layer3.c

自己移植的linux下的流媒体播放器原代码,支持mms协议,支持ftp和http协议.

     * short (count1table) values
     */
    for(;l3 && (part2remain+num > 0);l3--) {
      struct newhuff *h = htc+gr_info->count1table_select;
      register short *val = h->table,a;

      REFRESH_MASK;
      while((a=*val++)<0) {
        if (mask < 0)
          val -= a;
        num--;
        mask <<= 1;
      }
      if(part2remain+num <= 0) {
	num -= part2remain+num;
        break;
      }

      for(i=0;i<4;i++) {
        if(!(i & 1)) {
          if(!mc) {
            mc = *m++;
            cb = *m++;
#ifdef CUT_HF
            if(cb == 21) { 
              fprintf(stderr,"c");
              v = 0.0;
            }
            else
#endif
              v = gr_info->pow2gain[((*scf++) + (*pretab++)) << shift];
          }
          mc--;
        }
        if ( (a & (0x8>>i)) ) {
          max = cb;
          if(part2remain+num <= 0) {
            break;
          }
          if(mask < 0)
            *xrpnt++ = -v;
          else
            *xrpnt++ = v;
          num--;
          mask <<= 1;
        }
        else
          *xrpnt++ = 0.0;
      }
    }

    gr_info->maxbandl = max+1;
    gr_info->maxb = longLimit[sfreq][gr_info->maxbandl];
  }

  part2remain += num;
//  backbits(num);
  bitindex -= num; wordpointer += (bitindex>>3); bitindex &= 0x7;
  num = 0;

  while(xrpnt < &xr[SBLIMIT][0]) 
    *xrpnt++ = 0.0;

  while( part2remain > 16 ) {
    getbits(16); /* Dismiss stuffing Bits */
    part2remain -= 16;
  }
  if(part2remain > 0)
    getbits(part2remain);
  else if(part2remain < 0) {
      fprintf(stderr,"mpg123: Can't rewind stream by %d bits!\n",-part2remain);
    return 1; /* -> error */
  }
  return 0;
}




/* 
 * III_stereo: calculate real channel values for Joint-I-Stereo-mode
 */
static void III_i_stereo(real xr_buf[2][SBLIMIT][SSLIMIT],int *scalefac,
   struct gr_info_s *gr_info,int sfreq,int ms_stereo,int lsf)
{
      real (*xr)[SBLIMIT*SSLIMIT] = (real (*)[SBLIMIT*SSLIMIT] ) xr_buf;
      struct bandInfoStruct *bi = &bandInfo[sfreq];

      const real *tab1,*tab2;

      int tab;
      static const real *tabs[3][2][2] = { 
         { { tan1_1,tan2_1 }     , { tan1_2,tan2_2 } },
         { { pow1_1[0],pow2_1[0] } , { pow1_2[0],pow2_2[0] } } ,
         { { pow1_1[1],pow2_1[1] } , { pow1_2[1],pow2_2[1] } } 
      };

      tab = lsf + (gr_info->scalefac_compress & lsf);
      tab1 = tabs[tab][ms_stereo][0];
      tab2 = tabs[tab][ms_stereo][1];
#if 0
      if(lsf) {
        int p = gr_info->scalefac_compress & 0x1;
	if(ms_stereo) {
          tab1 = pow1_2[p]; tab2 = pow2_2[p];
        }
        else {
          tab1 = pow1_1[p]; tab2 = pow2_1[p];
        }
      }
      else {
        if(ms_stereo) {
          tab1 = tan1_2; tab2 = tan2_2;
        }
        else {
          tab1 = tan1_1; tab2 = tan2_1;
        }
      }
#endif

