ituh263dec.c
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1 /*
2  * ITU H263 bitstream decoder
3  * Copyright (c) 2000,2001 Fabrice Bellard
4  * H263+ support.
5  * Copyright (c) 2001 Juan J. Sierralta P
6  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
7  *
8  * This file is part of Libav.
9  *
10  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
30 //#define DEBUG
31 #include <limits.h>
32 
33 #include "libavutil/mathematics.h"
34 #include "dsputil.h"
35 #include "avcodec.h"
36 #include "mpegvideo.h"
37 #include "h263.h"
38 #include "mathops.h"
39 #include "unary.h"
40 #include "flv.h"
41 #include "mpeg4video.h"
42 
43 //#undef NDEBUG
44 //#include <assert.h>
45 
46 // The defines below define the number of bits that are read at once for
47 // reading vlc values. Changing these may improve speed and data cache needs
48 // be aware though that decreasing them may need the number of stages that is
49 // passed to get_vlc* to be increased.
50 #define MV_VLC_BITS 9
51 #define H263_MBTYPE_B_VLC_BITS 6
52 #define CBPC_B_VLC_BITS 3
53 
54 static const int h263_mb_type_b_map[15]= {
67  0, //stuffing
70 };
71 
74  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",
76  s->gb.size_in_bits, 1-s->no_rounding,
77  s->obmc ? " AP" : "",
78  s->umvplus ? " UMV" : "",
79  s->h263_long_vectors ? " LONG" : "",
80  s->h263_plus ? " +" : "",
81  s->h263_aic ? " AIC" : "",
82  s->alt_inter_vlc ? " AIV" : "",
83  s->modified_quant ? " MQ" : "",
84  s->loop_filter ? " LOOP" : "",
85  s->h263_slice_structured ? " SS" : "",
87  );
88  }
89 }
90 
91 /***********************************************/
92 /* decoding */
93 
97 static VLC mv_vlc;
99 static VLC cbpc_b_vlc;
100 
101 /* init vlcs */
102 
103 /* XXX: find a better solution to handle static init */
105 {
106  static int done = 0;
107 
108  if (!done) {
109  done = 1;
110 
111  INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
113  ff_h263_intra_MCBPC_code, 1, 1, 72);
114  INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
116  ff_h263_inter_MCBPC_code, 1, 1, 198);
117  INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
118  &ff_h263_cbpy_tab[0][1], 2, 1,
119  &ff_h263_cbpy_tab[0][0], 2, 1, 64);
120  INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
121  &ff_mvtab[0][1], 2, 1,
122  &ff_mvtab[0][0], 2, 1, 538);
127  INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
128  &ff_h263_mbtype_b_tab[0][1], 2, 1,
129  &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
130  INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
131  &ff_cbpc_b_tab[0][1], 2, 1,
132  &ff_cbpc_b_tab[0][0], 2, 1, 8);
133  }
134 }
135 
137 {
138  int i, mb_pos;
139 
140  for(i=0; i<6; i++){
141  if(s->mb_num-1 <= ff_mba_max[i]) break;
142  }
143  mb_pos= get_bits(&s->gb, ff_mba_length[i]);
144  s->mb_x= mb_pos % s->mb_width;
145  s->mb_y= mb_pos / s->mb_width;
146 
147  return mb_pos;
148 }
149 
155 {
156  unsigned int val, gob_number;
157  int left;
158 
159  /* Check for GOB Start Code */
160  val = show_bits(&s->gb, 16);
161  if(val)
162  return -1;
163 
164  /* We have a GBSC probably with GSTUFF */
165  skip_bits(&s->gb, 16); /* Drop the zeros */
166  left= get_bits_left(&s->gb);
167  //MN: we must check the bits left or we might end in a infinite loop (or segfault)
168  for(;left>13; left--){
169  if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
170  }
171  if(left<=13)
172  return -1;
173 
174  if(s->h263_slice_structured){
175  if(get_bits1(&s->gb)==0)
176  return -1;
177 
179 
180  if(s->mb_num > 1583)
181  if(get_bits1(&s->gb)==0)
182  return -1;
183 
184  s->qscale = get_bits(&s->gb, 5); /* SQUANT */
185  if(get_bits1(&s->gb)==0)
186  return -1;
187  skip_bits(&s->gb, 2); /* GFID */
188  }else{
