mirror of https://github.com/mpv-player/mpv
107 lines
3.7 KiB
C
107 lines
3.7 KiB
C
/*
|
|
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
|
|
** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
|
|
**
|
|
** 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.
|
|
**
|
|
** Any non-GPL usage of this software or parts of this software is strictly
|
|
** forbidden.
|
|
**
|
|
** Commercial non-GPL licensing of this software is possible.
|
|
** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
|
|
**
|
|
** $Id: is.c,v 1.24 2004/09/04 14:56:28 menno Exp $
|
|
**/
|
|
|
|
#include "common.h"
|
|
#include "structs.h"
|
|
|
|
#include "syntax.h"
|
|
#include "is.h"
|
|
|
|
#ifdef FIXED_POINT
|
|
static real_t pow05_table[] = {
|
|
COEF_CONST(1.68179283050743), /* 0.5^(-3/4) */
|
|
COEF_CONST(1.41421356237310), /* 0.5^(-2/4) */
|
|
COEF_CONST(1.18920711500272), /* 0.5^(-1/4) */
|
|
COEF_CONST(1.0), /* 0.5^( 0/4) */
|
|
COEF_CONST(0.84089641525371), /* 0.5^(+1/4) */
|
|
COEF_CONST(0.70710678118655), /* 0.5^(+2/4) */
|
|
COEF_CONST(0.59460355750136) /* 0.5^(+3/4) */
|
|
};
|
|
#endif
|
|
|
|
void is_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec,
|
|
uint16_t frame_len)
|
|
{
|
|
uint8_t g, sfb, b;
|
|
uint16_t i;
|
|
#ifndef FIXED_POINT
|
|
real_t scale;
|
|
#else
|
|
int32_t exp, frac;
|
|
#endif
|
|
|
|
uint16_t nshort = frame_len/8;
|
|
uint8_t group = 0;
|
|
|
|
for (g = 0; g < icsr->num_window_groups; g++)
|
|
{
|
|
/* Do intensity stereo decoding */
|
|
for (b = 0; b < icsr->window_group_length[g]; b++)
|
|
{
|
|
for (sfb = 0; sfb < icsr->max_sfb; sfb++)
|
|
{
|
|
if (is_intensity(icsr, g, sfb))
|
|
{
|
|
#ifdef MAIN_DEC
|
|
/* For scalefactor bands coded in intensity stereo the
|
|
corresponding predictors in the right channel are
|
|
switched to "off".
|
|
*/
|
|
ics->pred.prediction_used[sfb] = 0;
|
|
icsr->pred.prediction_used[sfb] = 0;
|
|
#endif
|
|
|
|
#ifndef FIXED_POINT
|
|
scale = (real_t)pow(0.5, (0.25*icsr->scale_factors[g][sfb]));
|
|
#else
|
|
exp = icsr->scale_factors[g][sfb] >> 2;
|
|
frac = icsr->scale_factors[g][sfb] & 3;
|
|
#endif
|
|
|
|
/* Scale from left to right channel,
|
|
do not touch left channel */
|
|
for (i = icsr->swb_offset[sfb]; i < icsr->swb_offset[sfb+1]; i++)
|
|
{
|
|
#ifndef FIXED_POINT
|
|
r_spec[(group*nshort)+i] = MUL_R(l_spec[(group*nshort)+i], scale);
|
|
#else
|
|
if (exp < 0)
|
|
r_spec[(group*nshort)+i] = l_spec[(group*nshort)+i] << -exp;
|
|
else
|
|
r_spec[(group*nshort)+i] = l_spec[(group*nshort)+i] >> exp;
|
|
r_spec[(group*nshort)+i] = MUL_C(r_spec[(group*nshort)+i], pow05_table[frac + 3]);
|
|
#endif
|
|
if (is_intensity(icsr, g, sfb) != invert_intensity(ics, g, sfb))
|
|
r_spec[(group*nshort)+i] = -r_spec[(group*nshort)+i];
|
|
}
|
|
}
|
|
}
|
|
group++;
|
|
}
|
|
}
|
|
}
|