kolibrios/programs/media/ac97 mp3/trunk/mp3dec/l3quant.c

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#include "layer3.h"
#include <math.h>
#include <string.h> //memmove
extern SIDE_INFO m_side_info;
extern SCALE_FACTOR m_scale_fac[2][2]; // [gr][ch]
extern CB_INFO m_cb_info[2][2]; // [gr][ch]
extern int m_nsamp[2][2];
extern int m_nBand[2][22];
extern int m_ncbl_mixed;
#define GLOBAL_GAIN_SCALE (4*15)
static const 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 */
static float look_global[256 + 2 + 4];
/*-------- scaling lookup
x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp)
look_scale[scalefact_scale][preemp][scalefac]
-----------------------*/
static float look_scale[2][4][32];
/*--- iSample**(4/3) lookup, -32<=i<=31 ---*/
#define ISMAX 32
static float look_pow[2 * ISMAX];
/*-- pow(2.0, -0.25*8.0*subblock_gain) --*/
static float look_subblock[8];
/*-- reorder buffer ---*/
static float re_buf[192][3];
typedef float ARRAY3[3];
void quant_init()
{
int i;
int scalefact_scale, preemp, scalefac;
double tmp;
/* 8 bit plus 2 lookup x = pow(2.0, 0.25*(global_gain-210)) */
/* extra 2 for ms scaling by 1/sqrt(2) */
/* extra 4 for cvt to mono scaling by 1/2 */
for (i = 0; i < 256 + 2 + 4; i++)
look_global[i] = (float) pow_test(2.0, 0.25 * ((i - (2 + 4)) - 210 + GLOBAL_GAIN_SCALE));
/* x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp) */
for (scalefact_scale = 0; scalefact_scale < 2; scalefact_scale++)
{
for (preemp = 0; preemp < 4; preemp++)
{
for (scalefac = 0; scalefac < 32; scalefac++)
{
look_scale[scalefact_scale][preemp][scalefac] =
(float) pow_test(2.0, -0.5 * (1 + scalefact_scale) * (scalefac + preemp));
}
}
}
/*--- iSample**(4/3) lookup, -32<=i<=31 ---*/
for (i = 0; i < 64; i++)
{
tmp = i - 32;
look_pow[i] = (float) (tmp * pow_test(fabs(tmp), (1.0 / 3.0)));
}
/*-- pow(2.0, -0.25*8.0*subblock_gain) 3 bits --*/
for (i = 0; i < 8; i++)
{
look_subblock[i] = (float) pow_test(2.0, 0.25 * -8.0 * i);
}
// quant_init_sf_band(sr_index); replaced by code in sup.c
}
void dequant(SAMPLE Sample[], int gr, int ch)
{
SCALE_FACTOR* sf = &m_scale_fac[gr][ch];
GR_INFO* gr_info = &m_side_info.gr[gr][ch];
CB_INFO* cb_info = &m_cb_info[gr][ch];
int* nsamp = &m_nsamp[gr][ch];
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_info->block_type == 2)
{
ncbl = 0;
cbs0 = 0;
if (gr_info->mixed_block_flag)
{
ncbl = m_ncbl_mixed;
cbs0 = 3;
}
}
/* fill in cb_info -- */
cb_info->lb_type = gr_info->block_type;
if (gr_info->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 = look_global[(2 + 4) + gr_info->global_gain];
i = 0;
/*----- long blocks ---*/
for (cb = 0; cb < ncbl; cb++)
{
non_zero = 0;
xs = x0 * look_scale[gr_info->scalefac_scale][pretab[gr_info->preflag][cb]][sf->l[cb]];
n = m_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 * look_pow[ISMAX + Sample[i].s];
else
{
tmp = (double) Sample[i].s;
Sample[i].x = (float) (xs * tmp * pow_test(fabs(tmp), (1.0 / 3.0)));
}
}
}
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 = re_buf;
for (w = 0; w < 3; w++)
xsb[w] = x0 * look_subblock[gr_info->subblock_gain[w]];
for (cb = cbs0; cb < 13; cb++)
{
n = m_nBand[1][cb];
for (w = 0; w < 3; w++)
{
non_zero = 0;
xs = xsb[w] * look_scale[gr_info->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 * look_pow[ISMAX + Sample[i].s];
else
{
tmp = (double) Sample[i].s;
buf[j][w] = (float) (xs * tmp * pow_test(fabs(tmp), (1.0 / 3.0)));
}
}
}
if (non_zero)
cbmax[w] = cb;
}
if (i >= nbands)
break;
buf += n;
}
memmove(&Sample[i0].x, &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 */
}