189  gob_number = get_bits(&s->gb, 5); /* GN */
190  s->mb_x= 0;
191  s->mb_y= s->gob_index* gob_number;
192  skip_bits(&s->gb, 2); /* GFID */
193  s->qscale = get_bits(&s->gb, 5); /* GQUANT */
194  }
195 
196  if(s->mb_y >= s->mb_height)
197  return -1;
198 
199  if(s->qscale==0)
200  return -1;
201 
202  return 0;
203 }
204 
211 const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
212 {
213  assert(p < end);
214 
215  end-=2;
216  p++;
217  for(;p<end; p+=2){
218  if(!*p){
219  if (!p[-1] && p[1]) return p - 1;
220  else if(!p[ 1] && p[2]) return p;
221  }
222  }
223  return end+2;
224 }
225 
231  int left, pos, ret;
232 
233  if(s->codec_id==CODEC_ID_MPEG4){
234  skip_bits1(&s->gb);
235  align_get_bits(&s->gb);
236  }
237 
238  if(show_bits(&s->gb, 16)==0){
239  pos= get_bits_count(&s->gb);
242  else
243  ret= h263_decode_gob_header(s);
244  if(ret>=0)
245  return pos;
246  }
247  //OK, it's not where it is supposed to be ...
248  s->gb= s->last_resync_gb;
249  align_get_bits(&s->gb);
250  left= get_bits_left(&s->gb);
251 
252  for(;left>16+1+5+5; left-=8){
253  if(show_bits(&s->gb, 16)==0){
254  GetBitContext bak= s->gb;
255 
256  pos= get_bits_count(&s->gb);
259  else
260  ret= h263_decode_gob_header(s);
261  if(ret>=0)
262  return pos;
263 
264  s->gb= bak;
265  }
266  skip_bits(&s->gb, 8);
267  }
268 
269  return -1;
270 }
271 
272 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
273 {
274  int code, val, sign, shift;
275  code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
276 
277  if (code == 0)
278  return pred;
279  if (code < 0)
280  return 0xffff;
281 
282  sign = get_bits1(&s->gb);
283  shift = f_code - 1;
284  val = code;
285  if (shift) {
286  val = (val - 1) << shift;
287  val |= get_bits(&s->gb, shift);
288  val++;
289  }
290  if (sign)
291  val = -val;
292  val += pred;
293 
294  /* modulo decoding */
295  if (!s->h263_long_vectors) {
296  val = sign_extend(val, 5 + f_code);
297  } else {
298  /* horrible h263 long vector mode */
299  if (pred < -31 && val < -63)
300  val += 64;
301  if (pred > 32 && val > 63)
302  val -= 64;
303 
304  }
305  return val;
306 }
307 
308 
309 /* Decode RVLC of H.263+ UMV */
311 {
312  int code = 0, sign;
313 
314  if (get_bits1(&s->gb)) /* Motion difference = 0 */
315  return pred;
316 
317  code = 2 + get_bits1(&s->gb);
318 
319  while (get_bits1(&s->gb))
320  {
321  code <<= 1;
322  code += get_bits1(&s->gb);
323  }
324  sign = code & 1;
325  code >>= 1;
326 
327  code = (sign) ? (pred - code) : (pred + code);
328  av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
329  return code;
330 
331 }
332 
336 static void preview_obmc(MpegEncContext *s){
337  GetBitContext gb= s->gb;
338 
339  int cbpc, i, pred_x, pred_y, mx, my;
340  int16_t *mot_val;
341  const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
342  const int stride= s->b8_stride*2;
343 
344  for(i=0; i<4; i++)
345  s->block_index[i]+= 2;
346  for(i=4; i<6; i++)
347  s->block_index[i]+= 1;
348  s->mb_x++;
349 
350  assert(s->pict_type == AV_PICTURE_TYPE_P);
351 
352  do{
353  if (get_bits1(&s->gb)) {
354  /* skip mb */
355  mot_val = s->current_picture.f.motion_val[0][s->block_index[0]];
356  mot_val[0 ]= mot_val[2 ]=
357  mot_val[0+stride]= mot_val[2+stride]= 0;
358  mot_val[1 ]= mot_val[3 ]=
359  mot_val[1+stride]= mot_val[3+stride]= 0;
360 
362  goto end;
363  }
364  cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
365  }while(cbpc == 20);
366 
367  if(cbpc & 4){
369  }else{
370  get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
371  if (cbpc & 8) {
372  if(s->modified_quant){
373  if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
374  else skip_bits(&s->gb, 5);
375  }else
376  skip_bits(&s->gb, 2);
377  }
378 
