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301 lines
7.2 KiB
301 lines
7.2 KiB
/*____________________________________________________________________________
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FreeAmp - The Free MP3 Player
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MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology
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Corp. http://www.xingtech.com
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Portions Copyright (C) 1998-1999 EMusic.com
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id$
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____________________________________________________________________________*/
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/**** msis.c ***************************************************
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Layer III
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antialias, ms and is stereo precessing
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**** is_process assumes never switch
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from short to long in is region *****
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is_process does ms or stereo in "forbidded sf regions"
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//ms_mode = 0
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lr[0][i][0] = 1.0f;
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lr[0][i][1] = 0.0f;
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// ms_mode = 1, in is bands is routine does ms processing
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lr[1][i][0] = 1.0f;
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lr[1][i][1] = 1.0f;
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******************************************************************/
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#include <stdlib.h>
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#include <stdio.h>
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#include <float.h>
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#include <math.h>
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#include "L3.h"
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#include "mhead.h"
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/* The functions are different than their prototypes, by design */
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typedef float ARRAY2[2];
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typedef float ARRAY8_2[8][2];
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/* nBand[0] = long, nBand[1] = short */
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/* intensity stereo */
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/* if ms mode quant pre-scales all values by 1.0/sqrt(2.0) ms_mode in table
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compensates */
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/* intensity stereo MPEG2 */
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/* lr2[intensity_scale][ms_mode][sflen_offset+sf][left/right] */
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typedef float ARRAY2_64_2[2][64][2];
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typedef float ARRAY64_2[64][2];
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#ifdef ASM_X86
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extern void antialias_asm(float x[], int n);
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#endif /* ASM_X86 */
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/*===============================================================*/
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ARRAY2 *alias_init_addr(MPEG *m)
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{
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return m->cupl.csa;
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}
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/*-----------------------------------------------------------*/
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ARRAY8_2 *msis_init_addr(MPEG *m)
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{
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/*-------
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pi = 4.0*atan(1.0);
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t = pi/12.0;
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for(i=0;i<7;i++) {
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s = sin(i*t);
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c = cos(i*t);
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// ms_mode = 0
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m->cupl.lr[0][i][0] = (float)(s/(s+c));
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m->cupl.lr[0][i][1] = (float)(c/(s+c));
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// ms_mode = 1
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m->cupl.lr[1][i][0] = (float)(sqrt(2.0)*(s/(s+c)));
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m->cupl.lr[1][i][1] = (float)(sqrt(2.0)*(c/(s+c)));
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}
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//sf = 7
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//ms_mode = 0
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m->cupl.lr[0][i][0] = 1.0f;
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m->cupl.lr[0][i][1] = 0.0f;
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// ms_mode = 1, in is bands is routine does ms processing
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m->cupl.lr[1][i][0] = 1.0f;
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m->cupl.lr[1][i][1] = 1.0f;
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------------*/
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return m->cupl.lr;
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}
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/*-------------------------------------------------------------*/
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ARRAY2_64_2 *msis_init_addr_MPEG2(MPEG *m)
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{
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return m->cupl.lr2;
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}
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/*===============================================================*/
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void antialias(MPEG *m, float x[], int n)
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{
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#ifdef ASM_X86
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antialias_asm(x, n);
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#else
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int i, k;
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float a, b;
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for (k = 0; k < n; k++)
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{
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for (i = 0; i < 8; i++)
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{
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a = x[17 - i];
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b = x[18 + i];
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x[17 - i] = a * m->cupl.csa[i][0] - b * m->cupl.csa[i][1];
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x[18 + i] = b * m->cupl.csa[i][0] + a * m->cupl.csa[i][1];
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}
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x += 18;
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}
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#endif
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}
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/*===============================================================*/
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void ms_process(float x[][1152], int n) /* sum-difference stereo */
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{
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int i;
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float xl, xr;
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/*-- note: sqrt(2) done scaling by dequant ---*/
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for (i = 0; i < n; i++)
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{
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xl = x[0][i] + x[1][i];
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xr = x[0][i] - x[1][i];
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x[0][i] = xl;
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x[1][i] = xr;
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}
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return;
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}
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/*===============================================================*/
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void is_process_MPEG1(MPEG *vm, float x[][1152], /* intensity stereo */
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SCALEFACT * sf,
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CB_INFO cb_info[2], /* [ch] */
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int nsamp, int ms_mode)
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{
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int i, j, n, cb, w;
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float fl, fr;
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int m;
