/* * Mpeg Layer-2 audio decoder * -------------------------- * copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README' * This file has been copied from mpglib. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA */ #include "mpg123.h" #include "l2tables.h" static int grp_3tab[32 * 3] = { 0, }; /* used: 27 */ static int grp_5tab[128 * 3] = { 0, }; /* used: 125 */ static int grp_9tab[1024 * 3] = { 0, }; /* used: 729 */ real muls[27][64]; /* also used by layer 1 */ void init_layer2(void) { static const double mulmul[27] = { 0.0 , -2.0/3.0 , 2.0/3.0 , 2.0/7.0 , 2.0/15.0 , 2.0/31.0, 2.0/63.0 , 2.0/127.0 , 2.0/255.0 , 2.0/511.0 , 2.0/1023.0 , 2.0/2047.0 , 2.0/4095.0 , 2.0/8191.0 , 2.0/16383.0 , 2.0/32767.0 , 2.0/65535.0 , -4.0/5.0 , -2.0/5.0 , 2.0/5.0, 4.0/5.0 , -8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0 }; static const int base[3][9] = { { 1 , 0, 2 , } , { 17, 18, 0 , 19, 20 , } , { 21, 1, 22, 23, 0, 24, 25, 2, 26 } }; int i,j,k,l,len; real *table; static const int tablen[3] = { 3 , 5 , 9 }; static int *itable,*tables[3] = { grp_3tab , grp_5tab , grp_9tab }; for(i=0;i<3;i++) { itable = tables[i]; len = tablen[i]; for(j=0;j<len;j++) for(k=0;k<len;k++) for(l=0;l<len;l++) { *itable++ = base[i][l]; *itable++ = base[i][k]; *itable++ = base[i][j]; } } for(k=0;k<27;k++) { double m=mulmul[k]; table = muls[k]; for(j=3,i=0;i<63;i++,j--) *table++ = m * pow(2.0,(double) j / 3.0); *table++ = 0.0; } } static void II_step_one(unsigned int *bit_alloc,int *scale,struct frame *fr) { int stereo = fr->stereo-1; int sblimit = fr->II_sblimit; int jsbound = fr->jsbound; int sblimit2 = fr->II_sblimit<<stereo; const struct al_table *alloc1 = fr->alloc; int i; static unsigned int scfsi_buf[64]; unsigned int *scfsi,*bita; int sc,step; bita = bit_alloc; if(stereo) { for (i=jsbound;i;i--,alloc1+=(1<<step)) { *bita++ = (char) getbits(step=alloc1->bits); *bita++ = (char) getbits(step); } for (i=sblimit-jsbound;i;i--,alloc1+=(1<<step)) { bita[0] = (char) getbits(step=alloc1->bits); bita[1] = bita[0]; bita+=2; } bita = bit_alloc; scfsi=scfsi_buf; for (i=sblimit2;i;i--) if (*bita++) *scfsi++ = (char) getbits_fast(2); } else /* mono */ { for (i=sblimit;i;i--,alloc1+=(1<<step)) *bita++ = (char) getbits(step=alloc1->bits); bita = bit_alloc; scfsi=scfsi_buf; for (i=sblimit;i;i--) if (*bita++) *scfsi++ = (char) getbits_fast(2); } bita = bit_alloc; scfsi=scfsi_buf; for (i=sblimit2;i;i--) if (*bita++) switch (*scfsi++) { case 0: *scale++ = getbits_fast(6); *scale++ = getbits_fast(6); *scale++ = getbits_fast(6); break; case 1 : *scale++ = sc = getbits_fast(6); *scale++ = sc; *scale++ = getbits_fast(6); break; case 2: *scale++ = sc = getbits_fast(6); *scale++ = sc; *scale++ = sc; break; default: /* case 3 */ *scale++ = getbits_fast(6); *scale++ = sc = getbits_fast(6); *scale++ = sc; break; } } static void II_step_two(unsigned int *bit_alloc, real fraction[2][4][SBLIMIT], int *scale, struct frame *fr, int x1) { int i,j,k,ba; int stereo = fr->stereo; int sblimit = fr->II_sblimit; int jsbound = fr->jsbound; const struct al_table *alloc2,*alloc1 = fr->alloc; unsigned int *bita=bit_alloc; int d1,step; for (i=0;i<jsbound;i++,alloc1+=(1<<step)) { step = alloc1->bits; for (j=0;j<stereo;j++) { if ( (ba=*bita++) ) { k=(alloc2 = alloc1+ba)->bits; if( (d1=alloc2->d) < 0) { real cm=muls[k][scale[x1]]; fraction[j][0][i] = ((real) ((int)getbits(k) + d1)) * cm; fraction[j][1][i] = ((real) ((int)getbits(k) + d1)) * cm; fraction[j][2][i] = ((real) ((int)getbits(k) + d1)) * cm; } else { static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab }; unsigned int idx,*tab,m=scale[x1]; idx = getbits(k); tab = (unsigned int *) (table[d1] + idx + idx + idx); fraction[j][0][i] = muls[*tab++][m]; fraction[j][1][i] = muls[*tab++][m]; fraction[j][2][i] = muls[*tab][m]; } scale+=3; } else fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0; } } for (i=jsbound;i<sblimit;i++,alloc1+=(1<<step)) { step = alloc1->bits; bita++; /* channel 1 and channel 2 bitalloc are the same */ if ( (ba=*bita++) ) { k=(alloc2 = alloc1+ba)->bits; if( (d1=alloc2->d) < 0) { real cm; cm=muls[k][scale[x1+3]]; fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(k) + d1) ) * cm; fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(k) + d1) ) * cm; fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(k) + d1) ) * cm; cm=muls[k][scale[x1]]; fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; fraction[0][2][i] *= cm; } else { static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab }; unsigned int idx,*tab,m1,m2; m1 = scale[x1]; m2 = scale[x1+3]; idx = getbits(k); tab = (unsigned int *) (table[d1] + idx + idx + idx); fraction[0][0][i] = muls[*tab][m1]; fraction[1][0][i] = muls[*tab++][m2]; fraction[0][1][i] = muls[*tab][m1]; fraction[1][1][i] = muls[*tab++][m2]; fraction[0][2][i] = muls[*tab][m1]; fraction[1][2][i] = muls[*tab][m2]; } scale+=6; } else { fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] = fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0; } /* should we use individual scalefac for channel 2 or is the current way the right one , where we just copy channel 1 to channel 2 ?? The current 'strange' thing is, that we throw away the scalefac values for the second channel ...!! -> changed .. now we use the scalefac values of channel one !! */ } for(i=sblimit;i<SBLIMIT;i++) for (j=0;j<stereo;j++) fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0; } static void II_select_table(struct frame *fr) { static const int translate[3][2][16] = { { { 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0 } , { 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0 } } , { { 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0 } , { 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0 } } , { { 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0 } , { 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0 } } }; int table,sblim; static const struct al_table *tables[5] = { alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 }; static const int sblims[5] = { 27 , 30 , 8, 12 , 30 }; if(fr->lsf) table = 4; else table = translate[fr->sampling_frequency][2-fr->stereo][fr->bitrate_index]; sblim = sblims[table]; fr->alloc = tables[table]; fr->II_sblimit = sblim; } int do_layer2(struct frame *fr,unsigned char *pcm_sample,int *pcm_point) { int clip=0; int i,j; int stereo = fr->stereo; real fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */ unsigned int bit_alloc[64]; int scale[192]; int single = fr->single; II_select_table(fr); fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext<<2)+4 : fr->II_sblimit; if(stereo == 1 || single == 3) single = 0; II_step_one(bit_alloc, scale, fr); for (i=0;i<SCALE_BLOCK;i++) { II_step_two(bit_alloc,fraction,scale,fr,i>>2); for (j=0;j<3;j++) { if(single >= 0) { clip += synth_1to1_mono(fr->mp,fraction[0][j],pcm_sample,pcm_point); } else { int p1 = *pcm_point; clip += synth_1to1(fr->mp,fraction[0][j],0,pcm_sample,&p1); clip += synth_1to1(fr->mp,fraction[1][j],1,pcm_sample,pcm_point); } } } return clip; }