| /* |
| * Copyright (C) 2011 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. |
| * |
| * 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 |
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| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| // FFTFrame implementation using FFmpeg's RDFT algorithm, |
| // suitable for use on Windows and Linux. |
| |
| #include "config.h" |
| |
| #if ENABLE(WEB_AUDIO) |
| |
| #if USE(WEBAUDIO_FFMPEG) |
| |
| #include "FFTFrame.h" |
| |
| #include "VectorMath.h" |
| |
| extern "C" { |
| #include <libavcodec/avfft.h> |
| } |
| |
| #include <wtf/MathExtras.h> |
| |
| namespace WebCore { |
| |
| const int kMaxFFTPow2Size = 24; |
| |
| // Normal constructor: allocates for a given fftSize. |
| FFTFrame::FFTFrame(unsigned fftSize) |
| : m_FFTSize(fftSize) |
| , m_log2FFTSize(static_cast<unsigned>(log2(fftSize))) |
| , m_forwardContext(0) |
| , m_inverseContext(0) |
| , m_complexData(fftSize) |
| , m_realData(fftSize / 2) |
| , m_imagData(fftSize / 2) |
| { |
| // We only allow power of two. |
| ASSERT(1UL << m_log2FFTSize == m_FFTSize); |
| |
| m_forwardContext = contextForSize(fftSize, DFT_R2C); |
| m_inverseContext = contextForSize(fftSize, IDFT_C2R); |
| } |
| |
| // Creates a blank/empty frame (interpolate() must later be called). |
| FFTFrame::FFTFrame() |
| : m_FFTSize(0) |
| , m_log2FFTSize(0) |
| , m_forwardContext(0) |
| , m_inverseContext(0) |
| { |
| } |
| |
| // Copy constructor. |
| FFTFrame::FFTFrame(const FFTFrame& frame) |
| : m_FFTSize(frame.m_FFTSize) |
| , m_log2FFTSize(frame.m_log2FFTSize) |
| , m_forwardContext(0) |
| , m_inverseContext(0) |
| , m_complexData(frame.m_FFTSize) |
| , m_realData(frame.m_FFTSize / 2) |
| , m_imagData(frame.m_FFTSize / 2) |
| { |
| m_forwardContext = contextForSize(m_FFTSize, DFT_R2C); |
| m_inverseContext = contextForSize(m_FFTSize, IDFT_C2R); |
| |
| // Copy/setup frame data. |
| unsigned nbytes = sizeof(float) * (m_FFTSize / 2); |
| memcpy(realData(), frame.realData(), nbytes); |
| memcpy(imagData(), frame.imagData(), nbytes); |
| } |
| |
| void FFTFrame::initialize() |
| { |
| } |
| |
| void FFTFrame::cleanup() |
| { |
| } |
| |
| FFTFrame::~FFTFrame() |
| { |
| av_rdft_end(m_forwardContext); |
| av_rdft_end(m_inverseContext); |
| } |
| |
| void FFTFrame::multiply(const FFTFrame& frame) |
| { |
| FFTFrame& frame1 = *this; |
| FFTFrame& frame2 = const_cast<FFTFrame&>(frame); |
| |
| float* realP1 = frame1.realData(); |
| float* imagP1 = frame1.imagData(); |
| const float* realP2 = frame2.realData(); |
| const float* imagP2 = frame2.imagData(); |
| |
| unsigned halfSize = fftSize() / 2; |
| float real0 = realP1[0]; |
| float imag0 = imagP1[0]; |
| |
| VectorMath::zvmul(realP1, imagP1, realP2, imagP2, realP1, imagP1, halfSize); |
| |
| // Multiply the packed DC/nyquist component |
| realP1[0] = real0 * realP2[0]; |
| imagP1[0] = imag0 * imagP2[0]; |
| |
| // Scale accounts the peculiar scaling of vecLib on the Mac. |
| // This ensures the right scaling all the way back to inverse FFT. |
| // FIXME: if we change the scaling on the Mac then this scale |
| // factor will need to change too. |
| float scale = 0.5f; |
| |
| VectorMath::vsmul(realP1, 1, &scale, realP1, 1, halfSize); |
| VectorMath::vsmul(imagP1, 1, &scale, imagP1, 1, halfSize); |
| } |
| |
| void FFTFrame::doFFT(const float* data) |
| { |
| // Copy since processing is in-place. |
| float* p = m_complexData.data(); |
| memcpy(p, data, sizeof(float) * m_FFTSize); |
| |
| // Compute Forward transform. |
| av_rdft_calc(m_forwardContext, p); |
| |
| // De-interleave to separate real and complex arrays. |
| int len = m_FFTSize / 2; |
| |
| // FIXME: see above comment in multiply() about scaling. |
| const float scale = 2.0f; |
| |
| for (int i = 0; i < len; ++i) { |
| int baseComplexIndex = 2 * i; |
| // m_realData[0] is the DC component and m_imagData[0] is the nyquist component |
| // since the interleaved complex data is packed. |
| m_realData[i] = scale * p[baseComplexIndex]; |
| m_imagData[i] = scale * p[baseComplexIndex + 1]; |
| } |
| } |
| |
| void FFTFrame::doInverseFFT(float* data) |
| { |
| // Prepare interleaved data. |
| float* interleavedData = getUpToDateComplexData(); |
| |
| // Compute inverse transform. |
| av_rdft_calc(m_inverseContext, interleavedData); |
| |
| // Scale so that a forward then inverse FFT yields exactly the original data. |
| const float scale = 1.0 / m_FFTSize; |
| VectorMath::vsmul(interleavedData, 1, &scale, data, 1, m_FFTSize); |
| } |
| |
| float* FFTFrame::realData() const |
| { |
| return const_cast<float*>(m_realData.data()); |
| } |
| |
| float* FFTFrame::imagData() const |
| { |
| return const_cast<float*>(m_imagData.data()); |
| } |
| |
| float* FFTFrame::getUpToDateComplexData() |
| { |
| // FIXME: if we can't completely get rid of this method, SSE |
| // optimization could be considered if it shows up hot on profiles. |
| int len = m_FFTSize / 2; |
| for (int i = 0; i < len; ++i) { |
| int baseComplexIndex = 2 * i; |
| m_complexData[baseComplexIndex] = m_realData[i]; |
| m_complexData[baseComplexIndex + 1] = m_imagData[i]; |
| } |
| return const_cast<float*>(m_complexData.data()); |
| } |
| |
| RDFTContext* FFTFrame::contextForSize(unsigned fftSize, int trans) |
| { |
| // FIXME: This is non-optimal. Ideally, we'd like to share the contexts for FFTFrames of the same size. |
| // But FFmpeg's RDFT uses a scratch buffer inside the context and so they are not thread-safe. |
| // We could improve this by sharing the FFTFrames on a per-thread basis. |
| ASSERT(fftSize); |
| int pow2size = static_cast<int>(log2(fftSize)); |
| ASSERT(pow2size < kMaxFFTPow2Size); |
| |
| RDFTContext* context = av_rdft_init(pow2size, (RDFTransformType)trans); |
| return context; |
| } |
| |
| } // namespace WebCore |
| |
| #endif // !OS(DARWIN) && USE(WEBAUDIO_FFMPEG) |
| |
| #endif // ENABLE(WEB_AUDIO) |