liba52/parse.c

   1 /*
   2  * parse.c
   3  * Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
   4  * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
   5  *
   6  * This file is part of a52dec, a free ATSC A-52 stream decoder.
   7  * See http://liba52.sourceforge.net/ for updates.
   8  *
   9  * Modified for use with MPlayer, changes contained in liba52_changes.diff.
  10  * detailed changelog at http://svn.mplayerhq.hu/mplayer/trunk/
  11  * $Id$
  12  *
  13  * a52dec is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * a52dec is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  26  */
  27
  28 #include "config.h"
  29
  30 #include <stdlib.h>
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <inttypes.h>
  34
  35 #include "a52.h"
  36 #include "a52_internal.h"
  37 #include "bitstream.h"
  38 #include "tables.h"
  39 #include "mm_accel.h"
  40 #include "libavutil/avutil.h"
  41
  42 #ifdef HAVE_MEMALIGN
  43 /* some systems have memalign() but no declaration for it */
  44 void * memalign (size_t align, size_t size);
  45 #endif
  46
  47 typedef struct {
  48     sample_t q1[2];
  49     sample_t q2[2];
  50     sample_t q4;
  51     int q1_ptr;
  52     int q2_ptr;
  53     int q4_ptr;
  54 } quantizer_t;
  55
  56 static uint8_t halfrate[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3};
  57
  58 a52_state_t * a52_init (uint32_t mm_accel)
  59 {
  60     a52_state_t * state;
  61     int i;
  62
  63     state = malloc (sizeof (a52_state_t));
  64     if (state == NULL)
  65         return NULL;
  66
  67 #if defined(__MINGW32__) && defined(HAVE_SSE)
  68     state->samples = av_malloc(256 * 12 * sizeof (sample_t));
  69 #else
  70     state->samples = memalign (16, 256 * 12 * sizeof (sample_t));
  71 #endif
  72     if(((int)state->samples%16) && (mm_accel&MM_ACCEL_X86_SSE)){
  73       mm_accel &=~MM_ACCEL_X86_SSE;
  74       fprintf(stderr, "liba52: unable to get 16 byte aligned memory disabling usage of SSE instructions\n");
  75     }
  76
  77     if (state->samples == NULL) {
  78         free (state);
  79         return NULL;
  80     }
  81
  82     for (i = 0; i < 256 * 12; i++)
  83         state->samples[i] = 0;
  84
  85     state->downmixed = 1;
  86
  87     state->lfsr_state = 1;
  88
  89     a52_imdct_init (mm_accel);
  90     downmix_accel_init(mm_accel);
  91
  92     return state;
  93 }
  94
  95 sample_t * a52_samples (a52_state_t * state)
  96 {
  97     return state->samples;
  98 }
  99
 100 int a52_syncinfo (uint8_t * buf, int * flags,
 101                   int * sample_rate, int * bit_rate)
 102 {
 103     static int rate[] = { 32,  40,  48,  56,  64,  80,  96, 112,
 104                          128, 160, 192, 224, 256, 320, 384, 448,
 105                          512, 576, 640};
 106     static uint8_t lfeon[8] = {0x10, 0x10, 0x04, 0x04, 0x04, 0x01, 0x04, 0x01};
 107     int frmsizecod;
 108     int bitrate;
 109     int half;
 110     int acmod;
 111
 112     if ((buf[0] != 0x0b) || (buf[1] != 0x77))   /* syncword */
 113         return 0;
 114
 115     if (buf[5] >= 0x60)         /* bsid >= 12 */
 116         return 0;
 117     half = halfrate[buf[5] >> 3];
 118
 119     /* acmod, dsurmod and lfeon */
 120     acmod = buf[6] >> 5;
 121     *flags = ((((buf[6] & 0xf8) == 0x50) ? A52_DOLBY : acmod) |
 122               ((buf[6] & lfeon[acmod]) ? A52_LFE : 0));
 123
 124     frmsizecod = buf[4] & 63;
 125     if (frmsizecod >= 38)
 126         return 0;
 127     bitrate = rate [frmsizecod >> 1];
 128     *bit_rate = (bitrate * 1000) >> half;
 129
 130     switch (buf[4] & 0xc0) {
 131     case 0:
 132         *sample_rate = 48000 >> half;
 133         return 4 * bitrate;
 134     case 0x40:
 135         *sample_rate = 44100 >> half;
 136         return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
 137     case 0x80:
 138         *sample_rate = 32000 >> half;
 139         return 6 * bitrate;
 140     default:
 141         return 0;
 142     }
 143 }
 144
 145 int a52_frame (a52_state_t * state, uint8_t * buf, int * flags,
