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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_h263_init_rl_inter();
 126         INIT_VLC_RL(ff_h263_rl_inter, 554);
 127         INIT_FIRST_VLC_RL(ff_rl_intra_aic, 554);
 128         INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
 129                  &ff_h263_mbtype_b_tab[0][1], 2, 1,
 130                  &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
 131         INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
 132                  &ff_cbpc_b_tab[0][1], 2, 1,
 133                  &ff_cbpc_b_tab[0][0], 2, 1, 8);
 134         done = 1;
 135     }
 136 }
 137
 138 int ff_h263_decode_mba(MpegEncContext *s)
 139 {
 140     int i, mb_pos;
 141
 142     for (i = 0; i < 6; i++)
 143         if (s->mb_num - 1 <= ff_mba_max[i])
 144             break;
 145     mb_pos  = get_bits(&s->gb, ff_mba_length[i]);
 146     s->mb_x = mb_pos % s->mb_width;
 147     s->mb_y = mb_pos / s->mb_width;
 148
 149     return mb_pos;
 150 }
 151
 152 /**
 153  * Decode the group of blocks header or slice header.
 154  * @return <0 if an error occurred
 155  */
 156 static int h263_decode_gob_header(MpegEncContext *s)
 157 {
 158     unsigned int val, gob_number;
 159     int left;
 160
 161     /* Check for GOB Start Code */
 162     val = show_bits(&s->gb, 16);
 163     if(val)
 164         return -1;
 165
 166         /* We have a GBSC probably with GSTUFF */
 167     skip_bits(&s->gb, 16); /* Drop the zeros */
 168     left= get_bits_left(&s->gb);
 169     left = FFMIN(left, 32);
 170     //MN: we must check the bits left or we might end in an infinite loop (or segfault)
 171     for(;left>13; left--){
 172         if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
 173     }
 174     if(left<=13)
 175         return -1;
 176
 177     if(s->h263_slice_structured){
 178         if(check_marker(s->avctx, &s->gb, "before MBA")==0)
 179             return -1;
 180
 181         ff_h263_decode_mba(s);
 182
 183         if(s->mb_num > 1583)
 184             if(check_marker(s->avctx, &s->gb, "after MBA")==0)
 185                 return -1;
 186
 187         s->qscale = get_bits(&s->gb, 5); /* SQUANT */
 188         if(check_marker(s->avctx, &s->gb, "after SQUANT")==0)
 189             return -1;
 190         skip_bits(&s->gb, 2); /* GFID */
 191     }else{
 192         gob_number = get_bits(&s->gb, 5); /* GN */
 193         s->mb_x= 0;
 194         s->mb_y= s->gob_index* gob_number;
 195         skip_bits(&s->gb, 2); /* GFID */
 196         s->qscale = get_bits(&s->gb, 5); /* GQUANT */
 197     }
 198
 199     if(s->mb_y >= s->mb_height)
 200         return -1;
 201
 202     if(s->qscale==0)
 203         return -1;
 204
 205     return 0;
 206 }
 207
 208 /**
 209  * Decode the group of blocks / video packet header / slice header (MPEG-4 Studio).
 210  * @return bit position of the resync_marker, or <0 if none was found
 211  */
 212 int ff_h263_resync(MpegEncContext *s){
 213     int left, pos, ret;
 214
 215     /* In MPEG-4 studio mode look for a new slice startcode
 216      * and decode slice header */
 217     if(s->codec_id==AV_CODEC_ID_MPEG4 && s->studio_profile) {
 218         align_get_bits(&s->gb);
 219
 220         while (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) != SLICE_START_CODE) {
 221             get_bits(&s->gb, 8);
 222         }
 223
 224         if (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) == SLICE_START_CODE)
 225             return get_bits_count(&s->gb);
 226         else
 227             return -1;
 228     }
 229
 230     if(s->codec_id==AV_CODEC_ID_MPEG4){
 231         skip_bits1(&s->gb);
 232         align_get_bits(&s->gb);
 233     }
 234
 235     if(show_bits(&s->gb, 16)==0){
 236         pos= get_bits_count(&s->gb);
 237         if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 238             ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 239         else
 240             ret= h263_decode_gob_header(s);
 241         if(ret>=0)
 242             return pos;
 243     }
 244     //OK, it's not where it is supposed to be ...
