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comparison: content/media/webaudio/blink/Biquad.h
content/media/webaudio/blink/Biquad.h
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- TOR_BUG_9701
- changeset 15
- b8a032363ba2
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| -1:000000000000 | 0:f26a4d3d5266 |
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| 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 <complex> | |
| 33 | |
| 34 namespace WebCore { | |
| 35 | |
| 36 typedef std::complex<double> Complex; | |
| 37 | |
| 38 // A basic biquad (two-zero / two-pole digital filter) | |
| 39 // | |
| 40 // It can be configured to a number of common and very useful filters: | |
| 41 // lowpass, highpass, shelving, parameteric, notch, allpass, ... | |
| 42 | |
| 43 class Biquad { | |
| 44 public: | |
| 45 Biquad(); | |
| 46 ~Biquad(); | |
| 47 | |
| 48 void process(const float* sourceP, float* destP, size_t framesToProcess); | |
| 49 | |
| 50 // frequency is 0 - 1 normalized, resonance and dbGain are in decibels. | |
| 51 // Q is a unitless quality factor. | |
| 52 void setLowpassParams(double frequency, double resonance); | |
| 53 void setHighpassParams(double frequency, double resonance); | |
| 54 void setBandpassParams(double frequency, double Q); | |
| 55 void setLowShelfParams(double frequency, double dbGain); | |
| 56 void setHighShelfParams(double frequency, double dbGain); | |
| 57 void setPeakingParams(double frequency, double Q, double dbGain); | |
| 58 void setAllpassParams(double frequency, double Q); | |
| 59 void setNotchParams(double frequency, double Q); | |
| 60 | |
| 61 // Set the biquad coefficients given a single zero (other zero will be conjugate) | |
| 62 // and a single pole (other pole will be conjugate) | |
| 63 void setZeroPolePairs(const Complex& zero, const Complex& pole); | |
| 64 | |
| 65 // Set the biquad coefficients given a single pole (other pole will be conjugate) | |
| 66 // (The zeroes will be the inverse of the poles) | |
| 67 void setAllpassPole(const Complex& pole); | |
| 68 | |
| 69 // Return true iff the next output block will contain sound even with | |
| 70 // silent input. | |
| 71 bool hasTail() const { return m_y1 || m_y2 || m_x1 || m_x2; } | |
| 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); | |
| 83 private: | |
| 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 // Filter memory | |
| 96 // | |
| 97 // Double precision for the output values is valuable because errors can | |
| 98 // accumulate. Input values are also stored as double so they need not be | |
| 99 // converted again for computation. | |
| 100 double m_x1; // input delayed by 1 sample | |
| 101 double m_x2; // input delayed by 2 samples | |
| 102 double m_y1; // output delayed by 1 sample | |
| 103 double m_y2; // output delayed by 2 samples | |
| 104 }; | |
| 105 | |
| 106 } // namespace WebCore | |
| 107 | |
| 108 #endif // Biquad_h |