 146                sample_t * level, sample_t bias)
 147 {
 148     static sample_t clev[4] = {LEVEL_3DB, LEVEL_45DB, LEVEL_6DB, LEVEL_45DB};
 149     static sample_t slev[4] = {LEVEL_3DB, LEVEL_6DB, 0, LEVEL_6DB};
 150     int chaninfo;
 151     int acmod;
 152
 153     state->fscod = buf[4] >> 6;
 154     state->halfrate = halfrate[buf[5] >> 3];
 155     state->acmod = acmod = buf[6] >> 5;
 156
 157     a52_bitstream_set_ptr (state, buf + 6);
 158     bitstream_skip (state, 3);  /* skip acmod we already parsed */
 159
 160     if ((acmod == 2) && (bitstream_get (state, 2) == 2))        /* dsurmod */
 161         acmod = A52_DOLBY;
 162
 163     if ((acmod & 1) && (acmod != 1))
 164         state->clev = clev[bitstream_get (state, 2)];   /* cmixlev */
 165
 166     if (acmod & 4)
 167         state->slev = slev[bitstream_get (state, 2)];   /* surmixlev */
 168
 169     state->lfeon = bitstream_get (state, 1);
 170
 171     state->output = a52_downmix_init (acmod, *flags, level,
 172                                       state->clev, state->slev);
 173     if (state->output < 0)
 174         return 1;
 175     if (state->lfeon && (*flags & A52_LFE))
 176         state->output |= A52_LFE;
 177     *flags = state->output;
 178     /* the 2* compensates for differences in imdct */
 179     state->dynrng = state->level = 2 * *level;
 180     state->bias = bias;
 181     state->dynrnge = 1;
 182     state->dynrngcall = NULL;
 183     state->cplba.deltbae = DELTA_BIT_NONE;
 184     state->ba[0].deltbae = state->ba[1].deltbae = state->ba[2].deltbae =
 185         state->ba[3].deltbae = state->ba[4].deltbae = DELTA_BIT_NONE;
 186
 187     chaninfo = !acmod;
 188     do {
 189         bitstream_skip (state, 5);      /* dialnorm */
 190         if (bitstream_get (state, 1))   /* compre */
 191             bitstream_skip (state, 8);  /* compr */
 192         if (bitstream_get (state, 1))   /* langcode */
 193             bitstream_skip (state, 8);  /* langcod */
 194         if (bitstream_get (state, 1))   /* audprodie */
 195             bitstream_skip (state, 7);  /* mixlevel + roomtyp */
 196     } while (chaninfo--);
 197
 198     bitstream_skip (state, 2);          /* copyrightb + origbs */
 199
 200     if (bitstream_get (state, 1))       /* timecod1e */
 201         bitstream_skip (state, 14);     /* timecod1 */
 202     if (bitstream_get (state, 1))       /* timecod2e */
 203         bitstream_skip (state, 14);     /* timecod2 */
 204
 205     if (bitstream_get (state, 1)) {     /* addbsie */
 206         int addbsil;
 207
 208         addbsil = bitstream_get (state, 6);
 209         do {
 210             bitstream_skip (state, 8);  /* addbsi */
 211         } while (addbsil--);
 212     }
 213
 214     return 0;
 215 }
 216
 217 void a52_dynrng (a52_state_t * state,
 218                  sample_t (* call) (sample_t, void *), void * data)
 219 {
 220     state->dynrnge = 0;
 221     if (call) {
 222         state->dynrnge = 1;
 223         state->dynrngcall = call;
 224         state->dynrngdata = data;
 225     }
 226 }
 227
 228 static int parse_exponents (a52_state_t * state, int expstr, int ngrps,
 229                             uint8_t exponent, uint8_t * dest)
 230 {
 231     int exps;
 232
 233     while (ngrps--) {
 234         exps = bitstream_get (state, 7);
 235
 236         exponent += exp_1[exps];
 237         if (exponent > 24)
 238             return 1;
 239
 240         switch (expstr) {
 241         case EXP_D45:
 242             *(dest++) = exponent;
 243             *(dest++) = exponent;
 244         case EXP_D25:
 245             *(dest++) = exponent;
 246         case EXP_D15:
 247             *(dest++) = exponent;
 248         }
 249
 250         exponent += exp_2[exps];
 251         if (exponent > 24)
 252             return 1;
 253
 254         switch (expstr) {
 255         case EXP_D45:
 256             *(dest++) = exponent;
 257             *(dest++) = exponent;
 258         case EXP_D25:
 259             *(dest++) = exponent;
 260         case EXP_D15:
