ardour/libs/vamp-plugins/ebu_r128_proc.cc
Robin Gareus 26270db8ae
Fix EBU-R128 loudness analysis for mono signals
This removes the special case which assumed unity gain
when reproducing mono files on a stereo system.

ITU-R BS.1770 however specifies a channel weight of 0dB for
left, right and centre, regardless of the total channel count.

Tech 3344 6.16 mentions a 3dB attenuation to maintain the
loudness level of a mono audio signal in multi-channel signals,
and Tech 3343-2016 further specifies that "Ideally, a downmix
operation should be loudness-agnostic".
2023-02-02 17:58:46 +01:00

362 lines
6.9 KiB
C++

// ------------------------------------------------------------------------
//
// Copyright (C) 2010-2011 Fons Adriaensen <fons@linuxaudio.org>
// Copyright (C) 2015 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., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// ------------------------------------------------------------------------
#include "ebu_r128_proc.h"
#include <math.h>
#include <string.h>
#ifdef COMPILER_MSVC
#include <float.h>
// C99 'isfinite()' is not available in MSVC.
#define isfinite_local(val) (bool)_finite((double)val)
#else
#define isfinite_local isfinite
#endif
using namespace FonsEBU;
float Ebu_r128_proc::Ebu_r128_hist::_bin_power[100] = { 0.0f };
float Ebu_r128_proc::_chan_gain[5] = { 1.0f, 1.0f, 1.0f, 1.41f, 1.41f };
Ebu_r128_proc::Ebu_r128_hist::Ebu_r128_hist ()
{
_histc = new int[751];
initstat ();
reset ();
}
Ebu_r128_proc::Ebu_r128_hist::~Ebu_r128_hist ()
{
delete[] _histc;
}
void
Ebu_r128_proc::Ebu_r128_hist::reset ()
{
memset (_histc, 0, 751 * sizeof (float));
_count = 0;
_error = 0;
}
void
Ebu_r128_proc::Ebu_r128_hist::initstat ()
{
if (_bin_power[0])
return;
for (int i = 0; i < 100; i++) {
_bin_power[i] = powf (10.0f, i / 100.0f);
}
}
void
Ebu_r128_proc::Ebu_r128_hist::addpoint (float v)
{
int k = (int)floorf (10 * v + 700.5f);
if (k < 0)
return;
if (k > 750) {
k = 750;
_error++;
}
_histc[k]++;
_count++;
}
float
Ebu_r128_proc::Ebu_r128_hist::integrate (int i)
{
int j, k, n;
float s;
j = i % 100;
n = 0;
s = 0;
while (i <= 750) {
k = _histc[i++];
n += k;
s += k * _bin_power[j++];
if (j == 100) {
j = 0;
s /= 10.0f;
}
}
return s / n;
}
void
Ebu_r128_proc::Ebu_r128_hist::calc_integ (float* vi, float* th)
{
int k;
float s;
if (_count < 50) {
*vi = -200.0f;
return;
}
s = integrate (0);
// Original threshold was -8 dB below result of first integration
// if (th) *th = 10 * log10f (s) - 8.0f;
// k = (int)(floorf (100 * log10f (s) + 0.5f)) + 620;
// Threshold redefined to -10 dB below result of first integration
if (th) {
*th = 10 * log10f (s) - 10.0f;
}
k = (int)(floorf (100 * log10f (s) + 0.5f)) + 600;
if (k < 0) {
k = 0;
}
s = integrate (k);
*vi = 10 * log10f (s);
}
void
Ebu_r128_proc::Ebu_r128_hist::calc_range (float* v0, float* v1, float* th)
{
int i, j, k, n;
float a, b, s;
if (_count < 20) {
*v0 = -200.0f;
*v1 = -200.0f;
return;
}
s = integrate (0);
if (th) {
*th = 10 * log10f (s) - 20.0f;
}
k = (int)(floorf (100 * log10f (s) + 0.5)) + 500;
if (k < 0) {
k = 0;
}
for (i = k, n = 0; i <= 750; i++) {
n += _histc[i];
}
a = 0.10f * n;
b = 0.95f * n;
for (i = k, s = 0; s < a; i++) {
s += _histc[i];
}
for (j = 750, s = n; s > b; j--) {
s -= _histc[j];
}
