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   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 #define UNCHECKED_BITSTREAM_READER 1
  31 #include <limits.h>
  32
  33 #include "libavutil/attributes.h"
  34 #include "libavutil/internal.h"
  35 #include "libavutil/mathematics.h"
  36 #include "avcodec.h"
  37 #include "mpegvideo.h"
  38 #include "h263.h"
  39 #include "h263data.h"
  40 #include "internal.h"
  41 #include "mathops.h"
  42 #include "mpegutils.h"
  43 #include "unary.h"
  44 #include "flv.h"
  45 #include "rv10.h"
  46 #include "mpeg4video.h"
  47 #include "mpegvideodata.h"
  48
  49 // The defines below define the number of bits that are read at once for
  50 // reading vlc values. Changing these may improve speed and data cache needs
  51 // be aware though that decreasing them may need the number of stages that is
  52 // passed to get_vlc* to be increased.
  53 #define MV_VLC_BITS 9
  54 #define H263_MBTYPE_B_VLC_BITS 6
  55 #define CBPC_B_VLC_BITS 3
  56
  57 static const int h263_mb_type_b_map[15]= {
  58     MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
  59     MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
  60     MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
  61                       MB_TYPE_L0                                 | MB_TYPE_16x16,
  62                       MB_TYPE_L0   | MB_TYPE_CBP                 | MB_TYPE_16x16,
  63                       MB_TYPE_L0   | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
  64                       MB_TYPE_L1                                 | MB_TYPE_16x16,
  65                       MB_TYPE_L1   | MB_TYPE_CBP                 | MB_TYPE_16x16,
  66                       MB_TYPE_L1   | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
  67                       MB_TYPE_L0L1                               | MB_TYPE_16x16,
  68                       MB_TYPE_L0L1 | MB_TYPE_CBP                 | MB_TYPE_16x16,
  69                       MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
  70     0, //stuffing
  71     MB_TYPE_INTRA4x4                | MB_TYPE_CBP,
  72     MB_TYPE_INTRA4x4                | MB_TYPE_CBP | MB_TYPE_QUANT,
  73 };
  74
  75 void ff_h263_show_pict_info(MpegEncContext *s){
  76     if(s->avctx->debug&FF_DEBUG_PICT_INFO){
  77     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",
  78          s->qscale, av_get_picture_type_char(s->pict_type),
  79          s->gb.size_in_bits, 1-s->no_rounding,
  80          s->obmc ? " AP" : "",
  81          s->umvplus ? " UMV" : "",
  82          s->h263_long_vectors ? " LONG" : "",
  83          s->h263_plus ? " +" : "",
  84          s->h263_aic ? " AIC" : "",
  85          s->alt_inter_vlc ? " AIV" : "",
  86          s->modified_quant ? " MQ" : "",
  87          s->loop_filter ? " LOOP" : "",
  88          s->h263_slice_structured ? " SS" : "",
  89          s->avctx->framerate.num, s->avctx->framerate.den
  90     );
  91     }
  92 }
  93
  94 /***********************************************/
  95 /* decoding */
  96
  97 VLC ff_h263_intra_MCBPC_vlc;
  98 VLC ff_h263_inter_MCBPC_vlc;
  99 VLC ff_h263_cbpy_vlc;
 100 static VLC mv_vlc;
 101 static VLC h263_mbtype_b_vlc;
 102 static VLC cbpc_b_vlc;
 103
 104 /* init vlcs */
 105
 106 /* XXX: find a better solution to handle static init */
 107 av_cold void ff_h263_decode_init_vlc(void)
 108 {
 109     static volatile int done = 0;
 110
 111     if (!done) {
 112         INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
 113                  ff_h263_intra_MCBPC_bits, 1, 1,
 114                  ff_h263_intra_MCBPC_code, 1, 1, 72);
 115         INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
 116                  ff_h263_inter_MCBPC_bits, 1, 1,
 117                  ff_h263_inter_MCBPC_code, 1, 1, 198);
 118         INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
 119                  &ff_h263_cbpy_tab[0][1], 2, 1,
 120                  &ff_h263_cbpy_tab[0][0], 2, 1, 64);
 121         INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
 122                  &ff_mvtab[0][1], 2, 1,
 123                  &ff_mvtab[0][0], 2, 1, 538);
 124         ff_rl_init(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
 125         ff_rl_init(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
 126         INIT_VLC_RL(ff_h263_rl_inter, 554);
 127         INIT_VLC_RL(ff_rl_intra_aic, 554);
 128         INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
 129                  &ff_h263_mbtype_b_tab[0][1], 2, 1,
 130                  &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
 131         INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
 132                  &ff_cbpc_b_tab[0][1], 2, 1,
 133                  &ff_cbpc_b_tab[0][0], 2, 1, 8);
 134         done = 1;
 135     }
 136 }
 137
 138 int ff_h263_decode_mba(MpegEncContext *s)
 139 {
 140     int i, mb_pos;
 141
 142     for(i=0; i<6; i++){
 143         if(s->mb_num-1 <= ff_mba_max[i]) break;
 144     }
 145     mb_pos= get_bits(&s->gb, ff_mba_length[i]);
 146     s->mb_x= mb_pos % s->mb_width;
 147     s->mb_y= mb_pos / s->mb_width;
 148
 149     return mb_pos;
 150 }
 151
 152 /**
 153  * Decode the group of blocks header or slice header.
