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   1 /*
   2  * ITU H.263 bitstream decoder
   3  * Copyright (c) 2000,2001 Fabrice Bellard
   4  * H.263+ 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  * H.263 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 "libavutil/mem_internal.h"
  38 #include "avcodec.h"
  39 #include "mpegvideo.h"
  40 #include "h263.h"
  41 #include "h263data.h"
  42 #include "internal.h"
  43 #include "mathops.h"
  44 #include "mpegutils.h"
  45 #include "unary.h"
  46 #include "flv.h"
  47 #include "rv10.h"
  48 #include "mpeg4video.h"
  49 #include "mpegvideodata.h"
  50
  51 // The defines below define the number of bits that are read at once for
  52 // reading vlc values. Changing these may improve speed and data cache needs
  53 // be aware though that decreasing them may need the number of stages that is
  54 // passed to get_vlc* to be increased.
  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 VLC ff_h263_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(&ff_h263_mv_vlc, H263_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_FIRST_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     left = FFMIN(left, 32);
 171     //MN: we must check the bits left or we might end in an infinite loop (or segfault)
 172     for(;left>13; left--){
 173         if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
 174     }
 175     if(left<=13)
 176         return -1;
 177
 178     if(s->h263_slice_structured){
 179         if(check_marker(s->avctx, &s->gb, "before MBA")==0)
 180             return -1;
 181
 182         ff_h263_decode_mba(s);
 183
 184         if(s->mb_num > 1583)
 185             if(check_marker(s->avctx, &s->gb, "after MBA")==0)
 186                 return -1;
 187
 188         s->qscale = get_bits(&s->gb, 5); /* SQUANT */
 189         if(check_marker(s->avctx, &s->gb, "after SQUANT")==0)
 190             return -1;
 191         skip_bits(&s->gb, 2); /* GFID */
 192     }else{
 193         gob_number = get_bits(&s->gb, 5); /* GN */
 194         s->mb_x= 0;
 195         s->mb_y= s->gob_index* gob_number;
 196         skip_bits(&s->gb, 2); /* GFID */
 197         s->qscale = get_bits(&s->gb, 5); /* GQUANT */
 198     }
 199
 200     if(s->mb_y >= s->mb_height)
 201         return -1;
 202
 203     if(s->qscale==0)
 204         return -1;
 205
 206     return 0;
 207 }
 208
 209 /**
 210  * Decode the group of blocks / video packet header / slice header (MPEG-4 Studio).
 211  * @return bit position of the resync_marker, or <0 if none was found
 212  */
 213 int ff_h263_resync(MpegEncContext *s){
 214     int left, pos, ret;
 215
 216     /* In MPEG-4 studio mode look for a new slice startcode
 217      * and decode slice header */
 218     if(s->codec_id==AV_CODEC_ID_MPEG4 && s->studio_profile) {
 219         align_get_bits(&s->gb);
 220
 221         while (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) != SLICE_START_CODE) {
 222             get_bits(&s->gb, 8);
 223         }
 224
 225         if (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) == SLICE_START_CODE)
 226             return get_bits_count(&s->gb);
 227         else
 228             return -1;
 229     }
 230
 231     if(s->codec_id==AV_CODEC_ID_MPEG4){
 232         skip_bits1(&s->gb);
 233         align_get_bits(&s->gb);
 234     }
 235
 236     if(show_bits(&s->gb, 16)==0){
 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     //OK, it's not where it is supposed to be ...
