ref: 36cc2a77dc286bd596f59166f6737ffb4a5e2e85
dir: /src/loudness.c/
/* Effect: loudness filter Copyright (c) 2008 robs@users.sourceforge.net
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This library 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 Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "sox_i.h"
#include "dft_filter.h"
#include <string.h>
typedef struct {
dft_filter_priv_t base;
double delta, start;
int n;
} priv_t;
static int create(sox_effect_t * effp, int argc, char **argv)
{
priv_t * p = (priv_t *)effp->priv;
dft_filter_priv_t * b = &p->base;
b->filter_ptr = &b->filter;
p->delta = -10;
p->start = 65;
p->n = 1023;
--argc, ++argv;
do { /* break-able block */
NUMERIC_PARAMETER(delta,-50 , 15) /* FIXME expand range */
NUMERIC_PARAMETER(start, 50 , 75) /* FIXME expand range */
NUMERIC_PARAMETER(n ,127 ,2047)
} while (0);
p->n = 2 * p->n + 1;
return argc? lsx_usage(effp) : SOX_SUCCESS;
}
static double * make_filter(int n, double start, double delta, double rate)
{
static const struct {double f, af, lu, tf;} iso226_table[] = {
{ 20,0.532,-31.6,78.5},{ 25,0.506,-27.2,68.7},{ 31.5,0.480,-23.0,59.5},
{ 40,0.455,-19.1,51.1},{ 50,0.432,-15.9,44.0},{ 63,0.409,-13.0,37.5},
{ 80,0.387,-10.3,31.5},{ 100,0.367, -8.1,26.5},{ 125,0.349, -6.2,22.1},
{ 160,0.330, -4.5,17.9},{ 200,0.315, -3.1,14.4},{ 250,0.301, -2.0,11.4},
{ 315,0.288, -1.1, 8.6},{ 400,0.276, -0.4, 6.2},{ 500,0.267, 0.0, 4.4},
{ 630,0.259, 0.3, 3.0},{ 800,0.253, 0.5, 2.2},{ 1000,0.250, 0.0, 2.4},
{ 1250,0.246, -2.7, 3.5},{ 1600,0.244, -4.1, 1.7},{ 2000,0.243, -1.0,-1.3},
{ 2500,0.243, 1.7,-4.2},{ 3150,0.243, 2.5,-6.0},{ 4000,0.242, 1.2,-5.4},
{ 5000,0.242, -2.1,-1.5},{ 6300,0.245, -7.1, 6.0},{ 8000,0.254,-11.2,12.6},
{10000,0.271,-10.7,13.9},{12500,0.301, -3.1,12.3},
};
#define LEN (array_length(iso226_table) + 2)
#define SPL(phon, t) (10 / t.af * log10(4.47e-3 * (pow(10., .025 * (phon)) - \
1.15) + pow(.4 * pow(10., (t.tf + t.lu) / 10 - 9), t.af)) - t.lu + 94)
double fs[LEN], spl[LEN], d[LEN], * work, * h;
int i, work_len;
fs[0] = log(1.);
spl[0] = delta * .2;
for (i = 0; i < (int)LEN - 2; ++i) {
spl[i + 1] = SPL(start + delta, iso226_table[i]) -
SPL(start , iso226_table[i]);
fs[i + 1] = log(iso226_table[i].f);
}
fs[i + 1] = log(100000.);
spl[i + 1] = spl[0];
lsx_prepare_spline3(fs, spl, (int)LEN, HUGE_VAL, HUGE_VAL, d);
for (work_len = 8192; work_len < rate / 2; work_len <<= 1);
work = lsx_calloc(work_len, sizeof(*work));
h = lsx_calloc(n, sizeof(*h));
for (i = 1; i <= work_len / 2; ++i) {
double f = rate * i / work_len;
double spl1 = f < 1? spl[0] : lsx_spline3(fs, spl, d, (int)LEN, log(f));
work[i < work_len / 2 ? 2 * i : 1] = dB_to_linear(spl1);
}
lsx_safe_rdft(work_len, -1, work);
for (i = 0; i < n; ++i)
h[i] = work[(work_len - n / 2 + i) % work_len] * 2. / work_len;
lsx_apply_kaiser(h, n, lsx_kaiser_beta(40 + 2./3 * fabs(delta)));
free(work);
return h;
#undef SPL
#undef LEN
}
static int start(sox_effect_t * effp)
{
priv_t * p = (priv_t *) effp->priv;
dft_filter_filter_t * f = p->base.filter_ptr;
if (p->delta == 0)
return SOX_EFF_NULL;
if (!f->num_taps) {
double * h = make_filter(p->n, p->start, p->delta, effp->in_signal.rate);
int i, dft_length = lsx_set_dft_length(p->n);
f->coefs = lsx_calloc(dft_length, sizeof(*f->coefs));
for (i = 0; i < p->n; ++i)
f->coefs[(i + dft_length - p->n + 1) & (dft_length - 1)]
= h[i] / dft_length * 2;
free(h);
f->num_taps = p->n;
f->post_peak = f->num_taps / 2;
f->dft_length = dft_length;
lsx_safe_rdft(dft_length, 1, f->coefs);
}
return sox_dft_filter_effect_fn()->start(effp);
}
sox_effect_handler_t const * sox_loudness_effect_fn(void)
{
static sox_effect_handler_t handler;
handler = *sox_dft_filter_effect_fn();
handler.name = "loudness";
handler.usage = "[gain [ref]]";
handler.getopts = create;
handler.start = start;
handler.priv_size = sizeof(priv_t);
return &handler;
}