libfaad2/rvlc.c

   1 /*
   2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
   3 ** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
   4 **
   5 ** This program is free software; you can redistribute it and/or modify
   6 ** it under the terms of the GNU General Public License as published by
   7 ** the Free Software Foundation; either version 2 of the License, or
   8 ** (at your option) any later version.
   9 **
  10 ** This program is distributed in the hope that it will be useful,
  11 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ** GNU General Public License for more details.
  14 **
  15 ** You should have received a copy of the GNU General Public License
  16 ** along with this program; if not, write to the Free Software
  17 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 **
  19 ** Any non-GPL usage of this software or parts of this software is strictly
  20 ** forbidden.
  21 **
  22 ** Commercial non-GPL licensing of this software is possible.
  23 ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
  24 **
  25 ** $Id: rvlc.c,v 1.17 2004/09/04 14:56:28 menno Exp $
  26 **/
  27
  28 /* RVLC scalefactor decoding
  29  *
  30  * RVLC works like this:
  31  *  1. Only symmetric huffman codewords are used
  32  *  2. Total length of the scalefactor data is stored in the bitsream
  33  *  3. Scalefactors are DPCM coded
  34  *  4. Next to the starting value for DPCM the ending value is also stored
  35  *
  36  * With all this it is possible to read the scalefactor data from 2 sides.
  37  * If there is a bit error in the scalefactor data it is possible to start
  38  * decoding from the other end of the data, to find all but 1 scalefactor.
  39  */
  40
  41 #include "common.h"
  42 #include "structs.h"
  43
  44 #include <stdlib.h>
  45
  46 #include "syntax.h"
  47 #include "bits.h"
  48 #include "rvlc.h"
  49
  50
  51 #ifdef ERROR_RESILIENCE
  52
  53 //#define PRINT_RVLC
  54
  55 /* static function declarations */
  56 static uint8_t rvlc_decode_sf_forward(ic_stream *ics,
  57                                       bitfile *ld_sf,
  58                                       bitfile *ld_esc,
  59                                       uint8_t *is_used);
  60 #if 0
  61 static uint8_t rvlc_decode_sf_reverse(ic_stream *ics,
  62                                       bitfile *ld_sf,
  63                                       bitfile *ld_esc,
  64                                       uint8_t is_used);
  65 #endif
  66 static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc,
  67                               int8_t direction);
  68 static int8_t rvlc_huffman_esc(bitfile *ld_esc, int8_t direction);
  69
  70
  71 uint8_t rvlc_scale_factor_data(ic_stream *ics, bitfile *ld)
  72 {
  73     uint8_t bits = 9;
  74
  75     ics->sf_concealment = faad_get1bit(ld
  76         DEBUGVAR(1,149,"rvlc_scale_factor_data(): sf_concealment"));
  77     ics->rev_global_gain = (uint8_t)faad_getbits(ld, 8
  78         DEBUGVAR(1,150,"rvlc_scale_factor_data(): rev_global_gain"));
  79
  80     if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
  81         bits = 11;
  82
  83     /* the number of bits used for the huffman codewords */
  84     ics->length_of_rvlc_sf = (uint16_t)faad_getbits(ld, bits
  85         DEBUGVAR(1,151,"rvlc_scale_factor_data(): length_of_rvlc_sf"));
  86
  87     if (ics->noise_used)
  88     {
  89         ics->dpcm_noise_nrg = (uint16_t)faad_getbits(ld, 9
  90             DEBUGVAR(1,152,"rvlc_scale_factor_data(): dpcm_noise_nrg"));
  91
  92         ics->length_of_rvlc_sf -= 9;
  93     }
  94
  95     ics->sf_escapes_present = faad_get1bit(ld
  96         DEBUGVAR(1,153,"rvlc_scale_factor_data(): sf_escapes_present"));
  97
  98     if (ics->sf_escapes_present)
  99     {
 100         ics->length_of_rvlc_escapes = (uint8_t)faad_getbits(ld, 8
 101             DEBUGVAR(1,154,"rvlc_scale_factor_data(): length_of_rvlc_escapes"));
 102     }
 103
 104     if (ics->noise_used)
 105     {
 106         ics->dpcm_noise_last_position = (uint16_t)faad_getbits(ld, 9
 107             DEBUGVAR(1,155,"rvlc_scale_factor_data(): dpcm_noise_last_position"));
 108     }
 109
 110     return 0;
 111 }
 112
 113 uint8_t rvlc_decode_scale_factors(ic_stream *ics, bitfile *ld)
 114 {
 115     uint8_t result;
 116     uint8_t intensity_used = 0;
 117     uint8_t *rvlc_sf_buffer = NULL;
 118     uint8_t *rvlc_esc_buffer = NULL;
 119     bitfile ld_rvlc_sf, ld_rvlc_esc;
 120 //    bitfile ld_rvlc_sf_rev, ld_rvlc_esc_rev;
 121
 122     if (ics->length_of_rvlc_sf > 0)
 123     {
 124         /* We read length_of_rvlc_sf bits here to put it in a
 125            seperate bitfile.