 246     s->gb= s->last_resync_gb;
 247     align_get_bits(&s->gb);
 248     left= get_bits_left(&s->gb);
 249
 250     for(;left>16+1+5+5; left-=8){
 251         if(show_bits(&s->gb, 16)==0){
 252             GetBitContext bak= s->gb;
 253
 254             pos= get_bits_count(&s->gb);
 255             if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 256                 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 257             else
 258                 ret= h263_decode_gob_header(s);
 259             if(ret>=0)
 260                 return pos;
 261
 262             s->gb= bak;
 263         }
 264         skip_bits(&s->gb, 8);
 265     }
 266
 267     return -1;
 268 }
 269
 270 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
 271 {
 272     int code, val, sign, shift;
 273     code = get_vlc2(&s->gb, ff_h263_mv_vlc.table, H263_MV_VLC_BITS, 2);
 274
 275     if (code == 0)
 276         return pred;
 277     if (code < 0)
 278         return 0xffff;
 279
 280     sign = get_bits1(&s->gb);
 281     shift = f_code - 1;
 282     val = code;
 283     if (shift) {
 284         val = (val - 1) << shift;
 285         val |= get_bits(&s->gb, shift);
 286         val++;
 287     }
 288     if (sign)
 289         val = -val;
 290     val += pred;
 291
 292     /* modulo decoding */
 293     if (!s->h263_long_vectors) {
 294         val = sign_extend(val, 5 + f_code);
 295     } else {
 296         /* horrible H.263 long vector mode */
 297         if (pred < -31 && val < -63)
 298             val += 64;
 299         if (pred > 32 && val > 63)
 300             val -= 64;
 301
 302     }
 303     return val;
 304 }
 305
 306
 307 /* Decode RVLC of H.263+ UMV */
 308 static int h263p_decode_umotion(MpegEncContext * s, int pred)
 309 {
 310    int code = 0, sign;
 311
 312    if (get_bits1(&s->gb)) /* Motion difference = 0 */
 313       return pred;
 314
 315    code = 2 + get_bits1(&s->gb);
 316
 317    while (get_bits1(&s->gb))
 318    {
 319       code <<= 1;
 320       code += get_bits1(&s->gb);
 321       if (code >= 32768) {
 322           avpriv_request_sample(s->avctx, "Huge DMV");
 323           return 0xffff;
 324       }
 325    }
 326    sign = code & 1;
 327    code >>= 1;
 328
 329    code = (sign) ? (pred - code) : (pred + code);
 330    ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
 331    return code;
 332
 333 }
 334
 335 /**
 336  * read the next MVs for OBMC. yes this is an ugly hack, feel free to send a patch :)
 337  */
 338 static void preview_obmc(MpegEncContext *s){
 339     GetBitContext gb= s->gb;
 340
 341     int cbpc, i, pred_x, pred_y, mx, my;
 342     int16_t *mot_val;
 343     const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 344     const int stride= s->b8_stride*2;
 345
 346     for(i=0; i<4; i++)
 347         s->block_index[i]+= 2;
 348     for(i=4; i<6; i++)
 349         s->block_index[i]+= 1;
 350     s->mb_x++;
 351
 352     av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
 353
 354     do{
 355         if (get_bits1(&s->gb)) {
 356             /* skip mb */
 357             mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 358             mot_val[0       ]= mot_val[2       ]=
 359             mot_val[0+stride]= mot_val[2+stride]= 0;
 360             mot_val[1       ]= mot_val[3       ]=
 361             mot_val[1+stride]= mot_val[3+stride]= 0;
 362
 363             s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 364             goto end;
 365         }
 366         cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 367     }while(cbpc == 20);
 368
 369     if(cbpc & 4){
 370         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 371     }else{
 372         get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 373         if (cbpc & 8) {
 374             if(s->modified_quant){
 375                 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
 376                 else                  skip_bits(&s->gb, 5);
 377             }else
 378                 skip_bits(&s->gb, 2);
 379         }
 380
 381         if ((cbpc & 16) == 0) {
 382                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 383                 /* 16x16 motion prediction */
 384                 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 385                 if (s->umvplus)
 386                     mx = h263p_decode_umotion(s, pred_x);
 387                 else
 388                     mx = ff_h263_decode_motion(s, pred_x, 1);
 389
 390                 if (s->umvplus)
 391                     my = h263p_decode_umotion(s, pred_y);
 392                 else
 393                     my = ff_h263_decode_motion(s, pred_y, 1);
 394
 395                 mot_val[0       ]= mot_val[2       ]=
 396                 mot_val[0+stride]= mot_val[2+stride]= mx;
 397                 mot_val[1       ]= mot_val[3       ]=
 398                 mot_val[1+stride]= mot_val[3+stride]= my;
 399         } else {
 400             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 401             for(i=0;i<4;i++) {
 402                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 403                 if (s->umvplus)
 404                     mx = h263p_decode_umotion(s, pred_x);
 405                 else
 406                     mx = ff_h263_decode_motion(s, pred_x, 1);
 407
 408                 if (s->umvplus)
 409                     my = h263p_decode_umotion(s, pred_y);
 410                 else
 411                     my = ff_h263_decode_motion(s, pred_y, 1);
 412                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 413                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 414                 mot_val[0] = mx;
 415                 mot_val[1] = my;
 416             }
 417         }
 418     }
 419 end:
 420
 421     for(i=0; i<4; i++)
 422         s->block_index[i]-= 2;
