Herwig Birke
337 lines
8.7 KiB
C
337 lines
8.7 KiB
C
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/*
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* Mpeg Layer-2 audio decoder
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* --------------------------
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* copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README'
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*
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*/
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#include "mpg123.h"
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#include "l2tables.h"
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#include "getbits.h"
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static int grp_3tab[32 * 3] =
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{0,}; /* used: 27 */
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static int grp_5tab[128 * 3] =
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{0,}; /* used: 125 */
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static int grp_9tab[1024 * 3] =
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{0,}; /* used: 729 */
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real mpg123_muls[27][64]; /* also used by layer 1 */
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/* Used by the getbits macros */
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static unsigned long rval;
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void mpg123_init_layer2(void)
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{
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static double mulmul[27] = {
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0.0, -2.0 / 3.0, 2.0 / 3.0, 2.0 / 7.0, 2.0 / 15.0,
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2.0 / 31.0, 2.0 / 63.0, 2.0 / 127.0, 2.0 / 255.0,
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2.0 / 511.0, 2.0 / 1023.0, 2.0 / 2047.0, 2.0 / 4095.0,
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2.0 / 8191.0, 2.0 / 16383.0, 2.0 / 32767.0, 2.0 / 65535.0,
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-4.0 / 5.0, -2.0 / 5.0, 2.0 / 5.0, 4.0 / 5.0, -8.0 / 9.0,
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-4.0 / 9.0, -2.0 / 9.0, 2.0 / 9.0, 4.0 / 9.0, 8.0 / 9.0 };
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static int base[3][9] = {
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{1, 0, 2,},
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{17, 18, 0, 19, 20,},
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{21, 1, 22, 23, 0, 24, 25, 2, 26}};
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int i, j, k, l, len;
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real *table;
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static int tablen[3] = {3, 5, 9};
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static int *itable, *tables[3] =
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{grp_3tab, grp_5tab, grp_9tab};
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for (i = 0; i < 3; i++)
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{
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itable = tables[i];
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len = tablen[i];
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for (j = 0; j < len; j++)
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for (k = 0; k < len; k++)
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for (l = 0; l < len; l++)
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{
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*itable++ = base[i][l];
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*itable++ = base[i][k];
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*itable++ = base[i][j];
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}
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}
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for (k = 0; k < 27; k++)
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{
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double m = mulmul[k];
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table = mpg123_muls[k];
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for (j = 3, i = 0; i < 63; i++, j--)
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*table++ = m * pow(2.0, (double) j / 3.0);
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*table++ = 0.0;
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}
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}
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void II_step_one(unsigned int *bit_alloc, int *scale, struct frame *fr)
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{
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int stereo = fr->stereo - 1;
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int sblimit = fr->II_sblimit;
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int jsbound = fr->jsbound;
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int sblimit2 = fr->II_sblimit << stereo;
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struct al_table *alloc1 = fr->alloc;
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int i;
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static unsigned int scfsi_buf[64];
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unsigned int *scfsi, *bita;
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int sc, step;
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bita = bit_alloc;
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if (stereo)
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{
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for (i = jsbound; i > 0; i--, alloc1 += (1 << step))
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{
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*bita++ = (char) mpg123_getbits(step = alloc1->bits);
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*bita++ = (char) mpg123_getbits(step);
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}
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for (i = sblimit - jsbound; i > 0; i--, alloc1 += (1 << step))
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{
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bita[0] = (char) mpg123_getbits(step = alloc1->bits);
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bita[1] = bita[0];
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bita += 2;
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}
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bita = bit_alloc;
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scfsi = scfsi_buf;
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for (i = sblimit2; i; i--)
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if (*bita++)
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*scfsi++ = (char) mpg123_getbits_fast(2);
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}
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else
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/* mono */
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{
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for (i = sblimit; i; i--, alloc1 += (1 << step))
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*bita++ = (char) mpg123_getbits(step = alloc1->bits);
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bita = bit_alloc;
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scfsi = scfsi_buf;
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for (i = sblimit; i; i--)
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if (*bita++)
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*scfsi++ = (char) mpg123_getbits_fast(2);
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}
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bita = bit_alloc;
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scfsi = scfsi_buf;
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for (i = sblimit2; i; i--)
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if (*bita++)
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switch (*scfsi++)
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{
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case 0:
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*scale++ = mpg123_getbits_fast(6);
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*scale++ = mpg123_getbits_fast(6);