 154  * @return <0 if an error occurred
 155  */
 156 static int h263_decode_gob_header(MpegEncContext *s)
 157 {
 158     unsigned int val, gob_number;
 159     int left;
 160
 161     /* Check for GOB Start Code */
 162     val = show_bits(&s->gb, 16);
 163     if(val)
 164         return -1;
 165
 166         /* We have a GBSC probably with GSTUFF */
 167     skip_bits(&s->gb, 16); /* Drop the zeros */
 168     left= get_bits_left(&s->gb);
 169     //MN: we must check the bits left or we might end in a infinite loop (or segfault)
 170     for(;left>13; left--){
 171         if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
 172     }
 173     if(left<=13)
 174         return -1;
 175
 176     if(s->h263_slice_structured){
 177         if(check_marker(&s->gb, "before MBA")==0)
 178             return -1;
 179
 180         ff_h263_decode_mba(s);
 181
 182         if(s->mb_num > 1583)
 183             if(check_marker(&s->gb, "after MBA")==0)
 184                 return -1;
 185
 186         s->qscale = get_bits(&s->gb, 5); /* SQUANT */
 187         if(check_marker(&s->gb, "after SQUANT")==0)
 188             return -1;
 189         skip_bits(&s->gb, 2); /* GFID */
 190     }else{
 191         gob_number = get_bits(&s->gb, 5); /* GN */
 192         s->mb_x= 0;
 193         s->mb_y= s->gob_index* gob_number;
 194         skip_bits(&s->gb, 2); /* GFID */
 195         s->qscale = get_bits(&s->gb, 5); /* GQUANT */
 196     }
 197
 198     if(s->mb_y >= s->mb_height)
 199         return -1;
 200
 201     if(s->qscale==0)
 202         return -1;
 203
 204     return 0;
 205 }
 206
 207 /**
 208  * Decode the group of blocks / video packet header.
 209  * @return bit position of the resync_marker, or <0 if none was found
 210  */
 211 int ff_h263_resync(MpegEncContext *s){
 212     int left, pos, ret;
 213
 214     if(s->codec_id==AV_CODEC_ID_MPEG4){
 215         skip_bits1(&s->gb);
 216         align_get_bits(&s->gb);
 217     }
 218
 219     if(show_bits(&s->gb, 16)==0){
 220         pos= get_bits_count(&s->gb);
 221         if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 222             ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 223         else
 224             ret= h263_decode_gob_header(s);
 225         if(ret>=0)
 226             return pos;
 227     }
 228     //OK, it's not where it is supposed to be ...