 423     for(i=4; i<6; i++)
 424         s->block_index[i]-= 1;
 425     s->mb_x--;
 426
 427     s->gb= gb;
 428 }
 429
 430 static void h263_decode_dquant(MpegEncContext *s){
 431     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 432
 433     if(s->modified_quant){
 434         if(get_bits1(&s->gb))
 435             s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
 436         else
 437             s->qscale= get_bits(&s->gb, 5);
 438     }else
 439         s->qscale += quant_tab[get_bits(&s->gb, 2)];
 440     ff_set_qscale(s, s->qscale);
 441 }
 442
 443 static int h263_decode_block(MpegEncContext * s, int16_t * block,
 444                              int n, int coded)
 445 {
 446     int level, i, j, run;
 447     RLTable *rl = &ff_h263_rl_inter;
 448     const uint8_t *scan_table;
 449     GetBitContext gb= s->gb;
 450
 451     scan_table = s->intra_scantable.permutated;
 452     if (s->h263_aic && s->mb_intra) {
 453         rl = &ff_rl_intra_aic;
 454         i = 0;
 455         if (s->ac_pred) {
 456             if (s->h263_aic_dir)
 457                 scan_table = s->intra_v_scantable.permutated; /* left */
 458             else
 459                 scan_table = s->intra_h_scantable.permutated; /* top */
 460         }
 461     } else if (s->mb_intra) {
 462         /* DC coef */
 463         if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
 464           if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
 465             int component, diff;
 466             component = (n <= 3 ? 0 : n - 4 + 1);
 467             level = s->last_dc[component];
 468             if (s->rv10_first_dc_coded[component]) {
 469                 diff = ff_rv_decode_dc(s, n);
 470                 if (diff < 0)
 471                     return -1;
 472                 level += diff;
 473                 level = level & 0xff; /* handle wrap round */
 474                 s->last_dc[component] = level;
 475             } else {
 476                 s->rv10_first_dc_coded[component] = 1;
 477             }
 478           } else {
 479                 level = get_bits(&s->gb, 8);
 480                 if (level == 255)
 481                     level = 128;
 482           }
 483         }else{
 484             level = get_bits(&s->gb, 8);
 485             if((level&0x7F) == 0){
 486                 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
 487                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
 488                     return -1;
 489             }
 490             if (level == 255)
 491                 level = 128;
 492         }
 493         block[0] = level;
 494         i = 1;
 495     } else {
 496         i = 0;
 497     }
 498     if (!coded) {
 499         if (s->mb_intra && s->h263_aic)
 500             goto not_coded;
 501         s->block_last_index[n] = i - 1;
 502         return 0;
 503     }
 504 retry:
 505     {
 506     OPEN_READER(re, &s->gb);
 507     i--; // offset by -1 to allow direct indexing of scan_table
 508     for(;;) {
 509         UPDATE_CACHE(re, &s->gb);
 510         GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 511         if (run == 66) {
 512             if (level){
 513                 CLOSE_READER(re, &s->gb);
 514                 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
 515                 return -1;
 516             }
 517             /* escape */
 518             if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
 519                 int is11 = SHOW_UBITS(re, &s->gb, 1);
 520                 SKIP_CACHE(re, &s->gb, 1);
 521                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 522                 if (is11) {
 523                     SKIP_COUNTER(re, &s->gb, 1 + 7);
 524                     UPDATE_CACHE(re, &s->gb);
 525                     level = SHOW_SBITS(re, &s->gb, 11);
 526                     SKIP_COUNTER(re, &s->gb, 11);
 527                 } else {
 528                     SKIP_CACHE(re, &s->gb, 7);
 529                     level = SHOW_SBITS(re, &s->gb, 7);
 530                     SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
 531                 }
 532             } else {
 533                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 534                 SKIP_CACHE(re, &s->gb, 7);
 535                 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
 536                 SKIP_COUNTER(re, &s->gb, 7 + 8);
 537                 if(level == -128){
 538                     UPDATE_CACHE(re, &s->gb);
 539                     if (s->codec_id == AV_CODEC_ID_RV10) {
 540                         /* XXX: should patch encoder too */
 541                         level = SHOW_SBITS(re, &s->gb, 12);
 542                         SKIP_COUNTER(re, &s->gb, 12);
 543                     }else{
 544                         level = SHOW_UBITS(re, &s->gb, 5);
 545                         SKIP_CACHE(re, &s->gb, 5);
 546                         level |= SHOW_SBITS(re, &s->gb, 6) * (1<<5);
 547                         SKIP_COUNTER(re, &s->gb, 5 + 6);
 548                     }
 549                 }
 550             }
 551         } else {
 552             if (SHOW_UBITS(re, &s->gb, 1))
 553                 level = -level;
 554             SKIP_COUNTER(re, &s->gb, 1);
 555         }
 556         i += run;
 557         if (i >= 64){
 558             CLOSE_READER(re, &s->gb);
 559             // redo update without last flag, revert -1 offset
 560             i = i - run + ((run-1)&63) + 1;
 561             if (i < 64) {
 562                 // only last marker, no overrun
 563                 block[scan_table[i]] = level;
 564                 break;
 565             }
 566             if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
 567                 //Looks like a hack but no, it's the way it is supposed to work ...
