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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /dom/media/webaudio/blink/Biquad.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'dom/media/webaudio/blink/Biquad.h')
-rw-r--r-- | dom/media/webaudio/blink/Biquad.h | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/dom/media/webaudio/blink/Biquad.h b/dom/media/webaudio/blink/Biquad.h new file mode 100644 index 000000000..f266af441 --- /dev/null +++ b/dom/media/webaudio/blink/Biquad.h @@ -0,0 +1,108 @@ +/* + * 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 <complex> + +namespace WebCore { + +typedef std::complex<double> Complex; + +// 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(); + ~Biquad(); + + void process(const float* sourceP, float* destP, size_t framesToProcess); + + // frequency is 0 - 1 normalized, resonance and dbGain are in decibels. + // Q is a unitless quality factor. + void setLowpassParams(double frequency, double resonance); + void setHighpassParams(double frequency, double resonance); + void setBandpassParams(double frequency, double Q); + void setLowShelfParams(double frequency, double dbGain); + void setHighShelfParams(double frequency, double dbGain); + void setPeakingParams(double frequency, double Q, double dbGain); + void setAllpassParams(double frequency, double Q); + void setNotchParams(double frequency, double Q); + + // 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); + + // Return true iff the next output block will contain sound even with + // silent input. + bool hasTail() const { return m_y1 || m_y2 || m_x1 || m_x2; } + + // Resets filter state + void reset(); + + // Filter response at a set of n frequencies. The magnitude and + // phase response are returned in magResponse and phaseResponse. + // The phase response is in radians. + void getFrequencyResponse(int nFrequencies, + const float* frequency, + float* magResponse, + float* phaseResponse); +private: + void setNormalizedCoefficients(double b0, double b1, double b2, double a0, double a1, double a2); + + // Filter coefficients. The filter is defined as + // + // 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]. + double m_b0; + double m_b1; + double m_b2; + double m_a1; + double m_a2; + + // Filter memory + // + // Double precision for the output values is valuable because errors can + // accumulate. Input values are also stored as double so they need not be + // converted again for computation. + 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 +}; + +} // namespace WebCore + +#endif // Biquad_h |