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ardour/libs/ardour/dsp_filter.cc

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/*
* Copyright (C) 2016-2017 Paul Davis <paul@linuxaudiosystems.com>
* Copyright (C) 2016-2018 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <algorithm>
#include <boost/math/special_functions/fpclassify.hpp>
#include <cmath>
#include <stdlib.h>
#include "ardour/buffer.h"
#include "ardour/dB.h"
#include "ardour/dsp_filter.h"
#include "ardour/runtime_functions.h"
#ifdef COMPILER_MSVC
#include <float.h>
#define isfinite_local(val) (bool)_finite ((double)val)
#else
#define isfinite_local std::isfinite
#endif
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
using namespace ARDOUR::DSP;
void
ARDOUR::DSP::memset (float* data, const float val, const uint32_t n_samples)
{
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] = val;
}
}
void
ARDOUR::DSP::mmult (float* data, float* mult, const uint32_t n_samples)
{
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] *= mult[i];
}
}
float
ARDOUR::DSP::log_meter (float power)
{
// compare to libs/ardour/log_meter.h
static const float lower_db = -192.f;
static const float upper_db = 0.f;
static const float non_linearity = 8.0;
return (power < lower_db ? 0.0 : powf ((power - lower_db) / (upper_db - lower_db), non_linearity));
}
float
ARDOUR::DSP::log_meter_coeff (float coeff)
{
if (coeff <= 0) {
return 0;
}
return log_meter (fast_coefficient_to_dB (coeff));
}
void
ARDOUR::DSP::peaks (const float* data, float& min, float& max, uint32_t n_samples)
{
ARDOUR::find_peaks (data, n_samples, &min, &max);
}
void
ARDOUR::DSP::process_map (BufferSet* bufs, const ChanCount& n_out, const ChanMapping& in_map, const ChanMapping& out_map, pframes_t nframes, samplecnt_t offset)
{
/* PluginInsert already handles most, in particular `no-inplace` buffers in case
* or x-over connections, and through connections.
*
* This just fills output buffers, forwarding inputs as needed:
* Input -> plugin-sink == plugin-src -> Output
*/
for (DataType::iterator t = DataType::begin (); t != DataType::end (); ++t) {
for (uint32_t out = 0; out < n_out.get (*t); ++out) {
bool valid;
uint32_t out_idx = out_map.get (*t, out, &valid);
if (!valid) {
continue;
}
uint32_t in_idx = in_map.get (*t, out, &valid);
if (!valid) {
bufs->get_available (*t, out_idx).silence (nframes, offset);
continue;
}
if (in_idx != out_idx) {
bufs->get_available (*t, out_idx).read_from (bufs->get_available (*t, in_idx), nframes, offset, offset);
}
}
}
}
LowPass::LowPass (double samplerate, float freq)
: _rate (samplerate)
, _z (0)
{
set_cutoff (freq);
}
void
LowPass::set_cutoff (float freq)
{
_a = 1.f - expf (-2.f * M_PI * freq / _rate);
}
void
LowPass::proc (float* data, const uint32_t n_samples)
{
// localize variables
const float a = _a;
float z = _z;
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] += a * (data[i] - z);
z = data[i];
}
_z = z;
if (!isfinite_local (_z)) {
_z = 0;
} else if (!boost::math::isnormal (_z)) {
_z = 0;
}
}
void
LowPass::ctrl (float* data, const float val, const uint32_t n_samples)
{
// localize variables
const float a = _a;
float z = _z;
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] += a * (val - z);
z = data[i];
}
_z = z;
}
///////////////////////////////////////////////////////////////////////////////
Biquad::Biquad (double samplerate)
: _rate (samplerate)
, _z1 (0.0)
, _z2 (0.0)
, _a1 (0.0)
, _a2 (0.0)
, _b0 (1.0)
, _b1 (0.0)
, _b2 (0.0)
{
}
Biquad::Biquad (const Biquad& other)
: _rate (other._rate)
, _z1 (0.0)
, _z2 (0.0)
, _a1 (other._a1)
, _a2 (other._a2)
, _b0 (other._b0)
, _b1 (other._b1)
, _b2 (other._b2)
{
}
void
Biquad::run (float* data, const uint32_t n_samples)
{
for (uint32_t i = 0; i < n_samples; ++i) {
const float xn = data[i];
const float z = _b0 * xn + _z1;
_z1 = _b1 * xn - _a1 * z + _z2;
_z2 = _b2 * xn - _a2 * z;
data[i] = z;
}
if (!isfinite_local (_z1)) {
_z1 = 0;
} else if (!boost::math::isnormal (_z1)) {
_z1 = 0;
}
if (!isfinite_local (_z2)) {
_z2 = 0;
} else if (!boost::math::isnormal (_z2)) {
_z2 = 0;
}
}
void
Biquad::configure (double a1, double a2, double b0, double b1, double b2)
{
_a1 = a1;
_a2 = a2;
_b0 = b0;
_b1 = b1;
_b2 = b2;
}
void
Biquad::configure (Biquad const& other)
{
_a1 = other._a1;
_a2 = other._a2;
_b0 = other._b0;
_b1 = other._b1;
_b2 = other._b2;
}
void
Biquad::set_vicanek_poles (const double W0, const double Q, const double A)
{
/* https://www.vicanek.de/articles/BiquadFits.pdf */
const double Q2 = Q * Q;
const double AA = A * A;
const double p = 1. / (4 * AA * Q2);
_a2 = exp (-.5 * W0 / (A * Q));
_a1 = p <= 1.
