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Diffstat (limited to 'dom/media/webaudio/blink/FFTConvolver.cpp')
| -rw-r--r-- | dom/media/webaudio/blink/FFTConvolver.cpp | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/dom/media/webaudio/blink/FFTConvolver.cpp b/dom/media/webaudio/blink/FFTConvolver.cpp new file mode 100644 index 000000000..8694073ae --- /dev/null +++ b/dom/media/webaudio/blink/FFTConvolver.cpp @@ -0,0 +1,119 @@ +/* + * 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 "FFTConvolver.h" +#include "mozilla/PodOperations.h" + +using namespace mozilla; + +namespace WebCore { + +FFTConvolver::FFTConvolver(size_t fftSize, size_t renderPhase) + : m_frame(fftSize) + , m_readWriteIndex(renderPhase % (fftSize / 2)) +{ + MOZ_ASSERT(fftSize >= 2 * WEBAUDIO_BLOCK_SIZE); + m_inputBuffer.SetLength(fftSize); + PodZero(m_inputBuffer.Elements(), fftSize); + m_outputBuffer.SetLength(fftSize); + PodZero(m_outputBuffer.Elements(), fftSize); + m_lastOverlapBuffer.SetLength(fftSize / 2); + PodZero(m_lastOverlapBuffer.Elements(), fftSize / 2); +} + +size_t FFTConvolver::sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const +{ + size_t amount = 0; + amount += m_frame.SizeOfExcludingThis(aMallocSizeOf); + amount += m_inputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf); + amount += m_outputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf); + amount += m_lastOverlapBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf); + return amount; +} + +size_t FFTConvolver::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const +{ + return aMallocSizeOf(this) + sizeOfExcludingThis(aMallocSizeOf); +} + +const float* FFTConvolver::process(FFTBlock* fftKernel, const float* sourceP) +{ + size_t halfSize = fftSize() / 2; + + // WEBAUDIO_BLOCK_SIZE must be an exact multiple of halfSize, + // halfSize must be a multiple of WEBAUDIO_BLOCK_SIZE + // and > WEBAUDIO_BLOCK_SIZE. + MOZ_ASSERT(halfSize % WEBAUDIO_BLOCK_SIZE == 0 && + WEBAUDIO_BLOCK_SIZE <= halfSize); + + // Copy samples to input buffer (note contraint above!) + float* inputP = m_inputBuffer.Elements(); + + MOZ_ASSERT(sourceP && inputP && m_readWriteIndex + WEBAUDIO_BLOCK_SIZE <= m_inputBuffer.Length()); + + memcpy(inputP + m_readWriteIndex, sourceP, sizeof(float) * WEBAUDIO_BLOCK_SIZE); + + float* outputP = m_outputBuffer.Elements(); + m_readWriteIndex += WEBAUDIO_BLOCK_SIZE; + + // 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.PerformFFT(m_inputBuffer.Elements()); + m_frame.Multiply(*fftKernel); + m_frame.GetInverseWithoutScaling(m_outputBuffer.Elements()); + + // Overlap-add 1st half from previous time + AudioBufferAddWithScale(m_lastOverlapBuffer.Elements(), 1.0f, + m_outputBuffer.Elements(), halfSize); + + // Finally, save 2nd half of result + MOZ_ASSERT(m_outputBuffer.Length() == 2 * halfSize && m_lastOverlapBuffer.Length() == halfSize); + + memcpy(m_lastOverlapBuffer.Elements(), m_outputBuffer.Elements() + halfSize, sizeof(float) * halfSize); + + // Reset index back to start for next time + m_readWriteIndex = 0; + } + + return outputP + m_readWriteIndex; +} + +void FFTConvolver::reset() +{ + PodZero(m_lastOverlapBuffer.Elements(), m_lastOverlapBuffer.Length()); + m_readWriteIndex = 0; +} + +size_t FFTConvolver::latencyFrames() const +{ + return std::max<size_t>(fftSize()/2, WEBAUDIO_BLOCK_SIZE) - + WEBAUDIO_BLOCK_SIZE; +} + +} // namespace WebCore |