 245     s->gb= s->last_resync_gb;
 246     align_get_bits(&s->gb);
 247     left= get_bits_left(&s->gb);
 248
 249     for(;left>16+1+5+5; left-=8){
 250         if(show_bits(&s->gb, 16)==0){
 251             GetBitContext bak= s->gb;
 252
 253             pos= get_bits_count(&s->gb);
 254             if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
 255                 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
 256             else
 257                 ret= h263_decode_gob_header(s);
 258             if(ret>=0)
 259                 return pos;
 260
 261             s->gb= bak;
 262         }
 263         skip_bits(&s->gb, 8);
 264     }
 265
 266     return -1;
 267 }
 268
 269 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
 270 {
 271     int code, val, sign, shift;
 272     code = get_vlc2(&s->gb, ff_h263_mv_vlc.table, H263_MV_VLC_BITS, 2);
 273
 274     if (code == 0)
 275         return pred;
 276     if (code < 0)
 277         return 0xffff;
 278
 279     sign = get_bits1(&s->gb);
 280     shift = f_code - 1;
 281     val = code;
 282     if (shift) {
 283         val = (val - 1) << shift;
 284         val |= get_bits(&s->gb, shift);
 285         val++;
 286     }
 287     if (sign)
 288         val = -val;
 289     val += pred;
 290
 291     /* modulo decoding */
 292     if (!s->h263_long_vectors) {
 293         val = sign_extend(val, 5 + f_code);
 294     } else {
 295         /* horrible H.263 long vector mode */
 296         if (pred < -31 && val < -63)
 297             val += 64;
 298         if (pred > 32 && val > 63)
 299             val -= 64;
 300
 301     }
 302     return val;
 303 }
 304
 305
 306 /* Decode RVLC of H.263+ UMV */
 307 static int h263p_decode_umotion(MpegEncContext * s, int pred)
 308 {
 309    int code = 0, sign;
 310
 311    if (get_bits1(&s->gb)) /* Motion difference = 0 */
 312       return pred;
 313
 314    code = 2 + get_bits1(&s->gb);
 315
 316    while (get_bits1(&s->gb))
 317    {
 318       code <<= 1;
 319       code += get_bits1(&s->gb);
 320       if (code >= 32768) {
 321           avpriv_request_sample(s->avctx, "Huge DMV");
 322           return 0xffff;
 323       }
 324    }
 325    sign = code & 1;
 326    code >>= 1;
 327
 328    code = (sign) ? (pred - code) : (pred + code);
 329    ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
 330    return code;
 331
 332 }
 333
 334 /**
 335  * read the next MVs for OBMC. yes this is an ugly hack, feel free to send a patch :)
 336  */
 337 static void preview_obmc(MpegEncContext *s){
 338     GetBitContext gb= s->gb;
 339
 340     int cbpc, i, pred_x, pred_y, mx, my;
 341     int16_t *mot_val;
 342     const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 343     const int stride= s->b8_stride*2;
 344
 345     for(i=0; i<4; i++)
 346         s->block_index[i]+= 2;
 347     for(i=4; i<6; i++)
 348         s->block_index[i]+= 1;
 349     s->mb_x++;
 350
 351     av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
 352
 353     do{
 354         if (get_bits1(&s->gb)) {
 355             /* skip mb */
 356             mot_val = s->current_picture.motion_val[0][s->block_index[0]];
 357             mot_val[0       ]= mot_val[2       ]=
 358             mot_val[0+stride]= mot_val[2+stride]= 0;
 359             mot_val[1       ]= mot_val[3       ]=
 360             mot_val[1+stride]= mot_val[3+stride]= 0;
 361
 362             s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 363             goto end;
 364         }
 365         cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 366     }while(cbpc == 20);
 367
 368     if(cbpc & 4){
 369         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 370     }else{
 371         get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 372         if (cbpc & 8) {
 373             if(s->modified_quant){
 374                 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
 375                 else                  skip_bits(&s->gb, 5);
 376             }else
 377                 skip_bits(&s->gb, 2);
 378         }
 379
 380         if ((cbpc & 16) == 0) {
 381                 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 382                 /* 16x16 motion prediction */
 383                 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 384                 if (s->umvplus)
 385                     mx = h263p_decode_umotion(s, pred_x);
 386                 else
 387                     mx = ff_h263_decode_motion(s, pred_x, 1);
 388
 389                 if (s->umvplus)
 390                     my = h263p_decode_umotion(s, pred_y);
 391                 else
 392                     my = ff_h263_decode_motion(s, pred_y, 1);
 393
 394                 mot_val[0       ]= mot_val[2       ]=
 395                 mot_val[0+stride]= mot_val[2+stride]= mx;
 396                 mot_val[1       ]= mot_val[3       ]=
 397                 mot_val[1+stride]= mot_val[3+stride]= my;
 398         } else {
 399             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 400             for(i=0;i<4;i++) {
 401                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 402                 if (s->umvplus)
 403                     mx = h263p_decode_umotion(s, pred_x);
 404                 else
 405                     mx = ff_h263_decode_motion(s, pred_x, 1);
 406
 407                 if (s->umvplus)
 408                     my = h263p_decode_umotion(s, pred_y);
 409                 else
 410                     my = ff_h263_decode_motion(s, pred_y, 1);
 411                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 412                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 413                 mot_val[0] = mx;
 414                 mot_val[1] = my;
 415             }
 416         }
 417     }
 418 end:
 419
 420     for(i=0; i<4; i++)
