/*
* 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
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef Biquad_h
#define Biquad_h
#include "platform/PlatformExport.h"
#include "platform/audio/AudioArray.h"
#include "wtf/Complex.h"
#include <sys/types.h>
#if USE(WEBAUDIO_IPP)
#include <ipps.h>
#endif // USE(WEBAUDIO_IPP)
namespace WebCore {
// A basic biquad (two-zero / two-pole digital filter)
//
// It can be configured to a number of common and very useful filters:
// lowpass, highpass, shelving, parameteric, notch, allpass, ...
class PLATFORM_EXPORT Biquad FINAL {
public:
Biquad();
~Biquad();
void process(const float* sourceP, float* destP, size_t framesToProcess);
// frequency is 0 - 1 normalized, resonance and dbGain are in decibels.
// Q is a unitless quality factor.
void setLowpassParams(double frequency, double resonance);
void setHighpassParams(double frequency, double resonance);
void setBandpassParams(double frequency, double Q);
void setLowShelfParams(double frequency, double dbGain);
void setHighShelfParams(double frequency, double dbGain);
void setPeakingParams(double frequency, double Q, double dbGain);
void setAllpassParams(double frequency, double Q);
void setNotchParams(double frequency, double Q);
// Set the biquad coefficients given a single zero (other zero will be conjugate)
// and a single pole (other pole will be conjugate)
void setZeroPolePairs(const Complex& zero, const Complex& pole);
// Set the biquad coefficients given a single pole (other pole will be conjugate)
// (The zeroes will be the inverse of the poles)
void setAllpassPole(const Complex& pole);
// Resets filter state
void reset();
// Filter response at a set of n frequencies. The magnitude and
// phase response are returned in magResponse and phaseResponse.
// The phase response is in radians.
void getFrequencyResponse(int nFrequencies,
const float* frequency,
float* magResponse,
float* phaseResponse);
private:
void setNormalizedCoefficients(double b0, double b1, double b2, double a0, double a1, double a2);
// Filter coefficients. The filter is defined as
//
// y[n] + m_a1*y[n-1] + m_a2*y[n-2] = m_b0*x[n] + m_b1*x[n-1] + m_b2*x[n-2].
double m_b0;
double m_b1;
double m_b2;
double m_a1;
double m_a2;
#if OS(MACOSX)
void processFast(const float* sourceP, float* destP, size_t framesToProcess);
void processSliceFast(double* sourceP, double* destP, double* coefficientsP, size_t framesToProcess);
AudioDoubleArray m_inputBuffer;
AudioDoubleArray m_outputBuffer;
#elif USE(WEBAUDIO_IPP)
IppsIIRState64f_32f* m_biquadState;
Ipp8u* m_ippInternalBuffer;
#else
// Filter memory
double m_x1; // input delayed by 1 sample
double m_x2; // input delayed by 2 samples
double m_y1; // output delayed by 1 sample
double m_y2; // output delayed by 2 samples
#endif
};
} // namespace WebCore
#endif // Biquad_h