379  if ((cbpc & 16) == 0) {
381  /* 16x16 motion prediction */
382  mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
383  if (s->umvplus)
384  mx = h263p_decode_umotion(s, pred_x);
385  else
386  mx = ff_h263_decode_motion(s, pred_x, 1);
387 
388  if (s->umvplus)
389  my = h263p_decode_umotion(s, pred_y);
390  else
391  my = ff_h263_decode_motion(s, pred_y, 1);
392 
393  mot_val[0 ]= mot_val[2 ]=
394  mot_val[0+stride]= mot_val[2+stride]= mx;
395  mot_val[1 ]= mot_val[3 ]=
396  mot_val[1+stride]= mot_val[3+stride]= my;
397  } else {
399  for(i=0;i<4;i++) {
400  mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
401  if (s->umvplus)
402  mx = h263p_decode_umotion(s, pred_x);
403  else
404  mx = ff_h263_decode_motion(s, pred_x, 1);
405 
406  if (s->umvplus)
407  my = h263p_decode_umotion(s, pred_y);
408  else
409  my = ff_h263_decode_motion(s, pred_y, 1);
410  if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
411  skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
412  mot_val[0] = mx;
413  mot_val[1] = my;
414  }
415  }
416  }
417 end:
418 
419  for(i=0; i<4; i++)
420  s->block_index[i]-= 2;
421  for(i=4; i<6; i++)
422  s->block_index[i]-= 1;
423  s->mb_x--;
424 
425  s->gb= gb;
426 }
427 
429  static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
430 
431  if(s->modified_quant){
432  if(get_bits1(&s->gb))
434  else
435  s->qscale= get_bits(&s->gb, 5);
436  }else
437  s->qscale += quant_tab[get_bits(&s->gb, 2)];
438  ff_set_qscale(s, s->qscale);
439 }
440 
442  int n, int coded)
443 {
444  int code, level, i, j, last, run;
445  RLTable *rl = &ff_h263_rl_inter;
446  const uint8_t *scan_table;
447  GetBitContext gb= s->gb;
448 
449  scan_table = s->intra_scantable.permutated;
450  if (s->h263_aic && s->mb_intra) {
451  rl = &ff_rl_intra_aic;
452  i = 0;
453  if (s->ac_pred) {
454  if (s->h263_aic_dir)
455  scan_table = s->intra_v_scantable.permutated; /* left */
456  else
457  scan_table = s->intra_h_scantable.permutated; /* top */
458  }
459  } else if (s->mb_intra) {
460  /* DC coef */
461  if(s->codec_id == CODEC_ID_RV10){
462 #if CONFIG_RV10_DECODER
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 = rv_decode_dc(s, n);
469  if (diff == 0xffff)
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 #endif
483  }else{
484  level = get_bits(&s->gb, 8);
485  if((level&0x7F) == 0){
486  av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
488  return -1;
489  }
490  if (level == 255)
491  level = 128;
492  }
493  block[0] = level;
494  i = 1;
495  } else {
496  i = 0;
497  }
498  if (!coded) {
499  if (s->mb_intra && s->h263_aic)
500  goto not_coded;
501  s->block_last_index[n] = i - 1;
502  return 0;
503  }
504 retry:
505  for(;;) {
506  code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
507  if (code < 0){
508  av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
509  return -1;
510  }
511  if (code == rl->n) {
512  /* escape */
513  if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
514  ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
515  } else {
516  last = get_bits1(&s->gb);
517  run = get_bits(&s->gb, 6);
518  level = (int8_t)get_bits(&s->gb, 8);
519  if(level == -128){
520  if (s->codec_id == CODEC_ID_RV10) {
521  /* XXX: should patch encoder too */
522  level = get_sbits(&s->gb, 12);
523  }else{
524  level = get_bits(&s->gb, 5);
525  level |= get_sbits(&s->gb, 6)<<5;
526  }
527  }
528  }
529  } else {
530  run = rl->table_run[code];
531  level = rl->table_level[code];
532  last = code >= rl->last;
533  if (get_bits1(&s->gb))
534  level = -level;
535  }
536  i += run;
537  if (i >= 64){
538  if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
539  //Looks like a hack but no, it's the way it is supposed to work ...
