuffer.data(); // Sanity check bool isCopyGood2 = destP && outputP && m_readWriteIndex + divisionSize <= m_outputBuffer.size(); ASSERT(isCopyGood2); if (!isCopyGood2) return; memcpy(destP, outputP + m_readWriteIndex, sizeof(float) * divisionSize); m_readWriteIndex += divisionSize; // Check if it's time to perform the next FFT if (m_readWriteIndex == halfSize) { // The input buffer is now filled (get frequency-domain version) m_frame.doFFT(m_inputBuffer.data()); m_frame.multiply(*fftKernel); m_frame.doInverseFFT(m_outputBuffer.data()); // Overlap-add 1st half from previous time vadd(m_outputBuffer.data(), 1, m_lastOverlapBuffer.data(), 1, m_outputBuffer.data(), 1, halfSize); // Finally, save 2nd half of result bool isCopyGood3 = m_outputBuffer.size() == 2 * halfSize && m_lastOverlapBuffer.size() == halfSize; ASSERT(isCopyGood3); if (!isCopyGood3) return; memcpy(m_lastOverlapBuffer.data(), m_outputBuffer.data() + halfSize, sizeof(float) * halfSize); // Reset index back to start for next time m_readWriteIndex = 0; } } } void FFTConvolver::reset() { m_lastOverlapBuffer.zero(); m_readWriteIndex = 0; } } // namespace WebCore #endif // ENABLE(WEB_AUDIO)