 421         s->block_index[i]-= 2;
 422     for(i=4; i<6; i++)
 423         s->block_index[i]-= 1;
 424     s->mb_x--;
 425
 426     s->gb= gb;
 427 }
 428
 429 static void h263_decode_dquant(MpegEncContext *s){
 430     static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
 431
 432     if(s->modified_quant){
 433         if(get_bits1(&s->gb))
 434             s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
 435         else
 436             s->qscale= get_bits(&s->gb, 5);
 437     }else
 438         s->qscale += quant_tab[get_bits(&s->gb, 2)];
 439     ff_set_qscale(s, s->qscale);
 440 }
 441
 442 static int h263_decode_block(MpegEncContext * s, int16_t * block,
 443                              int n, int coded)
 444 {
 445     int level, i, j, run;
 446     RLTable *rl = &ff_h263_rl_inter;
 447     const uint8_t *scan_table;
 448     GetBitContext gb= s->gb;
 449
 450     scan_table = s->intra_scantable.permutated;
 451     if (s->h263_aic && s->mb_intra) {
 452         rl = &ff_rl_intra_aic;
 453         i = 0;
 454         if (s->ac_pred) {
 455             if (s->h263_aic_dir)
 456                 scan_table = s->intra_v_scantable.permutated; /* left */
 457             else
 458                 scan_table = s->intra_h_scantable.permutated; /* top */
 459         }
 460     } else if (s->mb_intra) {
 461         /* DC coef */
 462         if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
 463           if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
 464             int component, diff;
 465             component = (n <= 3 ? 0 : n - 4 + 1);
 466             level = s->last_dc[component];
 467             if (s->rv10_first_dc_coded[component]) {
 468                 diff = ff_rv_decode_dc(s, n);
 469                 if (diff < 0)
 470                     return -1;
 471                 level += diff;
 472                 level = level & 0xff; /* handle wrap round */
 473                 s->last_dc[component] = level;
 474             } else {
 475                 s->rv10_first_dc_coded[component] = 1;
 476             }
 477           } else {
 478                 level = get_bits(&s->gb, 8);
 479                 if (level == 255)
 480                     level = 128;
 481           }
 482         }else{
 483             level = get_bits(&s->gb, 8);
 484             if((level&0x7F) == 0){
 485                 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
 486                 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
 487                     return -1;
 488             }
 489             if (level == 255)
 490                 level = 128;
 491         }
 492         block[0] = level;
 493         i = 1;
 494     } else {
 495         i = 0;
 496     }
 497     if (!coded) {
 498         if (s->mb_intra && s->h263_aic)
 499             goto not_coded;
 500         s->block_last_index[n] = i - 1;
 501         return 0;
 502     }
 503 retry:
 504     {
 505     OPEN_READER(re, &s->gb);
 506     i--; // offset by -1 to allow direct indexing of scan_table
 507     for(;;) {
 508         UPDATE_CACHE(re, &s->gb);
 509         GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
 510         if (run == 66) {
 511             if (level){
 512                 CLOSE_READER(re, &s->gb);
 513                 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
 514                 return -1;
 515             }
 516             /* escape */
 517             if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
 518                 int is11 = SHOW_UBITS(re, &s->gb, 1);
 519                 SKIP_CACHE(re, &s->gb, 1);
 520                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 521                 if (is11) {
 522                     SKIP_COUNTER(re, &s->gb, 1 + 7);
 523                     UPDATE_CACHE(re, &s->gb);
 524                     level = SHOW_SBITS(re, &s->gb, 11);
 525                     SKIP_COUNTER(re, &s->gb, 11);
 526                 } else {
 527                     SKIP_CACHE(re, &s->gb, 7);
 528                     level = SHOW_SBITS(re, &s->gb, 7);
 529                     SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
 530                 }
 531             } else {
 532                 run = SHOW_UBITS(re, &s->gb, 7) + 1;
 533                 SKIP_CACHE(re, &s->gb, 7);
 534                 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
 535                 SKIP_COUNTER(re, &s->gb, 7 + 8);
 536                 if(level == -128){
 537                     UPDATE_CACHE(re, &s->gb);
 538                     if (s->codec_id == AV_CODEC_ID_RV10) {
 539                         /* XXX: should patch encoder too */
 540                         level = SHOW_SBITS(re, &s->gb, 12);
 541                         SKIP_COUNTER(re, &s->gb, 12);
 542                     }else{
 543                         level = SHOW_UBITS(re, &s->gb, 5);
 544                         SKIP_CACHE(re, &s->gb, 5);
 545                         level |= SHOW_SBITS(re, &s->gb, 6) * (1<<5);
 546                         SKIP_COUNTER(re, &s->gb, 5 + 6);
 547                     }
 548                 }
 549             }
 550         } else {
 551             if (SHOW_UBITS(re, &s->gb, 1))
 552                 level = -level;
 553             SKIP_COUNTER(re, &s->gb, 1);
 554         }
 555         i += run;
 556         if (i >= 64){
 557             CLOSE_READER(re, &s->gb);
 558             // redo update without last flag, revert -1 offset
 559             i = i - run + ((run-1)&63) + 1;
 560             if (i < 64) {
 561                 // only last marker, no overrun
 562                 block[scan_table[i]] = level;
 563                 break;
 564             }
 565             if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
 566                 //Looks like a hack but no, it's the way it is supposed to work ...