 126         */
 127         rvlc_sf_buffer = faad_getbitbuffer(ld, ics->length_of_rvlc_sf
 128             DEBUGVAR(1,156,"rvlc_decode_scale_factors(): bitbuffer: length_of_rvlc_sf"));
 129
 130         faad_initbits(&ld_rvlc_sf, (void*)rvlc_sf_buffer, bit2byte(ics->length_of_rvlc_sf));
 131 //        faad_initbits_rev(&ld_rvlc_sf_rev, (void*)rvlc_sf_buffer,
 132 //            ics->length_of_rvlc_sf);
 133     }
 134
 135     if (ics->sf_escapes_present)
 136     {
 137         /* We read length_of_rvlc_escapes bits here to put it in a
 138            seperate bitfile.
 139         */
 140         rvlc_esc_buffer = faad_getbitbuffer(ld, ics->length_of_rvlc_escapes
 141             DEBUGVAR(1,157,"rvlc_decode_scale_factors(): bitbuffer: length_of_rvlc_escapes"));
 142
 143         faad_initbits(&ld_rvlc_esc, (void*)rvlc_esc_buffer, bit2byte(ics->length_of_rvlc_escapes));
 144 //        faad_initbits_rev(&ld_rvlc_esc_rev, (void*)rvlc_esc_buffer,
 145 //            ics->length_of_rvlc_escapes);
 146     }
 147
 148     /* decode the rvlc scale factors and escapes */
 149     result = rvlc_decode_sf_forward(ics, &ld_rvlc_sf,
 150         &ld_rvlc_esc, &intensity_used);
 151 //    result = rvlc_decode_sf_reverse(ics, &ld_rvlc_sf_rev,
 152 //        &ld_rvlc_esc_rev, intensity_used);
 153
 154
 155     if (rvlc_esc_buffer) faad_free(rvlc_esc_buffer);
 156     if (rvlc_sf_buffer) faad_free(rvlc_sf_buffer);
 157
 158     if (ics->length_of_rvlc_sf > 0)
 159         faad_endbits(&ld_rvlc_sf);
 160     if (ics->sf_escapes_present)
 161         faad_endbits(&ld_rvlc_esc);
 162
 163     return result;
 164 }
 165
 166 static uint8_t rvlc_decode_sf_forward(ic_stream *ics, bitfile *ld_sf, bitfile *ld_esc,
 167                                       uint8_t *intensity_used)
 168 {
 169     int8_t g, sfb;
 170     int8_t t = 0;
 171     int8_t error = 0;
 172     int8_t noise_pcm_flag = 1;
 173
 174     int16_t scale_factor = ics->global_gain;
 175     int16_t is_position = 0;
 176     int16_t noise_energy = ics->global_gain - 90 - 256;
 177
 178 #ifdef PRINT_RVLC
 179     printf("\nglobal_gain: %d\n", ics->global_gain);
 180 #endif
 181
 182     for (g = 0; g < ics->num_window_groups; g++)
 183     {
 184         for (sfb = 0; sfb < ics->max_sfb; sfb++)
 185         {
 186             if (error)
 187             {
 188                 ics->scale_factors[g][sfb] = 0;
 189             } else {
 190                 switch (ics->sfb_cb[g][sfb])
 191                 {
 192                 case ZERO_HCB: /* zero book */
 193                     ics->scale_factors[g][sfb] = 0;
 194                     break;
 195                 case INTENSITY_HCB: /* intensity books */
 196                 case INTENSITY_HCB2:
 197
 198                     *intensity_used = 1;
 199
 200                     /* decode intensity position */
 201                     t = rvlc_huffman_sf(ld_sf, ld_esc, +1);
 202
 203                     is_position += t;
 204                     ics->scale_factors[g][sfb] = is_position;
 205
 206                     break;
 207                 case NOISE_HCB: /* noise books */
 208
 209                     /* decode noise energy */
 210                     if (noise_pcm_flag)
 211                     {
 212                         int16_t n = ics->dpcm_noise_nrg;
