cinelerra-5.1/libzmpeg3/audio/layer2.C

   1 /*
   2  * most other tables are calculated on program start (which is (of course)
   3  * not ISO-conform) ..
   4  * Layer-3 huffman table is in huffman.h
   5  */
   6
   7 #include "../libzmpeg3.h"
   8
   9 static zaudio_t::imdct_al_table_t alloc_0[] = {
  10   {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  11   {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  12   {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  13   {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  14   {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  15   {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  16   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  17   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  18   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  19   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  20   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  21   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  22   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  23   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  24   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  25   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  26   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  27   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  28   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  29   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  30   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  31   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  32   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  33   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  34   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  35   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  36   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  37   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  38   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  39   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  40   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  41   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  42   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  43   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  44   {2,0},{5,3},{7,5},{16,-32767},
  45   {2,0},{5,3},{7,5},{16,-32767},
  46   {2,0},{5,3},{7,5},{16,-32767},
  47   {2,0},{5,3},{7,5},{16,-32767}
  48 };
  49
  50 static zaudio_t::imdct_al_table_t alloc_1[] = {
  51   {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  52   {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  53   {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  54   {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  55   {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  56   {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  57   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  58   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  59   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  60   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  61   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  62   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  63   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  64   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  65   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  66   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  67   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  68   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  69   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  70   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  71   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  72   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  73   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  74   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  75   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  76   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  77   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  78   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  79   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  80   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  81   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  82   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  83   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  84   {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  85   {2,0},{5,3},{7,5},{16,-32767},
  86   {2,0},{5,3},{7,5},{16,-32767},
  87   {2,0},{5,3},{7,5},{16,-32767},
  88   {2,0},{5,3},{7,5},{16,-32767},
  89   {2,0},{5,3},{7,5},{16,-32767},
  90   {2,0},{5,3},{7,5},{16,-32767},
  91   {2,0},{5,3},{7,5},{16,-32767}
  92 };
  93
  94 static zaudio_t::imdct_al_table_t alloc_2[] = {
  95   {4,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},
  96   {10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},
  97   {4,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},
  98   {10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},
  99   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 100   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 101   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 102   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 103   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 104   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63}
