1/*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
14 *     its contributors may be used to endorse or promote products derived
15 *     from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef Biquad_h
30#define Biquad_h
31
32#include "AudioArray.h"
33#include <complex>
34#include <sys/types.h>
35
36#if USE(WEBAUDIO_IPP)
37#include <ipps.h>
38#endif // USE(WEBAUDIO_IPP)
39
40namespace WebCore {
41
42// A basic biquad (two-zero / two-pole digital filter)
43//
44// It can be configured to a number of common and very useful filters:
45//    lowpass, highpass, shelving, parameteric, notch, allpass, ...
46
47class Biquad {
48public:
49    Biquad();
50    virtual ~Biquad();
51
52    void process(const float* sourceP, float* destP, size_t framesToProcess);
53
54    // frequency is 0 - 1 normalized, resonance and dbGain are in decibels.
55    // Q is a unitless quality factor.
56    void setLowpassParams(double frequency, double resonance);
57    void setHighpassParams(double frequency, double resonance);
58    void setBandpassParams(double frequency, double Q);
59    void setLowShelfParams(double frequency, double dbGain);
60    void setHighShelfParams(double frequency, double dbGain);
61    void setPeakingParams(double frequency, double Q, double dbGain);
62    void setAllpassParams(double frequency, double Q);
63    void setNotchParams(double frequency, double Q);
64
65    // Set the biquad coefficients given a single zero (other zero will be conjugate)
66    // and a single pole (other pole will be conjugate)
67    void setZeroPolePairs(std::complex<double> zero, std::complex<double> pole);
68
69    // Set the biquad coefficients given a single pole (other pole will be conjugate)
70    // (The zeroes will be the inverse of the poles)
71    void setAllpassPole(std::complex<double>);
72
73    // Resets filter state
74    void reset();
75
76    // Filter response at a set of n frequencies. The magnitude and
77    // phase response are returned in magResponse and phaseResponse.
78    // The phase response is in radians.
79    void getFrequencyResponse(int nFrequencies,
80                              const float* frequency,
81                              float* magResponse,
82                              float* phaseResponse);
83private:
84    void setNormalizedCoefficients(double b0, double b1, double b2, double a0, double a1, double a2);
85
86    // Filter coefficients. The filter is defined as
87    //
88    // 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].
89    double m_b0;
90    double m_b1;
91    double m_b2;
92    double m_a1;
93    double m_a2;
94
95#if OS(DARWIN)
96    void processFast(const float* sourceP, float* destP, size_t framesToProcess);
97    void processSliceFast(double* sourceP, double* destP, double* coefficientsP, size_t framesToProcess);
98
99    AudioDoubleArray m_inputBuffer;
100    AudioDoubleArray m_outputBuffer;
101
102#elif USE(WEBAUDIO_IPP)
103    IppsIIRState64f_32f* m_biquadState;
104    Ipp8u* m_ippInternalBuffer;
105
106#else
107    // Filter memory
108    double m_x1; // input delayed by 1 sample
109    double m_x2; // input delayed by 2 samples
110    double m_y1; // output delayed by 1 sample
111    double m_y2; // output delayed by 2 samples
112#endif
113};
114
115} // namespace WebCore
116
117#endif // Biquad_h
118