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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 "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     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.
 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     if(s->codec_id==AV_CODEC_ID_MPEG4){
 217         skip_bits1(&s->gb);
 218         align_get_bits(&s->gb);
 219     }
 220
 221     if(show_bits(&s->gb, 16)==0){
 222         pos= get_bits_count(&s->gb);
 223         if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 224             ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 225         else
 226             ret= h263_decode_gob_header(s);
 227         if(ret>=0)
 228             return pos;
 229     }
 230     //OK, it's not where it is supposed to be ...
 231     s->gb= s->last_resync_gb;
 232     align_get_bits(&s->gb);
 233     left= get_bits_left(&s->gb);
 234
 235     for(;left>16+1+5+5; left-=8){
 236         if(show_bits(&s->gb, 16)==0){
 237             GetBitContext bak= s->gb;
 238
 239             pos= get_bits_count(&s->gb);
 240             if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 241                 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 242             else
 243                 ret= h263_decode_gob_header(s);
 244             if(ret>=0)
 245                 return pos;
 246
 247             s->gb= bak;
 248         }
 249         skip_bits(&s->gb, 8);
 250     }
 251
 252     return -1;
 253 }
 254
 255 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
 256 {
 257     int code, val, sign, shift;
 258     code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
 259
 260     if (code == 0)
 261         return pred;
 262     if (code < 0)
 263         return 0xffff;
 264
 265     sign = get_bits1(&s->gb);
 266     shift = f_code - 1;
 267     val = code;
 268     if (shift) {
 269         val = (val - 1) << shift;
 270         val |= get_bits(&s->gb, shift);
 271         val++;
 272     }
 273     if (sign)
 274         val = -val;
 275     val += pred;
 276
 277     /* modulo decoding */
 278     if (!s->h263_long_vectors) {
 279         val = sign_extend(val, 5 + f_code);
 280     } else {
 281         /* horrible H.263 long vector mode */
 282         if (pred < -31 && val < -63)
 283             val += 64;
 284         if (pred > 32 && val > 63)
 285             val -= 64;
 286
 287     }
 288     return val;
 289 }
 290
 291
 292 /* Decode RVLC of H.263+ UMV */
 293 static int h263p_decode_umotion(MpegEncContext * s, int pred)
 294 {
 295    int code = 0, sign;
 296
 297    if (get_bits1(&s->gb)) /* Motion difference = 0 */
 298       return pred;
 299
 300    code = 2 + get_bits1(&s->gb);
 301
 302    while (get_bits1(&s->gb))
 303    {
 304       code <<= 1;
 305       code += get_bits1(&s->gb);
 306       if (code >= 32768) {
 307           avpriv_request_sample(s->avctx, "Huge DMV");
 308           return 0xffff;
 309       }
 310    }
 311    sign = code & 1;
 312    code >>= 1;
 313
 314    code = (sign) ? (pred - code) : (pred + code);
 315    ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
 316    return code;
 317
 318 }
 319
 320 /**
 321  * read the next MVs for OBMC. yes this is an ugly hack, feel free to send a patch :)
 322  */
 323 static void preview_obmc(MpegEncContext *s){
 324     GetBitContext gb= s->gb;
 325
 326     int cbpc, i, pred_x, pred_y, mx, my;
 327     int16_t *mot_val;
 328     const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 329     const int stride= s->b8_stride*2;
 330
 331     for(i=0; i<4; i++)
 332         s->block_index[i]+= 2;
 333     for(i=4; i<6; i++)
 334         s->block_index[i]+= 1;
 335     s->mb_x++;
 336
 337     av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
 338
 339     do{
 340         if (get_bits1(&s->gb)) {
 341             /* skip mb */
 342             mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 343             mot_val[0       ]= mot_val[2       ]=
 344             mot_val[0+stride]= mot_val[2+stride]= 0;
 345             mot_val[1       ]= mot_val[3       ]=
 346             mot_val[1+stride]= mot_val[3+stride]= 0;
 347
 348             s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 349             goto end;
 350         }
 351         cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 352     }while(cbpc == 20);
 353
 354     if(cbpc & 4){
 355         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 356     }else{
 357         get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 358         if (cbpc & 8) {
 359             if(s->modified_quant){
 360                 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
 361                 else                  skip_bits(&s->gb, 5);
 362             }else
 363                 skip_bits(&s->gb, 2);
 364         }
 365
 366         if ((cbpc & 16) == 0) {
