avcodec/ituh263dec: Fix runtime error: left shift of 1342177279 by 1 places cannot...
[ffmpeg.git] / libavcodec / ituh263dec.c
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 AVERROR_INVALIDDATA;
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_16(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         /* per-MB end of slice check */
966     {
967         int v= show_bits(&s->gb, 16);
968
969         if (get_bits_left(&s->gb) < 16) {
970             v >>= 16 - get_bits_left(&s->gb);
971         }
972
973         if(v==0)
974             return SLICE_END;
975     }
976
977     return SLICE_OK;
978 }
979
980 /* Most is hardcoded; should extend to handle all H.263 streams. */
981 int ff_h263_decode_picture_header(MpegEncContext *s)
982 {
983     int format, width, height, i, ret;
984     uint32_t startcode;
985
986     align_get_bits(&s->gb);
987
988     if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
989          av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
990     }
991
992     startcode= get_bits(&s->gb, 22-8);
993
994     for(i= get_bits_left(&s->gb); i>24; i-=8) {
995         startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
996
997         if(startcode == 0x20)
998             break;
999     }
1000
1001     if (startcode != 0x20) {
1002         av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
1003         return -1;
1004     }
1005     /* temporal reference */
1006     i = get_bits(&s->gb, 8); /* picture timestamp */
1007
1008     i -= (i - (s->picture_number & 0xFF) + 128) & ~0xFF;
1009
1010     s->picture_number= (s->picture_number&~0xFF) + i;
1011
1012     /* PTYPE starts here */
1013     if (check_marker(s->avctx, &s->gb, "in PTYPE") != 1) {
1014         return -1;
1015     }
1016     if (get_bits1(&s->gb) != 0) {
1017         av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
1018         return -1;      /* H.263 id */
1019     }
1020     skip_bits1(&s->gb);         /* split screen off */
1021     skip_bits1(&s->gb);         /* camera  off */
1022     skip_bits1(&s->gb);         /* freeze picture release off */
1023
1024     format = get_bits(&s->gb, 3);
1025     /*
1026         0    forbidden
1027         1    sub-QCIF
1028         10   QCIF
1029         7       extended PTYPE (PLUSPTYPE)
1030     */
1031
1032     if (format != 7 && format != 6) {
1033         s->h263_plus = 0;
1034         /* H.263v1 */
1035         width = ff_h263_format[format][0];
1036         height = ff_h263_format[format][1];
1037         if (!width)
1038             return -1;
1039
1040         s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
1041
1042         s->h263_long_vectors = get_bits1(&s->gb);
1043
1044         if (get_bits1(&s->gb) != 0) {
1045             av_log(s->avctx, AV_LOG_ERROR, "H.263 SAC not supported\n");
1046             return -1; /* SAC: off */
1047         }
1048         s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1049         s->unrestricted_mv = s->h263_long_vectors || s->obmc;
1050
1051         s->pb_frame = get_bits1(&s->gb);
1052         s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
1053         skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
1054
1055         s->width = width;
1056         s->height = height;
1057         s->avctx->sample_aspect_ratio= (AVRational){12,11};
1058         s->avctx->framerate = (AVRational){ 30000, 1001 };
1059     } else {
1060         int ufep;
1061
1062         /* H.263v2 */
1063         s->h263_plus = 1;
1064         ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
1065
1066         /* ufep other than 0 and 1 are reserved */
1067         if (ufep == 1) {
1068             /* OPPTYPE */
1069             format = get_bits(&s->gb, 3);
1070             ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
1071             s->custom_pcf= get_bits1(&s->gb);
1072             s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
1073             if (get_bits1(&s->gb) != 0) {
1074                 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
1075             }
1076             s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1077             s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
1078             s->loop_filter= get_bits1(&s->gb);
1079             s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
1080             if(s->avctx->lowres)
1081                 s->loop_filter = 0;
1082
1083             s->h263_slice_structured= get_bits1(&s->gb);
1084             if (get_bits1(&s->gb) != 0) {
1085                 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
1086             }
1087             if (get_bits1(&s->gb) != 0) {
1088                 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
1089             }
1090             s->alt_inter_vlc= get_bits1(&s->gb);
1091             s->modified_quant= get_bits1(&s->gb);
1092             if(s->modified_quant)
1093                 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
1094
1095             skip_bits(&s->gb, 1); /* Prevent start code emulation */
1096
1097             skip_bits(&s->gb, 3); /* Reserved */
1098         } else if (ufep != 0) {
1099             av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
1100             return -1;
1101         }
1102
1103         /* MPPTYPE */
1104         s->pict_type = get_bits(&s->gb, 3);
1105         switch(s->pict_type){
1106         case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1107         case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1108         case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1109         case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1110         case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1111         default:
1112             return -1;
1113         }
1114         skip_bits(&s->gb, 2);
1115         s->no_rounding = get_bits1(&s->gb);
1116         skip_bits(&s->gb, 4);
1117
1118         /* Get the picture dimensions */
1119         if (ufep) {
1120             if (format == 6) {