 567                 rl = &ff_rl_intra_aic;
 568                 i = 0;
 569                 s->gb= gb;
 570                 s->bdsp.clear_block(block);
 571                 goto retry;
 572             }
 573             av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
 574             return -1;
 575         }
 576         j = scan_table[i];
 577         block[j] = level;
 578     }
 579     }
 580 not_coded:
 581     if (s->mb_intra && s->h263_aic) {
 582         ff_h263_pred_acdc(s, block, n);
 583         i = 63;
 584     }
 585     s->block_last_index[n] = i;
 586     return 0;
 587 }
 588
 589 static int h263_skip_b_part(MpegEncContext *s, int cbp)
 590 {
 591     LOCAL_ALIGNED_32(int16_t, dblock, [64]);
 592     int i, mbi;
 593     int bli[6];
 594
 595     /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
 596      * but real value should be restored in order to be used later (in OBMC condition)
 597      */
 598     mbi = s->mb_intra;
 599     memcpy(bli, s->block_last_index, sizeof(bli));
 600     s->mb_intra = 0;
 601     for (i = 0; i < 6; i++) {
 602         if (h263_decode_block(s, dblock, i, cbp&32) < 0)
 603             return -1;
 604         cbp+=cbp;
 605     }
 606     s->mb_intra = mbi;
 607     memcpy(s->block_last_index, bli, sizeof(bli));
 608     return 0;
 609 }
 610
 611 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
 612 {
 613     int c, mv = 1;
 614
 615     if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
 616         c = get_bits1(gb);
 617         if (pb_frame == 2 && c)
 618             mv = !get_bits1(gb);
 619     } else { // h.263 Annex M improved PB-frame
 620         mv = get_unary(gb, 0, 4) + 1;
 621         c = mv & 1;
 622         mv = !!(mv & 2);
 623     }
 624     if(c)
 625         *cbpb = get_bits(gb, 6);
 626     return mv;
 627 }
 628
 629 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
 630 #define tab_bias (tab_size / 2)
 631 static inline void set_one_direct_mv(MpegEncContext *s, Picture *p, int i)
 632 {
 633     int xy           = s->block_index[i];
 634     uint16_t time_pp = s->pp_time;
 635     uint16_t time_pb = s->pb_time;
 636     int p_mx, p_my;
 637
 638     p_mx = p->motion_val[0][xy][0];
 639     if ((unsigned)(p_mx + tab_bias) < tab_size) {
 640         s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias];
 641         s->mv[1][i][0] = s->direct_scale_mv[1][p_mx + tab_bias];
 642     } else {
 643         s->mv[0][i][0] = p_mx * time_pb / time_pp;
 644         s->mv[1][i][0] = p_mx * (time_pb - time_pp) / time_pp;
 645     }
 646     p_my = p->motion_val[0][xy][1];
 647     if ((unsigned)(p_my + tab_bias) < tab_size) {
 648         s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias];
 649         s->mv[1][i][1] = s->direct_scale_mv[1][p_my + tab_bias];
 650     } else {
 651         s->mv[0][i][1] = p_my * time_pb / time_pp;
 652         s->mv[1][i][1] = p_my * (time_pb - time_pp) / time_pp;
 653     }
 654 }
 655
 656 /**
 657  * @return the mb_type
 658  */
 659 static int set_direct_mv(MpegEncContext *s)
 660 {
 661     const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
 662     Picture *p = &s->next_picture;
 663     int colocated_mb_type = p->mb_type[mb_index];
 664     int i;
 665
 666     if (s->codec_tag == AV_RL32("U263") && p->f->pict_type == AV_PICTURE_TYPE_I) {
 667         p = &s->last_picture;
 668         colocated_mb_type = p->mb_type[mb_index];
 669     }
 670
 671     if (IS_8X8(colocated_mb_type)) {
 672         s->mv_type = MV_TYPE_8X8;
 673         for (i = 0; i < 4; i++)
 674             set_one_direct_mv(s, p, i);
 675         return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
 676     } else {
 677         set_one_direct_mv(s, p, 0);
 678         s->mv[0][1][0] =
 679         s->mv[0][2][0] =
 680         s->mv[0][3][0] = s->mv[0][0][0];
 681         s->mv[0][1][1] =
 682         s->mv[0][2][1] =
 683         s->mv[0][3][1] = s->mv[0][0][1];
 684         s->mv[1][1][0] =
 685         s->mv[1][2][0] =
 686         s->mv[1][3][0] = s->mv[1][0][0];
 687         s->mv[1][1][1] =
 688         s->mv[1][2][1] =
 689         s->mv[1][3][1] = s->mv[1][0][1];
 690         s->mv_type = MV_TYPE_8X8;
 691         // Note see prev line
 692         return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
 693     }
 694 }
 695
 696 int ff_h263_decode_mb(MpegEncContext *s,
 697                       int16_t block[6][64])
 698 {
 699     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
 700     int16_t *mot_val;
 701     const int xy= s->mb_x + s->mb_y * s->mb_stride;
 702     int cbpb = 0, pb_mv_count = 0;
 703
 704     av_assert2(!s->h263_pred);
 705
 706     if (s->pict_type == AV_PICTURE_TYPE_P) {
 707         do{
 708             if (get_bits1(&s->gb)) {
 709                 /* skip mb */
 710                 s->mb_intra = 0;
 711                 for(i=0;i<6;i++)
 712                     s->block_last_index[i] = -1;
 713                 s->mv_dir = MV_DIR_FORWARD;
 714                 s->mv_type = MV_TYPE_16X16;
 715                 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
 716                 s->mv[0][0][0] = 0;
 717                 s->mv[0][0][1] = 0;
 718                 s->mb_skipped = !(s->obmc | s->loop_filter);
 719                 goto end;
 720             }
 721             cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
 722             if (cbpc < 0){
 723                 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 724                 return SLICE_ERROR;