 367                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 368                 /* 16x16 motion prediction */
 369                 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 370                 if (s->umvplus)
 371                     mx = h263p_decode_umotion(s, pred_x);
 372                 else
 373                     mx = ff_h263_decode_motion(s, pred_x, 1);
 374
 375                 if (s->umvplus)
 376                     my = h263p_decode_umotion(s, pred_y);
 377                 else
 378                     my = ff_h263_decode_motion(s, pred_y, 1);
 379
 380                 mot_val[0       ]= mot_val[2       ]=
 381                 mot_val[0+stride]= mot_val[2+stride]= mx;
 382                 mot_val[1       ]= mot_val[3       ]=
 383                 mot_val[1+stride]= mot_val[3+stride]= my;
 384         } else {
 385             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 386             for(i=0;i<4;i++) {
 387                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 388                 if (s->umvplus)
 389                     mx = h263p_decode_umotion(s, pred_x);
 390                 else
 391                     mx = ff_h263_decode_motion(s, pred_x, 1);
 392
 393                 if (s->umvplus)
 394                     my = h263p_decode_umotion(s, pred_y);
 395                 else
 396                     my = ff_h263_decode_motion(s, pred_y, 1);
 397                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 398                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 399                 mot_val[0] = mx;
 400                 mot_val[1] = my;
 401             }
 402         }
 403     }
 404 end:
 405
 406     for(i=0; i<4; i++)
 407         s->block_index[i]-= 2;
 408     for(i=4; i<6; i++)
 409         s->block_index[i]-= 1;
 410     s->mb_x--;
 411
 412     s->gb= gb;
 413 }
 414
 415 static void h263_decode_dquant(MpegEncContext *s){
 416     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 417
 418     if(s->modified_quant){
 419         if(get_bits1(&s->gb))
 420             s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
 421         else
 422             s->qscale= get_bits(&s->gb, 5);
 423     }else
 424         s->qscale += quant_tab[get_bits(&s->gb, 2)];
 425     ff_set_qscale(s, s->qscale);
 426 }
 427
 428 static int h263_decode_block(MpegEncContext * s, int16_t * block,
 429                              int n, int coded)
 430 {
 431     int level, i, j, run;
 432     RLTable *rl = &ff_h263_rl_inter;
 433     const uint8_t *scan_table;
 434     GetBitContext gb= s->gb;
 435
 436     scan_table = s->intra_scantable.permutated;
 437     if (s->h263_aic && s->mb_intra) {
 438         rl = &ff_rl_intra_aic;
 439         i = 0;
 440         if (s->ac_pred) {
 441             if (s->h263_aic_dir)
 442                 scan_table = s->intra_v_scantable.permutated; /* left */
 443             else
 444                 scan_table = s->intra_h_scantable.permutated; /* top */
 445         }
 446     } else if (s->mb_intra) {
 447         /* DC coef */
 448         if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
 449           if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
 450             int component, diff;
 451             component = (n <= 3 ? 0 : n - 4 + 1);
 452             level = s->last_dc[component];
 453             if (s->rv10_first_dc_coded[component]) {
 454                 diff = ff_rv_decode_dc(s, n);
 455                 if (diff == 0xffff)
 456                     return -1;
 457                 level += diff;
 458                 level = level & 0xff; /* handle wrap round */
 459                 s->last_dc[component] = level;
 460             } else {
 461                 s->rv10_first_dc_coded[component] = 1;
 462             }
 463           } else {
 464                 level = get_bits(&s->gb, 8);
 465                 if (level == 255)
 466                     level = 128;
 467           }
 468         }else{
 469             level = get_bits(&s->gb, 8);
 470             if((level&0x7F) == 0){
 471                 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
 472                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
 473                     return -1;
 474             }
 475             if (level == 255)
 476                 level = 128;
 477         }
 478         block[0] = level;
 479         i = 1;
 480     } else {
 481         i = 0;
 482     }
 483     if (!coded) {
 484         if (s->mb_intra && s->h263_aic)
 485             goto not_coded;
 486         s->block_last_index[n] = i - 1;
 487         return 0;
 488     }
 489 retry:
 490     {
 491     OPEN_READER(re, &s->gb);
 492     i--; // offset by -1 to allow direct indexing of scan_table
 493     for(;;) {
 494         UPDATE_CACHE(re, &s->gb);
 495         GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 496         if (run == 66) {
 497             if (level){
 498                 CLOSE_READER(re, &s->gb);