 105 };
 106
 107 static zaudio_t::imdct_al_table_t alloc_3[] = {
 108   {4,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},
 109   {10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},
 110   {4,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},
 111   {10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},
 112   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 113   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 114   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 115   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 116   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 117   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 118   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 119   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 120   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 121   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63}
 122 };
 123
 124 static zaudio_t::imdct_al_table_t alloc_4[] = {
 125   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
 126   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},
 127   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
 128   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},
 129   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
 130   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},
 131   {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
 132   {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},
 133   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 134   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 135   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 136   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 137   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 138   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 139   {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 140   {2,0},{5,3},{7,5},{10,9},
 141   {2,0},{5,3},{7,5},{10,9},
 142   {2,0},{5,3},{7,5},{10,9},
 143   {2,0},{5,3},{7,5},{10,9},
 144   {2,0},{5,3},{7,5},{10,9},
 145   {2,0},{5,3},{7,5},{10,9},
 146   {2,0},{5,3},{7,5},{10,9},
 147   {2,0},{5,3},{7,5},{10,9},
 148   {2,0},{5,3},{7,5},{10,9},
 149   {2,0},{5,3},{7,5},{10,9},
 150   {2,0},{5,3},{7,5},{10,9},
 151   {2,0},{5,3},{7,5},{10,9},
 152   {2,0},{5,3},{7,5},{10,9},
 153   {2,0},{5,3},{7,5},{10,9},
 154   {2,0},{5,3},{7,5},{10,9},
 155   {2,0},{5,3},{7,5},{10,9},
 156   {2,0},{5,3},{7,5},{10,9},
 157   {2,0},{5,3},{7,5},{10,9},
 158   {2,0},{5,3},{7,5},{10,9}
 159 };
 160
 161 int zaudio_decoder_layer_t::
 162 select_table()
 163 {
 164   static int translate[3][2][16] = {
 165     {{ 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0},
 166      { 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0}},
 167     {{ 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0},
 168      { 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0}},
 169     {{ 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0},
 170      { 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0}}
 171   };
 172   int table, sblim;
 173   static imdct_al_table_t *tables[5] = {
 174     alloc_0, alloc_1, alloc_2, alloc_3, alloc_4
 175   };
 176   static int sblims[5] = {27, 30, 8, 12, 30};
 177
 178   if( lsf )
 179     table = 4;
 180   else
 181     table = translate[sampling_frequency_code][2 - channels][bitrate_index];
 182   sblim = sblims[table];
 183
 184   alloc = tables[table];
 185   II_sblimit = sblim;
 186   return 0;
 187 }
 188
 189 int zaudio_decoder_layer_t::
 190 step_one(uint8_t *bit_alloc, int *scale)
 191 {
 192   int stereo = channels - 1;
 193   int sblimit = II_sblimit;
 194   int sblimit2 = II_sblimit << stereo;
 195   imdct_al_table_t *alloc1 = alloc;
 196   int i, result = 0;
 197   uint8_t *scfsi_buf = layer2_scfsi_buf;
 198   uint8_t *scfsi, *bita;
 199   uint8_t *bita_end = bit_alloc + 64;
 200   int sc, step;
 201
 202   bita = bit_alloc;
 203   if( stereo ) {
 204     /* Stereo */
 205     for( i=jsbound; --i>=0 && bita < bita_end-2; alloc1+=(1<<step) ) {
 206       *bita++ = (char)stream->get_bits(step = alloc1->bits);
 207       *bita++ = (char)stream->get_bits(step);
 208     }
 209     for( i=sblimit-jsbound; --i>=0 && bita < bita_end-2; alloc1+=(1<<step)) {
 210       bita[0] = (char)stream->get_bits(step = alloc1->bits);
 211       bita[1] = bita[0];
 212       bita += 2;
 213     }
 214     bita = bit_alloc;
 215     scfsi = scfsi_buf;
 216     for( i=sblimit2; --i>=0 ; )
 217       if( *bita++ )
 218         *scfsi++ = (char)stream->get_bits(2);
 219   }
 220   else {
 221     /* mono */
 222     for( i=sblimit; --i>=0 ; alloc1+=(1<<step) )
 223       *bita++ = (char)stream->get_bits(step = alloc1->bits);
 224     bita = bit_alloc;
 225     scfsi = scfsi_buf;
 226     for( i=sblimit; --i>=0 ; )
 227       if( *bita++ ) *scfsi++ = (char)stream->get_bits(2);
 228   }
 229
 230   bita = bit_alloc;
 231   scfsi = scfsi_buf;
 232   for( i=sblimit2; --i>=0; ) {
 233     if( *bita++ ) switch(*scfsi++) {
 234     case 0:
 235       *scale++ = stream->get_bits(6);
 236       *scale++ = stream->get_bits(6);
 237       *scale++ = stream->get_bits(6);
 238       break;
 239     case 1 :
 240       *scale++ = sc = stream->get_bits(6);
 241       *scale++ = sc;
 242       *scale++ = stream->get_bits(6);
 243       break;
 244     case 2:
 245       *scale++ = sc = stream->get_bits(6);
 246       *scale++ = sc;
 247       *scale++ = sc;
 248       break;