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*scale++ = mpg123_getbits_fast(6);
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break;
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case 1:
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*scale++ = sc = mpg123_getbits_fast(6);
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*scale++ = sc;
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*scale++ = mpg123_getbits_fast(6);
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break;
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case 2:
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*scale++ = sc = mpg123_getbits_fast(6);
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*scale++ = sc;
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*scale++ = sc;
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break;
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default: /* case 3 */
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*scale++ = mpg123_getbits_fast(6);
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*scale++ = sc = mpg123_getbits_fast(6);
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*scale++ = sc;
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break;
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}
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}
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void II_step_two(unsigned int *bit_alloc, real fraction[2][4][SBLIMIT], int *scale, struct frame *fr, int x1)
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{
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int i, j, k, ba;
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int stereo = fr->stereo;
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int sblimit = fr->II_sblimit;
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int jsbound = fr->jsbound;
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struct al_table *alloc2, *alloc1 = fr->alloc;
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unsigned int *bita = bit_alloc;
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int d1, step;
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for (i = 0; i < jsbound; i++, alloc1 += (1 << step))
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{
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step = alloc1->bits;
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for (j = 0; j < stereo; j++)
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{
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if ((ba = *bita++))
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{
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k = (alloc2 = alloc1 + ba)->bits;
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if ((d1 = alloc2->d) < 0)
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{
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real cm = mpg123_muls[k][scale[x1]];
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fraction[j][0][i] = ((real) ((int) mpg123_getbits(k) + d1)) * cm;
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fraction[j][1][i] = ((real) ((int) mpg123_getbits(k) + d1)) * cm;
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fraction[j][2][i] = ((real) ((int) mpg123_getbits(k) + d1)) * cm;
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}
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else
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{
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static int *table[] =
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{0, 0, 0, grp_3tab, 0, grp_5tab, 0, 0, 0, grp_9tab};
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unsigned int idx, *tab, m = scale[x1];
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idx = (unsigned int) mpg123_getbits(k);
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tab = (unsigned int *) (table[d1] + idx + idx + idx);
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fraction[j][0][i] = mpg123_muls[*tab++][m];
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fraction[j][1][i] = mpg123_muls[*tab++][m];
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fraction[j][2][i] = mpg123_muls[*tab][m];
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}
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scale += 3;
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}
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else
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fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
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}
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}
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for (i = jsbound; i < sblimit; i++, alloc1 += (1 << step))
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{
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step = alloc1->bits;
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bita++; /* channel 1 and channel 2 bitalloc are the same */
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if ((ba = *bita++))
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{
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k = (alloc2 = alloc1 + ba)->bits;
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if ((d1 = alloc2->d) < 0)
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{
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real cm;
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cm = mpg123_muls[k][scale[x1 + 3]];
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fraction[1][0][i] = (fraction[0][0][i] = (real) ((int) mpg123_getbits(k) + d1)) * cm;
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fraction[1][1][i] = (fraction[0][1][i] = (real) ((int) mpg123_getbits(k) + d1)) * cm;
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fraction[1][2][i] = (fraction[0][2][i] = (real) ((int) mpg123_getbits(k) + d1)) * cm;
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cm = mpg123_muls[k][scale[x1]];
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fraction[0][0][i] *= cm;
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fraction[0][1][i] *= cm;
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fraction[0][2][i] *= cm;
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}
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else
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{
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static int *table[] =
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{0, 0, 0, grp_3tab, 0, grp_5tab, 0, 0, 0, grp_9tab};
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unsigned int idx, *tab, m1, m2;
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m1 = scale[x1];
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m2 = scale[x1 + 3];
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idx = (unsigned int) mpg123_getbits(k);
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tab = (unsigned int *) (table[d1] + idx + idx + idx);
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fraction[0][0][i] = mpg123_muls[*tab][m1];
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fraction[1][0][i] = mpg123_muls[*tab++][m2];
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fraction[0][1][i] = mpg123_muls[*tab][m1];
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fraction[1][1][i] = mpg123_muls[*tab++][m2];
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fraction[0][2][i] = mpg123_muls[*tab][m1];
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fraction[1][2][i] = mpg123_muls[*tab][m2];
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}
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scale += 6;
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}
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else
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{
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fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
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fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
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}
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/*
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should we use individual scalefac for channel 2 or
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is the current way the right one , where we just copy channel 1 to
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channel 2 ??