//      printf("III_i_st: tab1=%p tab2=%p tab=%d ms=%d  \n", tab1, tab2, tab, ms_stereo);

      if (gr_info->block_type == 2) {
         int lwin,do_l = 0;
         if( gr_info->mixed_block_flag )
           do_l = 1;

         for (lwin=0;lwin<3;lwin++) { /* process each window */
             /* get first band with zero values */
           int is_p,sb,idx,sfb = gr_info->maxband[lwin];  /* sfb is minimal 3 for mixed mode */
           if(sfb > 3)
             do_l = 0;

           for(;sfb<12;sfb++) {
             is_p = scalefac[sfb*3+lwin-gr_info->mixed_block_flag]; /* scale: 0-15 */ 
             if(is_p != 7) {
               real t1,t2;
               sb  = bi->shortDiff[sfb];
               idx = bi->shortIdx[sfb] + lwin;
               t1  = tab1[is_p]; t2 = tab2[is_p];
               for (; sb > 0; sb--,idx+=3) {
                 real v = xr[0][idx];
                 xr[0][idx] = REAL_MUL(v, t1);
                 xr[1][idx] = REAL_MUL(v, t2);
               }
             }
           }

#if 1
/* in the original: copy 10 to 11 , here: copy 11 to 12 
maybe still wrong??? (copy 12 to 13?) */
           is_p = scalefac[11*3+lwin-gr_info->mixed_block_flag]; /* scale: 0-15 */
           sb   = bi->shortDiff[12];
           idx  = bi->shortIdx[12] + lwin;
#else
           is_p = scalefac[10*3+lwin-gr_info->mixed_block_flag]; /* scale: 0-15 */
           sb   = bi->shortDiff[11];
           idx  = bi->shortIdx[11] + lwin;
#endif
           if(is_p != 7) {
             real t1,t2;
             t1 = tab1[is_p]; t2 = tab2[is_p];
             for ( ; sb > 0; sb--,idx+=3 ) {  
               real v = xr[0][idx];
               xr[0][idx] = REAL_MUL(v, t1);
               xr[1][idx] = REAL_MUL(v, t2);
             }
           }
         } /* end for(lwin; .. ; . ) */

/* also check l-part, if ALL bands in the three windows are 'empty'
 * and mode = mixed_mode 
 */
         if (do_l) {
           int sfb = gr_info->maxbandl;
           int idx = bi->longIdx[sfb];

           for ( ; sfb<8; sfb++ ) {
             int sb = bi->longDiff[sfb];
             int is_p = scalefac[sfb]; /* scale: 0-15 */
             if(is_p != 7) {
               real t1,t2;
               t1 = tab1[is_p]; t2 = tab2[is_p];
               for ( ; sb > 0; sb--,idx++) {
                 real v = xr[0][idx];
                 xr[0][idx] = REAL_MUL(v, t1);
                 xr[1][idx] = REAL_MUL(v, t2);
               }
             }
             else 
               idx += sb;
           }
         }     
      } 
      else { /* ((gr_info->block_type != 2)) */
       int sfb = gr_info->maxbandl;
       int is_p,idx = bi->longIdx[sfb];

/* hmm ... maybe the maxbandl stuff for i-stereo is buggy? */
       if(sfb <= 21) { 
        for ( ; sfb<21; sfb++) {
          int sb = bi->longDiff[sfb];
          is_p = scalefac[sfb]; /* scale: 0-15 */
          if(is_p != 7) {
            real t1,t2;
            t1 = tab1[is_p]; t2 = tab2[is_p];
            for ( ; sb > 0; sb--,idx++) {
               real v = xr[0][idx];
               xr[0][idx] = REAL_MUL(v, t1);
               xr[1][idx] = REAL_MUL(v, t2);
            }
          }
          else
            idx += sb;
        }

        is_p = scalefac[20];
        if(is_p != 7) {  /* copy l-band 20 to l-band 21 */
          int sb;
          real t1 = tab1[is_p],t2 = tab2[is_p]; 

          for ( sb = bi->longDiff[21]; sb > 0; sb--,idx++ ) {
            real v = xr[0][idx];
            xr[0][idx] = REAL_MUL(v, t1);
            xr[1][idx] = REAL_MUL(v, t2);
          }
        }
       }        /* end: if(sfb <= 21) */
      } /* ... */
}

static void III_antialias(real xr[SBLIMIT][SSLIMIT],struct gr_info_s *gr_info) {
   int sblim;

   if(gr_info->block_type == 2) {
      if(!gr_info->mixed_block_flag) 
        return;
      sblim = 1; 
   }
   else {
     sblim = gr_info->maxb-1;
   }