540  rl = &ff_rl_intra_aic;
541  i = 0;
542  s->gb= gb;
543  s->dsp.clear_block(block);
544  goto retry;
545  }
546  av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
547  return -1;
548  }
549  j = scan_table[i];
550  block[j] = level;
551  if (last)
552  break;
553  i++;
554  }
555 not_coded:
556  if (s->mb_intra && s->h263_aic) {
557  ff_h263_pred_acdc(s, block, n);
558  i = 63;
559  }
560  s->block_last_index[n] = i;
561  return 0;
562 }
563 
564 static int h263_skip_b_part(MpegEncContext *s, int cbp)
565 {
566  LOCAL_ALIGNED_16(DCTELEM, dblock, [64]);
567  int i, mbi;
568 
569  /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
570  * but real value should be restored in order to be used later (in OBMC condition)
571  */
572  mbi = s->mb_intra;
573  s->mb_intra = 0;
574  for (i = 0; i < 6; i++) {
575  if (h263_decode_block(s, dblock, i, cbp&32) < 0)
576  return -1;
577  cbp+=cbp;
578  }
579  s->mb_intra = mbi;
580  return 0;
581 }
582 
583 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
584 {
585  int c, mv = 1;
586 
587  if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
588  c = get_bits1(gb);
589  if (pb_frame == 2 && c)
590  mv = !get_bits1(gb);
591  } else { // h.263 Annex M improved PB-frame
592  mv = get_unary(gb, 0, 4) + 1;
593  c = mv & 1;
594  mv = !!(mv & 2);
595  }
596  if(c)
597  *cbpb = get_bits(gb, 6);
598  return mv;
599 }
600 
602  DCTELEM block[6][64])
603 {
604  int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
605  int16_t *mot_val;
606  const int xy= s->mb_x + s->mb_y * s->mb_stride;
607  int cbpb = 0, pb_mv_count = 0;
608 
609  assert(!s->h263_pred);
610 
611  if (s->pict_type == AV_PICTURE_TYPE_P) {
612  do{
613  if (get_bits1(&s->gb)) {
614  /* skip mb */
615  s->mb_intra = 0;
616  for(i=0;i<6;i++)
617  s->block_last_index[i] = -1;
618  s->mv_dir = MV_DIR_FORWARD;
619  s->mv_type = MV_TYPE_16X16;
621  s->mv[0][0][0] = 0;
622  s->mv[0][0][1] = 0;
623  s->mb_skipped = !(s->obmc | s->loop_filter);
624  goto end;
625  }
626  cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
627  if (cbpc < 0){
628  av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
629  return -1;
630  }
631  }while(cbpc == 20);
632 
633  s->dsp.clear_blocks(s->block[0]);
634 
635  dquant = cbpc & 8;
636  s->mb_intra = ((cbpc & 4) != 0);
637  if (s->mb_intra) goto intra;
638 
639  if(s->pb_frame && get_bits1(&s->gb))
640  pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
641  cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
642 
643  if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
644  cbpy ^= 0xF;
645 
646  cbp = (cbpc & 3) | (cbpy << 2);
647  if (dquant) {
649  }
650 
651  s->mv_dir = MV_DIR_FORWARD;
652  if ((cbpc & 16) == 0) {
654  /* 16x16 motion prediction */
655  s->mv_type = MV_TYPE_16X16;
656  ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
657  if (s->umvplus)
658  mx = h263p_decode_umotion(s, pred_x);
659  else
660  mx = ff_h263_decode_motion(s, pred_x, 1);
661 
662  if (mx >= 0xffff)
663  return -1;
664 
665  if (s->umvplus)
666  my = h263p_decode_umotion(s, pred_y);
667  else
668  my = ff_h263_decode_motion(s, pred_y, 1);
669 
670  if (my >= 0xffff)
671  return -1;
672  s->mv[0][0][0] = mx;
673  s->mv[0][0][1] = my;
674 
675  if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
676  skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
677  } else {
679  s->mv_type = MV_TYPE_8X8;
680  for(i=0;i<4;i++) {
681  mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
682  if (s->umvplus)
683  mx = h263p_decode_umotion(s, pred_x);
684  else
685  mx = ff_h263_decode_motion(s, pred_x, 1);
686  if (mx >= 0xffff)
687  return -1;
688 
689  if (s->umvplus)
690  my = h263p_decode_umotion(s, pred_y);
691  else
692  my = ff_h263_decode_motion(s, pred_y, 1);
693  if (my >= 0xffff)
694  return -1;
695  s->mv[0][i][0] = mx;
696  s->mv[0][i][1] = my;
697  if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
698  skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
