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 <sys/types.h> 33 #include "core/platform/audio/AudioArray.h" 34 #include "wtf/Complex.h" 35 36 #if USE(WEBAUDIO_IPP) 37 #include <ipps.h> 38 #endif // USE(WEBAUDIO_IPP) 39 40 namespace WebCore { 41 42 // A basic biquad (two-zero / two-pole digital filter) 43 // 44 // It can be configured to a number of common and very useful filters: 45 // lowpass, highpass, shelving, parameteric, notch, allpass, ... 46 47 class Biquad { 48 public: 49 Biquad(); 50 virtual ~Biquad(); 51 52 void process(const float* sourceP, float* destP, size_t framesToProcess); 53 54 // frequency is 0 - 1 normalized, resonance and dbGain are in decibels. 55 // Q is a unitless quality factor. 56 void setLowpassParams(double frequency, double resonance); 57 void setHighpassParams(double frequency, double resonance); 58 void setBandpassParams(double frequency, double Q); 59 void setLowShelfParams(double frequency, double dbGain); 60 void setHighShelfParams(double frequency, double dbGain); 61 void setPeakingParams(double frequency, double Q, double dbGain); 62 void setAllpassParams(double frequency, double Q); 63 void setNotchParams(double frequency, double Q); 64 65 // Set the biquad coefficients given a single zero (other zero will be conjugate) 66 // and a single pole (other pole will be conjugate) 67 void setZeroPolePairs(const Complex& zero, const Complex& pole); 68 69 // Set the biquad coefficients given a single pole (other pole will be conjugate) 70 // (The zeroes will be the inverse of the poles) 71 void setAllpassPole(const Complex& pole); 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 #if OS(DARWIN) 96 void processFast(const float* sourceP, float* destP, size_t framesToProcess); 97 void processSliceFast(double* sourceP, double* destP, double* coefficientsP, size_t framesToProcess); 98 99 AudioDoubleArray m_inputBuffer; 100 AudioDoubleArray m_outputBuffer; 101 102 #elif USE(WEBAUDIO_IPP) 103 IppsIIRState64f_32f* m_biquadState; 104 Ipp8u* m_ippInternalBuffer; 105 106 #else 107 // Filter memory 108 double m_x1; // input delayed by 1 sample 109 double m_x2; // input delayed by 2 samples 110 double m_y1; // output delayed by 1 sample 111 double m_y2; // output delayed by 2 samples 112 #endif 113 }; 114 115 } // namespace WebCore 116 117 #endif // Biquad_h 118