 261             *(dest++) = exponent;
 262         }
 263
 264         exponent += exp_3[exps];
 265         if (exponent > 24)
 266             return 1;
 267
 268         switch (expstr) {
 269         case EXP_D45:
 270             *(dest++) = exponent;
 271             *(dest++) = exponent;
 272         case EXP_D25:
 273             *(dest++) = exponent;
 274         case EXP_D15:
 275             *(dest++) = exponent;
 276         }
 277     }
 278
 279     return 0;
 280 }
 281
 282 static int parse_deltba (a52_state_t * state, int8_t * deltba)
 283 {
 284     int deltnseg, deltlen, delta, j;
 285
 286     memset (deltba, 0, 50);
 287
 288     deltnseg = bitstream_get (state, 3);
 289     j = 0;
 290     do {
 291         j += bitstream_get (state, 5);
 292         deltlen = bitstream_get (state, 4);
 293         delta = bitstream_get (state, 3);
 294         delta -= (delta >= 4) ? 3 : 4;
 295         if (!deltlen)
 296             continue;
 297         if (j + deltlen >= 50)
 298             return 1;
 299         while (deltlen--)
 300             deltba[j++] = delta;
 301     } while (deltnseg--);
 302
 303     return 0;
 304 }
 305
 306 static inline int zero_snr_offsets (int nfchans, a52_state_t * state)
 307 {
 308     int i;
 309
 310     if ((state->csnroffst) ||
 311         (state->chincpl && state->cplba.bai >> 3) ||    /* cplinu, fsnroffst */
 312         (state->lfeon && state->lfeba.bai >> 3))        /* fsnroffst */
 313         return 0;
 314     for (i = 0; i < nfchans; i++)
 315         if (state->ba[i].bai >> 3)                      /* fsnroffst */
 316             return 0;
 317     return 1;
 318 }
 319
 320 static inline int16_t dither_gen (a52_state_t * state)
 321 {
 322     int16_t nstate;
 323
 324     nstate = dither_lut[state->lfsr_state >> 8] ^ (state->lfsr_state << 8);
 325
 326     state->lfsr_state = (uint16_t) nstate;
 327
 328     return nstate;
 329 }
 330
 331 static void coeff_get (a52_state_t * state, sample_t * coeff,
 332                        expbap_t * expbap, quantizer_t * quantizer,
 333                        sample_t level, int dither, int end)
 334 {
 335     int i;
 336     uint8_t * exp;
 337     int8_t * bap;
 338     sample_t factor[25];
 339
 340     for (i = 0; i <= 24; i++)
 341         factor[i] = scale_factor[i] * level;
 342
 343     exp = expbap->exp;
 344     bap = expbap->bap;
 345
 346     for (i = 0; i < end; i++) {
 347         int bapi;
 348
 349         bapi = bap[i];
 350         switch (bapi) {
 351         case 0:
 352             if (dither) {
 353                 coeff[i] = dither_gen (state) * LEVEL_3DB * factor[exp[i]];
 354                 continue;
 355             } else {
 356                 coeff[i] = 0;
 357                 continue;
 358             }
 359
 360         case -1:
 361             if (quantizer->q1_ptr >= 0) {
 362                 coeff[i] = quantizer->q1[quantizer->q1_ptr--] * factor[exp[i]];
 363                 continue;
 364             } else {
 365                 int code;
 366
 367                 code = bitstream_get (state, 5);
 368
 369                 quantizer->q1_ptr = 1;
 370                 quantizer->q1[0] = q_1_2[code];
 371                 quantizer->q1[1] = q_1_1[code];
 372                 coeff[i] = q_1_0[code] * factor[exp[i]];
 373                 continue;
 374             }
 375
 376         case -2:
 377             if (quantizer->q2_ptr >= 0) {
 378                 coeff[i] = quantizer->q2[quantizer->q2_ptr--] * factor[exp[i]];
 379                 continue;
 380             } else {
 381                 int code;
 382
 383                 code = bitstream_get (state, 7);
 384
 385                 quantizer->q2_ptr = 1;
 386                 quantizer->q2[0] = q_2_2[code];
 387                 quantizer->q2[1] = q_2_1[code];
 388                 coeff[i] = q_2_0[code] * factor[exp[i]];
 389                 continue;
 390             }
 391
 392         case 3:
 393             coeff[i] = q_3[bitstream_get (state, 3)] * factor[exp[i]];
