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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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 RealtimeAnalyser_h
#define RealtimeAnalyser_h
#include "core/dom/DOMTypedArray.h"
#include "platform/audio/AudioArray.h"
#include "platform/audio/FFTFrame.h"
#include "wtf/Noncopyable.h"
#include "wtf/OwnPtr.h"
namespace blink {
class AudioBus;
class RealtimeAnalyser final {
WTF_MAKE_NONCOPYABLE(RealtimeAnalyser);
DISALLOW_NEW();
public:
RealtimeAnalyser();
size_t fftSize() const { return m_fftSize; }
bool setFftSize(size_t);
unsigned frequencyBinCount() const { return m_fftSize / 2; }
void setMinDecibels(double k) { m_minDecibels = k; }
double minDecibels() const { return m_minDecibels; }
void setMaxDecibels(double k) { m_maxDecibels = k; }
double maxDecibels() const { return m_maxDecibels; }
void setSmoothingTimeConstant(double k) { m_smoothingTimeConstant = k; }
double smoothingTimeConstant() const { return m_smoothingTimeConstant; }
void getFloatFrequencyData(DOMFloat32Array*, double);
void getByteFrequencyData(DOMUint8Array*, double);
void getFloatTimeDomainData(DOMFloat32Array*);
void getByteTimeDomainData(DOMUint8Array*);
// The audio thread writes input data here.
void writeInput(AudioBus*, size_t framesToProcess);
static const double DefaultSmoothingTimeConstant;
static const double DefaultMinDecibels;
static const double DefaultMaxDecibels;
static const unsigned DefaultFFTSize;
static const unsigned MinFFTSize;
static const unsigned MaxFFTSize;
static const unsigned InputBufferSize;
private:
// The audio thread writes the input audio here.
AudioFloatArray m_inputBuffer;
unsigned m_writeIndex;
size_t m_fftSize;
OwnPtr<FFTFrame> m_analysisFrame;
void doFFTAnalysis();
// Convert the contents of magnitudeBuffer to byte values, saving the result in |destination|.
void convertToByteData(DOMUint8Array* destination);
// Convert magnidue buffer to dB, saving the result in |destination|
void convertFloatToDb(DOMFloat32Array* destination);
// doFFTAnalysis() stores the floating-point magnitude analysis data here.
AudioFloatArray m_magnitudeBuffer;
AudioFloatArray& magnitudeBuffer() { return m_magnitudeBuffer; }
// A value between 0 and 1 which averages the previous version of m_magnitudeBuffer with the current analysis magnitude data.
double m_smoothingTimeConstant;
// The range used when converting when using getByteFrequencyData().
double m_minDecibels;
double m_maxDecibels;
// Time at which the FFT was last computed.
double m_lastAnalysisTime;
};
} // namespace blink
#endif // RealtimeAnalyser_h
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