699  mot_val[0] = mx;
700  mot_val[1] = my;
701  }
702  }
703  } else if(s->pict_type==AV_PICTURE_TYPE_B) {
704  int mb_type;
705  const int stride= s->b8_stride;
706  int16_t *mot_val0 = s->current_picture.f.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
707  int16_t *mot_val1 = s->current_picture.f.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
708 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
709 
710  //FIXME ugly
711  mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
712  mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
713  mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
714  mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
715 
716  do{
717  mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
718  if (mb_type < 0){
719  av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
720  return -1;
721  }
722 
723  mb_type= h263_mb_type_b_map[ mb_type ];
724  }while(!mb_type);
725 
726  s->mb_intra = IS_INTRA(mb_type);
727  if(HAS_CBP(mb_type)){
728  s->dsp.clear_blocks(s->block[0]);
729  cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
730  if(s->mb_intra){
731  dquant = IS_QUANT(mb_type);
732  goto intra;
733  }
734 
735  cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
736 
737  if (cbpy < 0){
738  av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
739  return -1;
740  }
741 
742  if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
743  cbpy ^= 0xF;
744 
745  cbp = (cbpc & 3) | (cbpy << 2);
746  }else
747  cbp=0;
748 
749  assert(!s->mb_intra);
750 
751  if(IS_QUANT(mb_type)){
753  }
754 
755  if(IS_DIRECT(mb_type)){
756  if (!s->pp_time)
757  return AVERROR_INVALIDDATA;
759  mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
760  }else{
761  s->mv_dir = 0;
763 //FIXME UMV
764 
765  if(USES_LIST(mb_type, 0)){
766  int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
767  s->mv_dir = MV_DIR_FORWARD;
768 
769  mx = ff_h263_decode_motion(s, mx, 1);
770  my = ff_h263_decode_motion(s, my, 1);
771 
772  s->mv[0][0][0] = mx;
773  s->mv[0][0][1] = my;
774  mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
775  mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
776  }
777 
778  if(USES_LIST(mb_type, 1)){
779  int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
780  s->mv_dir |= MV_DIR_BACKWARD;
781 
782  mx = ff_h263_decode_motion(s, mx, 1);
783  my = ff_h263_decode_motion(s, my, 1);
784 
785  s->mv[1][0][0] = mx;
786  s->mv[1][0][1] = my;
787  mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
788  mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
789  }
790  }
791 
792  s->current_picture.f.mb_type[xy] = mb_type;
793  } else { /* I-Frame */
794  do{
795  cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
796  if (cbpc < 0){
797  av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
798  return -1;
799  }
800  }while(cbpc == 8);
801 
802  s->dsp.clear_blocks(s->block[0]);
803 
804  dquant = cbpc & 4;
805  s->mb_intra = 1;
806 intra:
808  if (s->h263_aic) {
809  s->ac_pred = get_bits1(&s->gb);
810  if(s->ac_pred){
812 
813  s->h263_aic_dir = get_bits1(&s->gb);
814  }
815  }else
816  s->ac_pred = 0;
817 
818  if(s->pb_frame && get_bits1(&s->gb))
819  pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
820  cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
821  if(cbpy<0){
822  av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
823  return -1;
824  }
825  cbp = (cbpc & 3) | (cbpy << 2);
826  if (dquant) {
828  }
829 
830  pb_mv_count += !!s->pb_frame;
831  }
832 
833  while(pb_mv_count--){
834  ff_h263_decode_motion(s, 0, 1);
835  ff_h263_decode_motion(s, 0, 1);
836  }
837 
838  /* decode each block */
839  for (i = 0; i < 6; i++) {
840  if (h263_decode_block(s, block[i], i, cbp&32) < 0)
841  return -1;
842  cbp+=cbp;
843  }
844 
845  if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
846  return -1;
847  if(s->obmc && !s->mb_intra){
