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/*
* Copyright (C) 2012 Igalia S.L
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
// FFTFrame implementation using the GStreamer FFT library.
#include "config.h"
#if USE(GSTREAMER)
#include "FFTFrame.h"
#include "VectorMath.h"
#include <wtf/FastMalloc.h>
#include <wtf/StdLibExtras.h>
namespace {
// FIXME: It is unclear what the limits are for gst_fft so we use the same ones as on macOS for now.
const int kMinFFTPow2Size = 2;
const int kMaxFFTPow2Size = 24;
size_t unpackedFFTDataSize(unsigned fftSize)
{
return fftSize / 2 + 1;
}
} // anonymous namespace
namespace WebCore {
// Normal constructor: allocates for a given fftSize.
FFTFrame::FFTFrame(unsigned fftSize)
: m_FFTSize(fftSize)
, m_log2FFTSize(static_cast<unsigned>(log2(fftSize)))
, m_complexData(makeUniqueArray<GstFFTF32Complex>(unpackedFFTDataSize(m_FFTSize)))
, m_realData(unpackedFFTDataSize(m_FFTSize))
, m_imagData(unpackedFFTDataSize(m_FFTSize))
{
int fftLength = gst_fft_next_fast_length(m_FFTSize);
m_fft = gst_fft_f32_new(fftLength, FALSE);
m_inverseFft = gst_fft_f32_new(fftLength, TRUE);
}
// Creates a blank/empty frame (interpolate() must later be called).
FFTFrame::FFTFrame()
: m_FFTSize(0)
, m_log2FFTSize(0)
{
int fftLength = gst_fft_next_fast_length(m_FFTSize);
m_fft = gst_fft_f32_new(fftLength, FALSE);
m_inverseFft = gst_fft_f32_new(fftLength, TRUE);
}
// Copy constructor.
FFTFrame::FFTFrame(const FFTFrame& frame)
: m_FFTSize(frame.m_FFTSize)
, m_log2FFTSize(frame.m_log2FFTSize)
, m_complexData(makeUniqueArray<GstFFTF32Complex>(unpackedFFTDataSize(m_FFTSize)))
, m_realData(unpackedFFTDataSize(frame.m_FFTSize))
, m_imagData(unpackedFFTDataSize(frame.m_FFTSize))
{
int fftLength = gst_fft_next_fast_length(m_FFTSize);
m_fft = gst_fft_f32_new(fftLength, FALSE);
m_inverseFft = gst_fft_f32_new(fftLength, TRUE);
// Copy/setup frame data.
memcpy(realData().data(), frame.realData().data(), sizeof(float) * realData().size());
memcpy(imagData().data(), frame.imagData().data(), sizeof(float) * imagData().size());
}
void FFTFrame::initialize()
{
}
FFTFrame::~FFTFrame()
{
if (!m_fft)
return;
gst_fft_f32_free(m_fft);
m_fft = 0;
gst_fft_f32_free(m_inverseFft);
m_inverseFft = 0;
}
void FFTFrame::doFFT(const float* data)
{
gst_fft_f32_fft(m_fft, data, m_complexData.get());
float* imagData = m_imagData.data();
float* realData = m_realData.data();
for (unsigned i = 0; i < unpackedFFTDataSize(m_FFTSize); ++i) {
imagData[i] = m_complexData[i].i;
realData[i] = m_complexData[i].r;
}
}
void FFTFrame::doInverseFFT(float* data)
{
// Merge the real and imaginary vectors to complex vector.
float* realData = m_realData.data();
float* imagData = m_imagData.data();
for (size_t i = 0; i < unpackedFFTDataSize(m_FFTSize); ++i) {
m_complexData[i].i = imagData[i];
m_complexData[i].r = realData[i];
}
gst_fft_f32_inverse_fft(m_inverseFft, m_complexData.get(), data);
// Scale so that a forward then inverse FFT yields exactly the original data.
VectorMath::multiplyByScalar(data, 1.0 / m_FFTSize, data, m_FFTSize);
}
int FFTFrame::minFFTSize()
{
return 1 << kMinFFTPow2Size;
}
int FFTFrame::maxFFTSize()
{
return 1 << kMaxFFTPow2Size;
}
} // namespace WebCore
#endif // USE(GSTREAMER)
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