libmpeg3/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 "mpeg3private.h"
   8 #include "mpeg3protos.h"
   9 #include "tables.h"
  10
  11 static struct al_table alloc_0[] = {
  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},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  17         {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{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         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  33         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{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         {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  45         {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{16,-32767},
  46         {2,0},{5,3},{7,5},{16,-32767},
  47         {2,0},{5,3},{7,5},{16,-32767},
  48         {2,0},{5,3},{7,5},{16,-32767},
  49         {2,0},{5,3},{7,5},{16,-32767} };
  50
  51 static struct al_table alloc_1[] = {
  52         {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  53         {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  54         {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  55         {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  56         {4,0},{5,3},{3,-3},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},{10,-511},
  57         {11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},{16,-32767},
  58         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  59         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  60         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  61         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  62         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  63         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  64         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  65         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  66         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  67         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  68         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  69         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  70         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  71         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{16,-32767},
  72         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
  73         {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{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         {3,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{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         {2,0},{5,3},{7,5},{16,-32767} };
  93
  94 static struct al_table 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 static struct al_table alloc_3[] = {
 107         {4,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},
 108         {10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},
 109         {4,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},{9,-255},
 110         {10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},{15,-16383},
 111         {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 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
 122 static struct al_table alloc_4[] = {
 123         {4,0},{5,3},{7,5},{3,-3},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},{8,-127},
 124                 {9,-255},{10,-511},{11,-1023},{12,-2047},{13,-4095},{14,-8191},
 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         {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 132         {3,0},{5,3},{7,5},{10,9},{4,-7},{5,-15},{6,-31},{7,-63},
 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         {2,0},{5,3},{7,5},{10,9},
 139         {2,0},{5,3},{7,5},{10,9},
 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
 158
 159 static int select_table(mpeg3_layer_t *audio)
 160 {
 161         static int translate[3][2][16] =
 162            {{{ 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0},
 163          { 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0}},
 164         {{ 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0},
 165          { 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0}},
 166         {{ 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0},
 167          { 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0}}};
 168         int table, sblim;
 169         static struct al_table *tables[5] =
 170         {alloc_0, alloc_1, alloc_2, alloc_3, alloc_4};
 171         static int sblims[5] = {27, 30, 8, 12, 30};
 172
 173         if(audio->lsf)
 174                 table = 4;
 175         else
 176         table = translate[audio->sampling_frequency_code][2 - audio->channels][audio->bitrate_index];
 177         sblim = sblims[table];
 178
 179         audio->alloc = tables[table];
 180         audio->II_sblimit = sblim;
 181         return 0;
 182 }
 183
 184 static int step_one(mpeg3_layer_t *audio,
 185         unsigned int *bit_alloc,
 186         int *scale)
 187 {
 188         int stereo = audio->channels - 1;
 189     int sblimit = audio->II_sblimit;
 190     int jsbound = audio->jsbound;
 191     int sblimit2 = audio->II_sblimit << stereo;
 192     struct al_table *alloc1 = audio->alloc;
 193     int i, result = 0;
 194     unsigned int *scfsi_buf = audio->layer2_scfsi_buf;
 195     unsigned int *scfsi, *bita;
 196         unsigned int *bita_end = bit_alloc + 64;