 249     default:              /* case 3 */
 250       *scale++ = stream->get_bits(6);
 251       *scale++ = sc = stream->get_bits(6);
 252       *scale++ = sc;
 253       break;
 254     }
 255   }
 256   return result;
 257 }
 258
 259 int zaudio_decoder_layer_t::
 260 step_two(uint8_t *bit_alloc, float fraction[2][4][SBLIMIT], int *scale, int x1)
 261 {
 262   int i, j, k, ba, result = 0;
 263   int sblimit = II_sblimit;
 264   imdct_al_table_t *alloc2, *alloc1 = alloc;
 265   uint8_t *bita = bit_alloc;
 266   int d1, step;
 267
 268   for( i=0; i<jsbound; ++i, alloc1+=(1<<step) ) {
 269     step = alloc1->bits;
 270     for( j=0; j<channels; ++j ) {
 271       if( (ba=*bita++) != 0 ) {
 272         k = (alloc2 = alloc1 + ba)->bits;
 273         if( (d1 = alloc2->d) < 0 ) {
 274           float cm = muls[k][scale[x1]];
 275           fraction[j][0][i] = ((float)((int)stream->get_bits(k) + d1)) * cm;
 276           fraction[j][1][i] = ((float)((int)stream->get_bits(k) + d1)) * cm;
 277           fraction[j][2][i] = ((float)((int)stream->get_bits(k) + d1)) * cm;
 278         }
 279         else {
 280           static int *table[] =
 281             {0, 0, 0, grp_3tab, 0, grp_5tab, 0, 0, 0, grp_9tab};
 282           uint32_t idx, *tab, m = scale[x1];
 283           idx = (uint32_t)stream->get_bits(k);
 284           tab = (uint32_t*)(table[d1] + idx + idx + idx);
 285           fraction[j][0][i] = muls[*tab++][m];
 286           fraction[j][1][i] = muls[*tab++][m];
 287           fraction[j][2][i] = muls[*tab][m];
 288         }
 289         scale += 3;
 290       }
 291       else
 292         fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
 293     }
 294   }
 295
 296   for( i=jsbound; i<sblimit; ++i, alloc1+=(1<<step) ) {
 297     step = alloc1->bits;
 298     /* channel 1 and channel 2 bitalloc are the same */
 299     ++bita;
 300     if( (ba=*bita++) != 0 ) {
 301       k= (alloc2 = alloc1+ba)->bits;
 302       if( (d1 = alloc2->d) < 0 ) {
 303         float cm = muls[k][scale[x1 + 3]];
 304         fraction[1][0][i] = (fraction[0][0][i] = (float)((int)stream->get_bits(k) + d1)) * cm;
 305         fraction[1][1][i] = (fraction[0][1][i] = (float)((int)stream->get_bits(k) + d1)) * cm;
 306         fraction[1][2][i] = (fraction[0][2][i] = (float)((int)stream->get_bits(k) + d1)) * cm;
 307         cm = muls[k][scale[x1]];
 308         fraction[0][0][i] *= cm;
 309         fraction[0][1][i] *= cm;
 310         fraction[0][2][i] *= cm;
 311       }
 312       else {
 313         static int *table[] = {0, 0, 0, grp_3tab, 0, grp_5tab, 0, 0, 0, grp_9tab};
 314         uint8_t idx, *tab, m1, m2;
 315         m1 = scale[x1];
 316         m2 = scale[x1+3];
 317         idx = (uint8_t)stream->get_bits(k);
 318         tab = (uint8_t*)(table[d1] + idx + idx + idx);
 319         fraction[0][0][i] = muls[*tab][m1];
 320         fraction[1][0][i] = muls[*tab++][m2];
 321         fraction[0][1][i] = muls[*tab][m1];
 322         fraction[1][1][i] = muls[*tab++][m2];
 323         fraction[0][2][i] = muls[*tab][m1];
 324         fraction[1][2][i] = muls[*tab][m2];
 325       }
 326       scale += 6;
 327     }
 328     else {
 329       fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
 330       fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
 331     }
 332 /*
 333    should we use individual scalefac for channel 2 or
 334    is the current way the right one , where we just copy channel 1 to
 335    channel 2 ??
 336    The current 'strange' thing is, that we throw away the scalefac
 337    values for the second channel ...!!
 338 -> changed .. now we use the scalefac values of channel one !!
 339 */
 340   }
 341
 342   if( sblimit > (int)SBLIMIT ) sblimit = SBLIMIT;
 343   for( i=sblimit; i < (int)SBLIMIT; ++i )
 344     for( j=0; j < channels; ++j )
 345       fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
 346
 347   return result;
 348 }
 349
 350 int zaudio_decoder_layer_t::
 351 do_layer2(uint8_t *zframe, int zframe_size, float **zoutput, int render)
 352 {
 353   int i, j, result = 0;
 354   float fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */
 355   uint8_t bit_alloc[64];
 356   int scale[192];
 357   int zsingle = single;
 358   int output_position = 0;
 359 //zmsg("1\n");
 360   zframe += 4;
 361   /* Set up bitstream to use buffer */
 362   stream->use_ptr(zframe);
 363   if( error_protection )
 364     stream->get_bits(16);
 365
 366   select_table();
 367
 368   jsbound = (mode == md_JOINT_STEREO) ?
 369     (mode_ext << 2) + 4 : II_sblimit;
 370
 371   if( channels == 1 || zsingle == 3 )
 372     zsingle = 0;
 373
 374   result |= step_one(bit_alloc, scale);
 375
 376   for( i=0; i < (int)SCALE_BLOCK && !result; ++i ) {
 377     result |= step_two(bit_alloc, fraction, scale, i >> 2);
 378     for( j=0; j < 3; ++j ) {
 379       if( zsingle >= 0 ) {
 380         /* Monaural */
 381         if( render )
 382           synth_stereo(fraction[0][j], 0, zoutput[0], &output_position);
 383         else
 384           output_position += 32;
 385       }
 386       else {
 387         /* Stereo */
 388         int p1 = output_position;
 389         if( render ) {
 390 //zmsg(" 3\n");
 391           synth_stereo(fraction[0][j], 0, zoutput[0], &p1);
 392 //zmsg(" 4\n");
 393           synth_stereo(fraction[1][j], 1, zoutput[1], &output_position);
 394 //zmsg(" 5\n");
 395         }
 396         else
 397           output_position += 32;
 398       }
 399     }
 400   }
 401
 402   return output_position;
 403 }
 404