 394             continue;
 395
 396         case -3:
 397             if (quantizer->q4_ptr == 0) {
 398                 quantizer->q4_ptr = -1;
 399                 coeff[i] = quantizer->q4 * factor[exp[i]];
 400                 continue;
 401             } else {
 402                 int code;
 403
 404                 code = bitstream_get (state, 7);
 405
 406                 quantizer->q4_ptr = 0;
 407                 quantizer->q4 = q_4_1[code];
 408                 coeff[i] = q_4_0[code] * factor[exp[i]];
 409                 continue;
 410             }
 411
 412         case 4:
 413             coeff[i] = q_5[bitstream_get (state, 4)] * factor[exp[i]];
 414             continue;
 415
 416         default:
 417             coeff[i] = ((bitstream_get_2 (state, bapi) << (16 - bapi)) *
 418                           factor[exp[i]]);
 419         }
 420     }
 421 }
 422
 423 static void coeff_get_coupling (a52_state_t * state, int nfchans,
 424                                 sample_t * coeff, sample_t (* samples)[256],
 425                                 quantizer_t * quantizer, uint8_t dithflag[5])
 426 {
 427     int cplbndstrc, bnd, i, i_end, ch;
 428     uint8_t * exp;
 429     int8_t * bap;
 430     sample_t cplco[5];
 431
 432     exp = state->cpl_expbap.exp;
 433     bap = state->cpl_expbap.bap;
 434     bnd = 0;
 435     cplbndstrc = state->cplbndstrc;
 436     i = state->cplstrtmant;
 437     while (i < state->cplendmant) {
 438         i_end = i + 12;
 439         while (cplbndstrc & 1) {
 440             cplbndstrc >>= 1;
 441             i_end += 12;
 442         }
 443         cplbndstrc >>= 1;
 444         for (ch = 0; ch < nfchans; ch++)
 445             cplco[ch] = state->cplco[ch][bnd] * coeff[ch];
 446         bnd++;
 447
 448         while (i < i_end) {
 449             sample_t cplcoeff;
 450             int bapi;
 451
 452             bapi = bap[i];
 453             switch (bapi) {
 454             case 0:
 455                 cplcoeff = LEVEL_3DB * scale_factor[exp[i]];
 456                 for (ch = 0; ch < nfchans; ch++)
 457                     if ((state->chincpl >> ch) & 1) {
 458                         if (dithflag[ch])
 459                             samples[ch][i] = (cplcoeff * cplco[ch] *
 460                                               dither_gen (state));
 461                         else
 462                             samples[ch][i] = 0;
 463                     }
 464                 i++;
 465                 continue;
 466
 467             case -1:
 468                 if (quantizer->q1_ptr >= 0) {
 469                     cplcoeff = quantizer->q1[quantizer->q1_ptr--];
 470                     break;
 471                 } else {
 472                     int code;
 473
 474                     code = bitstream_get (state, 5);
 475
 476                     quantizer->q1_ptr = 1;
 477                     quantizer->q1[0] = q_1_2[code];
 478                     quantizer->q1[1] = q_1_1[code];
 479                     cplcoeff = q_1_0[code];
 480                     break;
 481                 }
 482
 483             case -2:
 484                 if (quantizer->q2_ptr >= 0) {
 485                     cplcoeff = quantizer->q2[quantizer->q2_ptr--];
 486                     break;
 487                 } else {
 488                     int code;
 489
 490                     code = bitstream_get (state, 7);
 491
 492                     quantizer->q2_ptr = 1;
 493                     quantizer->q2[0] = q_2_2[code];
 494                     quantizer->q2[1] = q_2_1[code];
 495                     cplcoeff = q_2_0[code];
 496                     break;
 497                 }
 498
 499             case 3:
 500                 cplcoeff = q_3[bitstream_get (state, 3)];
 501                 break;
 502
 503             case -3:
 504                 if (quantizer->q4_ptr == 0) {
 505                     quantizer->q4_ptr = -1;
 506                     cplcoeff = quantizer->q4;
 507                     break;
 508                 } else {
 509                     int code;