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int isf;
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float fls[3], frs[3];
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int cb0;
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cb0 = cb_info[1].cbmax; /* start at end of right */
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i = vm->cupl.sfBandIndex[cb_info[1].cbtype][cb0];
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cb0++;
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m = nsamp - i; /* process to len of left */
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if (cb_info[1].cbtype)
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goto short_blocks;
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/*------------------------*/
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/* long_blocks: */
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for (cb = cb0; cb < 21; cb++)
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{
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isf = sf->l[cb];
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n = vm->cupl.nBand[0][cb];
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fl = vm->cupl.lr[ms_mode][isf][0];
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fr = vm->cupl.lr[ms_mode][isf][1];
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for (j = 0; j < n; j++, i++)
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{
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if (--m < 0)
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goto exit;
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x[1][i] = fr * x[0][i];
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x[0][i] = fl * x[0][i];
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}
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}
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return;
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/*------------------------*/
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short_blocks:
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for (cb = cb0; cb < 12; cb++)
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{
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for (w = 0; w < 3; w++)
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{
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isf = sf->s[w][cb];
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fls[w] = vm->cupl.lr[ms_mode][isf][0];
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frs[w] = vm->cupl.lr[ms_mode][isf][1];
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}
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n = vm->cupl.nBand[1][cb];
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for (j = 0; j < n; j++)
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{
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m -= 3;
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if (m < 0)
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goto exit;
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x[1][i] = frs[0] * x[0][i];
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x[0][i] = fls[0] * x[0][i];
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x[1][1 + i] = frs[1] * x[0][1 + i];
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x[0][1 + i] = fls[1] * x[0][1 + i];
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x[1][2 + i] = frs[2] * x[0][2 + i];
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x[0][2 + i] = fls[2] * x[0][2 + i];
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i += 3;
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}
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}
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exit:
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return;
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}
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/*===============================================================*/
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void is_process_MPEG2(MPEG *vm, float x[][1152], /* intensity stereo */
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SCALEFACT * sf,
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CB_INFO cb_info[2], /* [ch] */
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IS_SF_INFO * is_sf_info,
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int nsamp, int ms_mode)
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{
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int i, j, k, n, cb, w;
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float fl, fr;
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int m;
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int isf;
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int il[21];
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int tmp;
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int r;
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ARRAY2 *lr;
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int cb0, cb1;
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lr = vm->cupl.lr2[is_sf_info->intensity_scale][ms_mode];
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if (cb_info[1].cbtype)
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goto short_blocks;
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/*------------------------*/
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/* long_blocks: */
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cb0 = cb_info[1].cbmax; /* start at end of right */
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i = vm->cupl.sfBandIndex[0][cb0];
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m = nsamp - i; /* process to len of left */
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/* gen sf info */
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for (k = r = 0; r < 3; r++)
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{
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tmp = (1 << is_sf_info->slen[r]) - 1;
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for (j = 0; j < is_sf_info->nr[r]; j++, k++)
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il[k] = tmp;
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}
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for (cb = cb0 + 1; cb < 21; cb++)
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{
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isf = il[cb] + sf->l[cb];
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fl = lr[isf][0];
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fr = lr[isf][1];
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n = vm->cupl.nBand[0][cb];
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for (j = 0; j < n; j++, i++)
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{
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if (--m < 0)
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goto exit;
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x[1][i] = fr * x[0][i];
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x[0][i] = fl * x[0][i];
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}
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}
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return;
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/*------------------------*/
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short_blocks:
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for (k = r = 0; r < 3; r++)
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{
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tmp = (1 << is_sf_info->slen[r]) - 1;
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for (j = 0; j < is_sf_info->nr[r]; j++, k++)
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il[k] = tmp;
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}
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for (w = 0; w < 3; w++)
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{
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cb0 = cb_info[1].cbmax_s[w]; /* start at end of right */
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i = vm->cupl.sfBandIndex[1][cb0] + w;
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cb1 = cb_info[0].cbmax_s[w]; /* process to end of left */
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for (cb = cb0 + 1; cb <= cb1; cb++)
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{
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isf = il[cb] + sf->s[w][cb];
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fl = lr[isf][0];
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fr = lr[isf][1];
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n = vm->cupl.nBand[1][cb];
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for (j = 0; j < n; j++)
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{
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x[1][i] = fr * x[0][i];
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x[0][i] = fl * x[0][i];
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i += 3;
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}
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}
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}
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exit:
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return;
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}
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/*===============================================================*/
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