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jedi-academy/code/mp3code/l3init.c

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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 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.
$Id: l3init.c,v 1.2 1999/10/19 07:13:09 elrod Exp $
____________________________________________________________________________*/
/**** tinit.c ***************************************************
Layer III init tables
******************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <float.h>
#include <math.h>
#include "L3.h"
/* get rid of precision loss warnings on conversion */
#ifdef _MSC_VER
#pragma warning(disable:4244 4056)
#endif
/*---------- quant ---------------------------------*/
/* 8 bit lookup x = pow(2.0, 0.25*(global_gain-210)) */
float *quant_init_global_addr();
/* x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp) */
typedef float LS[4][32];
LS *quant_init_scale_addr();
float *quant_init_pow_addr();
float *quant_init_subblock_addr();
typedef int iARRAY22[22];
iARRAY22 *quant_init_band_addr();
/*---------- antialias ---------------------------------*/
typedef float PAIR[2];
PAIR *alias_init_addr();
static const float Ci[8] =
{
-0.6f, -0.535f, -0.33f, -0.185f, -0.095f, -0.041f, -0.0142f, -0.0037f};
void hwin_init(); /* hybrid windows -- */
void imdct_init();
typedef struct
{
float *w;
float *w2;
void *coef;
}
IMDCT_INIT_BLOCK;
void msis_init();
void msis_init_MPEG2();
/*=============================================================*/
int L3table_init()
{
int i;
float *x;
LS *ls;
int scalefact_scale, preemp, scalefac;
double tmp;
PAIR *csa;
static int iOnceOnly = 0;
if (!iOnceOnly++)
{
/*================ quant ===============================*/
/* 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 */
x = quant_init_global_addr();
for (i = 0; i < 256 + 2 + 4; i++)
x[i] = (float) pow(2.0, 0.25 * ((i - (2 + 4)) - 210 + GLOBAL_GAIN_SCALE));
/* x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp) */
ls = quant_init_scale_addr();
for (scalefact_scale = 0; scalefact_scale < 2; scalefact_scale++)
{
for (preemp = 0; preemp < 4; preemp++)
{
for (scalefac = 0; scalefac < 32; scalefac++)
{
ls[scalefact_scale][preemp][scalefac] =
(float) pow(2.0, -0.5 * (1 + scalefact_scale) * (scalefac + preemp));
}
}
}
/*--- iSample**(4/3) lookup, -32<=i<=31 ---*/
x = quant_init_pow_addr();
for (i = 0; i < 64; i++)
{
tmp = i - 32;
x[i] = (float) (tmp * pow(fabs(tmp), (1.0 / 3.0)));
}
/*-- pow(2.0, -0.25*8.0*subblock_gain) 3 bits --*/
x = quant_init_subblock_addr();
for (i = 0; i < 8; i++)
{
x[i] = (float) pow(2.0, 0.25 * -8.0 * i);
}
/*-------------------------*/
// quant_init_sf_band(sr_index); replaced by code in sup.c
/*================ antialias ===============================*/
// onceonly!!!!!!!!!!!!!!!!!!!!!
csa = alias_init_addr();
for (i = 0; i < 8; i++)
{
csa[i][0] = (float) (1.0 / sqrt(1.0 + Ci[i] * Ci[i]));
csa[i][1] = (float) (Ci[i] / sqrt(1.0 + Ci[i] * Ci[i]));
}
}
// these 4 are iOnceOnly-protected inside...
/*================ msis ===============================*/
msis_init();
msis_init_MPEG2();
/*================ imdct ===============================*/
imdct_init();
/*--- hybrid windows ------------*/
hwin_init();
return 0;
}
/*====================================================================*/
typedef float ARRAY36[36];
ARRAY36 *hwin_init_addr();
/*--------------------------------------------------------------------*/
void hwin_init()
{
int i, j;
double pi;
ARRAY36 *win;
static int iOnceOnly = 0;
if (!iOnceOnly++)
{
win = hwin_init_addr();
pi = 4.0 * atan(1.0);
/* type 0 */
for (i = 0; i < 36; i++)
win[0][i] = (float) sin(pi / 36 * (i + 0.5));
/* type 1 */
for (i = 0; i < 18; i++)
win[1][i] = (float) sin(pi / 36 * (i + 0.5));
for (i = 18; i < 24; i++)
win[1][i] = 1.0F;
for (i = 24; i < 30; i++)
win[1][i] = (float) sin(pi / 12 * (i + 0.5 - 18));
for (i = 30; i < 36; i++)
win[1][i] = 0.0F;
/* type 3 */
for (i = 0; i < 6; i++)
win[3][i] = 0.0F;
for (i = 6; i < 12; i++)
win[3][i] = (float) sin(pi / 12 * (i + 0.5 - 6));
for (i = 12; i < 18; i++)
win[3][i] = 1.0F;
for (i = 18; i < 36; i++)
win[3][i] = (float) sin(pi / 36 * (i + 0.5));
/* type 2 */
for (i = 0; i < 12; i++)
win[2][i] = (float) sin(pi / 12 * (i + 0.5));
for (i = 12; i < 36; i++)
win[2][i] = 0.0F;
/*--- invert signs by region to match mdct 18pt --> 36pt mapping */
