1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/media/webaudio/blink/FFTConvolver.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,80 @@
1.4 +/*
1.5 + * Copyright (C) 2010 Google Inc. All rights reserved.
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions
1.9 + * are met:
1.10 + *
1.11 + * 1. Redistributions of source code must retain the above copyright
1.12 + * notice, this list of conditions and the following disclaimer.
1.13 + * 2. Redistributions in binary form must reproduce the above copyright
1.14 + * notice, this list of conditions and the following disclaimer in the
1.15 + * documentation and/or other materials provided with the distribution.
1.16 + * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
1.17 + * its contributors may be used to endorse or promote products derived
1.18 + * from this software without specific prior written permission.
1.19 + *
1.20 + * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
1.21 + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1.22 + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1.23 + * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
1.24 + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
1.25 + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
1.26 + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
1.27 + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.28 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.29 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.30 + */
1.31 +
1.32 +#ifndef FFTConvolver_h
1.33 +#define FFTConvolver_h
1.34 +
1.35 +#include "nsTArray.h"
1.36 +#include "mozilla/FFTBlock.h"
1.37 +#include "mozilla/MemoryReporting.h"
1.38 +
1.39 +namespace WebCore {
1.40 +
1.41 +typedef nsTArray<float> AudioFloatArray;
1.42 +using mozilla::FFTBlock;
1.43 +
1.44 +class FFTConvolver {
1.45 +public:
1.46 + // fftSize must be a power of two
1.47 + FFTConvolver(size_t fftSize);
1.48 +
1.49 + // |fftKernel| must be pre-scaled for FFTBlock::GetInverseWithoutScaling().
1.50 + //
1.51 + // For now, with multiple calls to Process(), framesToProcess MUST add up EXACTLY to fftSize / 2
1.52 + //
1.53 + // FIXME: Later, we can do more sophisticated buffering to relax this requirement...
1.54 + //
1.55 + // The input to output latency is equal to fftSize / 2
1.56 + //
1.57 + // Processing in-place is allowed...
1.58 + void process(FFTBlock* fftKernel, const float* sourceP, float* destP, size_t framesToProcess);
1.59 +
1.60 + void reset();
1.61 +
1.62 + size_t fftSize() const { return m_frame.FFTSize(); }
1.63 +
1.64 + size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
1.65 + size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
1.66 +
1.67 +private:
1.68 + FFTBlock m_frame;
1.69 +
1.70 + // Buffer input until we get fftSize / 2 samples then do an FFT
1.71 + size_t m_readWriteIndex;
1.72 + AudioFloatArray m_inputBuffer;
1.73 +
1.74 + // Stores output which we read a little at a time
1.75 + AudioFloatArray m_outputBuffer;
1.76 +
1.77 + // Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the 1st half of the next one
1.78 + AudioFloatArray m_lastOverlapBuffer;
1.79 +};
1.80 +
1.81 +} // namespace WebCore
1.82 +
1.83 +#endif // FFTConvolver_h