 725             }
 726         }while(cbpc == 20);
 727
 728         s->bdsp.clear_blocks(s->block[0]);
 729
 730         dquant = cbpc & 8;
 731         s->mb_intra = ((cbpc & 4) != 0);
 732         if (s->mb_intra) goto intra;
 733
 734         if(s->pb_frame && get_bits1(&s->gb))
 735             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 736         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 737
 738         if (cbpy < 0) {
 739             av_log(s->avctx, AV_LOG_ERROR, "cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 740             return SLICE_ERROR;
 741         }
 742
 743         if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 744             cbpy ^= 0xF;
 745
 746         cbp = (cbpc & 3) | (cbpy << 2);
 747         if (dquant) {
 748             h263_decode_dquant(s);
 749         }
 750
 751         s->mv_dir = MV_DIR_FORWARD;
 752         if ((cbpc & 16) == 0) {
 753             s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
 754             /* 16x16 motion prediction */
 755             s->mv_type = MV_TYPE_16X16;
 756             ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 757             if (s->umvplus)
 758                mx = h263p_decode_umotion(s, pred_x);
 759             else
 760                mx = ff_h263_decode_motion(s, pred_x, 1);
 761
 762             if (mx >= 0xffff)
 763                 return SLICE_ERROR;
 764
 765             if (s->umvplus)
 766                my = h263p_decode_umotion(s, pred_y);
 767             else
 768                my = ff_h263_decode_motion(s, pred_y, 1);
 769
 770             if (my >= 0xffff)
 771                 return SLICE_ERROR;
 772             s->mv[0][0][0] = mx;
 773             s->mv[0][0][1] = my;
 774
 775             if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 776                skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 777         } else {
 778             s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
 779             s->mv_type = MV_TYPE_8X8;
 780             for(i=0;i<4;i++) {
 781                 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
 782                 if (s->umvplus)
 783                     mx = h263p_decode_umotion(s, pred_x);
 784                 else
 785                     mx = ff_h263_decode_motion(s, pred_x, 1);
 786                 if (mx >= 0xffff)
 787                     return SLICE_ERROR;
 788
 789                 if (s->umvplus)
 790                     my = h263p_decode_umotion(s, pred_y);
 791                 else
 792                     my = ff_h263_decode_motion(s, pred_y, 1);
 793                 if (my >= 0xffff)
 794                     return SLICE_ERROR;
 795                 s->mv[0][i][0] = mx;
 796                 s->mv[0][i][1] = my;
 797                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 798                   skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 799                 mot_val[0] = mx;
 800                 mot_val[1] = my;
 801             }
 802         }
 803     } else if(s->pict_type==AV_PICTURE_TYPE_B) {
 804         int mb_type;
 805         const int stride= s->b8_stride;
 806         int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
 807         int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
 808 //        const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
 809
 810         //FIXME ugly
 811         mot_val0[0       ]= mot_val0[2       ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
 812         mot_val0[1       ]= mot_val0[3       ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
 813         mot_val1[0       ]= mot_val1[2       ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
 814         mot_val1[1       ]= mot_val1[3       ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
 815
 816         do{
 817             mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
 818             if (mb_type < 0){
 819                 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
 820                 return SLICE_ERROR;
 821             }
 822
 823             mb_type= h263_mb_type_b_map[ mb_type ];
 824         }while(!mb_type);
 825
 826         s->mb_intra = IS_INTRA(mb_type);
 827         if(HAS_CBP(mb_type)){
 828             s->bdsp.clear_blocks(s->block[0]);
 829             cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
 830             if(s->mb_intra){
 831                 dquant = IS_QUANT(mb_type);
 832                 goto intra;
 833             }
 834
 835             cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 836
 837             if (cbpy < 0){
 838                 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 839                 return SLICE_ERROR;
 840             }
 841
 842             if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
 843                 cbpy ^= 0xF;
 844
 845             cbp = (cbpc & 3) | (cbpy << 2);
 846         }else
 847             cbp=0;
 848
 849         av_assert2(!s->mb_intra);
 850
 851         if(IS_QUANT(mb_type)){
 852             h263_decode_dquant(s);
 853         }
 854
 855         if(IS_DIRECT(mb_type)){
 856             s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
 857             mb_type |= set_direct_mv(s);
 858         }else{
 859             s->mv_dir = 0;
 860             s->mv_type= MV_TYPE_16X16;
 861 //FIXME UMV
 862
