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/*
* 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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_BIQUAD_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_BIQUAD_H_
#include <sys/types.h>
#include <complex>
#include "build/build_config.h"
#include "third_party/blink/renderer/platform/audio/audio_array.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/allocator.h"
namespace blink {
// 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 PLATFORM_EXPORT Biquad final {
DISALLOW_NEW();
public:
Biquad();
~Biquad();
void Process(const float* source_p, float* dest_p, size_t frames_to_process);
bool HasSampleAccurateValues() const { return has_sample_accurate_values_; }
void SetHasSampleAccurateValues(bool is_sample_accurate) {
has_sample_accurate_values_ = is_sample_accurate;
}
// frequency is 0 - 1 normalized, resonance and dbGain are in decibels.
// Q is a unitless quality factor.
void SetLowpassParams(int, double frequency, double resonance);
void SetHighpassParams(int, double frequency, double resonance);
void SetBandpassParams(int, double frequency, double q);
void SetLowShelfParams(int, double frequency, double db_gain);
void SetHighShelfParams(int, double frequency, double db_gain);
void SetPeakingParams(int, double frequency, double q, double db_gain);
void SetAllpassParams(int, double frequency, double q);
void SetNotchParams(int, double frequency, double q);
// Resets filter state
void Reset();
// Compute tail frame based on the filter coefficents at index
// |coef_index|. The tail frame is the frame number where the
// impulse response of the filter falls below a threshold value.
// The maximum allowed frame value is given by |max_frame|. This
// limits how much work is done in computing the frame numer.
double TailFrame(int coef_index, double max_frame);
// 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 n_frequencies,
const float* frequency,
float* mag_response,
float* phase_response);
private:
void SetNormalizedCoefficients(int,
double b0,
double b1,
double b2,
double a0,
double a1,
double a2);
// If true, the filter coefficients are (possibly) time-varying due to a
// timeline automation on at least one filter parameter.
bool has_sample_accurate_values_;
// 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].
AudioDoubleArray b0_;
AudioDoubleArray b1_;
AudioDoubleArray b2_;
AudioDoubleArray a1_;
AudioDoubleArray a2_;
#if defined(OS_MACOSX)
void ProcessFast(const float* source_p,
float* dest_p,
size_t frames_to_process);
void ProcessSliceFast(double* source_p,
double* dest_p,
double* coefficients_p,
size_t frames_to_process);
AudioDoubleArray input_buffer_;
AudioDoubleArray output_buffer_;
#endif
// Filter memory
double x1_; // input delayed by 1 sample
double x2_; // input delayed by 2 samples
double y1_; // output delayed by 1 sample
double y2_; // output delayed by 2 samples
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_BIQUAD_H_
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