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 "AudioArray.h" 33 #include <sys/types.h> 34 #include <wtf/Complex.h> 35 #include <wtf/Platform.h> 36 37 namespace WebCore { 38 39 // A basic biquad (two-zero / two-pole digital filter) 40 // 41 // It can be configured to a number of common and very useful filters: 42 // lowpass, highpass, shelving, parameteric, notch, allpass, ... 43 44 class Biquad { 45 public: 46 Biquad(); 47 virtual ~Biquad() { } 48 49 void process(const float* sourceP, float* destP, size_t framesToProcess); 50 51 // cutoff is 0-1 normalized, resonance is in dB >= 0.0 52 void setLowpassParams(double cutoff, double resonance); 53 void setHighpassParams(double cutoff, double resonance); 54 55 void setLowShelfParams(double cutoff, double dbGain); 56 57 // FIXME: need to implement a few more common filters 58 // void setHighShelfParams(double cutoff, double dbGain); 59 // void setParametricEQParams(double cutoff, double resonance); 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 // Resets filter state 70 void reset(); 71 72 private: 73 // Filter coefficients 74 double m_a0; 75 double m_a1; 76 double m_a2; 77 double m_b1; 78 double m_b2; 79 80 double m_g; 81 82 // Filter memory 83 double m_x1; // input delayed by 1 sample 84 double m_x2; // input delayed by 2 samples 85 double m_y1; // output delayed by 1 sample 86 double m_y2; // output delayed by 2 samples 87 88 #if OS(DARWIN) 89 void processFast(const float* sourceP, float* destP, size_t framesToProcess); 90 void processSliceFast(double* sourceP, double* destP, double* coefficientsP, size_t framesToProcess); 91 92 AudioDoubleArray m_inputBuffer; 93 AudioDoubleArray m_outputBuffer; 94 #endif 95 }; 96 97 } // namespace WebCore 98 99 #endif // Biquad_h 100