 229     s->gb= s->last_resync_gb;
 230     align_get_bits(&s->gb);
 231     left= get_bits_left(&s->gb);
 232
 233     for(;left>16+1+5+5; left-=8){
 234         if(show_bits(&s->gb, 16)==0){
 235             GetBitContext bak= s->gb;
 236
 237             pos= get_bits_count(&s->gb);
 238             if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 239                 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 240             else
 241                 ret= h263_decode_gob_header(s);
 242             if(ret>=0)
 243                 return pos;
 244
 245             s->gb= bak;
 246         }
 247         skip_bits(&s->gb, 8);
 248     }
 249
 250     return -1;
 251 }
 252
 253 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
 254 {
 255     int code, val, sign, shift;
 256     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
 257
 258     if (code == 0)
 259         return pred;
 260     if (code < 0)
 261         return 0xffff;
 262
 263     sign = get_bits1(&s->gb);
 264     shift = f_code - 1;
 265     val = code;
 266     if (shift) {
 267         val = (val - 1) << shift;
 268         val |= get_bits(&s->gb, shift);
 269         val++;
 270     }
 271     if (sign)
 272         val = -val;
 273     val += pred;
 274
 275     /* modulo decoding */
 276     if (!s->h263_long_vectors) {
 277         val = sign_extend(val, 5 + f_code);
 278     } else {
 279         /* horrible h263 long vector mode */
 280         if (pred < -31 && val < -63)
 281             val += 64;
 282         if (pred > 32 && val > 63)
 283             val -= 64;
 284
 285     }
 286     return val;
 287 }
 288
 289
 290 /* Decode RVLC of H.263+ UMV */
 291 static int h263p_decode_umotion(MpegEncContext * s, int pred)
 292 {
 293    int code = 0, sign;
 294
 295    if (get_bits1(&s->gb)) /* Motion difference = 0 */
 296       return pred;
 297
 298    code = 2 + get_bits1(&s->gb);
 299
 300    while (get_bits1(&s->gb))
 301    {
 302       code <<= 1;
 303       code += get_bits1(&s->gb);
 304    }
 305    sign = code & 1;
 306    code >>= 1;
 307
 308    code = (sign) ? (pred - code) : (pred + code);
 309    ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
 310    return code;
 311
 312 }
 313
 314 /**
 315  * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
 316  */
 317 static void preview_obmc(MpegEncContext *s){
 318     GetBitContext gb= s->gb;
 319
 320     int cbpc, i, pred_x, pred_y, mx, my;
 321     int16_t *mot_val;
 322     const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 323     const int stride= s->b8_stride*2;
 324
 325     for(i=0; i<4; i++)
 326         s->block_index[i]+= 2;
 327     for(i=4; i<6; i++)
 328         s->block_index[i]+= 1;
 329     s->mb_x++;
 330
 331     av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
 332
 333     do{
 334         if (get_bits1(&s->gb)) {
 335             /* skip mb */
 336             mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 337             mot_val[0       ]= mot_val[2       ]=
 338             mot_val[0+stride]= mot_val[2+stride]= 0;
 339             mot_val[1       ]= mot_val[3       ]=
 340             mot_val[1+stride]= mot_val[3+stride]= 0;
 341
 342             s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 343             goto end;
 344         }
 345         cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 346     }while(cbpc == 20);
 347
 348     if(cbpc & 4){
 349         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 350     }else{
 351         get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 352         if (cbpc & 8) {
 353             if(s->modified_quant){
 354                 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
 355                 else                  skip_bits(&s->gb, 5);
 356             }else
 357                 skip_bits(&s->gb, 2);
 358         }
 359
 360         if ((cbpc & 16) == 0) {
 361                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 362                 /* 16x16 motion prediction */
 363                 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 364                 if (s->umvplus)
 365                    mx = h263p_decode_umotion(s, pred_x);
 366                 else
 367                    mx = ff_h263_decode_motion(s, pred_x, 1);
 368
 369                 if (s->umvplus)
 370                    my = h263p_decode_umotion(s, pred_y);
 371                 else
 372                    my = ff_h263_decode_motion(s, pred_y, 1);
 373
 374                 mot_val[0       ]= mot_val[2       ]=
 375                 mot_val[0+stride]= mot_val[2+stride]= mx;
 376                 mot_val[1       ]= mot_val[3       ]=
 377                 mot_val[1+stride]= mot_val[3+stride]= my;
 378         } else {
 379             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 380             for(i=0;i<4;i++) {
 381                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 382                 if (s->umvplus)
 383                   mx = h263p_decode_umotion(s, pred_x);
 384                 else
 385                   mx = ff_h263_decode_motion(s, pred_x, 1);
 386
 387                 if (s->umvplus)
 388                   my = h263p_decode_umotion(s, pred_y);
 389                 else
 390                   my = ff_h263_decode_motion(s, pred_y, 1);
 391                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 392                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 393                 mot_val[0] = mx;
 394                 mot_val[1] = my;
 395             }
 396         }
 397     }
 398 end:
 399
 400     for(i=0; i<4; i++)
 401         s->block_index[i]-= 2;
 402     for(i=4; i<6; i++)
 403         s->block_index[i]-= 1;
 404     s->mb_x--;