 568                 rl = &ff_rl_intra_aic;
 569                 i = 0;
 570                 s->gb= gb;
 571                 s->bdsp.clear_block(block);
 572                 goto retry;
 573             }
 574             av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
 575             return -1;
 576         }
 577         j = scan_table[i];
 578         block[j] = level;
 579     }
 580     }
 581 not_coded:
 582     if (s->mb_intra && s->h263_aic) {
 583         ff_h263_pred_acdc(s, block, n);
 584         i = 63;
 585     }
 586     s->block_last_index[n] = i;
 587     return 0;
 588 }
 589
 590 static int h263_skip_b_part(MpegEncContext *s, int cbp)
 591 {
 592     LOCAL_ALIGNED_32(int16_t, dblock, [64]);
 593     int i, mbi;
 594     int bli[6];
 595
 596     /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
 597      * but real value should be restored in order to be used later (in OBMC condition)
 598      */
 599     mbi = s->mb_intra;
 600     memcpy(bli, s->block_last_index, sizeof(bli));
 601     s->mb_intra = 0;
 602     for (i = 0; i < 6; i++) {
 603         if (h263_decode_block(s, dblock, i, cbp&32) < 0)
 604             return -1;
 605         cbp+=cbp;
 606     }
 607     s->mb_intra = mbi;
 608     memcpy(s->block_last_index, bli, sizeof(bli));
 609     return 0;
 610 }
 611
 612 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
 613 {
 614     int c, mv = 1;
 615
 616     if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
 617         c = get_bits1(gb);
 618         if (pb_frame == 2 && c)
 619             mv = !get_bits1(gb);
 620     } else { // h.263 Annex M improved PB-frame
 621         mv = get_unary(gb, 0, 4) + 1;
 622         c = mv & 1;
 623         mv = !!(mv & 2);
 624     }
 625     if(c)
 626         *cbpb = get_bits(gb, 6);
 627     return mv;
 628 }
 629
 630 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
 631 #define tab_bias (tab_size / 2)
 632 static inline void set_one_direct_mv(MpegEncContext *s, Picture *p, int i)
 633 {
 634     int xy           = s->block_index[i];
 635     uint16_t time_pp = s->pp_time;
 636     uint16_t time_pb = s->pb_time;
 637     int p_mx, p_my;
 638
 639     p_mx = p->motion_val[0][xy][0];
 640     if ((unsigned)(p_mx + tab_bias) < tab_size) {
 641         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias];
 642         s->mv[1][i][0] = s->direct_scale_mv[1][p_mx + tab_bias];
 643     } else {
 644         s->mv[0][i][0] = p_mx * time_pb / time_pp;
 645         s->mv[1][i][0] = p_mx * (time_pb - time_pp) / time_pp;
 646     }
 647     p_my = p->motion_val[0][xy][1];
 648     if ((unsigned)(p_my + tab_bias) < tab_size) {
 649         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias];
 650         s->mv[1][i][1] = s->direct_scale_mv[1][p_my + tab_bias];
 651     } else {
 652         s->mv[0][i][1] = p_my * time_pb / time_pp;
 653         s->mv[1][i][1] = p_my * (time_pb - time_pp) / time_pp;
 654     }
 655 }
 656
 657 /**
 658  * @return the mb_type
 659  */
 660 static int set_direct_mv(MpegEncContext *s)
 661 {
 662     const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
 663     Picture *p = &s->next_picture;
 664     int colocated_mb_type = p->mb_type[mb_index];
 665     int i;
 666
 667     if (s->codec_tag == AV_RL32("U263") && p->f->pict_type == AV_PICTURE_TYPE_I) {
 668         p = &s->last_picture;
 669         colocated_mb_type = p->mb_type[mb_index];
 670     }
 671
 672     if (IS_8X8(colocated_mb_type)) {
 673         s->mv_type = MV_TYPE_8X8;
 674         for (i = 0; i < 4; i++)
 675             set_one_direct_mv(s, p, i);
 676         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 677     } else {
 678         set_one_direct_mv(s, p, 0);
 679         s->mv[0][1][0] =
 680         s->mv[0][2][0] =
 681         s->mv[0][3][0] = s->mv[0][0][0];
 682         s->mv[0][1][1] =
 683         s->mv[0][2][1] =
 684         s->mv[0][3][1] = s->mv[0][0][1];
 685         s->mv[1][1][0] =
 686         s->mv[1][2][0] =
 687         s->mv[1][3][0] = s->mv[1][0][0];
 688         s->mv[1][1][1] =
 689         s->mv[1][2][1] =
 690         s->mv[1][3][1] = s->mv[1][0][1];
 691         s->mv_type = MV_TYPE_8X8;
 692         // Note see prev line
 693         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
 694     }
 695 }
 696
 697 int ff_h263_decode_mb(MpegEncContext *s,
 698                       int16_t block[6][64])
 699 {
 700     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
 701     int16_t *mot_val;
 702     const int xy= s->mb_x + s->mb_y * s->mb_stride;
 703     int cbpb = 0, pb_mv_count = 0;
 704
 705     av_assert2(!s->h263_pred);
 706
 707     if (s->pict_type == AV_PICTURE_TYPE_P) {
 708         do{
 709             if (get_bits1(&s->gb)) {
 710                 /* skip mb */
 711                 s->mb_intra = 0;
 712                 for(i=0;i<6;i++)
 713                     s->block_last_index[i] = -1;
 714                 s->mv_dir = MV_DIR_FORWARD;
 715                 s->mv_type = MV_TYPE_16X16;
 716                 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 717                 s->mv[0][0][0] = 0;
 718                 s->mv[0][0][1] = 0;
 719                 s->mb_skipped = !(s->obmc | s->loop_filter);
 720                 goto end;
 721             }
 722             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 723             if (cbpc < 0){