 510
 511                     code = bitstream_get (state, 7);
 512
 513                     quantizer->q4_ptr = 0;
 514                     quantizer->q4 = q_4_1[code];
 515                     cplcoeff = q_4_0[code];
 516                     break;
 517                 }
 518
 519             case 4:
 520                 cplcoeff = q_5[bitstream_get (state, 4)];
 521                 break;
 522
 523             default:
 524                 cplcoeff = bitstream_get_2 (state, bapi) << (16 - bapi);
 525             }
 526
 527             cplcoeff *= scale_factor[exp[i]];
 528             for (ch = 0; ch < nfchans; ch++)
 529                 if ((state->chincpl >> ch) & 1)
 530                     samples[ch][i] = cplcoeff * cplco[ch];
 531             i++;
 532         }
 533     }
 534 }
 535
 536 int a52_block (a52_state_t * state)
 537 {
 538     static const uint8_t nfchans_tbl[] = {2, 1, 2, 3, 3, 4, 4, 5, 1, 1, 2};
 539     static int rematrix_band[4] = {25, 37, 61, 253};
 540     int i, nfchans, chaninfo;
 541     uint8_t cplexpstr, chexpstr[5], lfeexpstr, do_bit_alloc, done_cpl;
 542     uint8_t blksw[5], dithflag[5];
 543     sample_t coeff[5];
 544     int chanbias;
 545     quantizer_t quantizer;
 546     sample_t * samples;
 547
 548     nfchans = nfchans_tbl[state->acmod];
 549
 550     for (i = 0; i < nfchans; i++)
 551         blksw[i] = bitstream_get (state, 1);
 552
 553     for (i = 0; i < nfchans; i++)
 554         dithflag[i] = bitstream_get (state, 1);
 555
 556     chaninfo = !state->acmod;
 557     do {
 558         if (bitstream_get (state, 1)) { /* dynrnge */
 559             int dynrng;
 560
 561             dynrng = bitstream_get_2 (state, 8);
 562             if (state->dynrnge) {
 563                 sample_t range;
 564
 565                 range = ((((dynrng & 0x1f) | 0x20) << 13) *
 566                          scale_factor[3 - (dynrng >> 5)]);
 567                 if (state->dynrngcall)
 568                     range = state->dynrngcall (range, state->dynrngdata);
 569                 state->dynrng = state->level * range;
 570             }
 571         }
 572     } while (chaninfo--);
 573
 574     if (bitstream_get (state, 1)) {     /* cplstre */
 575         state->chincpl = 0;
 576         if (bitstream_get (state, 1)) { /* cplinu */
 577             static uint8_t bndtab[16] = {31, 35, 37, 39, 41, 42, 43, 44,
 578                                          45, 45, 46, 46, 47, 47, 48, 48};
 579             int cplbegf;
 580             int cplendf;
 581             int ncplsubnd;
 582
 583             for (i = 0; i < nfchans; i++)
 584                 state->chincpl |= bitstream_get (state, 1) << i;
 585             switch (state->acmod) {
 586             case 0: case 1:
 587                 return 1;
 588             case 2:
 589                 state->phsflginu = bitstream_get (state, 1);
 590             }
 591             cplbegf = bitstream_get (state, 4);
 592             cplendf = bitstream_get (state, 4);
 593
 594             if (cplendf + 3 - cplbegf < 0)
 595                 return 1;
 596             state->ncplbnd = ncplsubnd = cplendf + 3 - cplbegf;
 597             state->cplstrtbnd = bndtab[cplbegf];
 598             state->cplstrtmant = cplbegf * 12 + 37;
 599             state->cplendmant = cplendf * 12 + 73;
 600
 601             state->cplbndstrc = 0;
 602             for (i = 0; i < ncplsubnd - 1; i++)
 603                 if (bitstream_get (state, 1)) {
 604                     state->cplbndstrc |= 1 << i;
 605                     state->ncplbnd--;
 606                 }
 607         }
 608     }
 609
 610     if (state->chincpl) {       /* cplinu */
 611         int j, cplcoe;
 612
 613         cplcoe = 0;
 614         for (i = 0; i < nfchans; i++)
 615             if ((state->chincpl) >> i & 1)
 616                 if (bitstream_get (state, 1)) { /* cplcoe */
 617                     int mstrcplco, cplcoexp, cplcomant;
 618
 619                     cplcoe = 1;
 620                     mstrcplco = 3 * bitstream_get (state, 2);
