The Tor Browser: content/media/webaudio/FFTBlock.h@6474c204b198 (annotated)

content/media/webaudio/FFTBlock.h@6474c204b198 (annotated)

content/media/webaudio/FFTBlock.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim:set ts=2 sw=2 sts=2 et cindent: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef FFTBlock_h_
 #define FFTBlock_h_
 #include "nsTArray.h"
 #include "AudioNodeEngine.h"
 #include "kiss_fft/kiss_fftr.h"
 namespace mozilla {
 // This class defines an FFT block, loosely modeled after Blink's FFTFrame
 // class to make sharing code with Blink easy.
 // Currently it's implemented on top of KissFFT on all platforms.
 class FFTBlock {
 public:
   explicit FFTBlock(uint32_t aFFTSize)
     : mFFT(nullptr)
     , mIFFT(nullptr)
     , mFFTSize(aFFTSize)
   {
     MOZ_COUNT_CTOR(FFTBlock);
     mOutputBuffer.SetLength(aFFTSize / 2 + 1);
     PodZero(mOutputBuffer.Elements(), aFFTSize / 2 + 1);
   }
   ~FFTBlock()
   {
     MOZ_COUNT_DTOR(FFTBlock);
     Clear();
   }
   // Return a new FFTBlock with frequency components interpolated between
   // |block0| and |block1| with |interp| between 0.0 and 1.0.
   static FFTBlock*
   CreateInterpolatedBlock(const FFTBlock& block0,
                           const FFTBlock& block1, double interp);
   // Transform FFTSize() points of aData and store the result internally.
   void PerformFFT(const float* aData)
   {
     EnsureFFT();
     kiss_fftr(mFFT, aData, mOutputBuffer.Elements());
   }
   // Inverse-transform internal data and store the resulting FFTSize()
   // points in aData.
   void GetInverse(float* aDataOut)
   {
     GetInverseWithoutScaling(aDataOut);
     AudioBufferInPlaceScale(aDataOut, 1.0f / mFFTSize, mFFTSize);
   }
   // Inverse-transform internal frequency data and store the resulting
   // FFTSize() points in |aDataOut|.  If frequency data has not already been
   // scaled, then the output will need scaling by 1/FFTSize().
   void GetInverseWithoutScaling(float* aDataOut)
   {
     EnsureIFFT();
     kiss_fftri(mIFFT, mOutputBuffer.Elements(), aDataOut);
   }
   // Inverse-transform the FFTSize()/2+1 points of data in each
   // of aRealDataIn and aImagDataIn and store the resulting
   // FFTSize() points in aRealDataOut.
   void PerformInverseFFT(float* aRealDataIn,
                          float *aImagDataIn,
                          float *aRealDataOut)
   {
     EnsureIFFT();
     const uint32_t inputSize = mFFTSize / 2 + 1;
     nsTArray<kiss_fft_cpx> inputBuffer;
     inputBuffer.SetLength(inputSize);
     for (uint32_t i = 0; i < inputSize; ++i) {
       inputBuffer[i].r = aRealDataIn[i];
       inputBuffer[i].i = aImagDataIn[i];
     }
     kiss_fftri(mIFFT, inputBuffer.Elements(), aRealDataOut);
     for (uint32_t i = 0; i < mFFTSize; ++i) {
       aRealDataOut[i] /= mFFTSize;
     }
   }
   void Multiply(const FFTBlock& aFrame)
   {
     BufferComplexMultiply(reinterpret_cast<const float*>(mOutputBuffer.Elements()),
                           reinterpret_cast<const float*>(aFrame.mOutputBuffer.Elements()),
                           reinterpret_cast<float*>(mOutputBuffer.Elements()),
                           mFFTSize / 2 + 1);
   }
   // Perform a forward FFT on |aData|, assuming zeros after dataSize samples,
   // and pre-scale the generated internal frequency domain coefficients so
   // that GetInverseWithoutScaling() can be used to transform to the time
   // domain.  This is useful for convolution kernels.
   void PadAndMakeScaledDFT(const float* aData, size_t dataSize)
   {
     MOZ_ASSERT(dataSize <= FFTSize());
     nsTArray<float> paddedData;
     paddedData.SetLength(FFTSize());
     AudioBufferCopyWithScale(aData, 1.0f / FFTSize(),
                              paddedData.Elements(), dataSize);
     PodZero(paddedData.Elements() + dataSize, mFFTSize - dataSize);
     PerformFFT(paddedData.Elements());
   }
   void SetFFTSize(uint32_t aSize)
   {
     mFFTSize = aSize;
     mOutputBuffer.SetLength(aSize / 2 + 1);
     PodZero(mOutputBuffer.Elements(), aSize / 2 + 1);
     Clear();
   }
   // Return the average group delay and removes this from the frequency data.
   double ExtractAverageGroupDelay();
   uint32_t FFTSize() const
   {
     return mFFTSize;
   }
   float RealData(uint32_t aIndex) const
   {
     return mOutputBuffer[aIndex].r;
   }
   float ImagData(uint32_t aIndex) const
   {
     return mOutputBuffer[aIndex].i;
   }
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
   {
     size_t amount = 0;
     amount += aMallocSizeOf(mFFT);
     amount += aMallocSizeOf(mIFFT);
     amount += mOutputBuffer.SizeOfExcludingThis(aMallocSizeOf);
     return amount;
   }
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
 private:
   FFTBlock(const FFTBlock& other) MOZ_DELETE;
   void operator=(const FFTBlock& other) MOZ_DELETE;
   void EnsureFFT()
   {
     if (!mFFT) {
       mFFT = kiss_fftr_alloc(mFFTSize, 0, nullptr, nullptr);
     }
   }
   void EnsureIFFT()
   {
     if (!mIFFT) {
       mIFFT = kiss_fftr_alloc(mFFTSize, 1, nullptr, nullptr);
     }
   }
   void Clear()
   {
     free(mFFT);
     free(mIFFT);
     mFFT = mIFFT = nullptr;
   }
   void AddConstantGroupDelay(double sampleFrameDelay);
   void InterpolateFrequencyComponents(const FFTBlock& block0,
                                       const FFTBlock& block1, double interp);
   kiss_fftr_cfg mFFT, mIFFT;
   nsTArray<kiss_fft_cpx> mOutputBuffer;
   uint32_t mFFTSize;
 };
 }
 #endif

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content/media/webaudio/FFTBlock.h@6474c204b198 (annotated)

content/media/webaudio/FFTBlock.h