? -2 * _a2 * cos (W0 * sqrt (1 - p))
: -2 * _a2 * cosh (W0 * sqrt (p - 1));
_a2 = _a2 * _a2;
}
void
Biquad::calc_vicanek (const double W0, double& A0, double& A1, double& A2, double& phi0, double& phi1, double& phi2)
{
#define SQR(x) ((x) * (x))
A0 = SQR (1. + _a1 + _a2);
A1 = SQR (1. - _a1 + _a2);
A2 = -4 * _a2;
phi1 = SQR (sin (.5 * W0));
phi0 = 1.0 - phi1;
phi2 = 4 * phi0 * phi1;
#undef SQR
}
void
Biquad::compute (Type type, double freq, double Q, double gain)
{
if (Q <= .001) {
Q = 0.001;
}
if (freq <= 1.) {
freq = 1.;
}
if (freq >= 0.4998 * _rate) {
freq = 0.4998 * _rate;
}
/* Compute biquad filter settings.
* Based on 'Cookbook formulae for audio EQ biquad filter coefficents'
* by Robert Bristow-Johnson
*/
const double A = pow (10.0, (gain / 40.0));
const double W0 = (2.0 * M_PI * freq) / _rate;
const double sinW0 = sin (W0);
const double cosW0 = cos (W0);
const double alpha = sinW0 / (2.0 * Q);
const double beta = sqrt (A) / Q;
double _a0;
double A0, A1, A2;
double phi0, phi1, phi2;
switch (type) {
case LowPass:
_b0 = (1.0 - cosW0) / 2.0;
_b1 = 1.0 - cosW0;
_b2 = (1.0 - cosW0) / 2.0;
_a0 = 1.0 + alpha;
_a1 = -2.0 * cosW0;
_a2 = 1.0 - alpha;
break;
case HighPass:
_b0 = (1.0 + cosW0) / 2.0;
_b1 = -(1.0 + cosW0);
_b2 = (1.0 + cosW0) / 2.0;
_a0 = 1.0 + alpha;
_a1 = -2.0 * cosW0;
_a2 = 1.0 - alpha;
break;
case BandPassSkirt: /* Constant skirt gain, peak gain = Q */
_b0 = sinW0 / 2.0;
_b1 = 0.0;
_b2 = -sinW0 / 2.0;
_a0 = 1.0 + alpha;
_a1 = -2.0 * cosW0;
_a2 = 1.0 - alpha;
break;
case BandPass0dB: /* Constant 0 dB peak gain */
_b0 = alpha;
_b1 = 0.0;
_b2 = -alpha;
_a0 = 1.0 + alpha;
_a1 = -2.0 * cosW0;
_a2 = 1.0 - alpha;
break;
case Notch:
_b0 = 1.0;
_b1 = -2.0 * cosW0;
_b2 = 1.0;
_a0 = 1.0 + alpha;
_a1 = -2.0 * cosW0;
_a2 = 1.0 - alpha;
break;
case AllPass:
_b0 = 1.0 - alpha;
_b1 = -2.0 * cosW0;
_b2 = 1.0 + alpha;
_a0 = 1.0 + alpha;
_a1 = -2.0 * cosW0;
_a2 = 1.0 - alpha;
break;
case Peaking:
_b0 = 1.0 + (alpha * A);
_b1 = -2.0 * cosW0;
_b2 = 1.0 - (alpha * A);
_a0 = 1.0 + (alpha / A);
_a1 = -2.0 * cosW0;
_a2 = 1.0 - (alpha / A);
break;
case LowShelf:
_b0 = A * ((A + 1) - ((A - 1) * cosW0) + (beta * sinW0));
_b1 = (2.0 * A) * ((A - 1) - ((A + 1) * cosW0));
_b2 = A * ((A + 1) - ((A - 1) * cosW0) - (beta * sinW0));
_a0 = (A + 1) + ((A - 1) * cosW0) + (beta * sinW0);
_a1 = -2.0 * ((A - 1) + ((A + 1) * cosW0));
_a2 = (A + 1) + ((A - 1) * cosW0) - (beta * sinW0);
break;
case HighShelf:
_b0 = A * ((A + 1) + ((A - 1) * cosW0) + (beta * sinW0));
_b1 = -(2.0 * A) * ((A - 1) + ((A + 1) * cosW0));
_b2 = A * ((A + 1) + ((A - 1) * cosW0) - (beta * sinW0));
_a0 = (A + 1) - ((A - 1) * cosW0) + (beta * sinW0);
_a1 = 2.0 * ((A - 1) - ((A + 1) * cosW0));
_a2 = (A + 1) - ((A - 1) * cosW0) - (beta * sinW0);
break;
case MatchedHighPass:
_a0 = 1.0;
set_vicanek_poles (W0, Q);
calc_vicanek (W0, A0, A1, A2, phi0, phi1, phi2);
_b0 = sqrt (A0 * phi0 + A1 * phi1 + A2 * phi2) / (4 * phi1) * Q;