 621                     for (j = 0; j < state->ncplbnd; j++) {
 622                         cplcoexp = bitstream_get (state, 4);
 623                         cplcomant = bitstream_get (state, 4);
 624                         if (cplcoexp == 15)
 625                             cplcomant <<= 14;
 626                         else
 627                             cplcomant = (cplcomant | 0x10) << 13;
 628                         state->cplco[i][j] =
 629                             cplcomant * scale_factor[cplcoexp + mstrcplco];
 630                     }
 631                 }
 632         if ((state->acmod == 2) && state->phsflginu && cplcoe)
 633             for (j = 0; j < state->ncplbnd; j++)
 634                 if (bitstream_get (state, 1))   /* phsflg */
 635                     state->cplco[1][j] = -state->cplco[1][j];
 636     }
 637
 638     if ((state->acmod == 2) && (bitstream_get (state, 1))) {    /* rematstr */
 639         int end;
 640
 641         state->rematflg = 0;
 642         end = (state->chincpl) ? state->cplstrtmant : 253;      /* cplinu */
 643         i = 0;
 644         do
 645             state->rematflg |= bitstream_get (state, 1) << i;
 646         while (rematrix_band[i++] < end);
 647     }
 648
 649     cplexpstr = EXP_REUSE;
 650     lfeexpstr = EXP_REUSE;
 651     if (state->chincpl) /* cplinu */
 652         cplexpstr = bitstream_get (state, 2);
 653     for (i = 0; i < nfchans; i++)
 654         chexpstr[i] = bitstream_get (state, 2);
 655     if (state->lfeon)
 656         lfeexpstr = bitstream_get (state, 1);
 657
 658     for (i = 0; i < nfchans; i++)
 659         if (chexpstr[i] != EXP_REUSE) {
 660             if ((state->chincpl >> i) & 1)
 661                 state->endmant[i] = state->cplstrtmant;
 662             else {
 663                 int chbwcod;
 664
 665                 chbwcod = bitstream_get (state, 6);
 666                 if (chbwcod > 60)
 667                     return 1;
 668                 state->endmant[i] = chbwcod * 3 + 73;
 669             }
 670         }
 671
 672     do_bit_alloc = 0;
 673
 674     if (cplexpstr != EXP_REUSE) {
 675         int cplabsexp, ncplgrps;
 676
 677         do_bit_alloc = 64;
 678         ncplgrps = ((state->cplendmant - state->cplstrtmant) /
 679                     (3 << (cplexpstr - 1)));
 680         cplabsexp = bitstream_get (state, 4) << 1;
 681         if (parse_exponents (state, cplexpstr, ncplgrps, cplabsexp,
 682                              state->cpl_expbap.exp + state->cplstrtmant))
 683             return 1;
 684     }
 685     for (i = 0; i < nfchans; i++)
 686         if (chexpstr[i] != EXP_REUSE) {
 687             int grp_size, nchgrps;
 688
 689             do_bit_alloc |= 1 << i;
 690             grp_size = 3 << (chexpstr[i] - 1);
 691             nchgrps = (state->endmant[i] + grp_size - 4) / grp_size;
 692             state->fbw_expbap[i].exp[0] = bitstream_get (state, 4);
 693             if (parse_exponents (state, chexpstr[i], nchgrps,
 694                                  state->fbw_expbap[i].exp[0],
 695                                  state->fbw_expbap[i].exp + 1))
 696                 return 1;
 697             bitstream_skip (state, 2);  /* gainrng */
 698         }
 699     if (lfeexpstr != EXP_REUSE) {
 700         do_bit_alloc |= 32;
 701         state->lfe_expbap.exp[0] = bitstream_get (state, 4);
 702         if (parse_exponents (state, lfeexpstr, 2, state->lfe_expbap.exp[0],
 703                              state->lfe_expbap.exp + 1))
 704             return 1;
 705     }
 706
 707     if (bitstream_get (state, 1)) {     /* baie */
 708         do_bit_alloc = -1;
 709         state->bai = bitstream_get (state, 11);
 710     }
 711     if (bitstream_get (state, 1)) {     /* snroffste */
 712         do_bit_alloc = -1;
 713         state->csnroffst = bitstream_get (state, 6);
 714         if (state->chincpl)     /* cplinu */
 715             state->cplba.bai = bitstream_get (state, 7);
 716         for (i = 0; i < nfchans; i++)