 213                         noise_pcm_flag = 0;
 214                         noise_energy += n;
 215                     } else {
 216                         t = rvlc_huffman_sf(ld_sf, ld_esc, +1);
 217                         noise_energy += t;
 218                     }
 219
 220                     ics->scale_factors[g][sfb] = noise_energy;
 221
 222                     break;
 223                 default: /* spectral books */
 224
 225                     /* decode scale factor */
 226                     t = rvlc_huffman_sf(ld_sf, ld_esc, +1);
 227
 228                     scale_factor += t;
 229                     if (scale_factor < 0)
 230                         return 4;
 231
 232                     ics->scale_factors[g][sfb] = scale_factor;
 233
 234                     break;
 235                 }
 236 #ifdef PRINT_RVLC
 237                 printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],
 238                     ics->scale_factors[g][sfb]);
 239 #endif
 240                 if (t == 99)
 241                 {
 242                     error = 1;
 243                 }
 244             }
 245         }
 246     }
 247 #ifdef PRINT_RVLC
 248     printf("\n\n");
 249 #endif
 250
 251     return 0;
 252 }
 253
 254 #if 0 // not used right now, doesn't work correctly yet
 255 static uint8_t rvlc_decode_sf_reverse(ic_stream *ics, bitfile *ld_sf, bitfile *ld_esc,
 256                                       uint8_t intensity_used)
 257 {
 258     int8_t g, sfb;
 259     int8_t t = 0;
 260     int8_t error = 0;
 261     int8_t noise_pcm_flag = 1, is_pcm_flag = 1, sf_pcm_flag = 1;
 262
 263     int16_t scale_factor = ics->rev_global_gain;
 264     int16_t is_position = 0;
 265     int16_t noise_energy = ics->rev_global_gain;
 266
 267 #ifdef PRINT_RVLC
 268     printf("\nrev_global_gain: %d\n", ics->rev_global_gain);
 269 #endif
 270
 271     if (intensity_used)
 272     {
 273         is_position = rvlc_huffman_sf(ld_sf, ld_esc, -1);
 274 #ifdef PRINT_RVLC
 275         printf("is_position: %d\n", is_position);
 276 #endif
 277     }
 278
 279     for (g = ics->num_window_groups-1; g >= 0; g--)
 280     {
 281         for (sfb = ics->max_sfb-1; sfb >= 0; sfb--)
 282         {
 283             if (error)
 284             {
 285                 ics->scale_factors[g][sfb] = 0;
 286             } else {
 287                 switch (ics->sfb_cb[g][sfb])
 288                 {
 289                 case ZERO_HCB: /* zero book */
 290                     ics->scale_factors[g][sfb] = 0;
 291                     break;
 292                 case INTENSITY_HCB: /* intensity books */
 293                 case INTENSITY_HCB2:
 294
 295                     if (is_pcm_flag)
 296                     {
 297                         is_pcm_flag = 0;
 298                         ics->scale_factors[g][sfb] = is_position;
 299                     } else {
 300                         t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
 301                         is_position -= t;
 302
 303                         ics->scale_factors[g][sfb] = (uint8_t)is_position;
 304                     }
 305                     break;
 306                 case NOISE_HCB: /* noise books */
 307
 308                     /* decode noise energy */
 309                     if (noise_pcm_flag)
