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h263dec.c
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1 /*
2  * H.263 decoder
3  * Copyright (c) 2001 Fabrice Bellard
4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * H.263 decoder.
26  */
27 
28 #define UNCHECKED_BITSTREAM_READER 1
29 
30 #include "libavutil/cpu.h"
31 #include "internal.h"
32 #include "avcodec.h"
33 #include "error_resilience.h"
34 #include "mpegvideo.h"
35 #include "h263.h"
36 #include "h263_parser.h"
37 #include "mpeg4video_parser.h"
38 #include "msmpeg4.h"
39 #include "vdpau_internal.h"
40 #include "thread.h"
41 #include "flv.h"
42 #include "mpeg4video.h"
43 
45 {
46  MpegEncContext *s = avctx->priv_data;
47  int ret;
48 
49  s->avctx = avctx;
50  s->out_format = FMT_H263;
51 
52  s->width = avctx->coded_width;
53  s->height = avctx->coded_height;
55 
56  // set defaults
58  s->quant_precision=5;
60  s->low_delay= 1;
61  if (avctx->codec->id == AV_CODEC_ID_MSS2)
62  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
63  else
64  avctx->pix_fmt = avctx->get_format(avctx, avctx->codec->pix_fmts);
65  s->unrestricted_mv= 1;
66 
67  /* select sub codec */
68  switch(avctx->codec->id) {
69  case AV_CODEC_ID_H263:
70  case AV_CODEC_ID_H263P:
71  s->unrestricted_mv= 0;
73  break;
74  case AV_CODEC_ID_MPEG4:
75  break;
77  s->h263_pred = 1;
78  s->msmpeg4_version=1;
79  break;
81  s->h263_pred = 1;
82  s->msmpeg4_version=2;
83  break;
85  s->h263_pred = 1;
86  s->msmpeg4_version=3;
87  break;
88  case AV_CODEC_ID_WMV1:
89  s->h263_pred = 1;
90  s->msmpeg4_version=4;
91  break;
92  case AV_CODEC_ID_WMV2:
93  s->h263_pred = 1;
94  s->msmpeg4_version=5;
95  break;
96  case AV_CODEC_ID_VC1:
97  case AV_CODEC_ID_WMV3:
100  case AV_CODEC_ID_MSS2:
101  s->h263_pred = 1;
102  s->msmpeg4_version=6;
104  break;
105  case AV_CODEC_ID_H263I:
106  break;
107  case AV_CODEC_ID_FLV1:
108  s->h263_flv = 1;
109  break;
110  default:
111  return AVERROR(EINVAL);
112  }
113  s->codec_id= avctx->codec->id;
114  avctx->hwaccel= ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);
115 
116  /* for h263, we allocate the images after having read the header */
117  if (avctx->codec->id != AV_CODEC_ID_H263 && avctx->codec->id != AV_CODEC_ID_H263P && avctx->codec->id != AV_CODEC_ID_MPEG4)
118  if ((ret = ff_MPV_common_init(s)) < 0)
119  return ret;
120 
122 
123  return 0;
124 }
125 
127 {
128  MpegEncContext *s = avctx->priv_data;
129 
131  return 0;
132 }
133 
134 /**
135  * Return the number of bytes consumed for building the current frame.
136  */
137 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
138  int pos= (get_bits_count(&s->gb)+7)>>3;
139 
140  if(s->divx_packed || s->avctx->hwaccel){
141  //we would have to scan through the whole buf to handle the weird reordering ...
142  return buf_size;
143  }else if(s->flags&CODEC_FLAG_TRUNCATED){
144  pos -= s->parse_context.last_index;
145  if(pos<0) pos=0; // padding is not really read so this might be -1
146  return pos;
147  }else{
148  if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
149  if(pos+10>buf_size) pos=buf_size; // oops ;)
150 
151  return pos;
152  }
153 }
154 
156  const int part_mask= s->partitioned_frame ? (ER_AC_END|ER_AC_ERROR) : 0x7F;
157  const int mb_size= 16>>s->avctx->lowres;
158  int ret;
159 
160  s->last_resync_gb= s->gb;
161  s->first_slice_line= 1;
162 
163  s->resync_mb_x= s->mb_x;
164  s->resync_mb_y= s->mb_y;
165 
166  ff_set_qscale(s, s->qscale);
167 
168  if (s->avctx->hwaccel) {
169  const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
170  const uint8_t *end = ff_h263_find_resync_marker(s, start + 1, s->gb.buffer_end);
171  skip_bits_long(&s->gb, 8*(end - start));
172  return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
173  }
174 
175  if(s->partitioned_frame){
176  const int qscale= s->qscale;
177 
178  if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4){
179  if ((ret = ff_mpeg4_decode_partitions(s)) < 0)
180  return ret;
181  }
182 
183  /* restore variables which were modified */
184  s->first_slice_line=1;
185  s->mb_x= s->resync_mb_x;
186  s->mb_y= s->resync_mb_y;
187  ff_set_qscale(s, qscale);
188  }
189 
190  for(; s->mb_y < s->mb_height; s->mb_y++) {
191  /* per-row end of slice checks */
192  if(s->msmpeg4_version){
193  if(s->resync_mb_y + s->slice_height == s->mb_y){
194  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
195 
196  return 0;
197  }
198  }
199 
200  if(s->msmpeg4_version==1){
201  s->last_dc[0]=
202  s->last_dc[1]=
203  s->last_dc[2]= 128;
204  }
205 
207  for(; s->mb_x < s->mb_width; s->mb_x++) {
208  int ret;
209 
211 
212  if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
213  s->first_slice_line=0;
214  }
215 
216  /* DCT & quantize */
217 
218  s->mv_dir = MV_DIR_FORWARD;
219  s->mv_type = MV_TYPE_16X16;
220 // s->mb_skipped = 0;
221  av_dlog(s, "%d %d %06X\n",
222  ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
223  ret= s->decode_mb(s, s->block);
224 
227 
228  if(ret<0){
229  const int xy= s->mb_x + s->mb_y*s->mb_stride;
230  if(ret==SLICE_END){
231  ff_MPV_decode_mb(s, s->block);
232  if(s->loop_filter)
234 
235  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END&part_mask);
236 
237  s->padding_bug_score--;