for (j = 0; j < 4; j++)
{
if (j == 2)
continue;
for (i = 9; i < 36; i++)
win[j][i] = -win[j][i];
}
/*-- invert signs for short blocks --*/
for (i = 3; i < 12; i++)
win[2][i] = -win[2][i];
}
}
/*=============================================================*/
typedef float ARRAY4[4];
const IMDCT_INIT_BLOCK *imdct_init_addr_18();
const IMDCT_INIT_BLOCK *imdct_init_addr_6();
/*-------------------------------------------------------------*/
void imdct_init()
{
int k, p, n;
double t, pi;
const IMDCT_INIT_BLOCK *addr;
float *w, *w2;
float *v, *v2, *coef87;
ARRAY4 *coef;
static int iOnceOnly = 0;
if (!iOnceOnly++)
{
/*--- 18 point --*/
addr = imdct_init_addr_18();
w = addr->w;
w2 = addr->w2;
coef = addr->coef;
/*----*/
n = 18;
pi = 4.0 * atan(1.0);
t = pi / (4 * n);
for (p = 0; p < n; p++)
w[p] = (float) (2.0 * cos(t * (2 * p + 1)));
for (p = 0; p < 9; p++)
w2[p] = (float) 2.0 *cos(2 * t * (2 * p + 1));
t = pi / (2 * n);
for (k = 0; k < 9; k++)
{
for (p = 0; p < 4; p++)
coef[k][p] = (float) cos(t * (2 * k) * (2 * p + 1));
}
/*--- 6 point */
addr = imdct_init_addr_6();
v = addr->w;
v2 = addr->w2;
coef87 = addr->coef;
/*----*/
n = 6;
pi = 4.0 * atan(1.0);
t = pi / (4 * n);
for (p = 0; p < n; p++)
v[p] = (float) 2.0 *cos(t * (2 * p + 1));
for (p = 0; p < 3; p++)
v2[p] = (float) 2.0 *cos(2 * t * (2 * p + 1));
t = pi / (2 * n);
k = 1;
p = 0;
*coef87 = (float) cos(t * (2 * k) * (2 * p + 1));
/* adjust scaling to save a few mults */
for (p = 0; p < 6; p++)
v[p] = v[p] / 2.0f;
*coef87 = (float) 2.0 *(*coef87);
}
}
/*===============================================================*/
typedef float ARRAY8_2[8][2];
ARRAY8_2 *msis_init_addr();
/*-------------------------------------------------------------*/
void msis_init()
{
int i;
double s, c;
double pi;
double t;
ARRAY8_2 *lr;
static int iOnceOnly = 0;
if (!iOnceOnly++)
{
lr = msis_init_addr();
pi = 4.0 * atan(1.0);
t = pi / 12.0;
for (i = 0; i < 7; i++)
{
s = sin(i * t);
c = cos(i * t);
/* ms_mode = 0 */
lr[0][i][0] = (float) (s / (s + c));
lr[0][i][1] = (float) (c / (s + c));
/* ms_mode = 1 */
lr[1][i][0] = (float) (sqrt(2.0) * (s / (s + c)));
lr[1][i][1] = (float) (sqrt(2.0) * (c / (s + c)));
}
/* sf = 7 */
/* ms_mode = 0 */
lr[0][i][0] = 1.0f;
lr[0][i][1] = 0.0f;
/* ms_mode = 1, in is bands is routine does ms processing */
lr[1][i][0] = 1.0f;
lr[1][i][1] = 1.0f;
/*-------
for(i=0;i<21;i++) nBand[0][i] =
sfBandTable[sr_index].l[i+1] - sfBandTable[sr_index].l[i];
for(i=0;i<12;i++) nBand[1][i] =
sfBandTable[sr_index].s[i+1] - sfBandTable[sr_index].s[i];
-------------*/
}
}
/*-------------------------------------------------------------*/
/*===============================================================*/
typedef float ARRAY2_64_2[2][64][2];
ARRAY2_64_2 *msis_init_addr_MPEG2();
/*-------------------------------------------------------------*/
void msis_init_MPEG2()
{
int k, n;
double t;
ARRAY2_64_2 *lr2;
int intensity_scale, ms_mode, sf, sflen;
float ms_factor[2];
static int iOnceOnly = 0;
if (!iOnceOnly++)
{
ms_factor[0] = 1.0;
ms_factor[1] = (float) sqrt(2.0);
lr2 = msis_init_addr_MPEG2();
/* intensity stereo MPEG2 */
/* lr2[intensity_scale][ms_mode][sflen_offset+sf][left/right] */
for (intensity_scale = 0; intensity_scale < 2; intensity_scale++)
{
t = pow(2.0, -0.25 * (1 + intensity_scale));
for (ms_mode = 0; ms_mode < 2; ms_mode++)
{
n = 1;
k = 0;
for (sflen = 0; sflen < 6; sflen++)
{
for (sf = 0; sf < (n - 1); sf++, k++)
{
if (sf == 0)
{
lr2[intensity_scale][ms_mode][k][0] = ms_factor[ms_mode] * 1.0f;
lr2[intensity_scale][ms_mode][k][1] = ms_factor[ms_mode] * 1.0f;
}
else if ((sf & 1))
{
lr2[intensity_scale][ms_mode][k][0] =
(float) (ms_factor[ms_mode] * pow(t, (sf + 1) / 2));
lr2[intensity_scale][ms_mode][k][1] = ms_factor[ms_mode] * 1.0f;
}
else
{
lr2[intensity_scale][ms_mode][k][0] = ms_factor[ms_mode] * 1.0f;
lr2[intensity_scale][ms_mode][k][1] =
(float) (ms_factor[ms_mode] * pow(t, sf / 2));
}
}
/* illegal is_pos used to do ms processing */
if (ms_mode == 0)
{ /* ms_mode = 0 */
lr2[intensity_scale][ms_mode][k][0] = 1.0f;
lr2[intensity_scale][ms_mode][k][1] = 0.0f;
}
else
{
/* ms_mode = 1, in is bands is routine does ms processing */
lr2[intensity_scale][ms_mode][k][0] = 1.0f;
lr2[intensity_scale][ms_mode][k][1] = 1.0f;
}
k++;
n = n + n;
}
}
}
}
}
/*-------------------------------------------------------------*/
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