ref: a2ab4c0038a4894017f476e8014368690299bda6
dir: /libfaad/drc.c/
/*
** FAAD - Freeware Advanced Audio Decoder
** Copyright (C) 2002 M. Bakker
**
** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** $Id: drc.c,v 1.12 2002/11/28 18:48:30 menno Exp $
**/
#include "common.h"
#include "structs.h"
#include <stdlib.h>
#include <string.h>
#include "syntax.h"
#include "drc.h"
drc_info *drc_init(real_t cut, real_t boost)
{
drc_info *drc = (drc_info*)malloc(sizeof(drc_info));
memset(drc, 0, sizeof(drc_info));
drc->ctrl1 = cut;
drc->ctrl2 = boost;
drc->num_bands = 1;
drc->band_top[0] = 1024/4 - 1;
drc->dyn_rng_sgn[0] = 1;
drc->dyn_rng_ctl[0] = 0;
return drc;
}
void drc_end(drc_info *drc)
{
if (drc) free(drc);
}
#ifdef FIXED_POINT
static real_t drc_pow2_table[] =
{
COEF_CONST(0.5146511183),
COEF_CONST(0.5297315472),
COEF_CONST(0.5452538663),
COEF_CONST(0.5612310242),
COEF_CONST(0.5776763484),
COEF_CONST(0.5946035575),
COEF_CONST(0.6120267717),
COEF_CONST(0.6299605249),
COEF_CONST(0.6484197773),
COEF_CONST(0.6674199271),
COEF_CONST(0.6869768237),
COEF_CONST(0.7071067812),
COEF_CONST(0.7278265914),
COEF_CONST(0.7491535384),
COEF_CONST(0.7711054127),
COEF_CONST(0.7937005260),
COEF_CONST(0.8169577266),
COEF_CONST(0.8408964153),
COEF_CONST(0.8655365610),
COEF_CONST(0.8908987181),
COEF_CONST(0.9170040432),
COEF_CONST(0.9438743127),
COEF_CONST(0.9715319412),
COEF_CONST(1.0000000000),
COEF_CONST(1.0293022366),
COEF_CONST(1.0594630944),
COEF_CONST(1.0905077327),
COEF_CONST(1.1224620483),
COEF_CONST(1.1553526969),
COEF_CONST(1.1892071150),
COEF_CONST(1.2240535433),
COEF_CONST(1.2599210499),
COEF_CONST(1.2968395547),
COEF_CONST(1.3348398542),
COEF_CONST(1.3739536475),
COEF_CONST(1.4142135624),
COEF_CONST(1.4556531828),
COEF_CONST(1.4983070769),
COEF_CONST(1.5422108254),
COEF_CONST(1.5874010520),
COEF_CONST(1.6339154532),
COEF_CONST(1.6817928305),
COEF_CONST(1.7310731220),
COEF_CONST(1.7817974363),
COEF_CONST(1.8340080864),
COEF_CONST(1.8877486254),
COEF_CONST(1.9430638823)
};
#endif
void drc_decode(drc_info *drc, real_t *spec)
{
uint16_t i, bd, top;
#ifdef FIXED_POINT
int32_t exp, frac;
#else
real_t factor, exp;
#endif
uint16_t bottom = 0;
if (drc->num_bands == 1)
drc->band_top[0] = 1024/4 - 1;
for (bd = 0; bd < drc->num_bands; bd++)
{
top = 4 * (drc->band_top[bd] + 1);
#ifndef FIXED_POINT
/* Decode DRC gain factor */
if (drc->dyn_rng_sgn[bd]) /* compress */
exp = -drc->ctrl1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/24.0;
else /* boost */
exp = drc->ctrl2 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/24.0;
factor = (real_t)pow(2.0, exp);
/* Apply gain factor */
for (i = bottom; i < top; i++)
spec[i] *= factor;
#else
/* Decode DRC gain factor */
if (drc->dyn_rng_sgn[bd]) /* compress */
{
exp = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24;
frac = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
} else { /* boost */
exp = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24;
frac = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
}
/* Apply gain factor */
if (exp < 0)
{
for (i = bottom; i < top; i++)
{
spec[i] >>= -exp;
if (frac)
spec[i] = MUL(spec[i],drc_pow2_table[frac+23]);
}
} else {
for (i = bottom; i < top; i++)
{
spec[i] <<= exp;
if (frac)
spec[i] = MUL(spec[i],drc_pow2_table[frac+23]);
}
}
#endif
bottom = top;
}
}