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The current 'strange' thing is, that we throw away the scalefac
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values for the second channel ...!!
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-> changed .. now we use the scalefac values of channel one !!
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*/
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}
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if (sblimit > (fr->down_sample_sblimit))
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sblimit = fr->down_sample_sblimit;
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for (i = sblimit; i < SBLIMIT; i++)
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for (j = 0; j < stereo; j++)
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fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
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}
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static void II_select_table(struct frame *fr)
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{
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static int translate[3][2][16] = {
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{{0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 1, 1, 1, 1, 1, 0},
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{0, 2, 2, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0}},
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{{0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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{0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{{0, 3, 3, 3, 3, 3, 3, 0, 0, 0, 1, 1, 1, 1, 1, 0},
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{0, 3, 3, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0}}
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};
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int table, sblim;
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static struct al_table *tables[5] =
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{alloc_0, alloc_1, alloc_2, alloc_3, alloc_4};
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static int sblims[5] = { 27, 30, 8, 12, 30 };
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if (fr->lsf)
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table = 4;
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else
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table = translate[fr->sampling_frequency][2 - fr->stereo][fr->bitrate_index];
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sblim = sblims[table];
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fr->alloc = tables[table];
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fr->II_sblimit = sblim;
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}
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int mpg123_do_layer2(struct frame *fr)
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{
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int i, j;
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int stereo = fr->stereo;
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real fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */
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unsigned int bit_alloc[64];
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int scale[192];
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int single = fr->single;
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II_select_table(fr);
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fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?
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(fr->mode_ext << 2) + 4 : fr->II_sblimit;
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if (fr->jsbound > fr->II_sblimit)
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fr->jsbound = fr->II_sblimit;
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if (stereo == 1 || single == 3)
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single = 0;
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II_step_one(bit_alloc, scale, fr);
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for (i = 0; i < SCALE_BLOCK; i++)
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{
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II_step_two(bit_alloc, fraction, scale, fr, i >> 2);
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for (j = 0; j < 3; j++)
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{
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if (single >= 0)
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{
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(fr->synth_mono) (fraction[single][j], mpg123_pcm_sample, &mpg123_pcm_point);
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}
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else
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{
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int p1 = mpg123_pcm_point;
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(fr->synth) (fraction[0][j], 0, mpg123_pcm_sample, &p1);
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(fr->synth) (fraction[1][j], 1, mpg123_pcm_sample, &mpg123_pcm_point);
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}
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/* if(mpg123_pcm_point >= audiobufsize)
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audio_flush(outmode,ai); */
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}
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}
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/***
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if (mpg123_info->output_audio)
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{
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mpg123_ip.add_vis_pcm(mpg123_ip.output->written_time(), mpg123_cfg.resolution == 16 ? FMT_S16_NE : FMT_U8,
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mpg123_cfg.channels == 2 ? fr->stereo : 1, mpg123_pcm_point, mpg123_pcm_sample);
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while (mpg123_ip.output->buffer_free() < mpg123_pcm_point && mpg123_info->going && mpg123_info->jump_to_time == -1)
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xmms_usleep(10000);
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if (mpg123_info->going && mpg123_info->jump_to_time == -1)
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mpg123_ip.output->write_audio(mpg123_pcm_sample, mpg123_pcm_point);
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}
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***/
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mpg123_pcm_point = 0;
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return 1;
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}
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