_b1 = -2 * _b0;
_b2 = _b0;
break;
case MatchedLowPass:
_a0 = 1.0;
set_vicanek_poles (W0, Q);
calc_vicanek (W0, A0, A1, A2, phi0, phi1, phi2);
{
const double B0_2 = 1 + _a1 + _a2; // = sqrt (B0)
const double B1 = ((A0 * phi0 + A1 * phi1 + A2 * phi2) * Q * Q - A0 * phi0) / phi1;
_b0 = .5 * (B0_2 + sqrt (B1));
_b1 = B0_2 - _b0;
_b2 = 0;
}
break;
case MatchedBandPass0dB: /* Constant 0 dB peak gain */
_a0 = 1.0;
set_vicanek_poles (W0, Q);
{
float fq = 2 * freq / _rate;
float fq2 = fq * fq;
_b1 = -.5 * (1 - _a1 + _a2) * fq / Q / sqrt ((1 - fq2) * (1 - fq2) + fq2 / (Q * Q));
_b0 = .5 * ((1 + _a1 + _a2) / (W0 * Q) - _b1);
_b2 = -_b0 - _b1;
}
break;
case MatchedPeaking:
_a0 = 1.0;
set_vicanek_poles (W0, Q, A);
calc_vicanek (W0, A0, A1, A2, phi0, phi1, phi2);
{
const double AA = A * A;
const double AAAA = AA * AA;
const double R1 = (phi0 * A0 + phi1 * A1 + phi2 * A2) * AAAA;
const double R2 = (A1 - A0 + 4 * (phi0 - phi1) * A2) * AAAA;
const double B0 = A0;
const double B2 = (R1 - phi1 * R2 - B0) / (4 * phi1 * phi1);
const double B1 = R2 + B0 + 4 * (phi1 - phi0) * B2;
const double B0_2 = 1 + _a1 + _a2; // = sqrt (B0)
_b1 = .5 * (B0_2 - sqrt (B1));
const double w = B0_2 - _b1;
_b0 = .5 * (w + sqrt (w * w + B2));
_b2 = -B2 / (4 * _b0);
}
break;
default:
abort (); /*NOTREACHED*/
break;
}
_b0 /= _a0;
_b1 /= _a0;
_b2 /= _a0;
_a1 /= _a0;
_a2 /= _a0;
}
float
Biquad::dB_at_freq (float freq) const
{
const double W0 = (2.0 * M_PI * freq) / _rate;
const float c1 = cosf (W0);
const float s1 = sinf (W0);
const float A = _b0 + _b2;
const float B = _b0 - _b2;
const float C = 1.0 + _a2;
const float D = 1.0 - _a2;
const float a = A * c1 + _b1;
const float b = B * s1;
const float c = C * c1 + _a1;
const float d = D * s1;
#define SQUARE(x) ((x) * (x))
float rv = 20.f * log10f (sqrtf ((SQUARE (a) + SQUARE (b)) * (SQUARE (c) + SQUARE (d))) / (SQUARE (c) + SQUARE (d)));
if (!isfinite_local (rv)) {
rv = 0;
}
return std::min (120.f, std::max (-120.f, rv));
}
Glib::Threads::Mutex FFTSpectrum::fft_planner_lock;
FFTSpectrum::FFTSpectrum (uint32_t window_size, double rate)
: hann_window (0)
{
init (window_size, rate);
}
FFTSpectrum::~FFTSpectrum ()
{
{
Glib::Threads::Mutex::Lock lk (fft_planner_lock);
fftwf_destroy_plan (_fftplan);
}
fftwf_free (_fft_data_in);
fftwf_free (_fft_data_out);
free (_fft_power);
free (hann_window);
}
void
FFTSpectrum::init (uint32_t window_size, double rate)
{
assert (window_size > 0);
Glib::Threads::Mutex::Lock lk (fft_planner_lock);
_fft_window_size = window_size;
_fft_data_size = window_size / 2;
_fft_freq_per_bin = rate / _fft_data_size / 2.f;
_fft_data_in = (float*)fftwf_malloc (sizeof (float) * _fft_window_size);
_fft_data_out = (float*)fftwf_malloc (sizeof (float) * _fft_window_size);
_fft_power = (float*)malloc (sizeof (float) * _fft_data_size);
reset ();
_fftplan = fftwf_plan_r2r_1d (_fft_window_size, _fft_data_in, _fft_data_out, FFTW_R2HC, FFTW_MEASURE);
