src/third_party/ffmpeg/libavcodec/ituh263dec.c

   1 /*
   2  * ITU H263 bitstream decoder
   3  * Copyright (c) 2000,2001 Fabrice Bellard
   4  * H263+ support.
   5  * Copyright (c) 2001 Juan J. Sierralta P
   6  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
   7  *
   8  * This file is part of FFmpeg.
   9  *
  10  * FFmpeg is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * FFmpeg is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with FFmpeg; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 /**
  26  * @file
  27  * h263 decoder.
  28  */
  29
  30 #include <limits.h>
  31
  32 #include "libavutil/attributes.h"
  33 #include "libavutil/internal.h"
  34 #include "libavutil/mathematics.h"
  35 #include "avcodec.h"
  36 #include "mpegvideo.h"
  37 #include "h263.h"
  38 #include "mathops.h"
  39 #include "mpegutils.h"
  40 #include "unary.h"
  41 #include "flv.h"
  42 #include "mpeg4video.h"
  43
  44 // The defines below define the number of bits that are read at once for
  45 // reading vlc values. Changing these may improve speed and data cache needs
  46 // be aware though that decreasing them may need the number of stages that is
  47 // passed to get_vlc* to be increased.
  48 #define MV_VLC_BITS 9
  49 #define H263_MBTYPE_B_VLC_BITS 6
  50 #define CBPC_B_VLC_BITS 3
  51
  52 static const int h263_mb_type_b_map[15]= {
  53     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  54     MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
  55     MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
  56                       MB_TYPE_L0                                 | MB_TYPE_16x16,
  57                       MB_TYPE_L0   | MB_TYPE_CBP                 | MB_TYPE_16x16,
  58                       MB_TYPE_L0   | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
  59                       MB_TYPE_L1                                 | MB_TYPE_16x16,
  60                       MB_TYPE_L1   | MB_TYPE_CBP                 | MB_TYPE_16x16,
  61                       MB_TYPE_L1   | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
  62                       MB_TYPE_L0L1                               | MB_TYPE_16x16,
  63                       MB_TYPE_L0L1 | MB_TYPE_CBP                 | MB_TYPE_16x16,
  64                       MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
  65     0, //stuffing
  66     MB_TYPE_INTRA4x4                | MB_TYPE_CBP,
  67     MB_TYPE_INTRA4x4                | MB_TYPE_CBP | MB_TYPE_QUANT,
  68 };
  69
  70 void ff_h263_show_pict_info(MpegEncContext *s){
  71     if(s->avctx->debug&FF_DEBUG_PICT_INFO){
  72     av_log(s->avctx, AV_LOG_DEBUG, "qp:%d %c size:%d rnd:%d%s%s%s%s%s%s%s%s%s %d/%d\n",
  73          s->qscale, av_get_picture_type_char(s->pict_type),
  74          s->gb.size_in_bits, 1-s->no_rounding,
  75          s->obmc ? " AP" : "",
  76          s->umvplus ? " UMV" : "",
  77          s->h263_long_vectors ? " LONG" : "",
  78          s->h263_plus ? " +" : "",
  79          s->h263_aic ? " AIC" : "",
  80          s->alt_inter_vlc ? " AIV" : "",
  81          s->modified_quant ? " MQ" : "",
  82          s->loop_filter ? " LOOP" : "",
  83          s->h263_slice_structured ? " SS" : "",
  84          s->avctx->time_base.den, s->avctx->time_base.num
  85     );
  86     }
  87 }
  88
  89 /***********************************************/
  90 /* decoding */
  91
  92 VLC ff_h263_intra_MCBPC_vlc;
  93 VLC ff_h263_inter_MCBPC_vlc;
  94 VLC ff_h263_cbpy_vlc;
  95 static VLC mv_vlc;
  96 static VLC h263_mbtype_b_vlc;
  97 static VLC cbpc_b_vlc;
  98
  99 /* init vlcs */
 100
 101 /* XXX: find a better solution to handle static init */
 102 av_cold void ff_h263_decode_init_vlc(void)
 103 {
 104     static volatile int done = 0;
 105
 106     if (!done) {
 107         INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
 108                  ff_h263_intra_MCBPC_bits, 1, 1,
 109                  ff_h263_intra_MCBPC_code, 1, 1, 72);
 110         INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
 111                  ff_h263_inter_MCBPC_bits, 1, 1,
 112                  ff_h263_inter_MCBPC_code, 1, 1, 198);
 113         INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
 114                  &ff_h263_cbpy_tab[0][1], 2, 1,
 115                  &ff_h263_cbpy_tab[0][0], 2, 1, 64);
 116         INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
 117                  &ff_mvtab[0][1], 2, 1,
 118                  &ff_mvtab[0][0], 2, 1, 538);
 119         ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
 120         ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
 121         INIT_VLC_RL(ff_h263_rl_inter, 554);
 122         INIT_VLC_RL(ff_rl_intra_aic, 554);
 123         INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
 124                  &ff_h263_mbtype_b_tab[0][1], 2, 1,
 125                  &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
 126         INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
 127                  &ff_cbpc_b_tab[0][1], 2, 1,
 128                  &ff_cbpc_b_tab[0][0], 2, 1, 8);
 129         done = 1;
 130     }
 131 }
 132
 133 int ff_h263_decode_mba(MpegEncContext *s)
 134 {
 135     int i, mb_pos;
 136
 137     for(i=0; i<6; i++){
 138         if(s->mb_num-1 <= ff_mba_max[i]) break;
 139     }
 140     mb_pos= get_bits(&s->gb, ff_mba_length[i]);
 141     s->mb_x= mb_pos % s->mb_width;
 142     s->mb_y= mb_pos / s->mb_width;
 143
 144     return mb_pos;
 145 }
 146
 147 /**
 148  * Decode the group of blocks header or slice header.