 499                 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
 500                 return -1;
 501             }
 502             /* escape */
 503             if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
 504                 int is11 = SHOW_UBITS(re, &s->gb, 1);
 505                 SKIP_CACHE(re, &s->gb, 1);
 506                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 507                 if (is11) {
 508                     SKIP_COUNTER(re, &s->gb, 1 + 7);
 509                     UPDATE_CACHE(re, &s->gb);
 510                     level = SHOW_SBITS(re, &s->gb, 11);
 511                     SKIP_COUNTER(re, &s->gb, 11);
 512                 } else {
 513                     SKIP_CACHE(re, &s->gb, 7);
 514                     level = SHOW_SBITS(re, &s->gb, 7);
 515                     SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
 516                 }
 517             } else {
 518                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 519                 SKIP_CACHE(re, &s->gb, 7);
 520                 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
 521                 SKIP_COUNTER(re, &s->gb, 7 + 8);
 522                 if(level == -128){
 523                     UPDATE_CACHE(re, &s->gb);
 524                     if (s->codec_id == AV_CODEC_ID_RV10) {
 525                         /* XXX: should patch encoder too */
 526                         level = SHOW_SBITS(re, &s->gb, 12);
 527                         SKIP_COUNTER(re, &s->gb, 12);
 528                     }else{
 529                         level = SHOW_UBITS(re, &s->gb, 5);
 530                         SKIP_CACHE(re, &s->gb, 5);
 531                         level |= SHOW_SBITS(re, &s->gb, 6) * (1<<5);
 532                         SKIP_COUNTER(re, &s->gb, 5 + 6);
 533                     }
 534                 }
 535             }
 536         } else {
 537             if (SHOW_UBITS(re, &s->gb, 1))
 538                 level = -level;
 539             SKIP_COUNTER(re, &s->gb, 1);
 540         }
 541         i += run;
 542         if (i >= 64){
 543             CLOSE_READER(re, &s->gb);
 544             // redo update without last flag, revert -1 offset
 545             i = i - run + ((run-1)&63) + 1;
 546             if (i < 64) {
 547                 // only last marker, no overrun
 548                 block[scan_table[i]] = level;
 549                 break;
 550             }
 551             if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
 552                 //Looks like a hack but no, it's the way it is supposed to work ...
 553                 rl = &ff_rl_intra_aic;
 554                 i = 0;
 555                 s->gb= gb;
 556                 s->bdsp.clear_block(block);
 557                 goto retry;
 558             }
 559             av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
 560             return -1;
 561         }
 562         j = scan_table[i];
 563         block[j] = level;
 564     }
 565     }
 566 not_coded:
 567     if (s->mb_intra && s->h263_aic) {
 568         ff_h263_pred_acdc(s, block, n);
 569         i = 63;
 570     }
 571     s->block_last_index[n] = i;
 572     return 0;
 573 }
 574
 575 static int h263_skip_b_part(MpegEncContext *s, int cbp)
 576 {
 577     LOCAL_ALIGNED_32(int16_t, dblock, [64]);
 578     int i, mbi;
 579     int bli[6];
 580
 581     /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
 582      * but real value should be restored in order to be used later (in OBMC condition)
 583      */
 584     mbi = s->mb_intra;
 585     memcpy(bli, s->block_last_index, sizeof(bli));
 586     s->mb_intra = 0;
 587     for (i = 0; i < 6; i++) {
 588         if (h263_decode_block(s, dblock, i, cbp&32) < 0)
 589             return -1;
 590         cbp+=cbp;
 591     }
 592     s->mb_intra = mbi;
 593     memcpy(s->block_last_index, bli, sizeof(bli));
 594     return 0;
 595 }
 596
 597 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
 598 {
 599     int c, mv = 1;
 600
 601     if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
 602         c = get_bits1(gb);
 603         if (pb_frame == 2 && c)
 604             mv = !get_bits1(gb);
 605     } else { // h.263 Annex M improved PB-frame
 606         mv = get_unary(gb, 0, 4) + 1;
 607         c = mv & 1;
 608         mv = !!(mv & 2);
 609     }
 610     if(c)
 611         *cbpb = get_bits(gb, 6);
 612     return mv;
 613 }
 614
 615 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
 616 #define tab_bias (tab_size / 2)
 617 static inline void set_one_direct_mv(MpegEncContext *s, Picture *p, int i)
 618 {
 619     int xy           = s->block_index[i];
 620     uint16_t time_pp = s->pp_time;
 621     uint16_t time_pb = s->pb_time;
 622     int p_mx, p_my;
 623
 624     p_mx = p->motion_val[0][xy][0];
 625     if ((unsigned)(p_mx + tab_bias) < tab_size) {
 626         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias];