 724                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 725                 return SLICE_ERROR;
 726             }
 727         }while(cbpc == 20);
 728
 729         s->bdsp.clear_blocks(s->block[0]);
 730
 731         dquant = cbpc & 8;
 732         s->mb_intra = ((cbpc & 4) != 0);
 733         if (s->mb_intra) goto intra;
 734
 735         if(s->pb_frame && get_bits1(&s->gb))
 736             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 737         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 738
 739         if (cbpy < 0) {
 740             av_log(s->avctx, AV_LOG_ERROR, "cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 741             return SLICE_ERROR;
 742         }
 743
 744         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 745             cbpy ^= 0xF;
 746
 747         cbp = (cbpc & 3) | (cbpy << 2);
 748         if (dquant) {
 749             h263_decode_dquant(s);
 750         }
 751
 752         s->mv_dir = MV_DIR_FORWARD;
 753         if ((cbpc & 16) == 0) {
 754             s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 755             /* 16x16 motion prediction */
 756             s->mv_type = MV_TYPE_16X16;
 757             ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 758             if (s->umvplus)
 759                mx = h263p_decode_umotion(s, pred_x);
 760             else
 761                mx = ff_h263_decode_motion(s, pred_x, 1);
 762
 763             if (mx >= 0xffff)
 764                 return SLICE_ERROR;
 765
 766             if (s->umvplus)
 767                my = h263p_decode_umotion(s, pred_y);
 768             else
 769                my = ff_h263_decode_motion(s, pred_y, 1);
 770
 771             if (my >= 0xffff)
 772                 return SLICE_ERROR;
 773             s->mv[0][0][0] = mx;
 774             s->mv[0][0][1] = my;
 775
 776             if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 777                skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 778         } else {
 779             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 780             s->mv_type = MV_TYPE_8X8;
 781             for(i=0;i<4;i++) {
 782                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 783                 if (s->umvplus)
 784                     mx = h263p_decode_umotion(s, pred_x);
 785                 else
 786                     mx = ff_h263_decode_motion(s, pred_x, 1);
 787                 if (mx >= 0xffff)
 788                     return SLICE_ERROR;
 789
 790                 if (s->umvplus)
 791                     my = h263p_decode_umotion(s, pred_y);
 792                 else
 793                     my = ff_h263_decode_motion(s, pred_y, 1);
 794                 if (my >= 0xffff)
 795                     return SLICE_ERROR;
 796                 s->mv[0][i][0] = mx;
 797                 s->mv[0][i][1] = my;
 798                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 799                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 800                 mot_val[0] = mx;
 801                 mot_val[1] = my;
 802             }
 803         }
 804     } else if(s->pict_type==AV_PICTURE_TYPE_B) {
 805         int mb_type;
 806         const int stride= s->b8_stride;
 807         int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
 808         int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
 809 //        const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 810
 811         //FIXME ugly
 812         mot_val0[0       ]= mot_val0[2       ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
 813         mot_val0[1       ]= mot_val0[3       ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
 814         mot_val1[0       ]= mot_val1[2       ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
 815         mot_val1[1       ]= mot_val1[3       ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
 816
 817         do{
 818             mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
 819             if (mb_type < 0){
 820                 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
 821                 return SLICE_ERROR;
 822             }
 823
 824             mb_type= h263_mb_type_b_map[ mb_type ];
 825         }while(!mb_type);
 826
 827         s->mb_intra = IS_INTRA(mb_type);
 828         if(HAS_CBP(mb_type)){
 829             s->bdsp.clear_blocks(s->block[0]);
 830             cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
 831             if(s->mb_intra){
 832                 dquant = IS_QUANT(mb_type);
 833                 goto intra;
 834             }
 835
 836             cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 837
 838             if (cbpy < 0){
 839                 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 840                 return SLICE_ERROR;
 841             }
 842
 843             if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 844                 cbpy ^= 0xF;
 845
 846             cbp = (cbpc & 3) | (cbpy << 2);
 847         }else
 848             cbp=0;
 849
 850         av_assert2(!s->mb_intra);
 851
 852         if(IS_QUANT(mb_type)){
 853             h263_decode_dquant(s);
 854         }
 855
 856         if(IS_DIRECT(mb_type)){
 857             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
 858             mb_type |= set_direct_mv(s);
 859         }else{
 860             s->mv_dir = 0;
 861             s->mv_type= MV_TYPE_16X16;
 862 //FIXME UMV
 863
