1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
/*
* 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 Biquad_h
#define Biquad_h
#include "AudioArray.h"
#include <sys/types.h>
#include <wtf/Complex.h>
#include <wtf/Platform.h>
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 Biquad {
public:
Biquad();
virtual ~Biquad() { }
void process(const float* sourceP, float* destP, size_t framesToProcess);
// cutoff is 0-1 normalized, resonance is in dB >= 0.0
void setLowpassParams(double cutoff, double resonance);
void setHighpassParams(double cutoff, double resonance);
void setLowShelfParams(double cutoff, double dbGain);
// FIXME: need to implement a few more common filters
// void setHighShelfParams(double cutoff, double dbGain);
// void setParametricEQParams(double cutoff, double resonance);
// 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();
private:
// Filter coefficients
double m_a0;
double m_a1;
double m_a2;
double m_b1;
double m_b2;
double m_g;
// 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
#if OS(DARWIN)
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;
#endif
};
} // namespace WebCore
#endif // Biquad_h
|