 310                     {
 311                         noise_pcm_flag = 0;
 312                         noise_energy = ics->dpcm_noise_last_position;
 313                     } else {
 314                         t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
 315                         noise_energy -= t;
 316                     }
 317
 318                     ics->scale_factors[g][sfb] = (uint8_t)noise_energy;
 319                     break;
 320                 default: /* spectral books */
 321
 322                     if (sf_pcm_flag || (sfb == 0))
 323                     {
 324                         sf_pcm_flag = 0;
 325                         if (sfb == 0)
 326                             scale_factor = ics->global_gain;
 327                     } else {
 328                         /* decode scale factor */
 329                         t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
 330                         scale_factor -= t;
 331                     }
 332
 333                     if (scale_factor < 0)
 334                         return 4;
 335
 336                     ics->scale_factors[g][sfb] = (uint8_t)scale_factor;
 337                     break;
 338                 }
 339 #ifdef PRINT_RVLC
 340                 printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],
 341                     ics->scale_factors[g][sfb]);
 342 #endif
 343                 if (t == 99)
 344                 {
 345                     error = 1;
 346                 }
 347             }
 348         }
 349     }
 350
 351 #ifdef PRINT_RVLC
 352     printf("\n\n");
 353 #endif
 354
 355     return 0;
 356 }
 357 #endif
 358
 359 /* index == 99 means not allowed codeword */
 360 static rvlc_huff_table book_rvlc[] = {
 361     /*index  length  codeword */
 362     {  0, 1,   0 }, /*         0 */
 363     { -1, 3,   5 }, /*       101 */
 364     {  1, 3,   7 }, /*       111 */
 365     { -2, 4,   9 }, /*      1001 */
 366     { -3, 5,  17 }, /*     10001 */
 367     {  2, 5,  27 }, /*     11011 */
 368     { -4, 6,  33 }, /*    100001 */
 369     { 99, 6,  50 }, /*    110010 */
 370     {  3, 6,  51 }, /*    110011 */
 371     { 99, 6,  52 }, /*    110100 */
 372     { -7, 7,  65 }, /*   1000001 */
 373     { 99, 7,  96 }, /*   1100000 */
 374     { 99, 7,  98 }, /*   1100010 */
 375     {  7, 7,  99 }, /*   1100011 */
 376     {  4, 7, 107 }, /*   1101011 */
 377     { -5, 8, 129 }, /*  10000001 */
 378     { 99, 8, 194 }, /*  11000010 */
 379     {  5, 8, 195 }, /*  11000011 */
 380     { 99, 8, 212 }, /*  11010100 */
 381     { 99, 9, 256 }, /* 100000000 */
 382     { -6, 9, 257 }, /* 100000001 */
 383     { 99, 9, 426 }, /* 110101010 */
 384     {  6, 9, 427 }, /* 110101011 */
 385     { 99, 10,  0 } /* Shouldn't come this far */
 386 };
 387
 388 static rvlc_huff_table book_escape[] = {
 389     /*index  length  codeword */
 390     { 1, 2, 0 },
 391     { 0, 2, 2 },
 392     { 3, 3, 2 },
 393     { 2, 3, 6 },
 394     { 4, 4, 14 },
 395     { 7, 5, 13 },
 396     { 6, 5, 15 },
 397     { 5, 5, 31 },
 398     { 11, 6, 24 },
 399     { 10, 6, 25 },
 400     { 9, 6, 29 },
 401     { 8, 6, 61 },
 402     { 13, 7, 56  },
 403     { 12, 7, 120 },
 404     { 15, 8, 114 },
 405     { 14, 8, 242 },
 406     { 17, 9, 230 },