 149  * @return <0 if an error occurred
 150  */
 151 static int h263_decode_gob_header(MpegEncContext *s)
 152 {
 153     unsigned int val, gob_number;
 154     int left;
 155
 156     /* Check for GOB Start Code */
 157     val = show_bits(&s->gb, 16);
 158     if(val)
 159         return -1;
 160
 161         /* We have a GBSC probably with GSTUFF */
 162     skip_bits(&s->gb, 16); /* Drop the zeros */
 163     left= get_bits_left(&s->gb);
 164     //MN: we must check the bits left or we might end in a infinite loop (or segfault)
 165     for(;left>13; left--){
 166         if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
 167     }
 168     if(left<=13)
 169         return -1;
 170
 171     if(s->h263_slice_structured){
 172         if(get_bits1(&s->gb)==0)
 173             return -1;
 174
 175         ff_h263_decode_mba(s);
 176
 177         if(s->mb_num > 1583)
 178             if(get_bits1(&s->gb)==0)
 179                 return -1;
 180
 181         s->qscale = get_bits(&s->gb, 5); /* SQUANT */
 182         if(get_bits1(&s->gb)==0)
 183             return -1;
 184         skip_bits(&s->gb, 2); /* GFID */
 185     }else{
 186         gob_number = get_bits(&s->gb, 5); /* GN */
 187         s->mb_x= 0;
 188         s->mb_y= s->gob_index* gob_number;
 189         skip_bits(&s->gb, 2); /* GFID */
 190         s->qscale = get_bits(&s->gb, 5); /* GQUANT */
 191     }
 192
 193     if(s->mb_y >= s->mb_height)
 194         return -1;
 195
 196     if(s->qscale==0)
 197         return -1;
 198
 199     return 0;
 200 }
 201
 202 /**
 203  * Decode the group of blocks / video packet header.
 204  * @return bit position of the resync_marker, or <0 if none was found
 205  */
 206 int ff_h263_resync(MpegEncContext *s){
 207     int left, pos, ret;
 208
 209     if(s->codec_id==AV_CODEC_ID_MPEG4){
 210         skip_bits1(&s->gb);
 211         align_get_bits(&s->gb);
 212     }
 213
 214     if(show_bits(&s->gb, 16)==0){
 215         pos= get_bits_count(&s->gb);
 216         if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 217             ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 218         else
 219             ret= h263_decode_gob_header(s);
 220         if(ret>=0)
 221             return pos;
 222     }
 223     //OK, it's not where it is supposed to be ...