 405
 406     s->gb= gb;
 407 }
 408
 409 static void h263_decode_dquant(MpegEncContext *s){
 410     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 411
 412     if(s->modified_quant){
 413         if(get_bits1(&s->gb))
 414             s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
 415         else
 416             s->qscale= get_bits(&s->gb, 5);
 417     }else
 418         s->qscale += quant_tab[get_bits(&s->gb, 2)];
 419     ff_set_qscale(s, s->qscale);
 420 }
 421
 422 static int h263_decode_block(MpegEncContext * s, int16_t * block,
 423                              int n, int coded)
 424 {
 425     int level, i, j, run;
 426     RLTable *rl = &ff_h263_rl_inter;
 427     const uint8_t *scan_table;
 428     GetBitContext gb= s->gb;
 429
 430     scan_table = s->intra_scantable.permutated;
 431     if (s->h263_aic && s->mb_intra) {
 432         rl = &ff_rl_intra_aic;
 433         i = 0;
 434         if (s->ac_pred) {
 435             if (s->h263_aic_dir)
 436                 scan_table = s->intra_v_scantable.permutated; /* left */
 437             else
 438                 scan_table = s->intra_h_scantable.permutated; /* top */
 439         }
 440     } else if (s->mb_intra) {
 441         /* DC coef */
 442         if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
 443           if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
 444             int component, diff;
 445             component = (n <= 3 ? 0 : n - 4 + 1);
 446             level = s->last_dc[component];
 447             if (s->rv10_first_dc_coded[component]) {
 448                 diff = ff_rv_decode_dc(s, n);
 449                 if (diff == 0xffff)
 450                     return -1;
 451                 level += diff;
 452                 level = level & 0xff; /* handle wrap round */
 453                 s->last_dc[component] = level;
 454             } else {
 455                 s->rv10_first_dc_coded[component] = 1;
 456             }
 457           } else {
 458                 level = get_bits(&s->gb, 8);
 459                 if (level == 255)
 460                     level = 128;
 461           }
 462         }else{
 463             level = get_bits(&s->gb, 8);
 464             if((level&0x7F) == 0){
 465                 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
 466                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
 467                     return -1;
 468             }
 469             if (level == 255)
 470                 level = 128;
 471         }
 472         block[0] = level;
 473         i = 1;
 474     } else {
 475         i = 0;
 476     }
 477     if (!coded) {
 478         if (s->mb_intra && s->h263_aic)
 479             goto not_coded;
 480         s->block_last_index[n] = i - 1;
 481         return 0;
 482     }
 483 retry:
 484     {
 485     OPEN_READER(re, &s->gb);
 486     i--; // offset by -1 to allow direct indexing of scan_table
 487     for(;;) {
 488         UPDATE_CACHE(re, &s->gb);
 489         GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 490         if (run == 66) {
 491             if (level){
 492                 CLOSE_READER(re, &s->gb);
 493                 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
 494                 return -1;
 495             }
 496             /* escape */
 497             if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
 498                 int is11 = SHOW_UBITS(re, &s->gb, 1);
 499                 SKIP_CACHE(re, &s->gb, 1);
 500                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 501                 if (is11) {
 502                     SKIP_COUNTER(re, &s->gb, 1 + 7);
 503                     UPDATE_CACHE(re, &s->gb);
 504                     level = SHOW_SBITS(re, &s->gb, 11);
 505                     SKIP_COUNTER(re, &s->gb, 11);
 506                 } else {
 507                     SKIP_CACHE(re, &s->gb, 7);
 508                     level = SHOW_SBITS(re, &s->gb, 7);
 509                     SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
 510                 }
 511             } else {
 512                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 513                 SKIP_CACHE(re, &s->gb, 7);
 514                 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
 515                 SKIP_COUNTER(re, &s->gb, 7 + 8);
 516                 if(level == -128){
 517                     UPDATE_CACHE(re, &s->gb);
 518                     if (s->codec_id == AV_CODEC_ID_RV10) {
 519                         /* XXX: should patch encoder too */
 520                         level = SHOW_SBITS(re, &s->gb, 12);
 521                         SKIP_COUNTER(re, &s->gb, 12);
 522                     }else{
 523                         level = SHOW_UBITS(re, &s->gb, 5);
 524                         SKIP_CACHE(re, &s->gb, 5);
 525                         level |= SHOW_SBITS(re, &s->gb, 6)<<5;
 526                         SKIP_COUNTER(re, &s->gb, 5 + 6);
 527                     }
 528                 }
 529             }
 530         } else {
 531             if (SHOW_UBITS(re, &s->gb, 1))
 532                 level = -level;
 533             SKIP_COUNTER(re, &s->gb, 1);
 534         }
 535         i += run;
 536         if (i >= 64){
 537             CLOSE_READER(re, &s->gb);
 538             // redo update without last flag, revert -1 offset
 539             i = i - run + ((run-1)&63) + 1;
 540             if (i < 64) {
 541                 // only last marker, no overrun
 542                 block[scan_table[i]] = level;
 543                 break;
 544             }
 545             if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
 546                 //Looks like a hack but no, it's the way it is supposed to work ...
