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