 224     s->gb= s->last_resync_gb;
 225     align_get_bits(&s->gb);
 226     left= get_bits_left(&s->gb);
 227
 228     for(;left>16+1+5+5; left-=8){
 229         if(show_bits(&s->gb, 16)==0){
 230             GetBitContext bak= s->gb;
 231
 232             pos= get_bits_count(&s->gb);
 233             if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 234                 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 235             else
 236                 ret= h263_decode_gob_header(s);
 237             if(ret>=0)
 238                 return pos;
 239
 240             s->gb= bak;
 241         }
 242         skip_bits(&s->gb, 8);
 243     }
 244
 245     return -1;
 246 }
 247
 248 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
 249 {
 250     int code, val, sign, shift;
 251     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
 252
 253     if (code == 0)
 254         return pred;
 255     if (code < 0)
 256         return 0xffff;
 257
 258     sign = get_bits1(&s->gb);
 259     shift = f_code - 1;
 260     val = code;
 261     if (shift) {
 262         val = (val - 1) << shift;
 263         val |= get_bits(&s->gb, shift);
 264         val++;
 265     }
 266     if (sign)
 267         val = -val;
 268     val += pred;
 269
 270     /* modulo decoding */
 271     if (!s->h263_long_vectors) {
 272         val = sign_extend(val, 5 + f_code);
 273     } else {
 274         /* horrible h263 long vector mode */
 275         if (pred < -31 && val < -63)
 276             val += 64;
 277         if (pred > 32 && val > 63)
 278             val -= 64;
 279
 280     }
 281     return val;
 282 }
 283
 284
 285 /* Decode RVLC of H.263+ UMV */
 286 static int h263p_decode_umotion(MpegEncContext * s, int pred)
 287 {
 288    int code = 0, sign;
 289
 290    if (get_bits1(&s->gb)) /* Motion difference = 0 */
 291       return pred;
 292
 293    code = 2 + get_bits1(&s->gb);
 294
 295    while (get_bits1(&s->gb))
 296    {
 297       code <<= 1;
 298       code += get_bits1(&s->gb);
 299    }
 300    sign = code & 1;
 301    code >>= 1;
 302
 303    code = (sign) ? (pred - code) : (pred + code);
 304    av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
 305    return code;
 306
 307 }
 308
 309 /**
 310  * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
 311  */
 312 static void preview_obmc(MpegEncContext *s){
 313     GetBitContext gb= s->gb;
 314
 315     int cbpc, i, pred_x, pred_y, mx, my;
 316     int16_t *mot_val;
 317     const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 318     const int stride= s->b8_stride*2;
 319
 320     for(i=0; i<4; i++)
 321         s->block_index[i]+= 2;
 322     for(i=4; i<6; i++)
 323         s->block_index[i]+= 1;
 324     s->mb_x++;
 325
 326     av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
 327
 328     do{
 329         if (get_bits1(&s->gb)) {
 330             /* skip mb */
 331             mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 332             mot_val[0       ]= mot_val[2       ]=
 333             mot_val[0+stride]= mot_val[2+stride]= 0;
 334             mot_val[1       ]= mot_val[3       ]=
 335             mot_val[1+stride]= mot_val[3+stride]= 0;
 336
 337             s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 338             goto end;
 339         }
 340         cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 341     }while(cbpc == 20);
 342
 343     if(cbpc & 4){
 344         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 345     }else{
 346         get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 347         if (cbpc & 8) {
 348             if(s->modified_quant){
 349                 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
 350                 else                  skip_bits(&s->gb, 5);
 351             }else
 352                 skip_bits(&s->gb, 2);
 353         }
 354
 355         if ((cbpc & 16) == 0) {
 356                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 357                 /* 16x16 motion prediction */
 358                 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 359                 if (s->umvplus)
 360                    mx = h263p_decode_umotion(s, pred_x);
 361                 else
 362                    mx = ff_h263_decode_motion(s, pred_x, 1);
 363
 364                 if (s->umvplus)
 365                    my = h263p_decode_umotion(s, pred_y);
 366                 else
 367                    my = ff_h263_decode_motion(s, pred_y, 1);
 368
 369                 mot_val[0       ]= mot_val[2       ]=
 370                 mot_val[0+stride]= mot_val[2+stride]= mx;
 371                 mot_val[1       ]= mot_val[3       ]=
 372                 mot_val[1+stride]= mot_val[3+stride]= my;
 373         } else {
 374             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 375             for(i=0;i<4;i++) {
 376                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 377                 if (s->umvplus)
 378                   mx = h263p_decode_umotion(s, pred_x);
 379                 else
 380                   mx = ff_h263_decode_motion(s, pred_x, 1);
 381
 382                 if (s->umvplus)
 383                   my = h263p_decode_umotion(s, pred_y);
 384                 else
 385                   my = ff_h263_decode_motion(s, pred_y, 1);
 386                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 387                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 388                 mot_val[0] = mx;
 389                 mot_val[1] = my;
 390             }
 391         }
 392     }
 393 end:
 394
 395     for(i=0; i<4; i++)
 396         s->block_index[i]-= 2;
 397     for(i=4; i<6; i++)
 398         s->block_index[i]-= 1;
 399     s->mb_x--;
 400