 547                 rl = &ff_rl_intra_aic;
 548                 i = 0;
 549                 s->gb= gb;
 550                 s->bdsp.clear_block(block);
 551                 goto retry;
 552             }
 553             av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
 554             return -1;
 555         }
 556         j = scan_table[i];
 557         block[j] = level;
 558     }
 559     }
 560 not_coded:
 561     if (s->mb_intra && s->h263_aic) {
 562         ff_h263_pred_acdc(s, block, n);
 563         i = 63;
 564     }
 565     s->block_last_index[n] = i;
 566     return 0;
 567 }
 568
 569 static int h263_skip_b_part(MpegEncContext *s, int cbp)
 570 {
 571     LOCAL_ALIGNED_16(int16_t, dblock, [64]);
 572     int i, mbi;
 573     int bli[6];
 574
 575     /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
 576      * but real value should be restored in order to be used later (in OBMC condition)
 577      */
 578     mbi = s->mb_intra;
 579     memcpy(bli, s->block_last_index, sizeof(bli));
 580     s->mb_intra = 0;
 581     for (i = 0; i < 6; i++) {
 582         if (h263_decode_block(s, dblock, i, cbp&32) < 0)
 583             return -1;
 584         cbp+=cbp;
 585     }
 586     s->mb_intra = mbi;
 587     memcpy(s->block_last_index, bli, sizeof(bli));
 588     return 0;
 589 }
 590
 591 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
 592 {
 593     int c, mv = 1;
 594
 595     if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
 596         c = get_bits1(gb);
 597         if (pb_frame == 2 && c)
 598             mv = !get_bits1(gb);
 599     } else { // h.263 Annex M improved PB-frame
 600         mv = get_unary(gb, 0, 4) + 1;
 601         c = mv & 1;
 602         mv = !!(mv & 2);
 603     }
 604     if(c)
 605         *cbpb = get_bits(gb, 6);
 606     return mv;
 607 }
 608
 609 int ff_h263_decode_mb(MpegEncContext *s,
 610                       int16_t block[6][64])
 611 {
 612     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
 613     int16_t *mot_val;
 614     const int xy= s->mb_x + s->mb_y * s->mb_stride;
 615     int cbpb = 0, pb_mv_count = 0;
 616
 617     av_assert2(!s->h263_pred);
 618
 619     if (s->pict_type == AV_PICTURE_TYPE_P) {
 620         do{
 621             if (get_bits1(&s->gb)) {
 622                 /* skip mb */
 623                 s->mb_intra = 0;
 624                 for(i=0;i<6;i++)
 625                     s->block_last_index[i] = -1;
 626                 s->mv_dir = MV_DIR_FORWARD;
 627                 s->mv_type = MV_TYPE_16X16;
 628                 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 629                 s->mv[0][0][0] = 0;
 630                 s->mv[0][0][1] = 0;
 631                 s->mb_skipped = !(s->obmc | s->loop_filter);
 632                 goto end;
 633             }
 634             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 635             if (cbpc < 0){
 636                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 637                 return -1;
 638             }
 639         }while(cbpc == 20);
 640
 641         s->bdsp.clear_blocks(s->block[0]);
 642
 643         dquant = cbpc & 8;
 644         s->mb_intra = ((cbpc & 4) != 0);
 645         if (s->mb_intra) goto intra;
 646
 647         if(s->pb_frame && get_bits1(&s->gb))
 648             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 649         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 650
 651         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 652             cbpy ^= 0xF;
 653
 654         cbp = (cbpc & 3) | (cbpy << 2);
 655         if (dquant) {
 656             h263_decode_dquant(s);
 657         }
 658
 659         s->mv_dir = MV_DIR_FORWARD;
 660         if ((cbpc & 16) == 0) {
 661             s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 662             /* 16x16 motion prediction */
 663             s->mv_type = MV_TYPE_16X16;
 664             ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 665             if (s->umvplus)
 666                mx = h263p_decode_umotion(s, pred_x);
 667             else
 668                mx = ff_h263_decode_motion(s, pred_x, 1);
 669
 670             if (mx >= 0xffff)
 671                 return -1;
 672
 673             if (s->umvplus)
 674                my = h263p_decode_umotion(s, pred_y);
 675             else
 676                my = ff_h263_decode_motion(s, pred_y, 1);
 677
 678             if (my >= 0xffff)
 679                 return -1;
 680             s->mv[0][0][0] = mx;
 681             s->mv[0][0][1] = my;
 682
 683             if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 684                skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 685         } else {
 686             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 687             s->mv_type = MV_TYPE_8X8;
 688             for(i=0;i<4;i++) {
 689                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 690                 if (s->umvplus)
 691                   mx = h263p_decode_umotion(s, pred_x);
 692                 else
 693                   mx = ff_h263_decode_motion(s, pred_x, 1);
 694                 if (mx >= 0xffff)
 695                     return -1;
 696
 697                 if (s->umvplus)
 698                   my = h263p_decode_umotion(s, pred_y);
 699                 else
 700                   my = ff_h263_decode_motion(s, pred_y, 1);
 701                 if (my >= 0xffff)
 702                     return -1;
 703                 s->mv[0][i][0] = mx;
 704                 s->mv[0][i][1] = my;
 705                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 706                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 707                 mot_val[0] = mx;