 627         s->mv[1][i][0] = s->direct_scale_mv[1][p_mx + tab_bias];
 628     } else {
 629         s->mv[0][i][0] = p_mx * time_pb / time_pp;
 630         s->mv[1][i][0] = p_mx * (time_pb - time_pp) / time_pp;
 631     }
 632     p_my = p->motion_val[0][xy][1];
 633     if ((unsigned)(p_my + tab_bias) < tab_size) {
 634         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias];
 635         s->mv[1][i][1] = s->direct_scale_mv[1][p_my + tab_bias];
 636     } else {
 637         s->mv[0][i][1] = p_my * time_pb / time_pp;
 638         s->mv[1][i][1] = p_my * (time_pb - time_pp) / time_pp;
 639     }
 640 }
 641
 642 /**
 643  * @return the mb_type
 644  */
 645 static int set_direct_mv(MpegEncContext *s)
 646 {
 647     const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
 648     Picture *p = &s->next_picture;
 649     int colocated_mb_type = p->mb_type[mb_index];
 650     int i;
 651
 652     if (s->codec_tag == AV_RL32("U263") && p->f->pict_type == AV_PICTURE_TYPE_I) {
 653         p = &s->last_picture;
 654         colocated_mb_type = p->mb_type[mb_index];
 655     }
 656
 657     if (IS_8X8(colocated_mb_type)) {
 658         s->mv_type = MV_TYPE_8X8;
 659         for (i = 0; i < 4; i++)
 660             set_one_direct_mv(s, p, i);
 661         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 662     } else {
 663         set_one_direct_mv(s, p, 0);
 664         s->mv[0][1][0] =
 665         s->mv[0][2][0] =
 666         s->mv[0][3][0] = s->mv[0][0][0];
 667         s->mv[0][1][1] =
 668         s->mv[0][2][1] =
 669         s->mv[0][3][1] = s->mv[0][0][1];
 670         s->mv[1][1][0] =
 671         s->mv[1][2][0] =
 672         s->mv[1][3][0] = s->mv[1][0][0];
 673         s->mv[1][1][1] =
 674         s->mv[1][2][1] =
 675         s->mv[1][3][1] = s->mv[1][0][1];
 676         s->mv_type = MV_TYPE_8X8;
 677         // Note see prev line
 678         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
 679     }
 680 }
 681
 682 int ff_h263_decode_mb(MpegEncContext *s,
 683                       int16_t block[6][64])
 684 {
 685     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
 686     int16_t *mot_val;
 687     const int xy= s->mb_x + s->mb_y * s->mb_stride;
 688     int cbpb = 0, pb_mv_count = 0;
 689
 690     av_assert2(!s->h263_pred);
 691
 692     if (s->pict_type == AV_PICTURE_TYPE_P) {
 693         do{
 694             if (get_bits1(&s->gb)) {
 695                 /* skip mb */
 696                 s->mb_intra = 0;
 697                 for(i=0;i<6;i++)
 698                     s->block_last_index[i] = -1;
 699                 s->mv_dir = MV_DIR_FORWARD;
 700                 s->mv_type = MV_TYPE_16X16;
 701                 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 702                 s->mv[0][0][0] = 0;
 703                 s->mv[0][0][1] = 0;
 704                 s->mb_skipped = !(s->obmc | s->loop_filter);
 705                 goto end;
 706             }
 707             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 708             if (cbpc < 0){
 709                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 710                 return SLICE_ERROR;
 711             }
 712         }while(cbpc == 20);
 713
 714         s->bdsp.clear_blocks(s->block[0]);
 715
 716         dquant = cbpc & 8;
 717         s->mb_intra = ((cbpc & 4) != 0);
 718         if (s->mb_intra) goto intra;
 719
 720         if(s->pb_frame && get_bits1(&s->gb))
 721             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 722         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 723
 724         if (cbpy < 0) {
 725             av_log(s->avctx, AV_LOG_ERROR, "cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 726             return SLICE_ERROR;
 727         }
 728
 729         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 730             cbpy ^= 0xF;
 731
 732         cbp = (cbpc & 3) | (cbpy << 2);
 733         if (dquant) {
 734             h263_decode_dquant(s);
 735         }
 736
 737         s->mv_dir = MV_DIR_FORWARD;
 738         if ((cbpc & 16) == 0) {
 739             s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 740             /* 16x16 motion prediction */
 741             s->mv_type = MV_TYPE_16X16;
 742             ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 743             if (s->umvplus)
 744                mx = h263p_decode_umotion(s, pred_x);
 745             else
 746                mx = ff_h263_decode_motion(s, pred_x, 1);
 747
 748             if (mx >= 0xffff)
 749                 return SLICE_ERROR;
 750
 751             if (s->umvplus)
 752                my = h263p_decode_umotion(s, pred_y);
 753             else
 754                my = ff_h263_decode_motion(s, pred_y, 1);
 755
 756             if (my >= 0xffff)
 757                 return SLICE_ERROR;
 758             s->mv[0][0][0] = mx;
 759             s->mv[0][0][1] = my;
 760