 401     s->gb= gb;
 402 }
 403
 404 static void h263_decode_dquant(MpegEncContext *s){
 405     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 406
 407     if(s->modified_quant){
 408         if(get_bits1(&s->gb))
 409             s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
 410         else
 411             s->qscale= get_bits(&s->gb, 5);
 412     }else
 413         s->qscale += quant_tab[get_bits(&s->gb, 2)];
 414     ff_set_qscale(s, s->qscale);
 415 }
 416
 417 static int h263_decode_block(MpegEncContext * s, int16_t * block,
 418                              int n, int coded)
 419 {
 420     int level, i, j, run;
 421     RLTable *rl = &ff_h263_rl_inter;
 422     const uint8_t *scan_table;
 423     GetBitContext gb= s->gb;
 424
 425     scan_table = s->intra_scantable.permutated;
 426     if (s->h263_aic && s->mb_intra) {
 427         rl = &ff_rl_intra_aic;
 428         i = 0;
 429         if (s->ac_pred) {
 430             if (s->h263_aic_dir)
 431                 scan_table = s->intra_v_scantable.permutated; /* left */
 432             else
 433                 scan_table = s->intra_h_scantable.permutated; /* top */
 434         }
 435     } else if (s->mb_intra) {
 436         /* DC coef */
 437         if(s->codec_id == AV_CODEC_ID_RV10){
 438 #if CONFIG_RV10_DECODER
 439           if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
 440             int component, diff;
 441             component = (n <= 3 ? 0 : n - 4 + 1);
 442             level = s->last_dc[component];
 443             if (s->rv10_first_dc_coded[component]) {
 444                 diff = ff_rv_decode_dc(s, n);
 445                 if (diff == 0xffff)
 446                     return -1;
 447                 level += diff;
 448                 level = level & 0xff; /* handle wrap round */
 449                 s->last_dc[component] = level;
 450             } else {
 451                 s->rv10_first_dc_coded[component] = 1;
 452             }
 453           } else {
 454                 level = get_bits(&s->gb, 8);
 455                 if (level == 255)
 456                     level = 128;
 457           }
 458 #endif
 459         }else{
 460             level = get_bits(&s->gb, 8);
 461             if((level&0x7F) == 0){
 462                 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
 463                 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
 464                     return -1;
 465             }
 466             if (level == 255)
 467                 level = 128;
 468         }
 469         block[0] = level;
 470         i = 1;
 471     } else {
 472         i = 0;
 473     }
 474     if (!coded) {
 475         if (s->mb_intra && s->h263_aic)
 476             goto not_coded;
 477         s->block_last_index[n] = i - 1;
 478         return 0;
 479     }
 480 retry:
 481     {
 482     OPEN_READER(re, &s->gb);
 483     i--; // offset by -1 to allow direct indexing of scan_table
 484     for(;;) {
 485         UPDATE_CACHE(re, &s->gb);
 486         GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 487         if (run == 66) {
 488             if (level){
 489                 CLOSE_READER(re, &s->gb);
 490                 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
 491                 return -1;
 492             }
 493             /* escape */
 494             if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
 495                 int is11 = SHOW_UBITS(re, &s->gb, 1);
 496                 SKIP_CACHE(re, &s->gb, 1);
 497                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 498                 if (is11) {
 499                     SKIP_COUNTER(re, &s->gb, 1 + 7);
 500                     UPDATE_CACHE(re, &s->gb);
 501                     level = SHOW_SBITS(re, &s->gb, 11);
 502                     SKIP_COUNTER(re, &s->gb, 11);
 503                 } else {
 504                     SKIP_CACHE(re, &s->gb, 7);
 505                     level = SHOW_SBITS(re, &s->gb, 7);
 506                     SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
 507                 }
 508             } else {
 509                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 510                 SKIP_CACHE(re, &s->gb, 7);
 511                 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
 512                 SKIP_COUNTER(re, &s->gb, 7 + 8);
 513                 if(level == -128){
 514                     UPDATE_CACHE(re, &s->gb);
 515                     if (s->codec_id == AV_CODEC_ID_RV10) {
 516                         /* XXX: should patch encoder too */
 517                         level = SHOW_SBITS(re, &s->gb, 12);
 518                         SKIP_COUNTER(re, &s->gb, 12);
 519                     }else{
 520                         level = SHOW_UBITS(re, &s->gb, 5);
 521                         SKIP_CACHE(re, &s->gb, 5);
 522                         level |= SHOW_SBITS(re, &s->gb, 6)<<5;
 523                         SKIP_COUNTER(re, &s->gb, 5 + 6);
 524                     }
 525                 }
 526             }
 527         } else {
 528             if (SHOW_UBITS(re, &s->gb, 1))
 529                 level = -level;
 530             SKIP_COUNTER(re, &s->gb, 1);
 531         }
 532         i += run;
 533         if (i >= 64){
 534             CLOSE_READER(re, &s->gb);
 535             // redo update without last flag, revert -1 offset
 536             i = i - run + ((run-1)&63) + 1;
 537             if (i < 64) {
 538                 // only last marker, no overrun
 539                 block[scan_table[i]] = level;
 540                 break;
 541             }
 542             if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
 543                 //Looks like a hack but no, it's the way it is supposed to work ...
