ref: bca4f2b1da059fbf49a117f447b16b244fa7329a
dir: /libfaad/is.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: is.c,v 1.1 2002/01/14 19:15:56 menno Exp $
**/
#ifdef __ICL
#include <mathf.h>
#else
#include <math.h>
#endif
#include "syntax.h"
#include "is.h"
void is_decode(ic_stream *ics, ic_stream *icsr, float *l_spec, float *r_spec)
{
int g, sfb, b, i, k;
float scale;
int 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))
{
/* 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;
scale = is_intensity(icsr, g, sfb) *
invert_intensity(ics, g, sfb) *
#ifdef __ICL
powf(0.5f, (0.25f*icsr->scale_factors[g][sfb]));
#else
(float)pow(0.5, (0.25*icsr->scale_factors[g][sfb]));
#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++)
{
k = (group*128)+i;
r_spec[k] = l_spec[k] * scale;
}
}
}
group++;
}
}
}