 864             if(USES_LIST(mb_type, 0)){
 865                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 866                 s->mv_dir = MV_DIR_FORWARD;
 867
 868                 if (s->umvplus)
 869                     mx = h263p_decode_umotion(s, pred_x);
 870                 else
 871                     mx = ff_h263_decode_motion(s, pred_x, 1);
 872                 if (mx >= 0xffff)
 873                     return SLICE_ERROR;
 874
 875                 if (s->umvplus)
 876                     my = h263p_decode_umotion(s, pred_y);
 877                 else
 878                     my = ff_h263_decode_motion(s, pred_y, 1);
 879                 if (my >= 0xffff)
 880                     return SLICE_ERROR;
 881
 882                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 883                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 884
 885                 s->mv[0][0][0] = mx;
 886                 s->mv[0][0][1] = my;
 887                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 888                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 889             }
 890
 891             if(USES_LIST(mb_type, 1)){
 892                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &pred_x, &pred_y);
 893                 s->mv_dir |= MV_DIR_BACKWARD;
 894
 895                 if (s->umvplus)
 896                     mx = h263p_decode_umotion(s, pred_x);
 897                 else
 898                     mx = ff_h263_decode_motion(s, pred_x, 1);
 899                 if (mx >= 0xffff)
 900                     return SLICE_ERROR;
 901
 902                 if (s->umvplus)
 903                     my = h263p_decode_umotion(s, pred_y);
 904                 else
 905                     my = ff_h263_decode_motion(s, pred_y, 1);
 906                 if (my >= 0xffff)
 907                     return SLICE_ERROR;
 908
 909                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 910                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 911
 912                 s->mv[1][0][0] = mx;
 913                 s->mv[1][0][1] = my;
 914                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 915                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 916             }
 917         }
 918
 919         s->current_picture.mb_type[xy] = mb_type;
 920     } else { /* I-Frame */
 921         do{
 922             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 923             if (cbpc < 0){
 924                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 925                 return SLICE_ERROR;
 926             }
 927         }while(cbpc == 8);
 928
 929         s->bdsp.clear_blocks(s->block[0]);
 930
 931         dquant = cbpc & 4;
 932         s->mb_intra = 1;
 933 intra:
 934         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 935         if (s->h263_aic) {
 936             s->ac_pred = get_bits1(&s->gb);
 937             if(s->ac_pred){
 938                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
 939
 940                 s->h263_aic_dir = get_bits1(&s->gb);
 941             }
 942         }else
 943             s->ac_pred = 0;
 944
 945         if(s->pb_frame && get_bits1(&s->gb))
 946             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 947         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 948         if(cbpy<0){
 949             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 950             return SLICE_ERROR;
 951         }
 952         cbp = (cbpc & 3) | (cbpy << 2);
 953         if (dquant) {
 954             h263_decode_dquant(s);
 955         }
 956
 957         pb_mv_count += !!s->pb_frame;
 958     }
 959
 960     while(pb_mv_count--){
 961         ff_h263_decode_motion(s, 0, 1);
 962         ff_h263_decode_motion(s, 0, 1);
 963     }
 964
 965     /* decode each block */
 966     for (i = 0; i < 6; i++) {
 967         if (h263_decode_block(s, block[i], i, cbp&32) < 0)
 968             return -1;
 969         cbp+=cbp;
 970     }
 971
 972     if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
 973         return -1;
 974     if(s->obmc && !s->mb_intra){
 975         if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
 976             preview_obmc(s);
 977     }
 978 end:
 979
 980     if (get_bits_left(&s->gb) < 0)
 981         return AVERROR_INVALIDDATA;
 982
 983         /* per-MB end of slice check */
 984     {
 985         int v= show_bits(&s->gb, 16);
 986
 987         if (get_bits_left(&s->gb) < 16) {
 988             v >>= 16 - get_bits_left(&s->gb);
 989         }
 990
 991         if(v==0)
 992             return SLICE_END;
 993     }
 994
 995     return SLICE_OK;
 996 }
 997
 998 /* Most is hardcoded; should extend to handle all H.263 streams. */
 999 int ff_h263_decode_picture_header(MpegEncContext *s)
1000 {
1001     int format, width, height, i, ret;
1002     uint32_t startcode;
1003
1004     align_get_bits(&s->gb);
1005
1006     if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
1007          av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
1008     }
1009
1010     startcode= get_bits(&s->gb, 22-8);
1011
1012     for(i= get_bits_left(&s->gb); i>24; i-=8) {
1013         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
1014
1015         if(startcode == 0x20)
1016             break;
1017     }
1018
1019     if (startcode != 0x20) {