 708                 mot_val[1] = my;
 709             }
 710         }
 711     } else if(s->pict_type==AV_PICTURE_TYPE_B) {
 712         int mb_type;
 713         const int stride= s->b8_stride;
 714         int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
 715         int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
 716 //        const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 717
 718         //FIXME ugly
 719         mot_val0[0       ]= mot_val0[2       ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
 720         mot_val0[1       ]= mot_val0[3       ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
 721         mot_val1[0       ]= mot_val1[2       ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
 722         mot_val1[1       ]= mot_val1[3       ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
 723
 724         do{
 725             mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
 726             if (mb_type < 0){
 727                 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
 728                 return -1;
 729             }
 730
 731             mb_type= h263_mb_type_b_map[ mb_type ];
 732         }while(!mb_type);
 733
 734         s->mb_intra = IS_INTRA(mb_type);
 735         if(HAS_CBP(mb_type)){
 736             s->bdsp.clear_blocks(s->block[0]);
 737             cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
 738             if(s->mb_intra){
 739                 dquant = IS_QUANT(mb_type);
 740                 goto intra;
 741             }
 742
 743             cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 744
 745             if (cbpy < 0){
 746                 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 747                 return -1;
 748             }
 749
 750             if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 751                 cbpy ^= 0xF;
 752
 753             cbp = (cbpc & 3) | (cbpy << 2);
 754         }else
 755             cbp=0;
 756
 757         av_assert2(!s->mb_intra);
 758
 759         if(IS_QUANT(mb_type)){
 760             h263_decode_dquant(s);
 761         }
 762
 763         if(IS_DIRECT(mb_type)){
 764             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
 765             mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
 766         }else{
 767             s->mv_dir = 0;
 768             s->mv_type= MV_TYPE_16X16;
 769 //FIXME UMV
 770
 771             if(USES_LIST(mb_type, 0)){
 772                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
 773                 s->mv_dir = MV_DIR_FORWARD;
 774
 775                 mx = ff_h263_decode_motion(s, mx, 1);
 776                 my = ff_h263_decode_motion(s, my, 1);
 777
 778                 s->mv[0][0][0] = mx;
 779                 s->mv[0][0][1] = my;
 780                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 781                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 782             }
 783
 784             if(USES_LIST(mb_type, 1)){
 785                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
 786                 s->mv_dir |= MV_DIR_BACKWARD;
 787
 788                 mx = ff_h263_decode_motion(s, mx, 1);
 789                 my = ff_h263_decode_motion(s, my, 1);
 790
 791                 s->mv[1][0][0] = mx;
 792                 s->mv[1][0][1] = my;
 793                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 794                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 795             }
 796         }
 797
 798         s->current_picture.mb_type[xy] = mb_type;
 799     } else { /* I-Frame */
 800         do{
 801             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 802             if (cbpc < 0){
 803                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 804                 return -1;
 805             }
 806         }while(cbpc == 8);
 807
 808         s->bdsp.clear_blocks(s->block[0]);
 809
 810         dquant = cbpc & 4;
 811         s->mb_intra = 1;
 812 intra:
 813         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 814         if (s->h263_aic) {
 815             s->ac_pred = get_bits1(&s->gb);
 816             if(s->ac_pred){
 817                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
 818
 819                 s->h263_aic_dir = get_bits1(&s->gb);
 820             }
 821         }else
 822             s->ac_pred = 0;
 823
 824         if(s->pb_frame && get_bits1(&s->gb))
 825             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 826         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 827         if(cbpy<0){
 828             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 829             return -1;
 830         }
 831         cbp = (cbpc & 3) | (cbpy << 2);
 832         if (dquant) {
 833             h263_decode_dquant(s);
 834         }
 835
 836         pb_mv_count += !!s->pb_frame;
 837     }
 838
 839     while(pb_mv_count--){
 840         ff_h263_decode_motion(s, 0, 1);
 841         ff_h263_decode_motion(s, 0, 1);
 842     }
 843
 844     /* decode each block */
 845     for (i = 0; i < 6; i++) {
 846         if (h263_decode_block(s, block[i], i, cbp&32) < 0)
 847             return -1;
 848         cbp+=cbp;
 849     }
 850
 851     if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
 852         return -1;
 853     if(s->obmc && !s->mb_intra){
 854         if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
 855             preview_obmc(s);
 856     }
 857 end:
 858
 859         /* per-MB end of slice check */
 860     {