 544                 rl = &ff_rl_intra_aic;
 545                 i = 0;
 546                 s->gb= gb;
 547                 s->bdsp.clear_block(block);
 548                 goto retry;
 549             }
 550             av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
 551             return -1;
 552         }
 553         j = scan_table[i];
 554         block[j] = level;
 555     }
 556     }
 557 not_coded:
 558     if (s->mb_intra && s->h263_aic) {
 559         ff_h263_pred_acdc(s, block, n);
 560         i = 63;
 561     }
 562     s->block_last_index[n] = i;
 563     return 0;
 564 }
 565
 566 static int h263_skip_b_part(MpegEncContext *s, int cbp)
 567 {
 568     LOCAL_ALIGNED_16(int16_t, dblock, [64]);
 569     int i, mbi;
 570     int bli[6];
 571
 572     /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
 573      * but real value should be restored in order to be used later (in OBMC condition)
 574      */
 575     mbi = s->mb_intra;
 576     memcpy(bli, s->block_last_index, sizeof(bli));
 577     s->mb_intra = 0;
 578     for (i = 0; i < 6; i++) {
 579         if (h263_decode_block(s, dblock, i, cbp&32) < 0)
 580             return -1;
 581         cbp+=cbp;
 582     }
 583     s->mb_intra = mbi;
 584     memcpy(s->block_last_index, bli, sizeof(bli));
 585     return 0;
 586 }
 587
 588 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
 589 {
 590     int c, mv = 1;
 591
 592     if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
 593         c = get_bits1(gb);
 594         if (pb_frame == 2 && c)
 595             mv = !get_bits1(gb);
 596     } else { // h.263 Annex M improved PB-frame
 597         mv = get_unary(gb, 0, 4) + 1;
 598         c = mv & 1;
 599         mv = !!(mv & 2);
 600     }
 601     if(c)
 602         *cbpb = get_bits(gb, 6);
 603     return mv;
 604 }
 605
 606 int ff_h263_decode_mb(MpegEncContext *s,
 607                       int16_t block[6][64])
 608 {
 609     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
 610     int16_t *mot_val;
 611     const int xy= s->mb_x + s->mb_y * s->mb_stride;
 612     int cbpb = 0, pb_mv_count = 0;
 613
 614     av_assert2(!s->h263_pred);
 615
 616     if (s->pict_type == AV_PICTURE_TYPE_P) {
 617         do{
 618             if (get_bits1(&s->gb)) {
 619                 /* skip mb */
 620                 s->mb_intra = 0;
 621                 for(i=0;i<6;i++)
 622                     s->block_last_index[i] = -1;
 623                 s->mv_dir = MV_DIR_FORWARD;
 624                 s->mv_type = MV_TYPE_16X16;
 625                 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 626                 s->mv[0][0][0] = 0;
 627                 s->mv[0][0][1] = 0;
 628                 s->mb_skipped = !(s->obmc | s->loop_filter);
 629                 goto end;
 630             }
 631             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 632             if (cbpc < 0){
 633                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 634                 return -1;
 635             }
 636         }while(cbpc == 20);
 637
 638         s->bdsp.clear_blocks(s->block[0]);
 639
 640         dquant = cbpc & 8;
 641         s->mb_intra = ((cbpc & 4) != 0);
 642         if (s->mb_intra) goto intra;
 643
 644         if(s->pb_frame && get_bits1(&s->gb))
 645             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 646         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 647
 648         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 649             cbpy ^= 0xF;
 650
 651         cbp = (cbpc & 3) | (cbpy << 2);
 652         if (dquant) {
 653             h263_decode_dquant(s);
 654         }
 655
 656         s->mv_dir = MV_DIR_FORWARD;
 657         if ((cbpc & 16) == 0) {
 658             s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 659             /* 16x16 motion prediction */
 660             s->mv_type = MV_TYPE_16X16;
 661             ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 662             if (s->umvplus)
 663                mx = h263p_decode_umotion(s, pred_x);
 664             else
 665                mx = ff_h263_decode_motion(s, pred_x, 1);
 666
 667             if (mx >= 0xffff)
 668                 return -1;
 669
 670             if (s->umvplus)
 671                my = h263p_decode_umotion(s, pred_y);
 672             else
 673                my = ff_h263_decode_motion(s, pred_y, 1);
 674
 675             if (my >= 0xffff)
 676                 return -1;
 677             s->mv[0][0][0] = mx;
 678             s->mv[0][0][1] = my;
 679
 680             if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 681                skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 682         } else {
 683             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 684             s->mv_type = MV_TYPE_8X8;
 685             for(i=0;i<4;i++) {
 686                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 687                 if (s->umvplus)
 688                   mx = h263p_decode_umotion(s, pred_x);
 689                 else
 690                   mx = ff_h263_decode_motion(s, pred_x, 1);
 691                 if (mx >= 0xffff)
 692                     return -1;
 693
 694                 if (s->umvplus)
 695                   my = h263p_decode_umotion(s, pred_y);
 696                 else
 697                   my = ff_h263_decode_motion(s, pred_y, 1);
 698                 if (my >= 0xffff)
 699                     return -1;
 700                 s->mv[0][i][0] = mx;
 701                 s->mv[0][i][1] = my;
 702                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 703                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 704                 mot_val[0] = mx;