 717             state->ba[i].bai = bitstream_get (state, 7);
 718         if (state->lfeon)
 719             state->lfeba.bai = bitstream_get (state, 7);
 720     }
 721     if ((state->chincpl) && (bitstream_get (state, 1))) { /* cplleake */
 722         do_bit_alloc |= 64;
 723         state->cplfleak = 9 - bitstream_get (state, 3);
 724         state->cplsleak = 9 - bitstream_get (state, 3);
 725     }
 726
 727     if (bitstream_get (state, 1)) {     /* deltbaie */
 728         do_bit_alloc = -1;
 729         if (state->chincpl)     /* cplinu */
 730             state->cplba.deltbae = bitstream_get (state, 2);
 731         for (i = 0; i < nfchans; i++)
 732             state->ba[i].deltbae = bitstream_get (state, 2);
 733         if (state->chincpl &&   /* cplinu */
 734             (state->cplba.deltbae == DELTA_BIT_NEW) &&
 735             parse_deltba (state, state->cplba.deltba))
 736             return 1;
 737         for (i = 0; i < nfchans; i++)
 738             if ((state->ba[i].deltbae == DELTA_BIT_NEW) &&
 739                 parse_deltba (state, state->ba[i].deltba))
 740                 return 1;
 741     }
 742
 743     if (do_bit_alloc) {
 744         if (zero_snr_offsets (nfchans, state)) {
 745             memset (state->cpl_expbap.bap, 0, sizeof (state->cpl_expbap.bap));
 746             for (i = 0; i < nfchans; i++)
 747                 memset (state->fbw_expbap[i].bap, 0,
 748                         sizeof (state->fbw_expbap[i].bap));
 749             memset (state->lfe_expbap.bap, 0, sizeof (state->lfe_expbap.bap));
 750         } else {
 751             if (state->chincpl && (do_bit_alloc & 64))  /* cplinu */
 752                 a52_bit_allocate (state, &state->cplba, state->cplstrtbnd,
 753                                   state->cplstrtmant, state->cplendmant,
 754                                   state->cplfleak << 8, state->cplsleak << 8,
 755                                   &state->cpl_expbap);
 756             for (i = 0; i < nfchans; i++)
 757                 if (do_bit_alloc & (1 << i))
 758                     a52_bit_allocate (state, state->ba + i, 0, 0,
 759                                       state->endmant[i], 0, 0,
 760                                       state->fbw_expbap +i);
 761             if (state->lfeon && (do_bit_alloc & 32)) {
 762                 state->lfeba.deltbae = DELTA_BIT_NONE;
 763                 a52_bit_allocate (state, &state->lfeba, 0, 0, 7, 0, 0,
 764                                   &state->lfe_expbap);
 765             }
 766         }
 767     }
 768
 769     if (bitstream_get (state, 1)) {     /* skiple */
 770         i = bitstream_get (state, 9);   /* skipl */
 771         while (i--)
 772             bitstream_skip (state, 8);
 773     }
 774
 775     samples = state->samples;
 776     if (state->output & A52_LFE)
 777         samples += 256; /* shift for LFE channel */
 778
 779     chanbias = a52_downmix_coeff (coeff, state->acmod, state->output,
 780                                   state->dynrng, state->clev, state->slev);
 781
 782     quantizer.q1_ptr = quantizer.q2_ptr = quantizer.q4_ptr = -1;
 783     done_cpl = 0;
 784
 785     for (i = 0; i < nfchans; i++) {
 786         int j;
 787
 788         coeff_get (state, samples + 256 * i, state->fbw_expbap +i, &quantizer,
 789                    coeff[i], dithflag[i], state->endmant[i]);
 790
 791         if ((state->chincpl >> i) & 1) {
 792             if (!done_cpl) {
 793                 done_cpl = 1;
 794                 coeff_get_coupling (state, nfchans, coeff,
 795                                     (sample_t (*)[256])samples, &quantizer,
 796                                     dithflag);
 797             }
 798             j = state->cplendmant;
 799         } else
 800             j = state->endmant[i];
 801         do
 802             (samples + 256 * i)[j] = 0;
 803         while (++j < 256);
 804     }
 805
 806     if (state->acmod == 2) {
 807         int j, end, band, rematflg;
 808
 809         end = ((state->endmant[0] < state->endmant[1]) ?