*v0 = (i - 701) / 10.0f;
*v1 = (j - 699) / 10.0f;
}
Ebu_r128_proc::Ebu_r128_proc ()
{
reset ();
}
Ebu_r128_proc::~Ebu_r128_proc ()
{
}
void
Ebu_r128_proc::init (int nchan, float fsamp)
{
_nchan = nchan;
_fsamp = fsamp;
_fragm = (int)fsamp / 20;
detect_init (_fsamp);
reset ();
}
void
Ebu_r128_proc::reset ()
{
_integr = false;
_frcnt = _fragm;
_frpwr = 1e-30f;
_wrind = 0;
_div1 = 0;
_div2 = 0;
_loudness_M = -200.0f;
_loudness_S = -200.0f;
memset (_power, 0, 64 * sizeof (float));
integr_reset ();
detect_reset ();
}
void
Ebu_r128_proc::integr_reset ()
{
_hist_M.reset ();
_hist_S.reset ();
_maxloudn_M = -200.0f;
_maxloudn_S = -200.0f;
_integrated = -200.0f;
_integ_thr = -200.0f;
_range_min = -200.0f;
_range_max = -200.0f;
_range_thr = -200.0f;
_div1 = _div2 = 0;
}
void
Ebu_r128_proc::process (int nfram, const float* const* input)
{
int i, k;
for (i = 0; i < _nchan; i++) {
_ipp[i] = input[i];
}
while (nfram) {
k = (_frcnt < nfram) ? _frcnt : nfram;
_frpwr += detect_process (k);
_frcnt -= k;
if (_frcnt == 0) {
_power[_wrind++] = _frpwr / _fragm;
_frcnt = _fragm;
_frpwr = 1e-30f;
_wrind &= 63;
_loudness_M = addfrags (8);
_loudness_S = addfrags (60);
if (!isfinite_local (_loudness_M) || _loudness_M < -200.f) {
_loudness_M = -200.0f;
}
if (!isfinite_local (_loudness_S) || _loudness_S < -200.f) {
_loudness_S = -200.0f;
}
if (_loudness_M > _maxloudn_M) {
_maxloudn_M = _loudness_M;
}
if (_loudness_S > _maxloudn_S) {
_maxloudn_S = _loudness_S;
}
if (_integr) {
if (++_div1 == 2) {
_hist_M.addpoint (_loudness_M);
_div1 = 0;
}
if (++_div2 == 10) {
_hist_S.addpoint (_loudness_S);
_div2 = 0;
_hist_M.calc_integ (&_integrated, &_integ_thr);
_hist_S.calc_range (&_range_min, &_range_max, &_range_thr);
}
}
}
for (i = 0; i < _nchan; i++) {
_ipp[i] += k;
}
nfram -= k;
}
}
float
Ebu_r128_proc::addfrags (int nfrag)
{
int i, k;
float s;
s = 0;
k = (_wrind - nfrag) & 63;
for (i = 0; i < nfrag; i++) {
s += _power[(i + k) & 63];
}
return -0.6976f + 10 * log10f (s / nfrag);
}
void
Ebu_r128_proc::detect_init (float fsamp)
{
float a, b, c, d, r, u1, u2, w1, w2;
r = 1 / tan (4712.3890f / fsamp);
w1 = r / 1.12201f;
w2 = r * 1.12201f;
u1 = u2 = 1.4085f + 210.0f / fsamp;
a = u1 * w1;
b = w1 * w1;
c = u2 * w2;
d = w2 * w2;
r = 1 + a + b;
_a0 = (1 + c + d) / r;
_a1 = (2 - 2 * d) / r;
_a2 = (1 - c + d) / r;
_b1 = (2 - 2 * b) / r;
_b2 = (1 - a + b) / r;
r = 48.0f / fsamp;
a = 4.9886075f * r;
b = 6.2298014f * r * r;
r = 1 + a + b;
a *= 2 / r;
b *= 4 / r;
_c3 = a + b;
_c4 = b;
r = 1.004995f / r;
_a0 *= r;
_a1 *= r;
_a2 *= r;
}
void
Ebu_r128_proc::detect_reset ()
{
for (int i = 0; i < MAXCH; i++)
_fst[i].reset ();
}
float
Ebu_r128_proc::detect_process (int nfram)
{
int i, j;
float si, sj;
float x, y, z1, z2, z3, z4;
float const* p;
Ebu_r128_fst* S;
si = 0;
for (i = 0, S = _fst; i < _nchan; i++, S++) {
z1 = S->_z1;
z2 = S->_z2;
z3 = S->_z3;
z4 = S->_z4;
p = _ipp[i];
sj = 0;
for (j = 0; j < nfram; j++) {
x = p[j] - _b1 * z1 - _b2 * z2 + 1e-15f;
y = _a0 * x + _a1 * z1 + _a2 * z2 - _c3 * z3 - _c4 * z4;
z2 = z1;
z1 = x;
z4 += z3;
z3 += y;
sj += y * y;
}
si += _chan_gain[i] * sj;
S->_z1 = !isfinite_local (z1) ? 0 : z1;
S->_z2 = !isfinite_local (z2) ? 0 : z2;
S->_z3 = !isfinite_local (z3) ? 0 : z3;
S->_z4 = !isfinite_local (z4) ? 0 : z4;
}
return si;
}