 705                 mot_val[1] = my;
 706             }
 707         }
 708     } else if(s->pict_type==AV_PICTURE_TYPE_B) {
 709         int mb_type;
 710         const int stride= s->b8_stride;
 711         int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
 712         int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
 713 //        const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 714
 715         //FIXME ugly
 716         mot_val0[0       ]= mot_val0[2       ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
 717         mot_val0[1       ]= mot_val0[3       ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
 718         mot_val1[0       ]= mot_val1[2       ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
 719         mot_val1[1       ]= mot_val1[3       ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
 720
 721         do{
 722             mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
 723             if (mb_type < 0){
 724                 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
 725                 return -1;
 726             }
 727
 728             mb_type= h263_mb_type_b_map[ mb_type ];
 729         }while(!mb_type);
 730
 731         s->mb_intra = IS_INTRA(mb_type);
 732         if(HAS_CBP(mb_type)){
 733             s->bdsp.clear_blocks(s->block[0]);
 734             cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
 735             if(s->mb_intra){
 736                 dquant = IS_QUANT(mb_type);
 737                 goto intra;
 738             }
 739
 740             cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 741
 742             if (cbpy < 0){
 743                 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 744                 return -1;
 745             }
 746
 747             if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 748                 cbpy ^= 0xF;
 749
 750             cbp = (cbpc & 3) | (cbpy << 2);
 751         }else
 752             cbp=0;
 753
 754         av_assert2(!s->mb_intra);
 755
 756         if(IS_QUANT(mb_type)){
 757             h263_decode_dquant(s);
 758         }
 759
 760         if(IS_DIRECT(mb_type)){
 761             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
 762             mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
 763         }else{
 764             s->mv_dir = 0;
 765             s->mv_type= MV_TYPE_16X16;
 766 //FIXME UMV
 767
 768             if(USES_LIST(mb_type, 0)){
 769                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
 770                 s->mv_dir = MV_DIR_FORWARD;
 771
 772                 mx = ff_h263_decode_motion(s, mx, 1);
 773                 my = ff_h263_decode_motion(s, my, 1);
 774
 775                 s->mv[0][0][0] = mx;
 776                 s->mv[0][0][1] = my;
 777                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 778                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 779             }
 780
 781             if(USES_LIST(mb_type, 1)){
 782                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
 783                 s->mv_dir |= MV_DIR_BACKWARD;
 784
 785                 mx = ff_h263_decode_motion(s, mx, 1);
 786                 my = ff_h263_decode_motion(s, my, 1);
 787
 788                 s->mv[1][0][0] = mx;
 789                 s->mv[1][0][1] = my;
 790                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 791                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 792             }
 793         }
 794
 795         s->current_picture.mb_type[xy] = mb_type;
 796     } else { /* I-Frame */
 797         do{
 798             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 799             if (cbpc < 0){
 800                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 801                 return -1;
 802             }
 803         }while(cbpc == 8);
 804
 805         s->bdsp.clear_blocks(s->block[0]);
 806
 807         dquant = cbpc & 4;
 808         s->mb_intra = 1;
 809 intra:
 810         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 811         if (s->h263_aic) {
 812             s->ac_pred = get_bits1(&s->gb);
 813             if(s->ac_pred){
 814                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
 815
 816                 s->h263_aic_dir = get_bits1(&s->gb);
 817             }
 818         }else
 819             s->ac_pred = 0;
 820
 821         if(s->pb_frame && get_bits1(&s->gb))
 822             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 823         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 824         if(cbpy<0){
 825             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 826             return -1;
 827         }
 828         cbp = (cbpc & 3) | (cbpy << 2);
 829         if (dquant) {
 830             h263_decode_dquant(s);
 831         }
 832
 833         pb_mv_count += !!s->pb_frame;
 834     }
 835
 836     while(pb_mv_count--){
 837         ff_h263_decode_motion(s, 0, 1);
 838         ff_h263_decode_motion(s, 0, 1);
 839     }
 840
 841     /* decode each block */
 842     for (i = 0; i < 6; i++) {
 843         if (h263_decode_block(s, block[i], i, cbp&32) < 0)
 844             return -1;
 845         cbp+=cbp;
 846     }
 847
 848     if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
 849         return -1;
 850     if(s->obmc && !s->mb_intra){
 851         if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
 852             preview_obmc(s);
 853     }
 854 end:
 855
 856         /* per-MB end of slice check */
 857     {
 858         int v= show_bits(&s->gb, 16);
 859
 860         if (get_bits_left(&s->gb) < 16) {