1121                 /* Custom Picture Format (CPFMT) */
1122                 s->aspect_ratio_info = get_bits(&s->gb, 4);
1123                 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1124                 /* aspect ratios:
1125                 0 - forbidden
1126                 1 - 1:1
1127                 2 - 12:11 (CIF 4:3)
1128                 3 - 10:11 (525-type 4:3)
1129                 4 - 16:11 (CIF 16:9)
1130                 5 - 40:33 (525-type 16:9)
1131                 6-14 - reserved
1132                 */
1133                 width = (get_bits(&s->gb, 9) + 1) * 4;
1134                 check_marker(s->avctx, &s->gb, "in dimensions");
1135                 height = get_bits(&s->gb, 9) * 4;
1136                 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1137                 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1138                     /* expected dimensions */
1139                     s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1140                     s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1141                 }else{
1142                     s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1143                 }
1144             } else {
1145                 width = ff_h263_format[format][0];
1146                 height = ff_h263_format[format][1];
1147                 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1148             }
1149             s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1150             if ((width == 0) || (height == 0))
1151                 return -1;
1152             s->width = width;
1153             s->height = height;
1154
1155             if(s->custom_pcf){
1156                 int gcd;
1157                 s->avctx->framerate.num  = 1800000;
1158                 s->avctx->framerate.den  = 1000 + get_bits1(&s->gb);
1159                 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1160                 if(s->avctx->framerate.den == 0){
1161                     av_log(s, AV_LOG_ERROR, "zero framerate\n");
1162                     return -1;
1163                 }
1164                 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1165                 s->avctx->framerate.den /= gcd;
1166                 s->avctx->framerate.num /= gcd;
1167             }else{
1168                 s->avctx->framerate = (AVRational){ 30000, 1001 };
1169             }
1170         }
1171
1172         if(s->custom_pcf){
1173             skip_bits(&s->gb, 2); //extended Temporal reference
1174         }
1175
1176         if (ufep) {
1177             if (s->umvplus) {
1178                 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1179                     skip_bits1(&s->gb);
1180             }
1181             if(s->h263_slice_structured){
1182                 if (get_bits1(&s->gb) != 0) {
1183                     av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1184                 }
1185                 if (get_bits1(&s->gb) != 0) {
1186                     av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1187                 }
1188             }
1189             if (s->pict_type == AV_PICTURE_TYPE_B) {
1190                 skip_bits(&s->gb, 4); //ELNUM
1191                 if (ufep == 1) {
1192                     skip_bits(&s->gb, 4); // RLNUM
1193                 }
1194             }
1195         }
1196
1197         s->qscale = get_bits(&s->gb, 5);
1198     }
1199
1200     if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
1201         return ret;
1202
1203     s->mb_width = (s->width  + 15) / 16;
1204     s->mb_height = (s->height  + 15) / 16;
1205     s->mb_num = s->mb_width * s->mb_height;
1206
1207     if (s->pb_frame) {
1208         skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1209         if (s->custom_pcf)
1210             skip_bits(&s->gb, 2); //extended Temporal reference
1211         skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1212     }
1213
1214     if (s->pict_type!=AV_PICTURE_TYPE_B) {
1215         s->time            = s->picture_number;
1216         s->pp_time         = s->time - s->last_non_b_time;
1217         s->last_non_b_time = s->time;
1218     }else{
1219         s->time    = s->picture_number;
1220         s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1221         if (s->pp_time <=s->pb_time ||
1222             s->pp_time <= s->pp_time - s->pb_time ||
1223             s->pp_time <= 0){
1224             s->pp_time = 2;
1225             s->pb_time = 1;
1226         }
1227         ff_mpeg4_init_direct_mv(s);
1228     }
1229
1230     /* PEI */
1231     if (skip_1stop_8data_bits(&s->gb) < 0)
1232         return AVERROR_INVALIDDATA;
1233
1234     if(s->h263_slice_structured){
1235         if (check_marker(s->avctx, &s->gb, "SEPB1") != 1) {
1236             return -1;
1237         }
1238
1239         ff_h263_decode_mba(s);
1240
1241         if (check_marker(s->avctx, &s->gb, "SEPB2") != 1) {
1242             return -1;
1243         }
1244     }
1245     s->f_code = 1;
1246
1247     if (s->pict_type == AV_PICTURE_TYPE_B)
1248         s->low_delay = 0;
1249
1250     if(s->h263_aic){
1251          s->y_dc_scale_table=
1252          s->c_dc_scale_table= ff_aic_dc_scale_table;
1253     }else{
1254         s->y_dc_scale_table=
1255         s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1256     }
1257
1258         ff_h263_show_pict_info(s);
1259     if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1260         int i,j;
1261         for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1262         av_log(s->avctx, AV_LOG_DEBUG, "\n");
1263         for(i=0; i<13; i++){
1264             for(j=0; j<3; j++){
1265                 int v= get_bits(&s->gb, 8);
1266                 v |= get_sbits(&s->gb, 8)<<8;
1267                 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1268             }
1269             av_log(s->avctx, AV_LOG_DEBUG, "\n");
1270         }
1271         for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1272     }
1273
1274     return 0;
1275 }