 407     { 16, 9, 486 },
 408     { 19, 10, 463  },
 409     { 18, 10, 974  },
 410     { 22, 11, 925  },
 411     { 20, 11, 1950 },
 412     { 21, 11, 1951 },
 413     { 23, 12, 1848 },
 414     { 25, 13, 3698 },
 415     { 24, 14, 7399 },
 416     { 26, 15, 14797 },
 417     { 49, 19, 236736 },
 418     { 50, 19, 236737 },
 419     { 51, 19, 236738 },
 420     { 52, 19, 236739 },
 421     { 53, 19, 236740 },
 422     { 27, 20, 473482 },
 423     { 28, 20, 473483 },
 424     { 29, 20, 473484 },
 425     { 30, 20, 473485 },
 426     { 31, 20, 473486 },
 427     { 32, 20, 473487 },
 428     { 33, 20, 473488 },
 429     { 34, 20, 473489 },
 430     { 35, 20, 473490 },
 431     { 36, 20, 473491 },
 432     { 37, 20, 473492 },
 433     { 38, 20, 473493 },
 434     { 39, 20, 473494 },
 435     { 40, 20, 473495 },
 436     { 41, 20, 473496 },
 437     { 42, 20, 473497 },
 438     { 43, 20, 473498 },
 439     { 44, 20, 473499 },
 440     { 45, 20, 473500 },
 441     { 46, 20, 473501 },
 442     { 47, 20, 473502 },
 443     { 48, 20, 473503 },
 444     { 99, 21,  0 } /* Shouldn't come this far */
 445 };
 446
 447 static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc,
 448                               int8_t direction)
 449 {
 450     uint8_t i, j;
 451     int8_t index;
 452     uint32_t cw;
 453     rvlc_huff_table *h = book_rvlc;
 454
 455     i = h->len;
 456     if (direction > 0)
 457         cw = faad_getbits(ld_sf, i DEBUGVAR(1,0,""));
 458     else
 459         cw = faad_getbits_rev(ld_sf, i DEBUGVAR(1,0,""));
 460
 461     while ((cw != h->cw)
 462         && (i < 10))
 463     {
 464         h++;
 465         j = h->len-i;
 466         i += j;
 467         cw <<= j;
 468         if (direction > 0)
 469             cw |= faad_getbits(ld_sf, j DEBUGVAR(1,0,""));
 470         else
 471             cw |= faad_getbits_rev(ld_sf, j DEBUGVAR(1,0,""));
 472     }
 473
 474     index = h->index;
 475
 476     if (index == +ESC_VAL)
 477     {
 478         int8_t esc = rvlc_huffman_esc(ld_esc, direction);
 479         if (esc == 99)
 480             return 99;
 481         index += esc;
 482 #ifdef PRINT_RVLC
 483         printf("esc: %d - ", esc);
 484 #endif
 485     }
 486     if (index == -ESC_VAL)
 487     {
 488         int8_t esc = rvlc_huffman_esc(ld_esc, direction);
 489         if (esc == 99)
 490             return 99;
 491         index -= esc;
 492 #ifdef PRINT_RVLC
 493         printf("esc: %d - ", esc);
 494 #endif
 495     }
 496
 497     return index;
 498 }
 499
 500 static int8_t rvlc_huffman_esc(bitfile *ld,
 501                                int8_t direction)
 502 {
 503     uint8_t i, j;
 504     uint32_t cw;
 505     rvlc_huff_table *h = book_escape;
 506
 507     i = h->len;
 508     if (direction > 0)
 509         cw = faad_getbits(ld, i DEBUGVAR(1,0,""));
 510     else
 511         cw = faad_getbits_rev(ld, i DEBUGVAR(1,0,""));
 512
 513     while ((cw != h->cw)
 514         && (i < 21))
 515     {
 516         h++;
 517         j = h->len-i;
 518         i += j;
 519         cw <<= j;
 520         if (direction > 0)
 521             cw |= faad_getbits(ld, j DEBUGVAR(1,0,""));
 522         else
 523             cw |= faad_getbits_rev(ld, j DEBUGVAR(1,0,""));
 524     }
 525
 526     return h->index;
 527 }
 528
 529 #endif
 530