 861             v >>= 16 - get_bits_left(&s->gb);
 862         }
 863
 864         if(v==0)
 865             return SLICE_END;
 866     }
 867
 868     return SLICE_OK;
 869 }
 870
 871 /* most is hardcoded. should extend to handle all h263 streams */
 872 int ff_h263_decode_picture_header(MpegEncContext *s)
 873 {
 874     int format, width, height, i;
 875     uint32_t startcode;
 876
 877     align_get_bits(&s->gb);
 878
 879     if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
 880          av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
 881     }
 882
 883     startcode= get_bits(&s->gb, 22-8);
 884
 885     for(i= get_bits_left(&s->gb); i>24; i-=8) {
 886         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
 887
 888         if(startcode == 0x20)
 889             break;
 890     }
 891
 892     if (startcode != 0x20) {
 893         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
 894         return -1;
 895     }
 896     /* temporal reference */
 897     i = get_bits(&s->gb, 8); /* picture timestamp */
 898     if( (s->picture_number&~0xFF)+i < s->picture_number)
 899         i+= 256;
 900     s->picture_number= (s->picture_number&~0xFF) + i;
 901
 902     /* PTYPE starts here */
 903     if (get_bits1(&s->gb) != 1) {
 904         /* marker */
 905         av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
 906         return -1;
 907     }
 908     if (get_bits1(&s->gb) != 0) {
 909         av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
 910         return -1;      /* h263 id */
 911     }
 912     skip_bits1(&s->gb);         /* split screen off */
 913     skip_bits1(&s->gb);         /* camera  off */
 914     skip_bits1(&s->gb);         /* freeze picture release off */
 915
 916     format = get_bits(&s->gb, 3);
 917     /*
 918         0    forbidden
 919         1    sub-QCIF
 920         10   QCIF
 921         7       extended PTYPE (PLUSPTYPE)
 922     */
 923
 924     if (format != 7 && format != 6) {
 925         s->h263_plus = 0;
 926         /* H.263v1 */
 927         width = ff_h263_format[format][0];
 928         height = ff_h263_format[format][1];
 929         if (!width)
 930             return -1;
 931
 932         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
 933
 934         s->h263_long_vectors = get_bits1(&s->gb);
 935
 936         if (get_bits1(&s->gb) != 0) {
 937             av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
 938             return -1; /* SAC: off */
 939         }
 940         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
 941         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
 942
 943         s->pb_frame = get_bits1(&s->gb);
 944         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
 945         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
 946
 947         s->width = width;
 948         s->height = height;
 949         s->avctx->sample_aspect_ratio= (AVRational){12,11};
 950         s->avctx->time_base= (AVRational){1001, 30000};
 951     } else {
 952         int ufep;
 953
 954         /* H.263v2 */
 955         s->h263_plus = 1;
 956         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
 957
 958         /* ufep other than 0 and 1 are reserved */
 959         if (ufep == 1) {
 960             /* OPPTYPE */
 961             format = get_bits(&s->gb, 3);
 962             av_dlog(s->avctx, "ufep=1, format: %d\n", format);
 963             s->custom_pcf= get_bits1(&s->gb);
 964             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
 965             if (get_bits1(&s->gb) != 0) {
 966                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
 967             }
 968             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
 969             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
 970             s->loop_filter= get_bits1(&s->gb);
 971             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
 972             if(s->avctx->lowres)
 973                 s->loop_filter = 0;
 974
 975             s->h263_slice_structured= get_bits1(&s->gb);
 976             if (get_bits1(&s->gb) != 0) {
 977                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
 978             }
 979             if (get_bits1(&s->gb) != 0) {
 980                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
 981             }
 982             s->alt_inter_vlc= get_bits1(&s->gb);
 983             s->modified_quant= get_bits1(&s->gb);
 984             if(s->modified_quant)
 985                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
 986
 987             skip_bits(&s->gb, 1); /* Prevent start code emulation */
 988
 989             skip_bits(&s->gb, 3); /* Reserved */
 990         } else if (ufep != 0) {
 991             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
 992             return -1;
 993         }
 994
 995         /* MPPTYPE */
 996         s->pict_type = get_bits(&s->gb, 3);
 997         switch(s->pict_type){
 998         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
 999         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1000         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1001         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1002         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1003         default:
1004             return -1;
1005         }
1006         skip_bits(&s->gb, 2);
1007         s->no_rounding = get_bits1(&s->gb);
1008         skip_bits(&s->gb, 4);
1009
1010         /* Get the picture dimensions */
1011         if (ufep) {
1012             if (format == 6) {
1013                 /* Custom Picture Format (CPFMT) */