   /* 31 alias-reduction operations between each pair of sub-bands */
   /* with 8 butterflies between each pair                         */

   {
     int sb;
     real *xr1=(real *) xr[1];

     for(sb=sblim;sb;sb--,xr1+=10) {
       int ss;
       real *cs=aa_cs,*ca=aa_ca;
       real *xr2 = xr1;

       for(ss=7;ss>=0;ss--) {    /* upper and lower butterfly inputs */
         register real bu = *--xr2,bd = *xr1;
         *xr2   = (bu * (*cs)   ) - (bd * (*ca)   );
         *xr1++ = (bd * (*cs++) ) + (bu * (*ca++) );
       }
     }
     
  }
}

#include "dct64.c"
#include "dct36.c"
#include "dct12.c"

#include "decod386.c"

/*
 * III_hybrid
 */
 
static dct36_func_t dct36_func;
  
static void III_hybrid(real fsIn[SBLIMIT][SSLIMIT],real tsOut[SSLIMIT][SBLIMIT],
   int ch,struct gr_info_s *gr_info)
{
   real *tspnt = (real *) tsOut;
   static real block[2][2][SBLIMIT*SSLIMIT] = { { { 0, } } };
   static int blc[2]={0,0};
   real *rawout1,*rawout2;
   int bt;
   int sb = 0;

   {
     int b = blc[ch];
     rawout1=block[b][ch];
     b=-b+1;
     rawout2=block[b][ch];
     blc[ch] = b;
   }

   if(gr_info->mixed_block_flag) {
     sb = 2;
     (*dct36_func)(fsIn[0],rawout1,rawout2,win[0],tspnt);
     (*dct36_func)(fsIn[1],rawout1+18,rawout2+18,win1[0],tspnt+1);
     rawout1 += 36; rawout2 += 36; tspnt += 2;
   }
 
   bt = gr_info->block_type;
   if(bt == 2) {
     for (; sb<gr_info->maxb; sb+=2,tspnt+=2,rawout1+=36,rawout2+=36) {
       dct12(fsIn[sb],rawout1,rawout2,win[2],tspnt);
       dct12(fsIn[sb+1],rawout1+18,rawout2+18,win1[2],tspnt+1);
     }
   }
   else {
     for (; sb<gr_info->maxb; sb+=2,tspnt+=2,rawout1+=36,rawout2+=36) {
       (*dct36_func)(fsIn[sb],rawout1,rawout2,win[bt],tspnt);
       (*dct36_func)(fsIn[sb+1],rawout1+18,rawout2+18,win1[bt],tspnt+1);
     }
   }

   for(;sb<SBLIMIT;sb++,tspnt++) {
     int i;
     for(i=0;i<SSLIMIT;i++) {
       tspnt[i*SBLIMIT] = *rawout1++;
       *rawout2++ = 0.0;
     }
   }
}

/*
 * main layer3 handler
 */
/* int do_layer3(struct frame *fr,int outmode,struct audio_info_struct *ai) */
static int do_layer3(struct frame *fr,int single){
  int gr, ch, ss,clip=0;
  int scalefacs[2][39]; /* max 39 for short[13][3] mode, mixed: 38, long: 22 */
  struct III_sideinfo sideinfo;
  int stereo = fr->stereo;
  int ms_stereo,i_stereo;
  int sfreq = fr->sampling_frequency;
  int stereo1,granules;