 863             if(USES_LIST(mb_type, 0)){
 864                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
 865                 s->mv_dir = MV_DIR_FORWARD;
 866
 867                 if (s->umvplus)
 868                     mx = h263p_decode_umotion(s, pred_x);
 869                 else
 870                     mx = ff_h263_decode_motion(s, pred_x, 1);
 871                 if (mx >= 0xffff)
 872                     return SLICE_ERROR;
 873
 874                 if (s->umvplus)
 875                     my = h263p_decode_umotion(s, pred_y);
 876                 else
 877                     my = ff_h263_decode_motion(s, pred_y, 1);
 878                 if (my >= 0xffff)
 879                     return SLICE_ERROR;
 880
 881                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 882                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 883
 884                 s->mv[0][0][0] = mx;
 885                 s->mv[0][0][1] = my;
 886                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 887                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 888             }
 889
 890             if(USES_LIST(mb_type, 1)){
 891                 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &pred_x, &pred_y);
 892                 s->mv_dir |= MV_DIR_BACKWARD;
 893
 894                 if (s->umvplus)
 895                     mx = h263p_decode_umotion(s, pred_x);
 896                 else
 897                     mx = ff_h263_decode_motion(s, pred_x, 1);
 898                 if (mx >= 0xffff)
 899                     return SLICE_ERROR;
 900
 901                 if (s->umvplus)
 902                     my = h263p_decode_umotion(s, pred_y);
 903                 else
 904                     my = ff_h263_decode_motion(s, pred_y, 1);
 905                 if (my >= 0xffff)
 906                     return SLICE_ERROR;
 907
 908                 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
 909                     skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
 910
 911                 s->mv[1][0][0] = mx;
 912                 s->mv[1][0][1] = my;
 913                 mot_val[0       ]= mot_val[2       ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
 914                 mot_val[1       ]= mot_val[3       ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
 915             }
 916         }
 917
 918         s->current_picture.mb_type[xy] = mb_type;
 919     } else { /* I-Frame */
 920         do{
 921             cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
 922             if (cbpc < 0){
 923                 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
 924                 return SLICE_ERROR;
 925             }
 926         }while(cbpc == 8);
 927
 928         s->bdsp.clear_blocks(s->block[0]);
 929
 930         dquant = cbpc & 4;
 931         s->mb_intra = 1;
 932 intra:
 933         s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
 934         if (s->h263_aic) {
 935             s->ac_pred = get_bits1(&s->gb);
 936             if(s->ac_pred){
 937                 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
 938
 939                 s->h263_aic_dir = get_bits1(&s->gb);
 940             }
 941         }else
 942             s->ac_pred = 0;
 943
 944         if(s->pb_frame && get_bits1(&s->gb))
 945             pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
 946         cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
 947         if(cbpy<0){
 948             av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
 949             return SLICE_ERROR;
 950         }
 951         cbp = (cbpc & 3) | (cbpy << 2);
 952         if (dquant) {
 953             h263_decode_dquant(s);
 954         }
 955
 956         pb_mv_count += !!s->pb_frame;
 957     }
 958
 959     while(pb_mv_count--){
 960         ff_h263_decode_motion(s, 0, 1);
 961         ff_h263_decode_motion(s, 0, 1);
 962     }
 963
 964     /* decode each block */
 965     for (i = 0; i < 6; i++) {
 966         if (h263_decode_block(s, block[i], i, cbp&32) < 0)
 967             return -1;
 968         cbp+=cbp;
 969     }
 970
 971     if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
 972         return -1;
 973     if(s->obmc && !s->mb_intra){
 974         if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
 975             preview_obmc(s);
 976     }
 977 end:
 978
 979     if (get_bits_left(&s->gb) < 0)
 980         return AVERROR_INVALIDDATA;
 981
 982         /* per-MB end of slice check */
 983     {
 984         int v= show_bits(&s->gb, 16);
 985
 986         if (get_bits_left(&s->gb) < 16) {
 987             v >>= 16 - get_bits_left(&s->gb);
 988         }
 989
 990         if(v==0)
 991             return SLICE_END;
 992     }
 993
 994     return SLICE_OK;
 995 }
 996
 997 /* Most is hardcoded; should extend to handle all H.263 streams. */
 998 int ff_h263_decode_picture_header(MpegEncContext *s)
 999 {
1000     int format, width, height, i, ret;
1001     uint32_t startcode;
1002
1003     align_get_bits(&s->gb);
1004
1005     if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
1006          av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
1007     }
1008
1009     startcode= get_bits(&s->gb, 22-8);
1010
1011     for(i= get_bits_left(&s->gb); i>24; i-=8) {
1012         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
1013
1014         if(startcode == 0x20)
1015             break;
1016     }
1017