 197     int sc, step;
 198
 199     bita = bit_alloc;
 200     if(stereo)
 201     {
 202 /* Stereo */
 203         for(i = jsbound;
 204                         i && bita < bita_end - 2;
 205                         i--, alloc1 += (1 << step))
 206         {
 207                 *bita++ = (char)mpeg3bits_getbits(audio->stream, step = alloc1->bits);
 208                 *bita++ = (char)mpeg3bits_getbits(audio->stream, step);
 209         }
 210         for(i = sblimit - jsbound;
 211                         i && bita < bita_end - 2;
 212                         i--, alloc1 += (1 << step))
 213         {
 214                 bita[0] = (char)mpeg3bits_getbits(audio->stream,
 215                                 step = alloc1->bits);
 216                 bita[1] = bita[0];
 217                 bita += 2;
 218         }
 219                 bita = bit_alloc;
 220         scfsi = scfsi_buf;
 221         for(i = sblimit2; i; i--)
 222                 if(*bita++) *scfsi++ = (char)mpeg3bits_getbits(audio->stream, 2);
 223     }
 224     else
 225     {
 226 /* mono */
 227         for(i = sblimit; i; i--, alloc1 += (1 << step))
 228                 *bita++ = (char)mpeg3bits_getbits(audio->stream, step = alloc1->bits);
 229
 230         bita = bit_alloc;
 231         scfsi = scfsi_buf;
 232         for(i = sblimit; i; i--) if (*bita++) *scfsi++ = (char)mpeg3bits_getbits(audio->stream, 2);
 233      }
 234
 235     bita = bit_alloc;
 236     scfsi = scfsi_buf;
 237     for(i = sblimit2; i; i--)
 238         {
 239         if(*bita++)
 240                 switch(*scfsi++)
 241                 {
 242                   case 0:
 243                         *scale++ = mpeg3bits_getbits(audio->stream, 6);
 244                         *scale++ = mpeg3bits_getbits(audio->stream, 6);
 245                         *scale++ = mpeg3bits_getbits(audio->stream, 6);
 246                         break;
 247                   case 1 :
 248                         *scale++ = sc = mpeg3bits_getbits(audio->stream, 6);
 249                         *scale++ = sc;
 250                         *scale++ = mpeg3bits_getbits(audio->stream, 6);
 251                         break;
 252                   case 2:
 253                         *scale++ = sc = mpeg3bits_getbits(audio->stream, 6);
 254                         *scale++ = sc;
 255                         *scale++ = sc;
 256                         break;
 257                   default:              /* case 3 */
 258                         *scale++ = mpeg3bits_getbits(audio->stream, 6);
 259                         *scale++ = sc = mpeg3bits_getbits(audio->stream, 6);
 260                         *scale++ = sc;
 261                         break;
 262                 }
 263         }
 264         return result;
 265 }
 266
 267 static int step_two(mpeg3_layer_t *audio, unsigned int *bit_alloc, float fraction[2][4][SBLIMIT], int *scale, int x1)
 268 {
 269     int i, j, k, ba, result = 0;
 270     int channels = audio->channels;
 271     int sblimit = audio->II_sblimit;
 272     int jsbound = audio->jsbound;
 273     struct al_table *alloc2, *alloc1 = audio->alloc;
 274     unsigned int *bita = bit_alloc;
 275     int d1, step, test;
 276
 277     for(i = 0; i < jsbound; i++, alloc1 += (1 << step))
 278     {
 279         step = alloc1->bits;
 280         for(j = 0; j < channels; j++)
 281         {
 282                 if(ba = *bita++)
 283                 {
 284                         k = (alloc2 = alloc1 + ba)->bits;
 285                         if((d1 = alloc2->d) < 0)
 286                         {
 287                         float cm = mpeg3_muls[k][scale[x1]];
 288
 289                         fraction[j][0][i] = ((float)((int)mpeg3bits_getbits(audio->stream, k) + d1)) * cm;
 290                         fraction[j][1][i] = ((float)((int)mpeg3bits_getbits(audio->stream, k) + d1)) * cm;
 291                         fraction[j][2][i] = ((float)((int)mpeg3bits_getbits(audio->stream, k) + d1)) * cm;
 292                         }
 293                         else
 294                         {
 295                         static int *table[] =
 296                                                 {0, 0, 0, mpeg3_grp_3tab, 0, mpeg3_grp_5tab, 0, 0, 0, mpeg3_grp_9tab};
 297                         unsigned int idx, *tab, m = scale[x1];
 298
 299                         idx = (unsigned int)mpeg3bits_getbits(audio->stream, k);
 300                         tab = (unsigned int*)(table[d1] + idx + idx + idx);
 301                         fraction[j][0][i] = mpeg3_muls[*tab++][m];
 302                         fraction[j][1][i] = mpeg3_muls[*tab++][m];
 303                         fraction[j][2][i] = mpeg3_muls[*tab][m];
 304                         }
 305                         scale += 3;
 306                 }
 307                 else
 308                         fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
 309         }
 310     }
 311
 312     for(i = jsbound; i < sblimit; i++, alloc1 += (1 << step))
 313     {
 314         step = alloc1->bits;
 315 /* channel 1 and channel 2 bitalloc are the same */
 316         bita++;
 317         if((ba = *bita++))
 318         {
 319                 k=(alloc2 = alloc1+ba)->bits;
 320                 if((d1 = alloc2->d) < 0)
 321                 {
 322                         float cm;
 323
 324                         cm = mpeg3_muls[k][scale[x1 + 3]];
