| /* |
| * 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 |
| * 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 "platform/audio/FFTConvolver.h" |
| |
| #include "platform/audio/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) |