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253 lines (214 loc) · 6.46 KB
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/*____________________________________________________________________________
FreeAmp - The Free MP3 Player
MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology
Corp. http://www.xingtech.com
Portions Copyright (C) 1998-1999 EMusic.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., 675 Mass Ave, Cambridge, MA 02139, USA.
____________________________________________________________________________*/
/**** quant.c ***************************************************
Layer III dequant
does reordering of short blocks
mod 8/19/98 decode 22 sf bands
******************************************************************/
#include <float.h>
#include <math.h>
#include <string.h>
#include "L3.h"
#include "mhead.h"
#include "protos.h"
/*----------
static struct {
int l[23];
int s[14];} sfBandTable[3] =
{{{0,4,8,12,16,20,24,30,36,44,52,62,74,90,110,134,162,196,238,288,342,418,576},
{0,4,8,12,16,22,30,40,52,66,84,106,136,192}},
{{0,4,8,12,16,20,24,30,36,42,50,60,72,88,106,128,156,190,230,276,330,384,576},
{0,4,8,12,16,22,28,38,50,64,80,100,126,192}},
{{0,4,8,12,16,20,24,30,36,44,54,66,82,102,126,156,194,240,296,364,448,550,576},
{0,4,8,12,16,22,30,42,58,78,104,138,180,192}}};
----------*/
/*--------------------------------*/
static int pretab[2][22] =
{
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0},
};
/* 8 bit plus 2 lookup x = pow(2.0, 0.25*(global_gain-210)) */
/* two extra slots to do 1/sqrt(2) scaling for ms */
/* 4 extra slots to do 1/2 scaling for cvt to mono */
/*-------- scaling lookup
x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp)
look_scale[scalefact_scale][preemp][scalefac]
-----------------------*/
#if 0
typedef float LS[4][32];
#endif
/*--- iSample**(4/3) lookup, -32<=i<=31 ---*/
/*-- pow(2.0, -0.25*8.0*subblock_gain) --*/
/*-- reorder buffer ---*/
typedef float ARRAY3[3];
/*=============================================================*/
float *quant_init_global_addr(MPEG *m)
{
return m->cupl.look_global;
}
/*-------------------------------------------------------------*/
LS *quant_init_scale_addr(MPEG *m)
{
return m->cupl.look_scale;
}
/*-------------------------------------------------------------*/
float *quant_init_pow_addr(MPEG *m)
{
return m->cupl.look_pow;
}
/*-------------------------------------------------------------*/
float *quant_init_subblock_addr(MPEG *m)
{
return m->cupl.look_subblock;
}
/*=============================================================*/
#ifdef _MSC_VER
#pragma warning(disable: 4056)
#endif
void dequant(MPEG *m, SAMPLE Sample[], int *nsamp,
SCALEFACT * sf,
GR * gr,
CB_INFO * cb_info, int ncbl_mixed)
{
int i, j;
int cb, n, w;
float x0, xs;
float xsb[3];
double tmp;
int ncbl;
int cbs0;
ARRAY3 *buf; /* short block reorder */
int nbands;
int i0;
int non_zero;
int cbmax[3];
nbands = *nsamp;
ncbl = 22; /* long block cb end */
cbs0 = 12; /* short block cb start */
/* ncbl_mixed = 8 or 6 mpeg1 or 2 */
if (gr->block_type == 2)
{
ncbl = 0;
cbs0 = 0;
if (gr->mixed_block_flag)
{
ncbl = ncbl_mixed;
cbs0 = 3;
}
}
/* fill in cb_info -- */
/* This doesn't seem used anywhere...
cb_info->lb_type = gr->block_type;
if (gr->block_type == 2)
cb_info->lb_type;
*/
cb_info->cbs0 = cbs0;
cb_info->ncbl = ncbl;
cbmax[2] = cbmax[1] = cbmax[0] = 0;
/* global gain pre-adjusted by 2 if ms_mode, 0 otherwise */
x0 = m->cupl.look_global[(2 + 4) + gr->global_gain];
i = 0;
/*----- long blocks ---*/
for (cb = 0; cb < ncbl; cb++)
{
non_zero = 0;
xs = x0 * m->cupl.look_scale[gr->scalefac_scale][pretab[gr->preflag][cb]][sf->l[cb]];
n = m->cupl.nBand[0][cb];
for (j = 0; j < n; j++, i++)
{
if (Sample[i].s == 0)
Sample[i].x = 0.0F;
else
{
non_zero = 1;
if ((Sample[i].s >= (-ISMAX)) && (Sample[i].s < ISMAX))
Sample[i].x = xs * m->cupl.look_pow[ISMAX + Sample[i].s];
else
{
float tmpConst = (float)(1.0/3.0);
tmp = (double) Sample[i].s;
Sample[i].x = (float) (xs * tmp * pow(fabs(tmp), tmpConst));
}
}
}
if (non_zero)
cbmax[0] = cb;
if (i >= nbands)
break;
}
cb_info->cbmax = cbmax[0];
cb_info->cbtype = 0; // type = long
if (cbs0 >= 12)
return;
/*---------------------------
block type = 2 short blocks
----------------------------*/
cbmax[2] = cbmax[1] = cbmax[0] = cbs0;
i0 = i; /* save for reorder */
buf = m->cupl.re_buf;
for (w = 0; w < 3; w++)
xsb[w] = x0 * m->cupl.look_subblock[gr->subblock_gain[w]];
for (cb = cbs0; cb < 13; cb++)
{
n = m->cupl.nBand[1][cb];
for (w = 0; w < 3; w++)
{
non_zero = 0;
xs = xsb[w] * m->cupl.look_scale[gr->scalefac_scale][0][sf->s[w][cb]];
for (j = 0; j < n; j++, i++)
{
if (Sample[i].s == 0)
buf[j][w] = 0.0F;
else
{
non_zero = 1;
if ((Sample[i].s >= (-ISMAX)) && (Sample[i].s < ISMAX))
buf[j][w] = xs * m->cupl.look_pow[ISMAX + Sample[i].s];
else
{
float tmpConst = (float)(1.0/3.0);
tmp = (double) Sample[i].s;
buf[j][w] = (float) (xs * tmp * pow(fabs(tmp), tmpConst));
}
}
}
if (non_zero)
cbmax[w] = cb;
}
if (i >= nbands)
break;
buf += n;
}
memmove(&Sample[i0].x, &m->cupl.re_buf[0][0], sizeof(float) * (i - i0));
*nsamp = i; /* update nsamp */
cb_info->cbmax_s[0] = cbmax[0];
cb_info->cbmax_s[1] = cbmax[1];
cb_info->cbmax_s[2] = cbmax[2];
if (cbmax[1] > cbmax[0])
cbmax[0] = cbmax[1];
if (cbmax[2] > cbmax[0])
cbmax[0] = cbmax[2];
cb_info->cbmax = cbmax[0];
cb_info->cbtype = 1; /* type = short */
return;
}
#ifdef _MSC_VER
#pragma warning(default: 4056)
#endif
/*-------------------------------------------------------------*/