| /* |
| * 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 = (unsigned int) 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 = (unsigned int) 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; |
| } |