hann_window = (float*)malloc (sizeof (float) * window_size);
double sum = 0.0;
for (uint32_t i = 0; i < window_size; ++i) {
hann_window[i] = 0.5f - (0.5f * (float)cos (2.0f * M_PI * (float)i / (float)(window_size)));
sum += hann_window[i];
}
const double isum = 2.0 / sum;
for (uint32_t i = 0; i < window_size; ++i) {
hann_window[i] *= isum;
}
}
void
FFTSpectrum::reset ()
{
for (uint32_t i = 0; i < _fft_data_size; ++i) {
_fft_power[i] = 0;
}
for (uint32_t i = 0; i < _fft_window_size; ++i) {
_fft_data_out[i] = 0;
}
}
void
FFTSpectrum::set_data_hann (float const* const data, uint32_t n_samples, uint32_t offset)
{
assert (n_samples + offset <= _fft_window_size);
for (uint32_t i = 0; i < n_samples; ++i) {
_fft_data_in[i + offset] = data[i] * hann_window[i + offset];
}
}
void
FFTSpectrum::execute ()
{
fftwf_execute (_fftplan);
_fft_power[0] = _fft_data_out[0] * _fft_data_out[0];
#define FRe (_fft_data_out[i])
#define FIm (_fft_data_out[_fft_window_size - i])
for (uint32_t i = 1; i < _fft_data_size - 1; ++i) {
_fft_power[i] = (FRe * FRe) + (FIm * FIm);
//_fft_phase[i] = atan2f (FIm, FRe);
}
#undef FRe
#undef FIm
}
float
FFTSpectrum::power_at_bin (const uint32_t b, const float norm) const
{
assert (b < _fft_data_size);
const float a = _fft_power[b] * norm;
return a > 1e-12 ? 10.0 * fast_log10 (a) : -INFINITY;
}
Generator::Generator ()
: _type (UniformWhiteNoise)
, _rseed (1)
{
set_type (UniformWhiteNoise);
}
void
Generator::set_type (Generator::Type t)
{
_type = t;
_b0 = _b1 = _b2 = _b3 = _b4 = _b5 = _b6 = 0;
_pass = false;
_rn = 0;
}
void
Generator::run (float* data, const uint32_t n_samples)
{
switch (_type) {
default:
case UniformWhiteNoise:
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] = randf ();
}
break;
case GaussianWhiteNoise:
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] = 0.7079f * grandf ();
}
break;
case PinkNoise:
for (uint32_t i = 0; i < n_samples; ++i) {
const float white = .39572f * randf ();
_b0 = .99886f * _b0 + white * .0555179f;
_b1 = .99332f * _b1 + white * .0750759f;
_b2 = .96900f * _b2 + white * .1538520f;
_b3 = .86650f * _b3 + white * .3104856f;
_b4 = .55000f * _b4 + white * .5329522f;
_b5 = -.7616f * _b5 - white * .0168980f;
data[i] = _b0 + _b1 + _b2 + _b3 + _b4 + _b5 + _b6 + white * 0.5362f;
_b6 = white * 0.115926f;
}
break;
}
}
inline uint32_t
Generator::randi ()
{
// 31bit Park-Miller-Carta Pseudo-Random Number Generator
uint32_t hi, lo;
lo = 16807 * (_rseed & 0xffff);
hi = 16807 * (_rseed >> 16);
lo += (hi & 0x7fff) << 16;
lo += hi >> 15;
lo = (lo & 0x7fffffff) + (lo >> 31);
return (_rseed = lo);
}
inline float
Generator::grandf ()
{
float x1, x2, r;
if (_pass) {
_pass = false;
return _rn;
}
do {
x1 = randf ();
x2 = randf ();
r = x1 * x1 + x2 * x2;
} while ((r >= 1.0f) || (r < 1e-22f));
r = sqrtf (-2.f * logf (r) / r);
_pass = true;
_rn = r * x2;
return r * x1;
}
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