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 41 namespace 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 48 class PLATFORM_EXPORT Biquad FINAL { 49 public: 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); 84 private: 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