 761             if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 762                skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 763         } else {
 764             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 765             s->mv_type = MV_TYPE_8X8;
 766             for(i=0;i<4;i++) {
 767                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 768                 if (s->umvplus)
 769                     mx = h263p_decode_umotion(s, pred_x);
 770                 else
 771                     mx = ff_h263_decode_motion(s, pred_x, 1);
 772                 if (mx >= 0xffff)
 773                     return SLICE_ERROR;
 774
 775                 if (s->umvplus)
 776                     my = h263p_decode_umotion(s, pred_y);
 777                 else
 778                     my = ff_h263_decode_motion(s, pred_y, 1);
 779                 if (my >= 0xffff)
 780                     return SLICE_ERROR;
 781                 s->mv[0][i][0] = mx;
 782                 s->mv[0][i][1] = my;
 783                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 784                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 785                 mot_val[0] = mx;
 786                 mot_val[1] = my;
 787             }
 788         }
 789     } else if(s->pict_type==AV_PICTURE_TYPE_B) {
 790         int mb_type;
 791         const int stride= s->b8_stride;
 792         int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
 793         int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
 794 //        const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 795
 796         //FIXME ugly
 797         mot_val0[0       ]= mot_val0[2       ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
 798         mot_val0[1       ]= mot_val0[3       ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
 799         mot_val1[0       ]= mot_val1[2       ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
 800         mot_val1[1       ]= mot_val1[3       ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
 801
 802         do{
 803             mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
 804             if (mb_type < 0){
 805                 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
 806                 return SLICE_ERROR;
 807             }
 808
 809             mb_type= h263_mb_type_b_map[ mb_type ];
 810         }while(!mb_type);
 811
 812         s->mb_intra = IS_INTRA(mb_type);
 813         if(HAS_CBP(mb_type)){
 814             s->bdsp.clear_blocks(s->block[0]);
 815             cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
 816             if(s->mb_intra){
 817                 dquant = IS_QUANT(mb_type);
 818                 goto intra;
 819             }
 820
 821             cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 822
 823             if (cbpy < 0){
 824                 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 825                 return SLICE_ERROR;
 826             }
 827
 828             if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 829                 cbpy ^= 0xF;
 830
 831             cbp = (cbpc & 3) | (cbpy << 2);
 832         }else
 833             cbp=0;
 834
 835         av_assert2(!s->mb_intra);
 836
 837         if(IS_QUANT(mb_type)){
 838             h263_decode_dquant(s);
 839         }
 840
 841         if(IS_DIRECT(mb_type)){
 842             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
 843             mb_type |= set_direct_mv(s);
 844         }else{
 845             s->mv_dir = 0;
 846             s->mv_type= MV_TYPE_16X16;
 847 //FIXME UMV
 848
 849             if(USES_LIST(mb_type, 0)){
 850                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 851                 s->mv_dir = MV_DIR_FORWARD;
 852
 853                 if (s->umvplus)
 854                     mx = h263p_decode_umotion(s, pred_x);
 855                 else
 856                     mx = ff_h263_decode_motion(s, pred_x, 1);
 857                 if (mx >= 0xffff)
 858                     return SLICE_ERROR;
 859
 860                 if (s->umvplus)
 861                     my = h263p_decode_umotion(s, pred_y);
 862                 else
 863                     my = ff_h263_decode_motion(s, pred_y, 1);
 864                 if (my >= 0xffff)
 865                     return SLICE_ERROR;
 866
 867                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 868                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 869
 870                 s->mv[0][0][0] = mx;
 871                 s->mv[0][0][1] = my;
 872                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 873                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 874             }
 875
 876             if(USES_LIST(mb_type, 1)){
 877                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &pred_x, &pred_y);
 878                 s->mv_dir |= MV_DIR_BACKWARD;