 861         int v= show_bits(&s->gb, 16);
 862
 863         if (get_bits_left(&s->gb) < 16) {
 864             v >>= 16 - get_bits_left(&s->gb);
 865         }
 866
 867         if(v==0)
 868             return SLICE_END;
 869     }
 870
 871     return SLICE_OK;
 872 }
 873
 874 /* most is hardcoded. should extend to handle all h263 streams */
 875 int ff_h263_decode_picture_header(MpegEncContext *s)
 876 {
 877     int format, width, height, i;
 878     uint32_t startcode;
 879
 880     align_get_bits(&s->gb);
 881
 882     if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
 883          av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
 884     }
 885
 886     startcode= get_bits(&s->gb, 22-8);
 887
 888     for(i= get_bits_left(&s->gb); i>24; i-=8) {
 889         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
 890
 891         if(startcode == 0x20)
 892             break;
 893     }
 894
 895     if (startcode != 0x20) {
 896         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
 897         return -1;
 898     }
 899     /* temporal reference */
 900     i = get_bits(&s->gb, 8); /* picture timestamp */
 901     if( (s->picture_number&~0xFF)+i < s->picture_number)
 902         i+= 256;
 903     s->picture_number= (s->picture_number&~0xFF) + i;
 904
 905     /* PTYPE starts here */
 906     if (check_marker(&s->gb, "in PTYPE") != 1) {
 907         return -1;
 908     }
 909     if (get_bits1(&s->gb) != 0) {
 910         av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
 911         return -1;      /* h263 id */
 912     }
 913     skip_bits1(&s->gb);         /* split screen off */
 914     skip_bits1(&s->gb);         /* camera  off */
 915     skip_bits1(&s->gb);         /* freeze picture release off */
 916
 917     format = get_bits(&s->gb, 3);
 918     /*
 919         0    forbidden
 920         1    sub-QCIF
 921         10   QCIF
 922         7       extended PTYPE (PLUSPTYPE)
 923     */
 924
 925     if (format != 7 && format != 6) {
 926         s->h263_plus = 0;
 927         /* H.263v1 */
 928         width = ff_h263_format[format][0];
 929         height = ff_h263_format[format][1];
 930         if (!width)
 931             return -1;
 932
 933         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
 934
 935         s->h263_long_vectors = get_bits1(&s->gb);
 936
 937         if (get_bits1(&s->gb) != 0) {
 938             av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
 939             return -1; /* SAC: off */
 940         }
 941         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
 942         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
 943
 944         s->pb_frame = get_bits1(&s->gb);
 945         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
 946         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
 947
 948         s->width = width;
 949         s->height = height;
 950         s->avctx->sample_aspect_ratio= (AVRational){12,11};
 951         s->avctx->framerate = (AVRational){ 30000, 1001 };
 952     } else {
 953         int ufep;
 954
 955         /* H.263v2 */
 956         s->h263_plus = 1;
 957         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
 958
 959         /* ufep other than 0 and 1 are reserved */
 960         if (ufep == 1) {
 961             /* OPPTYPE */
 962             format = get_bits(&s->gb, 3);
 963             ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
 964             s->custom_pcf= get_bits1(&s->gb);
 965             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
 966             if (get_bits1(&s->gb) != 0) {
 967                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
 968             }
 969             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
 970             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
 971             s->loop_filter= get_bits1(&s->gb);
 972             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
 973             if(s->avctx->lowres)
 974                 s->loop_filter = 0;
 975
 976             s->h263_slice_structured= get_bits1(&s->gb);
 977             if (get_bits1(&s->gb) != 0) {
 978                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
 979             }
 980             if (get_bits1(&s->gb) != 0) {
 981                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
 982             }
 983             s->alt_inter_vlc= get_bits1(&s->gb);
 984             s->modified_quant= get_bits1(&s->gb);
 985             if(s->modified_quant)
 986                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
 987
 988             skip_bits(&s->gb, 1); /* Prevent start code emulation */
 989
 990             skip_bits(&s->gb, 3); /* Reserved */
 991         } else if (ufep != 0) {
 992             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
 993             return -1;
 994         }
 995
 996         /* MPPTYPE */
 997         s->pict_type = get_bits(&s->gb, 3);
 998         switch(s->pict_type){
 999         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1000         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1001         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1002         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1003         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1004         default:
1005             return -1;
1006         }
1007         skip_bits(&s->gb, 2);
1008         s->no_rounding = get_bits1(&s->gb);
1009         skip_bits(&s->gb, 4);
1010
1011         /* Get the picture dimensions */
1012         if (ufep) {
1013             if (format == 6) {
1014                 /* Custom Picture Format (CPFMT) */