848  if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
849  preview_obmc(s);
850  }
851 end:
852 
853  /* per-MB end of slice check */
854  {
855  int v= show_bits(&s->gb, 16);
856 
857  if (get_bits_left(&s->gb) < 16) {
858  v >>= 16 - get_bits_left(&s->gb);
859  }
860 
861  if(v==0)
862  return SLICE_END;
863  }
864 
865  return SLICE_OK;
866 }
867 
868 /* most is hardcoded. should extend to handle all h263 streams */
870 {
871  int format, width, height, i;
872  uint32_t startcode;
873 
874  align_get_bits(&s->gb);
875 
876  startcode= get_bits(&s->gb, 22-8);
877 
878  for(i= get_bits_left(&s->gb); i>24; i-=8) {
879  startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
880 
881  if(startcode == 0x20)
882  break;
883  }
884 
885  if (startcode != 0x20) {
886  av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
887  return -1;
888  }
889  /* temporal reference */
890  i = get_bits(&s->gb, 8); /* picture timestamp */
891  if( (s->picture_number&~0xFF)+i < s->picture_number)
892  i+= 256;
894  s->picture_number= (s->picture_number&~0xFF) + i;
895 
896  /* PTYPE starts here */
897  if (get_bits1(&s->gb) != 1) {
898  /* marker */
899  av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
900  return -1;
901  }
902  if (get_bits1(&s->gb) != 0) {
903  av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
904  return -1; /* h263 id */
905  }
906  skip_bits1(&s->gb); /* split screen off */
907  skip_bits1(&s->gb); /* camera off */
908  skip_bits1(&s->gb); /* freeze picture release off */
909 
910  format = get_bits(&s->gb, 3);
911  /*
912  0 forbidden
913  1 sub-QCIF
914  10 QCIF
915  7 extended PTYPE (PLUSPTYPE)
916  */
917 
918  if (format != 7 && format != 6) {
919  s->h263_plus = 0;
920  /* H.263v1 */
921  width = ff_h263_format[format][0];
922  height = ff_h263_format[format][1];
923  if (!width)
924  return -1;
925 
927 
928  s->h263_long_vectors = get_bits1(&s->gb);
929 
930  if (get_bits1(&s->gb) != 0) {
931  av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
932  return -1; /* SAC: off */
933  }
934  s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
935  s->unrestricted_mv = s->h263_long_vectors || s->obmc;
936 
937  s->pb_frame = get_bits1(&s->gb);
938  s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
939  skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
940 
941  s->width = width;
942  s->height = height;
943  s->avctx->sample_aspect_ratio= (AVRational){12,11};
944  s->avctx->time_base= (AVRational){1001, 30000};
945  } else {
946  int ufep;
947 
948  /* H.263v2 */
949  s->h263_plus = 1;
950  ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
951 
952  /* ufep other than 0 and 1 are reserved */
953  if (ufep == 1) {
954  /* OPPTYPE */
955  format = get_bits(&s->gb, 3);
956  av_dlog(s->avctx, "ufep=1, format: %d\n", format);
957  s->custom_pcf= get_bits1(&s->gb);
958  s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
959  if (get_bits1(&s->gb) != 0) {
960  av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
961  }
962  s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
963  s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
964  s->loop_filter= get_bits1(&s->gb);
965  s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
966 
968  if (get_bits1(&s->gb) != 0) {
969  av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
970  }
971  if (get_bits1(&s->gb) != 0) {
972  av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
973  }
974  s->alt_inter_vlc= get_bits1(&s->gb);
975  s->modified_quant= get_bits1(&s->gb);
976  if(s->modified_quant)
978 
979  skip_bits(&s->gb, 1); /* Prevent start code emulation */
980 
981  skip_bits(&s->gb, 3); /* Reserved */
982  } else if (ufep != 0) {
983  av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
984  return -1;
985  }
986 
987  /* MPPTYPE */
988  s->pict_type = get_bits(&s->gb, 3);
989  switch(s->pict_type){
990  case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
991  case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