1018     if (startcode != 0x20) {
1019         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
1020         return -1;
1021     }
1022     /* temporal reference */
1023     i = get_bits(&s->gb, 8); /* picture timestamp */
1024
1025     i -= (i - (s->picture_number & 0xFF) + 128) & ~0xFF;
1026
1027     s->picture_number= (s->picture_number&~0xFF) + i;
1028
1029     /* PTYPE starts here */
1030     if (check_marker(s->avctx, &s->gb, "in PTYPE") != 1) {
1031         return -1;
1032     }
1033     if (get_bits1(&s->gb) != 0) {
1034         av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
1035         return -1;      /* H.263 id */
1036     }
1037     skip_bits1(&s->gb);         /* split screen off */
1038     skip_bits1(&s->gb);         /* camera  off */
1039     skip_bits1(&s->gb);         /* freeze picture release off */
1040
1041     format = get_bits(&s->gb, 3);
1042     /*
1043         0    forbidden
1044         1    sub-QCIF
1045         10   QCIF
1046         7       extended PTYPE (PLUSPTYPE)
1047     */
1048
1049     if (format != 7 && format != 6) {
1050         s->h263_plus = 0;
1051         /* H.263v1 */
1052         width = ff_h263_format[format][0];
1053         height = ff_h263_format[format][1];
1054         if (!width)
1055             return -1;
1056
1057         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
1058
1059         s->h263_long_vectors = get_bits1(&s->gb);
1060
1061         if (get_bits1(&s->gb) != 0) {
1062             av_log(s->avctx, AV_LOG_ERROR, "H.263 SAC not supported\n");
1063             return -1; /* SAC: off */
1064         }
1065         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1066         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
1067
1068         s->pb_frame = get_bits1(&s->gb);
1069         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
1070         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
1071
1072         s->width = width;
1073         s->height = height;
1074         s->avctx->sample_aspect_ratio= (AVRational){12,11};
1075         s->avctx->framerate = (AVRational){ 30000, 1001 };
1076     } else {
1077         int ufep;
1078
1079         /* H.263v2 */
1080         s->h263_plus = 1;
1081         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
1082
1083         /* ufep other than 0 and 1 are reserved */
1084         if (ufep == 1) {
1085             /* OPPTYPE */
1086             format = get_bits(&s->gb, 3);
1087             ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
1088             s->custom_pcf= get_bits1(&s->gb);
1089             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
1090             if (get_bits1(&s->gb) != 0) {
1091                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
1092             }
1093             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1094             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
1095             s->loop_filter= get_bits1(&s->gb);
1096             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
1097             if(s->avctx->lowres)
1098                 s->loop_filter = 0;
1099
1100             s->h263_slice_structured= get_bits1(&s->gb);
1101             if (get_bits1(&s->gb) != 0) {
1102                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
1103             }
1104             if (get_bits1(&s->gb) != 0) {
1105                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
1106             }
1107             s->alt_inter_vlc= get_bits1(&s->gb);
1108             s->modified_quant= get_bits1(&s->gb);
1109             if(s->modified_quant)
1110                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
1111
1112             skip_bits(&s->gb, 1); /* Prevent start code emulation */
1113
1114             skip_bits(&s->gb, 3); /* Reserved */
1115         } else if (ufep != 0) {
1116             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
1117             return -1;
1118         }
1119
1120         /* MPPTYPE */
1121         s->pict_type = get_bits(&s->gb, 3);
1122         switch(s->pict_type){
1123         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1124         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1125         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1126         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1127         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1128         default:
1129             return -1;
1130         }
1131         skip_bits(&s->gb, 2);
1132         s->no_rounding = get_bits1(&s->gb);
1133         skip_bits(&s->gb, 4);
1134
1135         /* Get the picture dimensions */
1136         if (ufep) {
1137             if (format == 6) {
1138                 /* Custom Picture Format (CPFMT) */
1139                 s->aspect_ratio_info = get_bits(&s->gb, 4);
1140                 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1141                 /* aspect ratios:
1142                 0 - forbidden
1143                 1 - 1:1
1144                 2 - 12:11 (CIF 4:3)
1145                 3 - 10:11 (525-type 4:3)
1146                 4 - 16:11 (CIF 16:9)
1147                 5 - 40:33 (525-type 16:9)
1148                 6-14 - reserved
1149                 */
1150                 width = (get_bits(&s->gb, 9) + 1) * 4;
1151                 check_marker(s->avctx, &s->gb, "in dimensions");
1152                 height = get_bits(&s->gb, 9) * 4;
