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/*
* Copyright (C) 2010 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.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_FFT_FRAME_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_FFT_FRAME_H_
#include <memory>
#include "build/build_config.h"
#include "third_party/blink/renderer/platform/audio/audio_array.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/forward.h"
#include "third_party/blink/renderer/platform/wtf/threading.h"
#if defined(WTF_USE_WEBAUDIO_FFMPEG)
struct RDFTContext;
#elif defined(WTF_USE_WEBAUDIO_PFFFT)
#include "third_party/blink/renderer/platform/wtf/vector.h"
#include "third_party/pffft/src/pffft.h"
#elif defined(OS_MAC)
#include <Accelerate/Accelerate.h>
#endif
namespace blink {
// Defines the interface for an "FFT frame", an object which is able to perform
// a forward and reverse FFT, internally storing the resultant frequency-domain
// data.
class PLATFORM_EXPORT FFTFrame {
USING_FAST_MALLOC(FFTFrame);
public:
// The constructors, destructor, and methods up to the CROSS-PLATFORM section
// have platform-dependent implementations.
FFTFrame(unsigned fft_size);
// creates a blank/empty frame for later use with createInterpolatedFrame()
FFTFrame();
FFTFrame(const FFTFrame& frame);
~FFTFrame();
// Returns the smallest and largest supported FFT lengths.
static int MinFFTSize();
static int MaxFFTSize();
// Perform any initialization needed. Must be called from the main thread.
static void Initialize(float sample_rate);
static void Cleanup();
// Compute the FFT of |data|, storing the resulting FFT in |real_data_| and
// |imag_data_|. |data| MUST have size at least |fft_size_| elements.
void DoFFT(const float* data);
// Compute the inverse FFT using the FFT data in |real_data_| and
// |imag_data_|. The inverse is saved in |data|. |data| MUST have size at
// least |fft_size_| elements.
void DoInverseFFT(float* data);
AudioFloatArray& RealData() { return real_data_; }
const AudioFloatArray& RealData() const { return real_data_; }
AudioFloatArray& ImagData() { return imag_data_; }
const AudioFloatArray& ImagData() const { return imag_data_; }
unsigned FftSize() const { return fft_size_; }
unsigned Log2FFTSize() const { return log2fft_size_; }
// CROSS-PLATFORM
// The remaining public methods have cross-platform implementations:
// Interpolates from frame1 -> frame2 as x goes from 0.0 -> 1.0
static std::unique_ptr<FFTFrame> CreateInterpolatedFrame(
const FFTFrame& frame1,
const FFTFrame& frame2,
double x);
// zero-padding with dataSize <= fftSize
void DoPaddedFFT(const float* data, size_t data_size);
double ExtractAverageGroupDelay();
void AddConstantGroupDelay(double sample_frame_delay);
// multiplies ourself with frame : effectively operator*=()
void Multiply(const FFTFrame&);
// Scale the FFT data by the given scaling factor
void ScaleFFT(float factor);
private:
void InterpolateFrequencyComponents(const FFTFrame& frame1,
const FFTFrame& frame2,
double x);
unsigned fft_size_;
unsigned log2fft_size_;
// These two arrays contain the transformed data. Instead of a single array
// of complex numbers, we split the complex data into an array of the real
// part and the imaginary part.
//
// Let the forward transform, X[k], of the real signal x[n] be defined by
//
// X[k] = sum(x[n]*W^(k*n)) for n = 0 to N-1
//
// where W = exp(-2*pi*i/N), and N is the FFT size.
//
// Since x[n] is assumed to be real, X[k] has complex conjugate symmetry with
// X[N-k] = conj(X[k]). Thus, we only need to keep X[k] for k = 0 to N/2.
// But since X[0] is purely real and X[N/2] is also purely real, so we could
// place the real part of X[N/2] in the imaginary part of X[0]. Thus
// for k = 1 to N/2:
//
// real_data[k] = Re(X[k])
// imag_data[k] = Im(X[k])
//
// and
//
// real_data[0] = Re(X[0]);
// imag_data[0] = Re(X[N/2])
//
// The routine |DoFFT| must produce transformed data in this format, and the
// routine |DoInverseFFT| must expect transformed data in this format.
AudioFloatArray real_data_;
AudioFloatArray imag_data_;
#if defined(OS_MAC) && !defined(WTF_USE_WEBAUDIO_PFFFT)
// Thin wrapper around FFTSetup so we can call the appropriate routines to
// construct or release the FFTSetup objects.
class FFTSetupDatum {
public:
FFTSetupDatum(unsigned fft_size);
~FFTSetupDatum();
FFTSetup GetSetup() const { return setup_; }
private:
FFTSetup setup_;
};
// Returns the vector that holds all of the possible FFTSetupData
// objects. This should be set up in the |Initialize()| method that is called
// when the context is created.
static Vector<std::unique_ptr<FFTSetupDatum>>& FFTSetups();
static void InitializeFFTSetupForSize(wtf_size_t fft_order);
DSPSplitComplex& DspSplitComplex() { return frame_; }
DSPSplitComplex DspSplitComplex() const { return frame_; }
static FFTSetup FftSetupForSize(unsigned fft_size);
FFTSetup fft_setup_;
DSPSplitComplex frame_;
#elif defined(WTF_USE_WEBAUDIO_FFMPEG)
static RDFTContext* ContextForSize(unsigned fft_size, int trans);
RDFTContext* forward_context_;
RDFTContext* inverse_context_;
float* GetUpToDateComplexData();
AudioFloatArray complex_data_;
#elif defined(WTF_USE_WEBAUDIO_PFFFT)
// Thin wrapper around PFFFT_Setup so we can call the appropriate PFFFT
// routines to construct or release the PFFFT_Setup objects.
class FFTSetup {
public:
FFTSetup(unsigned fft_size);
~FFTSetup();
PFFFT_Setup* GetSetup() const { return setup_; }
private:
PFFFT_Setup* setup_;
};
// Returns the vector that holds all of the possible FFTSetup objects. This
// should be setup in the |Initialize()| method that is called when a context
// is created.
static Vector<std::unique_ptr<FFTSetup>>& FFTSetups();
// Initialize an entry in FFTSetups for an FFT of order |fft_order|. This can
// be called from any thread, but if a new FFTSetup needs to be allocated,
// then it MUST happen on the main thread.
static void InitializeFFTSetupForSize(wtf_size_t fft_order);
// Get the PFFFT_Setup that is appropriate for an FFT of order
// |fft_order|. This can be called from any thread.
// |InitializeFFTSetupForSize()| must be called for this size before calling
// |FFTSetupForSize()|.
static PFFFT_Setup* FFTSetupForSize(wtf_size_t fft_order);
// Work array for converting PFFFT results to and from the format expected in
// |real_data_| and |imag_datra_|.
AudioFloatArray complex_data_;
// Work array used by the PFFFT transform routines. For real FFTs, this must
// be the same size as the FFT size.
AudioFloatArray pffft_work_;
#endif
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_FFT_FRAME_H_
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