1015                 s->aspect_ratio_info = get_bits(&s->gb, 4);
1016                 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1017                 /* aspect ratios:
1018                 0 - forbidden
1019                 1 - 1:1
1020                 2 - 12:11 (CIF 4:3)
1021                 3 - 10:11 (525-type 4:3)
1022                 4 - 16:11 (CIF 16:9)
1023                 5 - 40:33 (525-type 16:9)
1024                 6-14 - reserved
1025                 */
1026                 width = (get_bits(&s->gb, 9) + 1) * 4;
1027                 check_marker(&s->gb, "in dimensions");
1028                 height = get_bits(&s->gb, 9) * 4;
1029                 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1030                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1031                     /* aspected dimensions */
1032                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1033                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1034                 }else{
1035                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1036                 }
1037             } else {
1038                 width = ff_h263_format[format][0];
1039                 height = ff_h263_format[format][1];
1040                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1041             }
1042             s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1043             if ((width == 0) || (height == 0))
1044                 return -1;
1045             s->width = width;
1046             s->height = height;
1047
1048             if(s->custom_pcf){
1049                 int gcd;
1050                 s->avctx->framerate.num  = 1800000;
1051                 s->avctx->framerate.den  = 1000 + get_bits1(&s->gb);
1052                 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1053                 if(s->avctx->framerate.den == 0){
1054                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
1055                     return -1;
1056                 }
1057                 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1058                 s->avctx->framerate.den /= gcd;
1059                 s->avctx->framerate.num /= gcd;
1060             }else{
1061                 s->avctx->framerate = (AVRational){ 30000, 1001 };
1062             }
1063         }
1064
1065         if(s->custom_pcf){
1066             skip_bits(&s->gb, 2); //extended Temporal reference
1067         }
1068
1069         if (ufep) {
1070             if (s->umvplus) {
1071                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1072                     skip_bits1(&s->gb);
1073             }
1074             if(s->h263_slice_structured){
1075                 if (get_bits1(&s->gb) != 0) {
1076                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1077                 }
1078                 if (get_bits1(&s->gb) != 0) {
1079                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1080                 }
1081             }
1082         }
1083
1084         s->qscale = get_bits(&s->gb, 5);
1085     }
1086
1087     if (s->width == 0 || s->height == 0) {
1088         av_log(s->avctx, AV_LOG_ERROR, "dimensions 0\n");
1089         return -1;
1090     }
1091     s->mb_width = (s->width  + 15) / 16;
1092     s->mb_height = (s->height  + 15) / 16;
1093     s->mb_num = s->mb_width * s->mb_height;
1094
1095     if (s->pb_frame) {
1096         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1097         if (s->custom_pcf)
1098             skip_bits(&s->gb, 2); //extended Temporal reference
1099         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1100     }
1101
1102     if (s->pict_type!=AV_PICTURE_TYPE_B) {
1103         s->time            = s->picture_number;
1104         s->pp_time         = s->time - s->last_non_b_time;
1105         s->last_non_b_time = s->time;
1106     }else{
1107         s->time    = s->picture_number;
1108         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1109         if (s->pp_time <=s->pb_time ||
1110             s->pp_time <= s->pp_time - s->pb_time ||
1111             s->pp_time <= 0){
1112             s->pp_time = 2;
1113             s->pb_time = 1;
1114         }
1115         ff_mpeg4_init_direct_mv(s);
1116     }
1117
1118     /* PEI */
1119     if (skip_1stop_8data_bits(&s->gb) < 0)
1120         return AVERROR_INVALIDDATA;
1121
1122     if(s->h263_slice_structured){
1123         if (check_marker(&s->gb, "SEPB1") != 1) {
1124             return -1;
1125         }
1126
1127         ff_h263_decode_mba(s);
1128
1129         if (check_marker(&s->gb, "SEPB2") != 1) {
1130             return -1;
1131         }
1132     }
1133     s->f_code = 1;
1134
1135     if(s->h263_aic){
1136          s->y_dc_scale_table=
1137          s->c_dc_scale_table= ff_aic_dc_scale_table;
1138     }else{
1139         s->y_dc_scale_table=
1140         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1141     }
1142
1143         ff_h263_show_pict_info(s);
1144     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1145         int i,j;
1146         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1147         av_log(s->avctx, AV_LOG_DEBUG, "\n");
1148         for(i=0; i<13; i++){
1149             for(j=0; j<3; j++){
1150                 int v= get_bits(&s->gb, 8);
1151                 v |= get_sbits(&s->gb, 8)<<8;
1152                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1153             }
1154             av_log(s->avctx, AV_LOG_DEBUG, "\n");
1155         }
1156         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1157     }
1158
1159     return 0;
1160 }