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 Computer, 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 "platform/PlatformExport.h"
33#include "platform/audio/AudioArray.h"
34#include "wtf/Complex.h"
35#include <sys/types.h>
36
37#if USE(WEBAUDIO_IPP)
38#include <ipps.h>
39#endif // USE(WEBAUDIO_IPP)
40
41namespace blink {
42
43// A basic biquad (two-zero / two-pole digital filter)
44//
45// It can be configured to a number of common and very useful filters:
46//    lowpass, highpass, shelving, parameteric, notch, allpass, ...
47
48class PLATFORM_EXPORT Biquad FINAL {
49public:
50    Biquad();
51    ~Biquad();
52
53    void process(const float* sourceP, float* destP, size_t framesToProcess);
54
55    // frequency is 0 - 1 normalized, resonance and dbGain are in decibels.
56    // Q is a unitless quality factor.
57    void setLowpassParams(double frequency, double resonance);
58    void setHighpassParams(double frequency, double resonance);
59    void setBandpassParams(double frequency, double Q);
60    void setLowShelfParams(double frequency, double dbGain);
61    void setHighShelfParams(double frequency, double dbGain);
62    void setPeakingParams(double frequency, double Q, double dbGain);
63    void setAllpassParams(double frequency, double Q);
64    void setNotchParams(double frequency, double Q);
65
66    // Set the biquad coefficients given a single zero (other zero will be conjugate)
67    // and a single pole (other pole will be conjugate)
68    void setZeroPolePairs(const Complex& zero, const Complex& pole);
69
70    // Set the biquad coefficients given a single pole (other pole will be conjugate)
71    // (The zeroes will be the inverse of the poles)
72    void setAllpassPole(const Complex& pole);
73
74    // Resets filter state
75    void reset();
76
77    // Filter response at a set of n frequencies. The magnitude and
78    // phase response are returned in magResponse and phaseResponse.
79    // The phase response is in radians.
80    void getFrequencyResponse(int nFrequencies,
81                              const float* frequency,
82                              float* magResponse,
83                              float* phaseResponse);
84private:
85    void setNormalizedCoefficients(double b0, double b1, double b2, double a0, double a1, double a2);
86
87    // Filter coefficients. The filter is defined as
88    //
89    // 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].
90    double m_b0;
91    double m_b1;
92    double m_b2;
93    double m_a1;
94    double m_a2;
95
96#if OS(MACOSX)
97    void processFast(const float* sourceP, float* destP, size_t framesToProcess);
98    void processSliceFast(double* sourceP, double* destP, double* coefficientsP, size_t framesToProcess);
99
100    AudioDoubleArray m_inputBuffer;
101    AudioDoubleArray m_outputBuffer;
102
103#elif USE(WEBAUDIO_IPP)
104    IppsIIRState64f_32f* m_biquadState;
105    Ipp8u* m_ippInternalBuffer;
106
107#else
108    // Filter memory
109    double m_x1; // input delayed by 1 sample
110    double m_x2; // input delayed by 2 samples
111    double m_y1; // output delayed by 1 sample
112    double m_y2; // output delayed by 2 samples
113#endif
114};
115
116} // namespace blink
117
118#endif // Biquad_h
119