//  if (fr->error_protection) getbits(16); /* skip crc */

  if(stereo == 1) { /* stream is mono */
    stereo1 = 1;
    single = 0;
  } else
  if(single >= 0) /* stream is stereo, but force to mono */
    stereo1 = 1;
  else
    stereo1 = 2;

  if(fr->mode == MPG_MD_JOINT_STEREO) {
    ms_stereo = (fr->mode_ext & 0x2)>>1;
    i_stereo  = fr->mode_ext & 0x1;
  } else
    ms_stereo = i_stereo = 0;

  if(!III_get_side_info(&sideinfo,stereo,ms_stereo,sfreq,single,fr->lsf))
    return -1;
  
  set_pointer(sideinfo.main_data_begin);

  granules = (fr->lsf) ? 1 : 2;
  for (gr=0;gr<granules;gr++){
    static real hybridIn[2][SBLIMIT][SSLIMIT];
    static real hybridOut[2][SSLIMIT][SBLIMIT];

    { struct gr_info_s *gr_info = &(sideinfo.ch[0].gr[gr]);
      long part2bits;
      if(fr->lsf)
        part2bits = III_get_scale_factors_2(scalefacs[0],gr_info,0);
      else
        part2bits = III_get_scale_factors_1(scalefacs[0],gr_info);
      if(III_dequantize_sample(hybridIn[0], scalefacs[0],gr_info,sfreq,part2bits))
        return clip;
    }

    if(stereo == 2) {
      struct gr_info_s *gr_info = &(sideinfo.ch[1].gr[gr]);
      
      long part2bits;
      if(fr->lsf) 
        part2bits = III_get_scale_factors_2(scalefacs[1],gr_info,i_stereo);
      else
        part2bits = III_get_scale_factors_1(scalefacs[1],gr_info);

      if(III_dequantize_sample(hybridIn[1],scalefacs[1],gr_info,sfreq,part2bits))
          return clip;

      if(ms_stereo) {
        int i;
        int maxb = sideinfo.ch[0].gr[gr].maxb;
        if(sideinfo.ch[1].gr[gr].maxb > maxb)
            maxb = sideinfo.ch[1].gr[gr].maxb;
        for(i=0;i<SSLIMIT*maxb;i++) {
          real tmp0 = ((real *)hybridIn[0])[i];
          real tmp1 = ((real *)hybridIn[1])[i];
          ((real *)hybridIn[0])[i] = tmp0 + tmp1;
          ((real *)hybridIn[1])[i] = tmp0 - tmp1;
        }
      }

      if(i_stereo)
        III_i_stereo(hybridIn,scalefacs[1],gr_info,sfreq,ms_stereo,fr->lsf);

      if(ms_stereo || i_stereo || (single == 3) ) {
        if(gr_info->maxb > sideinfo.ch[0].gr[gr].maxb) 
          sideinfo.ch[0].gr[gr].maxb = gr_info->maxb;
        else
          gr_info->maxb = sideinfo.ch[0].gr[gr].maxb;
      }

      switch(single) {
        case 3: {
          register int i;
          register real *in0 = (real *) hybridIn[0],*in1 = (real *) hybridIn[1];
          for(i=0;i<SSLIMIT*gr_info->maxb;i++,in0++)
            *in0 = (*in0 + *in1++); /* *0.5 done by pow-scale */ 
          break; }
        case 1: {
          register int i;
          register real *in0 = (real *) hybridIn[0],*in1 = (real *) hybridIn[1];
          for(i=0;i<SSLIMIT*gr_info->maxb;i++)
            *in0++ = *in1++;
          break; }
      }

    }  // if(stereo == 2)

    for(ch=0;ch<stereo1;ch++) {
      struct gr_info_s *gr_info = &(sideinfo.ch[ch].gr[gr]);
		  III_antialias(hybridIn[ch],gr_info);
		  III_hybrid(hybridIn[ch], hybridOut[ch], ch,gr_info);
    }

    for(ss=0;ss<SSLIMIT;ss++) {
      if(single >= 0) {
		    clip += (fr->synth_mono)(hybridOut[0][ss],pcm_sample,&pcm_point);
  		} else {
	  	  int p1 = pcm_point;
		    clip += (fr->synth)(hybridOut[0][ss],0,pcm_sample,&p1);
		    clip += (fr->synth)(hybridOut[1][ss],1,pcm_sample,&pcm_point);
      }
    }
    
  }

  return clip;
}