 810                state->endmant[0] : state->endmant[1]);
 811
 812         i = 0;
 813         j = 13;
 814         rematflg = state->rematflg;
 815         do {
 816             if (! (rematflg & 1)) {
 817                 rematflg >>= 1;
 818                 j = rematrix_band[i++];
 819                 continue;
 820             }
 821             rematflg >>= 1;
 822             band = rematrix_band[i++];
 823             if (band > end)
 824                 band = end;
 825             do {
 826                 sample_t tmp0, tmp1;
 827
 828                 tmp0 = samples[j];
 829                 tmp1 = (samples+256)[j];
 830                 samples[j] = tmp0 + tmp1;
 831                 (samples+256)[j] = tmp0 - tmp1;
 832             } while (++j < band);
 833         } while (j < end);
 834     }
 835
 836     if (state->lfeon) {
 837         if (state->output & A52_LFE) {
 838             coeff_get (state, samples - 256, &state->lfe_expbap, &quantizer,
 839                        state->dynrng, 0, 7);
 840             for (i = 7; i < 256; i++)
 841                 (samples-256)[i] = 0;
 842             a52_imdct_512 (samples - 256, samples + 1536 - 256, state->bias);
 843         } else {
 844             /* just skip the LFE coefficients */
 845             coeff_get (state, samples + 1280, &state->lfe_expbap, &quantizer,
 846                        0, 0, 7);
 847         }
 848     }
 849
 850     i = 0;
 851     if (nfchans_tbl[state->output & A52_CHANNEL_MASK] < nfchans)
 852         for (i = 1; i < nfchans; i++)
 853             if (blksw[i] != blksw[0])
 854                 break;
 855
 856     if (i < nfchans) {
 857         if (state->downmixed) {
 858             state->downmixed = 0;
 859             a52_upmix (samples + 1536, state->acmod, state->output);
 860         }
 861
 862         for (i = 0; i < nfchans; i++) {
 863             sample_t bias;
 864
 865             bias = 0;
 866             if (!(chanbias & (1 << i)))
 867                 bias = state->bias;
 868
 869             if (coeff[i]) {
 870                 if (blksw[i])
 871                     a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
 872                                    bias);
 873                 else
 874                     a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
 875                                    bias);
 876             } else {
 877                 int j;
 878
 879                 for (j = 0; j < 256; j++)
 880                     (samples + 256 * i)[j] = bias;
 881             }
 882         }
 883
 884         a52_downmix (samples, state->acmod, state->output, state->bias,
 885                      state->clev, state->slev);
 886     } else {
 887         nfchans = nfchans_tbl[state->output & A52_CHANNEL_MASK];
 888
 889         a52_downmix (samples, state->acmod, state->output, 0,
 890                      state->clev, state->slev);
 891
 892         if (!state->downmixed) {
 893             state->downmixed = 1;
 894             a52_downmix (samples + 1536, state->acmod, state->output, 0,
 895                          state->clev, state->slev);
 896         }
 897
 898         if (blksw[0])
 899             for (i = 0; i < nfchans; i++)
 900                 a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
 901                                state->bias);
 902         else
 903             for (i = 0; i < nfchans; i++)
 904                 a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
 905                                state->bias);
 906     }
 907
 908     return 0;
 909 }
 910
 911 void a52_free (a52_state_t * state)
 912 {
 913 #if defined(__MINGW32__) && defined(HAVE_SSE)
 914     av_free (state->samples);
 915 #else
 916      free (state->samples);
 917 #endif
 918     free (state);
 919 }