 879
 880                 if (s->umvplus)
 881                     mx = h263p_decode_umotion(s, pred_x);
 882                 else
 883                     mx = ff_h263_decode_motion(s, pred_x, 1);
 884                 if (mx >= 0xffff)
 885                     return SLICE_ERROR;
 886
 887                 if (s->umvplus)
 888                     my = h263p_decode_umotion(s, pred_y);
 889                 else
 890                     my = ff_h263_decode_motion(s, pred_y, 1);
 891                 if (my >= 0xffff)
 892                     return SLICE_ERROR;
 893
 894                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 895                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 896
 897                 s->mv[1][0][0] = mx;
 898                 s->mv[1][0][1] = my;
 899                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 900                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 901             }
 902         }
 903
 904         s->current_picture.mb_type[xy] = mb_type;
 905     } else { /* I-Frame */
 906         do{
 907             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 908             if (cbpc < 0){
 909                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 910                 return SLICE_ERROR;
 911             }
 912         }while(cbpc == 8);
 913
 914         s->bdsp.clear_blocks(s->block[0]);
 915
 916         dquant = cbpc & 4;
 917         s->mb_intra = 1;
 918 intra:
 919         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 920         if (s->h263_aic) {
 921             s->ac_pred = get_bits1(&s->gb);
 922             if(s->ac_pred){
 923                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
 924
 925                 s->h263_aic_dir = get_bits1(&s->gb);
 926             }
 927         }else
 928             s->ac_pred = 0;
 929
 930         if(s->pb_frame && get_bits1(&s->gb))
 931             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 932         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 933         if(cbpy<0){
 934             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 935             return SLICE_ERROR;
 936         }
 937         cbp = (cbpc & 3) | (cbpy << 2);
 938         if (dquant) {
 939             h263_decode_dquant(s);
 940         }
 941
 942         pb_mv_count += !!s->pb_frame;
 943     }
 944
 945     while(pb_mv_count--){
 946         ff_h263_decode_motion(s, 0, 1);
 947         ff_h263_decode_motion(s, 0, 1);
 948     }
 949
 950     /* decode each block */
 951     for (i = 0; i < 6; i++) {
 952         if (h263_decode_block(s, block[i], i, cbp&32) < 0)
 953             return -1;
 954         cbp+=cbp;
 955     }
 956
 957     if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
 958         return -1;
 959     if(s->obmc && !s->mb_intra){
 960         if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
 961             preview_obmc(s);
 962     }
 963 end:
 964
 965     if (get_bits_left(&s->gb) < 0)
 966         return AVERROR_INVALIDDATA;
 967
 968         /* per-MB end of slice check */
 969     {
 970         int v= show_bits(&s->gb, 16);
 971
 972         if (get_bits_left(&s->gb) < 16) {
 973             v >>= 16 - get_bits_left(&s->gb);
 974         }
 975
 976         if(v==0)
 977             return SLICE_END;
 978     }
 979
 980     return SLICE_OK;
 981 }
 982
 983 /* Most is hardcoded; should extend to handle all H.263 streams. */
 984 int ff_h263_decode_picture_header(MpegEncContext *s)
 985 {
 986     int format, width, height, i, ret;
 987     uint32_t startcode;
 988
 989     align_get_bits(&s->gb);
 990
 991     if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
 992          av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
 993     }
 994
 995     startcode= get_bits(&s->gb, 22-8);
 996
 997     for(i= get_bits_left(&s->gb); i>24; i-=8) {
 998         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
 999
1000         if(startcode == 0x20)
1001             break;
1002     }
1003
1004     if (startcode != 0x20) {
1005         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
1006         return -1;
1007     }
1008     /* temporal reference */
1009     i = get_bits(&s->gb, 8); /* picture timestamp */
1010
1011     i -= (i - (s->picture_number & 0xFF) + 128) & ~0xFF;
1012
1013     s->picture_number= (s->picture_number&~0xFF) + i;
1014
1015     /* PTYPE starts here */
1016     if (check_marker(s->avctx, &s->gb, "in PTYPE") != 1) {
1017         return -1;
1018     }
1019     if (get_bits1(&s->gb) != 0) {
1020         av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
1021         return -1;      /* H.263 id */
1022     }
1023     skip_bits1(&s->gb);         /* split screen off */
1024     skip_bits1(&s->gb);         /* camera  off */
1025     skip_bits1(&s->gb);         /* freeze picture release off */
1026