1153                 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1154                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1155                     /* expected dimensions */
1156                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1157                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1158                 }else{
1159                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1160                 }
1161             } else {
1162                 width = ff_h263_format[format][0];
1163                 height = ff_h263_format[format][1];
1164                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1165             }
1166             s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1167             if ((width == 0) || (height == 0))
1168                 return -1;
1169             s->width = width;
1170             s->height = height;
1171
1172             if(s->custom_pcf){
1173                 int gcd;
1174                 s->avctx->framerate.num  = 1800000;
1175                 s->avctx->framerate.den  = 1000 + get_bits1(&s->gb);
1176                 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1177                 if(s->avctx->framerate.den == 0){
1178                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
1179                     return -1;
1180                 }
1181                 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1182                 s->avctx->framerate.den /= gcd;
1183                 s->avctx->framerate.num /= gcd;
1184             }else{
1185                 s->avctx->framerate = (AVRational){ 30000, 1001 };
1186             }
1187         }
1188
1189         if(s->custom_pcf){
1190             skip_bits(&s->gb, 2); //extended Temporal reference
1191         }
1192
1193         if (ufep) {
1194             if (s->umvplus) {
1195                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1196                     skip_bits1(&s->gb);
1197             }
1198             if(s->h263_slice_structured){
1199                 if (get_bits1(&s->gb) != 0) {
1200                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1201                 }
1202                 if (get_bits1(&s->gb) != 0) {
1203                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1204                 }
1205             }
1206             if (s->pict_type == AV_PICTURE_TYPE_B) {
1207                 skip_bits(&s->gb, 4); //ELNUM
1208                 if (ufep == 1) {
1209                     skip_bits(&s->gb, 4); // RLNUM
1210                 }
1211             }
1212         }
1213
1214         s->qscale = get_bits(&s->gb, 5);
1215     }
1216
1217     if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
1218         return ret;
1219
1220     if (!(s->avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)) {
1221         if ((s->width * s->height / 256 / 8) > get_bits_left(&s->gb))
1222             return AVERROR_INVALIDDATA;
1223     }
1224
1225     s->mb_width = (s->width  + 15) / 16;
1226     s->mb_height = (s->height  + 15) / 16;
1227     s->mb_num = s->mb_width * s->mb_height;
1228
1229     if (s->pb_frame) {
1230         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1231         if (s->custom_pcf)
1232             skip_bits(&s->gb, 2); //extended Temporal reference
1233         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1234     }
1235
1236     if (s->pict_type!=AV_PICTURE_TYPE_B) {
1237         s->time            = s->picture_number;
1238         s->pp_time         = s->time - s->last_non_b_time;
1239         s->last_non_b_time = s->time;
1240     }else{
1241         s->time    = s->picture_number;
1242         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1243         if (s->pp_time <=s->pb_time ||
1244             s->pp_time <= s->pp_time - s->pb_time ||
1245             s->pp_time <= 0){
1246             s->pp_time = 2;
1247             s->pb_time = 1;
1248         }
1249         ff_mpeg4_init_direct_mv(s);
1250     }
1251
1252     /* PEI */
1253     if (skip_1stop_8data_bits(&s->gb) < 0)
1254         return AVERROR_INVALIDDATA;
1255
1256     if(s->h263_slice_structured){
1257         if (check_marker(s->avctx, &s->gb, "SEPB1") != 1) {
1258             return -1;
1259         }
1260
1261         ff_h263_decode_mba(s);
1262
1263         if (check_marker(s->avctx, &s->gb, "SEPB2") != 1) {
1264             return -1;
1265         }
1266     }
1267     s->f_code = 1;
1268
1269     if (s->pict_type == AV_PICTURE_TYPE_B)
1270         s->low_delay = 0;
1271
1272     if(s->h263_aic){
1273          s->y_dc_scale_table=
1274          s->c_dc_scale_table= ff_aic_dc_scale_table;
1275     }else{
1276         s->y_dc_scale_table=
1277         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1278     }
1279
1280         ff_h263_show_pict_info(s);
1281     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1282         int i,j;
1283         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1284         av_log(s->avctx, AV_LOG_DEBUG, "\n");
1285         for(i=0; i<13; i++){
1286             for(j=0; j<3; j++){
1287                 int v= get_bits(&s->gb, 8);
1288                 v |= get_sbits(&s->gb, 8) * (1 << 8);
1289                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1290             }
1291             av_log(s->avctx, AV_LOG_DEBUG, "\n");
1292         }
1293         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1294     }
1295
1296     return 0;
1297 }