992  case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
993  case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
994  case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
995  default:
996  return -1;
997  }
998  skip_bits(&s->gb, 2);
999  s->no_rounding = get_bits1(&s->gb);
1000  skip_bits(&s->gb, 4);
1001 
1002  /* Get the picture dimensions */
1003  if (ufep) {
1004  if (format == 6) {
1005  /* Custom Picture Format (CPFMT) */
1006  s->aspect_ratio_info = get_bits(&s->gb, 4);
1007  av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1008  /* aspect ratios:
1009  0 - forbidden
1010  1 - 1:1
1011  2 - 12:11 (CIF 4:3)
1012  3 - 10:11 (525-type 4:3)
1013  4 - 16:11 (CIF 16:9)
1014  5 - 40:33 (525-type 16:9)
1015  6-14 - reserved
1016  */
1017  width = (get_bits(&s->gb, 9) + 1) * 4;
1018  skip_bits1(&s->gb);
1019  height = get_bits(&s->gb, 9) * 4;
1020  av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1022  /* aspected dimensions */
1023  s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1024  s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1025  }else{
1027  }
1028  } else {
1029  width = ff_h263_format[format][0];
1030  height = ff_h263_format[format][1];
1031  s->avctx->sample_aspect_ratio= (AVRational){12,11};
1032  }
1033  if ((width == 0) || (height == 0))
1034  return -1;
1035  s->width = width;
1036  s->height = height;
1037 
1038  if(s->custom_pcf){
1039  int gcd;
1040  s->avctx->time_base.den= 1800000;
1041  s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
1042  s->avctx->time_base.num*= get_bits(&s->gb, 7);
1043  if(s->avctx->time_base.num == 0){
1044  av_log(s, AV_LOG_ERROR, "zero framerate\n");
1045  return -1;
1046  }
1047  gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
1048  s->avctx->time_base.den /= gcd;
1049  s->avctx->time_base.num /= gcd;
1050  }else{
1051  s->avctx->time_base= (AVRational){1001, 30000};
1052  }
1053  }
1054 
1055  if(s->custom_pcf){
1056  skip_bits(&s->gb, 2); //extended Temporal reference
1057  }
1058 
1059  if (ufep) {
1060  if (s->umvplus) {
1061  if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1062  skip_bits1(&s->gb);
1063  }
1064  if(s->h263_slice_structured){
1065  if (get_bits1(&s->gb) != 0) {
1066  av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1067  }
1068  if (get_bits1(&s->gb) != 0) {
1069  av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1070  }
1071  }
1072  }
1073 
1074  s->qscale = get_bits(&s->gb, 5);
1075  }
1076 
1077  s->mb_width = (s->width + 15) / 16;
1078  s->mb_height = (s->height + 15) / 16;
1079  s->mb_num = s->mb_width * s->mb_height;
1080 
1081  if (s->pb_frame) {
1082  skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1083  if (s->custom_pcf)
1084  skip_bits(&s->gb, 2); //extended Temporal reference
1085  skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1086  }
1087 
1088  /* PEI */
1089  while (get_bits1(&s->gb) != 0) {
1090  skip_bits(&s->gb, 8);
1091  }
1092 
1093  if(s->h263_slice_structured){
1094  if (get_bits1(&s->gb) != 1) {
1095  av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1096  return -1;
1097  }
1098 
1099  ff_h263_decode_mba(s);
1100 
1101  if (get_bits1(&s->gb) != 1) {
1102  av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1103  return -1;
1104  }
1105  }
1106  s->f_code = 1;
1107 
1108  if(s->h263_aic){
1109  s->y_dc_scale_table=
1111  }else{
1112  s->y_dc_scale_table=
1114  }
1115 
1117  if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO")){
1118  int i,j;
1119  for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1120  av_log(s->avctx, AV_LOG_DEBUG, "\n");
1121  for(i=0; i<13; i++){
1122  for(j=0; j<3; j++){
1123  int v= get_bits(&s->gb, 8);
1124  v |= get_sbits(&s->gb, 8)<<8;
1125  av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1126  }
1127  av_log(s->avctx, AV_LOG_DEBUG, "\n");
1128  }
1129  for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1130  }
1131 
1132  return 0;
1133 }