1027     format = get_bits(&s->gb, 3);
1028     /*
1029         0    forbidden
1030         1    sub-QCIF
1031         10   QCIF
1032         7       extended PTYPE (PLUSPTYPE)
1033     */
1034
1035     if (format != 7 && format != 6) {
1036         s->h263_plus = 0;
1037         /* H.263v1 */
1038         width = ff_h263_format[format][0];
1039         height = ff_h263_format[format][1];
1040         if (!width)
1041             return -1;
1042
1043         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
1044
1045         s->h263_long_vectors = get_bits1(&s->gb);
1046
1047         if (get_bits1(&s->gb) != 0) {
1048             av_log(s->avctx, AV_LOG_ERROR, "H.263 SAC not supported\n");
1049             return -1; /* SAC: off */
1050         }
1051         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1052         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
1053
1054         s->pb_frame = get_bits1(&s->gb);
1055         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
1056         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
1057
1058         s->width = width;
1059         s->height = height;
1060         s->avctx->sample_aspect_ratio= (AVRational){12,11};
1061         s->avctx->framerate = (AVRational){ 30000, 1001 };
1062     } else {
1063         int ufep;
1064
1065         /* H.263v2 */
1066         s->h263_plus = 1;
1067         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
1068
1069         /* ufep other than 0 and 1 are reserved */
1070         if (ufep == 1) {
1071             /* OPPTYPE */
1072             format = get_bits(&s->gb, 3);
1073             ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
1074             s->custom_pcf= get_bits1(&s->gb);
1075             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
1076             if (get_bits1(&s->gb) != 0) {
1077                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
1078             }
1079             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1080             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
1081             s->loop_filter= get_bits1(&s->gb);
1082             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
1083             if(s->avctx->lowres)
1084                 s->loop_filter = 0;
1085
1086             s->h263_slice_structured= get_bits1(&s->gb);
1087             if (get_bits1(&s->gb) != 0) {
1088                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
1089             }
1090             if (get_bits1(&s->gb) != 0) {
1091                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
1092             }
1093             s->alt_inter_vlc= get_bits1(&s->gb);
1094             s->modified_quant= get_bits1(&s->gb);
1095             if(s->modified_quant)
1096                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
1097
1098             skip_bits(&s->gb, 1); /* Prevent start code emulation */
1099
1100             skip_bits(&s->gb, 3); /* Reserved */
1101         } else if (ufep != 0) {
1102             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
1103             return -1;
1104         }
1105
1106         /* MPPTYPE */
1107         s->pict_type = get_bits(&s->gb, 3);
1108         switch(s->pict_type){
1109         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1110         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1111         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1112         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1113         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1114         default:
1115             return -1;
1116         }
1117         skip_bits(&s->gb, 2);
1118         s->no_rounding = get_bits1(&s->gb);
1119         skip_bits(&s->gb, 4);
1120
1121         /* Get the picture dimensions */
1122         if (ufep) {
1123             if (format == 6) {
1124                 /* Custom Picture Format (CPFMT) */
1125                 s->aspect_ratio_info = get_bits(&s->gb, 4);
1126                 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1127                 /* aspect ratios:
1128                 0 - forbidden
1129                 1 - 1:1
1130                 2 - 12:11 (CIF 4:3)
1131                 3 - 10:11 (525-type 4:3)
1132                 4 - 16:11 (CIF 16:9)
1133                 5 - 40:33 (525-type 16:9)
1134                 6-14 - reserved
1135                 */
1136                 width = (get_bits(&s->gb, 9) + 1) * 4;
1137                 check_marker(s->avctx, &s->gb, "in dimensions");
1138                 height = get_bits(&s->gb, 9) * 4;
1139                 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1140                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1141                     /* expected dimensions */
1142                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1143                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1144                 }else{
