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ComplexU

FFTBlock

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/* -*- 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_

#ifdef BUILD_ARM_NEON
#include <cmath>
#include "mozilla/arm.h"
#include "dl/sp/api/omxSP.h"
#endif

#include "AlignedTArray.h"
#include "AudioNodeEngine.h"
#if defined(MOZ_LIBAV_FFT)
#ifdef __cplusplus
extern "C" {
#endif
#include "libavcodec/avfft.h"
#ifdef __cplusplus
}
#endif
#else
#include "kiss_fft/kiss_fftr.h"
#endif

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 final
{
  union ComplexU {
#if !defined(MOZ_LIBAV_FFT)
    kiss_fft_cpx c;
#endif
    float f[2];
    struct {
      float r;
      float i;
    };
  };

public:
  explicit FFTBlock(uint32_t aFFTSize)
#if defined(MOZ_LIBAV_FFT)
    : mAvRDFT(nullptr)
    , mAvIRDFT(nullptr)
#else
    : mKissFFT(nullptr)
    , mKissIFFT(nullptr)
#ifdef BUILD_ARM_NEON
    , mOmxFFT(nullptr)
    , mOmxIFFT(nullptr)
#endif
#endif
  {
    MOZ_COUNT_CTOR(FFTBlock);
    SetFFTSize(aFFTSize);
  }
  ~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();
#if defined(MOZ_LIBAV_FFT)
    PodCopy(mOutputBuffer.Elements()->f, aData, mFFTSize);
    av_rdft_calc(mAvRDFT, mOutputBuffer.Elements()->f);
    // Recover packed Nyquist.
    mOutputBuffer[mFFTSize / 2].r = mOutputBuffer[0].i;
    mOutputBuffer[0].i = 0.0f;
#else
#ifdef BUILD_ARM_NEON
    if (mozilla::supports_neon()) {
      omxSP_FFTFwd_RToCCS_F32_Sfs(aData, mOutputBuffer.Elements()->f, mOmxFFT);
    } else
#endif
    {
      kiss_fftr(mKissFFT, aData, &(mOutputBuffer.Elements()->c));
    }
#endif
  }
  // Inverse-transform internal data and store the resulting FFTSize()
  // points in aDataOut.
  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();
#if defined(MOZ_LIBAV_FFT)
    {
      // Even though this function doesn't scale, the libav forward transform
      // gives a value that needs scaling by 2 in order for things to turn out
      // similar to how we expect from kissfft/openmax.
      AudioBufferCopyWithScale(mOutputBuffer.Elements()->f, 2.0f,
                               aDataOut, mFFTSize);
      aDataOut[1] = 2.0f * mOutputBuffer[mFFTSize/2].r; // Packed Nyquist
      av_rdft_calc(mAvIRDFT, aDataOut);
    }
#else
#ifdef BUILD_ARM_NEON
    if (mozilla::supports_neon()) {
      omxSP_FFTInv_CCSToR_F32_Sfs_unscaled(mOutputBuffer.Elements()->f, aDataOut, mOmxIFFT);
    } else
#endif
    {
      kiss_fftri(mKissIFFT, &(mOutputBuffer.Elements()->c), aDataOut);
    }
#endif
  }

  void Multiply(const FFTBlock& aFrame)
  {
    uint32_t halfSize = mFFTSize / 2;
    // DFTs are not packed.
    MOZ_ASSERT(mOutputBuffer[0].i == 0);
    MOZ_ASSERT(aFrame.mOutputBuffer[0].i == 0);

    BufferComplexMultiply(mOutputBuffer.Elements()->f,
                          aFrame.mOutputBuffer.Elements()->f,
                          mOutputBuffer.Elements()->f,
                          halfSize);
    mOutputBuffer[halfSize].r *= aFrame.mOutputBuffer[halfSize].r;
    // This would have been set to NaN if either real component was NaN.
    mOutputBuffer[0].i = 0.0f;
  }

  // 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());
    AlignedTArray<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& RealData(uint32_t aIndex)
  {
    return mOutputBuffer[aIndex].r;
  }
  float ImagData(uint32_t aIndex) const
  {
    return mOutputBuffer[aIndex].i;
  }
  float& ImagData(uint32_t aIndex)
  {
    return mOutputBuffer[aIndex].i;
  }