 325                         fraction[1][0][i] = (fraction[0][0][i] = (float)((int)mpeg3bits_getbits(audio->stream, k) + d1)) * cm;
 326                         fraction[1][1][i] = (fraction[0][1][i] = (float)((int)mpeg3bits_getbits(audio->stream, k) + d1)) * cm;
 327                         fraction[1][2][i] = (fraction[0][2][i] = (float)((int)mpeg3bits_getbits(audio->stream, k) + d1)) * cm;
 328                         cm = mpeg3_muls[k][scale[x1]];
 329                         fraction[0][0][i] *= cm;
 330                                 fraction[0][1][i] *= cm;
 331                                 fraction[0][2][i] *= cm;
 332                 }
 333                 else
 334                 {
 335                   static int *table[] = {0, 0, 0, mpeg3_grp_3tab, 0, mpeg3_grp_5tab, 0, 0, 0, mpeg3_grp_9tab};
 336                   unsigned int idx, *tab, m1, m2;
 337
 338                   m1 = scale[x1];
 339                           m2 = scale[x1+3];
 340                   idx = (unsigned int)mpeg3bits_getbits(audio->stream, k);
 341                   tab = (unsigned int*)(table[d1] + idx + idx + idx);
 342                   fraction[0][0][i] = mpeg3_muls[*tab][m1];
 343                           fraction[1][0][i] = mpeg3_muls[*tab++][m2];
 344                   fraction[0][1][i] = mpeg3_muls[*tab][m1];
 345                           fraction[1][1][i] = mpeg3_muls[*tab++][m2];
 346                   fraction[0][2][i] = mpeg3_muls[*tab][m1];
 347                           fraction[1][2][i] = mpeg3_muls[*tab][m2];
 348                 }
 349                 scale += 6;
 350         }
 351         else
 352                 {
 353                 fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
 354                 fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
 355         }
 356 /*
 357    should we use individual scalefac for channel 2 or
 358    is the current way the right one , where we just copy channel 1 to
 359    channel 2 ??
 360    The current 'strange' thing is, that we throw away the scalefac
 361    values for the second channel ...!!
 362 -> changed .. now we use the scalefac values of channel one !!
 363 */
 364     }
 365
 366     if(sblimit > SBLIMIT) sblimit = SBLIMIT;
 367
 368     for(i = sblimit; i < SBLIMIT; i++)
 369         for(j = 0; j < channels; j++)
 370                 fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
 371
 372         return result;
 373 }
 374
 375 int mpeg3audio_dolayer2(mpeg3_layer_t *audio,
 376         char *frame,
 377         int frame_size,
 378         float **output,
 379         int render)
 380 {
 381         int i, j, result = 0;
 382         int channels = audio->channels;
 383         float fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */
 384         unsigned int bit_alloc[64];
 385         int scale[192];
 386         int single = audio->single;
 387         int output_position = 0;
 388
 389
 390         frame += 4;
 391 /* Set up bitstream to use buffer */
 392         mpeg3bits_use_ptr(audio->stream, frame);
 393
 394
 395
 396         if(audio->error_protection)
 397                 mpeg3bits_getbits(audio->stream, 16);
 398
 399         select_table(audio);
 400
 401         audio->jsbound = (audio->mode == MPG_MD_JOINT_STEREO) ?
 402         (audio->mode_ext << 2) + 4 : audio->II_sblimit;
 403
 404         if(channels == 1 || single == 3)
 405         single = 0;
 406
 407         result |= step_one(audio, bit_alloc, scale);
 408
 409         for(i = 0; i < SCALE_BLOCK && !result; i++)
 410         {
 411         result |= step_two(audio, bit_alloc, fraction, scale, i >> 2);
 412
 413         for(j = 0; j < 3; j++)
 414         {
 415                 if(single >= 0)
 416                 {
 417 /* Monaural */
 418                         if(render)
 419                                 mpeg3audio_synth_stereo(audio,
 420                                                 fraction[0][j],
 421                                                 0,
 422                                                 output[0],
 423                                                 &(output_position));
 424                         else
 425                                         output_position += 32;
 426                         }
 427                 else
 428                         {
 429 /* Stereo */
 430                         int p1 = output_position;
 431                                 if(render)
 432                                 {
 433 //printf(__FUNCTION__ " 3\n");
 434                                 mpeg3audio_synth_stereo(audio,
 435                                                 fraction[0][j],
 436                                                 0,
 437                                                 output[0],
 438                                                 &p1);
 439 //printf(__FUNCTION__ " 4\n");
 440                                 mpeg3audio_synth_stereo(audio,
 441                                                 fraction[1][j],
 442                                                 1,
 443                                                 output[1],
 444                                                 &(output_position));
 445 //printf(__FUNCTION__ " 5\n");
 446                                 }
 447                                 else
 448                                         output_position += 32;
 449                 }
 450                 }
 451         }
 452
 453
 454         return output_position;
 455 }