1145                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1146                 }
1147             } else {
1148                 width = ff_h263_format[format][0];
1149                 height = ff_h263_format[format][1];
1150                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1151             }
1152             s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1153             if ((width == 0) || (height == 0))
1154                 return -1;
1155             s->width = width;
1156             s->height = height;
1157
1158             if(s->custom_pcf){
1159                 int gcd;
1160                 s->avctx->framerate.num  = 1800000;
1161                 s->avctx->framerate.den  = 1000 + get_bits1(&s->gb);
1162                 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1163                 if(s->avctx->framerate.den == 0){
1164                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
1165                     return -1;
1166                 }
1167                 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1168                 s->avctx->framerate.den /= gcd;
1169                 s->avctx->framerate.num /= gcd;
1170             }else{
1171                 s->avctx->framerate = (AVRational){ 30000, 1001 };
1172             }
1173         }
1174
1175         if(s->custom_pcf){
1176             skip_bits(&s->gb, 2); //extended Temporal reference
1177         }
1178
1179         if (ufep) {
1180             if (s->umvplus) {
1181                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1182                     skip_bits1(&s->gb);
1183             }
1184             if(s->h263_slice_structured){
1185                 if (get_bits1(&s->gb) != 0) {
1186                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1187                 }
1188                 if (get_bits1(&s->gb) != 0) {
1189                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1190                 }
1191             }
1192             if (s->pict_type == AV_PICTURE_TYPE_B) {
1193                 skip_bits(&s->gb, 4); //ELNUM
1194                 if (ufep == 1) {
1195                     skip_bits(&s->gb, 4); // RLNUM
1196                 }
1197             }
1198         }
1199
1200         s->qscale = get_bits(&s->gb, 5);
1201     }
1202
1203     if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
1204         return ret;
1205
1206     s->mb_width = (s->width  + 15) / 16;
1207     s->mb_height = (s->height  + 15) / 16;
1208     s->mb_num = s->mb_width * s->mb_height;
1209
1210     if (s->pb_frame) {
1211         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1212         if (s->custom_pcf)
1213             skip_bits(&s->gb, 2); //extended Temporal reference
1214         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1215     }
1216
1217     if (s->pict_type!=AV_PICTURE_TYPE_B) {
1218         s->time            = s->picture_number;
1219         s->pp_time         = s->time - s->last_non_b_time;
1220         s->last_non_b_time = s->time;
1221     }else{
1222         s->time    = s->picture_number;
1223         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1224         if (s->pp_time <=s->pb_time ||
1225             s->pp_time <= s->pp_time - s->pb_time ||
1226             s->pp_time <= 0){
1227             s->pp_time = 2;
1228             s->pb_time = 1;
1229         }
1230         ff_mpeg4_init_direct_mv(s);
1231     }
1232
1233     /* PEI */
1234     if (skip_1stop_8data_bits(&s->gb) < 0)
1235         return AVERROR_INVALIDDATA;
1236
1237     if(s->h263_slice_structured){
1238         if (check_marker(s->avctx, &s->gb, "SEPB1") != 1) {
1239             return -1;
1240         }
1241
1242         ff_h263_decode_mba(s);
1243
1244         if (check_marker(s->avctx, &s->gb, "SEPB2") != 1) {
1245             return -1;
1246         }
1247     }
1248     s->f_code = 1;
1249
1250     if (s->pict_type == AV_PICTURE_TYPE_B)
1251         s->low_delay = 0;
1252
1253     if(s->h263_aic){
1254          s->y_dc_scale_table=
1255          s->c_dc_scale_table= ff_aic_dc_scale_table;
1256     }else{
1257         s->y_dc_scale_table=
1258         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1259     }
1260
1261         ff_h263_show_pict_info(s);
1262     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1263         int i,j;
1264         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1265         av_log(s->avctx, AV_LOG_DEBUG, "\n");
1266         for(i=0; i<13; i++){
1267             for(j=0; j<3; j++){
1268                 int v= get_bits(&s->gb, 8);
1269                 v |= get_sbits(&s->gb, 8)<<8;
1270                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1271             }
1272             av_log(s->avctx, AV_LOG_DEBUG, "\n");
1273         }
1274         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1275     }
1276
1277     return 0;
1278 }