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
  {
    size_t amount = 0;
#if defined(MOZ_LIBAV_FFT)
    amount += aMallocSizeOf(mAvRDFT);
    amount += aMallocSizeOf(mAvIRDFT);
#else
    amount += aMallocSizeOf(mKissFFT);
    amount += aMallocSizeOf(mKissIFFT);
#endif
    amount += mOutputBuffer.ShallowSizeOfExcludingThis(aMallocSizeOf);
    return amount;
  }

  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
  {
    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
  }

private:
  FFTBlock(const FFTBlock& other) = delete;
  void operator=(const FFTBlock& other) = delete;

  void EnsureFFT()
  {
#if defined(MOZ_LIBAV_FFT)
    if (!mAvRDFT) {
      mAvRDFT = av_rdft_init(log((double)mFFTSize)/M_LN2, DFT_R2C);
    }
#else
#ifdef BUILD_ARM_NEON
    if (mozilla::supports_neon()) {
      if (!mOmxFFT) {
        mOmxFFT = createOmxFFT(mFFTSize);
      }
    } else
#endif
    {
      if (!mKissFFT) {
        mKissFFT = kiss_fftr_alloc(mFFTSize, 0, nullptr, nullptr);
      }
    }
#endif
  }
  void EnsureIFFT()
  {
#if defined(MOZ_LIBAV_FFT)
    if (!mAvIRDFT) {
      mAvIRDFT = av_rdft_init(log((double)mFFTSize)/M_LN2, IDFT_C2R);
    }
#else
#ifdef BUILD_ARM_NEON
    if (mozilla::supports_neon()) {
      if (!mOmxIFFT) {
        mOmxIFFT = createOmxFFT(mFFTSize);
      }
    } else
#endif
    {
      if (!mKissIFFT) {
        mKissIFFT = kiss_fftr_alloc(mFFTSize, 1, nullptr, nullptr);
      }
    }
#endif
  }

#ifdef BUILD_ARM_NEON
  static OMXFFTSpec_R_F32* createOmxFFT(uint32_t aFFTSize)
  {
    MOZ_ASSERT((aFFTSize & (aFFTSize-1)) == 0);
    OMX_INT bufSize;
    OMX_INT order = log((double)aFFTSize)/M_LN2;
    MOZ_ASSERT(aFFTSize>>order == 1);
    OMXResult status = omxSP_FFTGetBufSize_R_F32(order, &bufSize);
    if (status == OMX_Sts_NoErr) {
      OMXFFTSpec_R_F32* context = static_cast<OMXFFTSpec_R_F32*>(malloc(bufSize));
      if (omxSP_FFTInit_R_F32(context, order) != OMX_Sts_NoErr) {
        return nullptr;
      }
      return context;
    }
    return nullptr;
  }
#endif

  void Clear()
  {
#if defined(MOZ_LIBAV_FFT)
    av_rdft_end(mAvRDFT);
    av_rdft_end(mAvIRDFT);
    mAvRDFT = mAvIRDFT = nullptr;
#else
#ifdef BUILD_ARM_NEON
    free(mOmxFFT);
    free(mOmxIFFT);
    mOmxFFT = mOmxIFFT = nullptr;
#endif
    free(mKissFFT);
    free(mKissIFFT);
    mKissFFT = mKissIFFT = nullptr;
#endif
  }
  void AddConstantGroupDelay(double sampleFrameDelay);
  void InterpolateFrequencyComponents(const FFTBlock& block0,
                                      const FFTBlock& block1, double interp);
#if defined(MOZ_LIBAV_FFT)
  RDFTContext *mAvRDFT;
  RDFTContext *mAvIRDFT;
#else
  kiss_fftr_cfg mKissFFT;
  kiss_fftr_cfg mKissIFFT;
#ifdef BUILD_ARM_NEON
  OMXFFTSpec_R_F32* mOmxFFT;
  OMXFFTSpec_R_F32* mOmxIFFT;
#endif
#endif
  AlignedTArray<ComplexU> mOutputBuffer;
  uint32_t mFFTSize;
};

} // namespace mozilla

#endif