1014                 s->aspect_ratio_info = get_bits(&s->gb, 4);
1015                 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1016                 /* aspect ratios:
1017                 0 - forbidden
1018                 1 - 1:1
1019                 2 - 12:11 (CIF 4:3)
1020                 3 - 10:11 (525-type 4:3)
1021                 4 - 16:11 (CIF 16:9)
1022                 5 - 40:33 (525-type 16:9)
1023                 6-14 - reserved
1024                 */
1025                 width = (get_bits(&s->gb, 9) + 1) * 4;
1026                 skip_bits1(&s->gb);
1027                 height = get_bits(&s->gb, 9) * 4;
1028                 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1029                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1030                     /* aspected dimensions */
1031                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1032                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1033                 }else{
1034                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1035                 }
1036             } else {
1037                 width = ff_h263_format[format][0];
1038                 height = ff_h263_format[format][1];
1039                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1040             }
1041             s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1042             if ((width == 0) || (height == 0))
1043                 return -1;
1044             s->width = width;
1045             s->height = height;
1046
1047             if(s->custom_pcf){
1048                 int gcd;
1049                 s->avctx->time_base.den= 1800000;
1050                 s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
1051                 s->avctx->time_base.num*= get_bits(&s->gb, 7);
1052                 if(s->avctx->time_base.num == 0){
1053                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
1054                     return -1;
1055                 }
1056                 gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
1057                 s->avctx->time_base.den /= gcd;
1058                 s->avctx->time_base.num /= gcd;
1059             }else{
1060                 s->avctx->time_base= (AVRational){1001, 30000};
1061             }
1062         }
1063
1064         if(s->custom_pcf){
1065             skip_bits(&s->gb, 2); //extended Temporal reference
1066         }
1067
1068         if (ufep) {
1069             if (s->umvplus) {
1070                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1071                     skip_bits1(&s->gb);
1072             }
1073             if(s->h263_slice_structured){
1074                 if (get_bits1(&s->gb) != 0) {
1075                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1076                 }
1077                 if (get_bits1(&s->gb) != 0) {
1078                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1079                 }
1080             }
1081         }
1082
1083         s->qscale = get_bits(&s->gb, 5);
1084     }
1085
1086     if (s->width == 0 || s->height == 0) {
1087         av_log(s->avctx, AV_LOG_ERROR, "dimensions 0\n");
1088         return -1;
1089     }
1090     s->mb_width = (s->width  + 15) / 16;
1091     s->mb_height = (s->height  + 15) / 16;
1092     s->mb_num = s->mb_width * s->mb_height;
1093
1094     if (s->pb_frame) {
1095         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1096         if (s->custom_pcf)
1097             skip_bits(&s->gb, 2); //extended Temporal reference
1098         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1099     }
1100
1101     if (s->pict_type!=AV_PICTURE_TYPE_B) {
1102         s->time            = s->picture_number;
1103         s->pp_time         = s->time - s->last_non_b_time;
1104         s->last_non_b_time = s->time;
1105     }else{
1106         s->time    = s->picture_number;
1107         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1108         if (s->pp_time <=s->pb_time ||
1109             s->pp_time <= s->pp_time - s->pb_time ||
1110             s->pp_time <= 0){
1111             s->pp_time = 2;
1112             s->pb_time = 1;
1113         }
1114         ff_mpeg4_init_direct_mv(s);
1115     }
1116
1117     /* PEI */
1118     if (skip_1stop_8data_bits(&s->gb) < 0)
1119         return AVERROR_INVALIDDATA;
1120
1121     if(s->h263_slice_structured){
1122         if (get_bits1(&s->gb) != 1) {
1123             av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1124             return -1;
1125         }
1126
1127         ff_h263_decode_mba(s);
1128
1129         if (get_bits1(&s->gb) != 1) {
1130             av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1131             return -1;
1132         }
1133     }
1134     s->f_code = 1;
1135
1136     if(s->h263_aic){
1137          s->y_dc_scale_table=
1138          s->c_dc_scale_table= ff_aic_dc_scale_table;
1139     }else{
1140         s->y_dc_scale_table=
1141         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1142     }
1143
1144         ff_h263_show_pict_info(s);
1145     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1146         int i,j;
1147         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1148         av_log(s->avctx, AV_LOG_DEBUG, "\n");
1149         for(i=0; i<13; i++){
1150             for(j=0; j<3; j++){
1151                 int v= get_bits(&s->gb, 8);
1152                 v |= get_sbits(&s->gb, 8)<<8;
1153                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1154             }
1155             av_log(s->avctx, AV_LOG_DEBUG, "\n");
1156         }
1157         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1158     }
1159
1160     return 0;
1161 }