1020         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
1021         return -1;
1022     }
1023     /* temporal reference */
1024     i = get_bits(&s->gb, 8); /* picture timestamp */
1025
1026     i -= (i - (s->picture_number & 0xFF) + 128) & ~0xFF;
1027
1028     s->picture_number= (s->picture_number&~0xFF) + i;
1029
1030     /* PTYPE starts here */
1031     if (check_marker(s->avctx, &s->gb, "in PTYPE") != 1) {
1032         return -1;
1033     }
1034     if (get_bits1(&s->gb) != 0) {
1035         av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
1036         return -1;      /* H.263 id */
1037     }
1038     skip_bits1(&s->gb);         /* split screen off */
1039     skip_bits1(&s->gb);         /* camera  off */
1040     skip_bits1(&s->gb);         /* freeze picture release off */
1041
1042     format = get_bits(&s->gb, 3);
1043     /*
1044         0    forbidden
1045         1    sub-QCIF
1046         10   QCIF
1047         7       extended PTYPE (PLUSPTYPE)
1048     */
1049
1050     if (format != 7 && format != 6) {
1051         s->h263_plus = 0;
1052         /* H.263v1 */
1053         width = ff_h263_format[format][0];
1054         height = ff_h263_format[format][1];
1055         if (!width)
1056             return -1;
1057
1058         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
1059
1060         s->h263_long_vectors = get_bits1(&s->gb);
1061
1062         if (get_bits1(&s->gb) != 0) {
1063             av_log(s->avctx, AV_LOG_ERROR, "H.263 SAC not supported\n");
1064             return -1; /* SAC: off */
1065         }
1066         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1067         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
1068
1069         s->pb_frame = get_bits1(&s->gb);
1070         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
1071         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
1072
1073         s->width = width;
1074         s->height = height;
1075         s->avctx->sample_aspect_ratio= (AVRational){12,11};
1076         s->avctx->framerate = (AVRational){ 30000, 1001 };
1077     } else {
1078         int ufep;
1079
1080         /* H.263v2 */
1081         s->h263_plus = 1;
1082         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
1083
1084         /* ufep other than 0 and 1 are reserved */
1085         if (ufep == 1) {
1086             /* OPPTYPE */
1087             format = get_bits(&s->gb, 3);
1088             ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
1089             s->custom_pcf= get_bits1(&s->gb);
1090             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
1091             if (get_bits1(&s->gb) != 0) {
1092                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
1093             }
1094             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1095             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
1096             s->loop_filter= get_bits1(&s->gb);
1097             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
1098             if(s->avctx->lowres)
1099                 s->loop_filter = 0;
1100
1101             s->h263_slice_structured= get_bits1(&s->gb);
1102             if (get_bits1(&s->gb) != 0) {
1103                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
1104             }
1105             if (get_bits1(&s->gb) != 0) {
1106                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
1107             }
1108             s->alt_inter_vlc= get_bits1(&s->gb);
1109             s->modified_quant= get_bits1(&s->gb);
1110             if(s->modified_quant)
1111                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
1112
1113             skip_bits(&s->gb, 1); /* Prevent start code emulation */
1114
1115             skip_bits(&s->gb, 3); /* Reserved */
1116         } else if (ufep != 0) {
1117             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
1118             return -1;
1119         }
1120
1121         /* MPPTYPE */
1122         s->pict_type = get_bits(&s->gb, 3);
1123         switch(s->pict_type){
1124         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1125         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1126         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1127         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1128         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1129         default:
1130             return -1;
1131         }
1132         skip_bits(&s->gb, 2);
1133         s->no_rounding = get_bits1(&s->gb);
1134         skip_bits(&s->gb, 4);
1135
1136         /* Get the picture dimensions */
1137         if (ufep) {
1138             if (format == 6) {
1139                 /* Custom Picture Format (CPFMT) */
1140                 s->aspect_ratio_info = get_bits(&s->gb, 4);
1141                 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1142                 /* aspect ratios:
1143                 0 - forbidden
1144                 1 - 1:1
1145                 2 - 12:11 (CIF 4:3)
1146                 3 - 10:11 (525-type 4:3)
1147                 4 - 16:11 (CIF 16:9)
1148                 5 - 40:33 (525-type 16:9)
1149                 6-14 - reserved
1150                 */
1151                 width = (get_bits(&s->gb, 9) + 1) * 4;
1152                 check_marker(s->avctx, &s->gb, "in dimensions");
1153                 height = get_bits(&s->gb, 9) * 4;
