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315 lines
9 KiB
C
315 lines
9 KiB
C
/*
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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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void init_layer2(struct StaticData * psd)
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{
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const double mulmul[27] = {
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0.0 , -2.0/3.0 , 2.0/3.0 ,
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2.0/7.0 , 2.0/15.0 , 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 , 2.0/8191.0 ,
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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 ,
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-8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0 };
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const 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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const int tablen[3] = { 3 , 5 , 9 };
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int *itable,*tables[3];
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tables[0] = psd->grp_3tab;
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tables[1] = psd->grp_5tab;
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tables[2] = psd->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 = psd->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(struct StaticData * psd, 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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const struct al_table *alloc1 = fr->alloc;
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int i;
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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;i--,alloc1+=(1<<step))
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{
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*bita++ = (char) getbits(psd, step=alloc1->bits);
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*bita++ = (char) getbits(psd, step);
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}
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for (i=sblimit-jsbound;i;i--,alloc1+=(1<<step))
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{
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bita[0] = (char) getbits(psd, 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=psd->scfsi_buf;
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for (i=sblimit2;i;i--)
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if (*bita++)
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*scfsi++ = (char) getbits_fast(psd, 2);
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}
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else /* mono */
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{
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for (i=sblimit;i;i--,alloc1+=(1<<step))
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*bita++ = (char) getbits(psd, step=alloc1->bits);
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bita = bit_alloc;
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scfsi=psd->scfsi_buf;
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for (i=sblimit;i;i--)
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if (*bita++)
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*scfsi++ = (char) getbits_fast(psd, 2);
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}
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bita = bit_alloc;
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scfsi=psd->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++ = getbits_fast(psd, 6);
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*scale++ = getbits_fast(psd, 6);
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*scale++ = getbits_fast(psd, 6);
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break;
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case 1 :
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*scale++ = sc = getbits_fast(psd, 6);
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*scale++ = sc;
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*scale++ = getbits_fast(psd, 6);
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break;
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case 2:
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*scale++ = sc = getbits_fast(psd, 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++ = getbits_fast(psd, 6);
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*scale++ = sc = getbits_fast(psd, 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(struct StaticData * psd, 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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const 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=psd->muls[k][scale[x1]];
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fraction[j][0][i] = ((real) ((int)getbits(psd, k) + d1)) * cm;
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fraction[j][1][i] = ((real) ((int)getbits(psd, k) + d1)) * cm;
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fraction[j][2][i] = ((real) ((int)getbits(psd, k) + d1)) * cm;
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}
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else
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{
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int *table[10];
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unsigned int idx,*tab,m=scale[x1];
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memset(table, 0, sizeof(NULL));
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table[3] = psd->grp_3tab;
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table[5] = psd->grp_5tab;
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table[9] = psd->grp_9tab;
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idx = (unsigned int) getbits(psd, k);
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tab = (unsigned int *) (table[d1] + idx + idx + idx);
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fraction[j][0][i] = psd->muls[*tab++][m];
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fraction[j][1][i] = psd->muls[*tab++][m];
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fraction[j][2][i] = psd->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=psd->muls[k][scale[x1+3]];
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fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(psd, k) + d1) ) * cm;
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fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(psd, k) + d1) ) * cm;
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fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(psd, k) + d1) ) * cm;
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cm=psd->muls[k][scale[x1]];
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fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; fraction[0][2][i] *= cm;
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}
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else
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{
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int *table[10];
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unsigned int idx,*tab,m1,m2;
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memset(table, 0, sizeof(NULL));
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table[3] = psd->grp_3tab;
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table[5] = psd->grp_5tab;
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table[9] = psd->grp_9tab;
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m1 = scale[x1]; m2 = scale[x1+3];
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idx = (unsigned int) getbits(psd, k);
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tab = (unsigned int *) (table[d1] + idx + idx + idx);
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fraction[0][0][i] = psd->muls[*tab][m1]; fraction[1][0][i] = psd->muls[*tab++][m2];
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fraction[0][1][i] = psd->muls[*tab][m1]; fraction[1][1][i] = psd->muls[*tab++][m2];
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fraction[0][2][i] = psd->muls[*tab][m1]; fraction[1][2][i] = psd->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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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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if(sblimit > (fr->II_sblimit) )
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sblimit = fr->II_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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void II_select_table(struct frame *fr)
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{
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const 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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int table,sblim;
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const struct al_table *tables[5] =
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{ alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 };
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const 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 do_layer2(struct StaticData * psd, struct mpstr * gmp, struct frame *fr,unsigned char *pcm_sample,int *pcm_point)
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{
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int clip=0;
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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(stereo == 1 || single == 3)
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single = 0;
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II_step_one(psd, 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(psd, 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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clip += synth_1to1_mono(psd, gmp, fraction[single][j],pcm_sample,pcm_point);
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}
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else {
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int p1 = *pcm_point;
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clip += synth_1to1(psd, gmp, fraction[0][j],0,pcm_sample,&p1);
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clip += synth_1to1(psd, gmp, fraction[1][j],1,pcm_sample,pcm_point);
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}
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}
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}
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return clip;
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}
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