1154                 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1155                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1156                     /* expected dimensions */
1157                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1158                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1159                 }else{
1160                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1161                 }
1162             } else {
1163                 width = ff_h263_format[format][0];
1164                 height = ff_h263_format[format][1];
1165                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1166             }
1167             s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1168             if ((width == 0) || (height == 0))
1169                 return -1;
1170             s->width = width;
1171             s->height = height;
1172
1173             if(s->custom_pcf){
1174                 int gcd;
1175                 s->avctx->framerate.num  = 1800000;
1176                 s->avctx->framerate.den  = 1000 + get_bits1(&s->gb);
1177                 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1178                 if(s->avctx->framerate.den == 0){
1179                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
1180                     return -1;
1181                 }
1182                 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1183                 s->avctx->framerate.den /= gcd;
1184                 s->avctx->framerate.num /= gcd;
1185             }else{
1186                 s->avctx->framerate = (AVRational){ 30000, 1001 };
1187             }
1188         }
1189
1190         if(s->custom_pcf){
1191             skip_bits(&s->gb, 2); //extended Temporal reference
1192         }
1193
1194         if (ufep) {
1195             if (s->umvplus) {
1196                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1197                     skip_bits1(&s->gb);
1198             }
1199             if(s->h263_slice_structured){
1200                 if (get_bits1(&s->gb) != 0) {
1201                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1202                 }
1203                 if (get_bits1(&s->gb) != 0) {
1204                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1205                 }
1206             }
1207             if (s->pict_type == AV_PICTURE_TYPE_B) {
1208                 skip_bits(&s->gb, 4); //ELNUM
1209                 if (ufep == 1) {
1210                     skip_bits(&s->gb, 4); // RLNUM
1211                 }
1212             }
1213         }
1214
1215         s->qscale = get_bits(&s->gb, 5);
1216     }
1217
1218     if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
1219         return ret;
1220
1221     if (!(s->avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)) {
1222         if ((s->width * s->height / 256 / 8) > get_bits_left(&s->gb))
1223             return AVERROR_INVALIDDATA;
1224     }
1225
1226     s->mb_width = (s->width  + 15) / 16;
1227     s->mb_height = (s->height  + 15) / 16;
1228     s->mb_num = s->mb_width * s->mb_height;
1229
1230     if (s->pb_frame) {
1231         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1232         if (s->custom_pcf)
1233             skip_bits(&s->gb, 2); //extended Temporal reference
1234         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1235     }
1236
1237     if (s->pict_type!=AV_PICTURE_TYPE_B) {
1238         s->time            = s->picture_number;
1239         s->pp_time         = s->time - s->last_non_b_time;
1240         s->last_non_b_time = s->time;
1241     }else{
1242         s->time    = s->picture_number;
1243         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1244         if (s->pp_time <=s->pb_time ||
1245             s->pp_time <= s->pp_time - s->pb_time ||
1246             s->pp_time <= 0){
1247             s->pp_time = 2;
1248             s->pb_time = 1;
1249         }
1250         ff_mpeg4_init_direct_mv(s);
1251     }
1252
1253     /* PEI */
1254     if (skip_1stop_8data_bits(&s->gb) < 0)
1255         return AVERROR_INVALIDDATA;
1256
1257     if(s->h263_slice_structured){
1258         if (check_marker(s->avctx, &s->gb, "SEPB1") != 1) {
1259             return -1;
1260         }
1261
1262         ff_h263_decode_mba(s);
1263
1264         if (check_marker(s->avctx, &s->gb, "SEPB2") != 1) {
1265             return -1;
1266         }
1267     }
1268     s->f_code = 1;
1269
1270     if (s->pict_type == AV_PICTURE_TYPE_B)
1271         s->low_delay = 0;
1272
1273     if(s->h263_aic){
1274          s->y_dc_scale_table=
1275          s->c_dc_scale_table= ff_aic_dc_scale_table;
1276     }else{
1277         s->y_dc_scale_table=
1278         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1279     }
1280
1281         ff_h263_show_pict_info(s);
1282     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1283         int i,j;
1284         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1285         av_log(s->avctx, AV_LOG_DEBUG, "\n");
1286         for(i=0; i<13; i++){
1287             for(j=0; j<3; j++){
1288                 int v= get_bits(&s->gb, 8);
1289                 v |= get_sbits(&s->gb, 8) * (1 << 8);
1290                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1291             }
1292             av_log(s->avctx, AV_LOG_DEBUG, "\n");
1293         }
1294         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1295     }
1296
1297     return 0;
1298 }