238 
239  if(++s->mb_x >= s->mb_width){
240  s->mb_x=0;
241  ff_mpeg_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
243  s->mb_y++;
244  }
245  return 0;
246  }else if(ret==SLICE_NOEND){
247  av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
248  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x+1, s->mb_y, ER_MB_END&part_mask);
249  return AVERROR_INVALIDDATA;
250  }
251  av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
252  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR&part_mask);
253 
254  return AVERROR_INVALIDDATA;
255  }
256 
257  ff_MPV_decode_mb(s, s->block);
258  if(s->loop_filter)
260  }
261 
262  ff_mpeg_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
264 
265  s->mb_x= 0;
266  }
267 
268  av_assert1(s->mb_x==0 && s->mb_y==s->mb_height);
269 
272  && get_bits_left(&s->gb) >= 48
273  && show_bits(&s->gb, 24)==0x4010
274  && !s->data_partitioning)
275  s->padding_bug_score+=32;
276 
277  /* try to detect the padding bug */
280  && get_bits_left(&s->gb) >=0
281  && get_bits_left(&s->gb) < 137
282 // && !s->resync_marker
283  && !s->data_partitioning){
284 
285  const int bits_count= get_bits_count(&s->gb);
286  const int bits_left = s->gb.size_in_bits - bits_count;
287 
288  if(bits_left==0){
289  s->padding_bug_score+=16;
290  } else if(bits_left != 1){
291  int v= show_bits(&s->gb, 8);
292  v|= 0x7F >> (7-(bits_count&7));
293 
294  if(v==0x7F && bits_left<=8)
295  s->padding_bug_score--;
296  else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
297  s->padding_bug_score+= 4;
298  else
299  s->padding_bug_score++;
300  }
301  }
302 
304  if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version>=0 || !s->resync_marker)*/)
306  else
308  }
309 
310  // handle formats which don't have unique end markers
311  if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
312  int left= get_bits_left(&s->gb);
313  int max_extra=7;
314 
315  /* no markers in M$ crap */
317  max_extra+= 17;
318 
319  /* buggy padding but the frame should still end approximately at the bitstream end */
321  max_extra+= 48;
322  else if((s->workaround_bugs&FF_BUG_NO_PADDING))
323  max_extra+= 256*256*256*64;
324 
325  if(left>max_extra){
326  av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
327  }
328  else if(left<0){
329  av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
330  }else
331  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, ER_MB_END);
332 
333  return 0;
334  }
335 
336  av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
337  get_bits_left(&s->gb),
338  show_bits(&s->gb, 24), s->padding_bug_score);
339 
340  ff_er_add_slice(&s->er, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, ER_MB_END&part_mask);
341 
342  return AVERROR_INVALIDDATA;
343 }
344 
346  void *data, int *got_frame,
347  AVPacket *avpkt)
348 {
349  const uint8_t *buf = avpkt->data;
350  int buf_size = avpkt->size;
351  MpegEncContext *s = avctx->priv_data;
352  int ret;
353  AVFrame *pict = data;
354 
355  s->flags= avctx->flags;
356  s->flags2= avctx->flags2;
357 
358  /* no supplementary picture */
359  if (buf_size == 0) {
360  /* special case for last picture */
361  if (s->low_delay==0 && s->next_picture_ptr) {
362  if ((ret = av_frame_ref(pict, &s->next_picture_ptr->f)) < 0)
363  return ret;
364  s->next_picture_ptr= NULL;
365 
366  *got_frame = 1;
367  }
368 
369  return 0;
370  }
371 
373  int next;
374 
375  if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4){
376  next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
377  }else if(CONFIG_H263_DECODER && s->codec_id==AV_CODEC_ID_H263){
378  next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
379  }else if(CONFIG_H263P_DECODER && s->codec_id==AV_CODEC_ID_H263P){
380  next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
381  }else{
382  av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
383  return AVERROR(EINVAL);
384  }
385 
386  if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
387  return buf_size;
388  }
389 
390 
391 retry:
392  if(s->divx_packed && s->bitstream_buffer_size){
393  int i;
394  for(i=0; i<buf_size-3; i++){
395  if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1){
396  if(buf[i+3]==0xB0){
397  av_log(s->avctx, AV_LOG_WARNING, "Discarding excessive bitstream in packed xvid\n");
399  }
400  break;
401  }
402  }
403  }
404 
405  if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
407  }else
408  init_get_bits(&s->gb, buf, buf_size*8);
410 
411  if (!s->context_initialized) {
412  if ((ret = ff_MPV_common_init(s)) < 0) //we need the idct permutaton for reading a custom matrix
413  return ret;
414  }
415 
416  /* We need to set current_picture_ptr before reading the header,
417  * otherwise we cannot store anyting in there */
418  if (s->current_picture_ptr == NULL || s->current_picture_ptr->f.data[0]) {
419  int i= ff_find_unused_picture(s, 0);
420  if (i < 0)
421  return i;
422  s->current_picture_ptr= &s->picture[i];
423  }
424 
425  /* let's go :-) */
426  if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
428  } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
430  } else if (CONFIG_MPEG4_DECODER && s->h263_pred) {
431  if(s->avctx->extradata_size && s->picture_number==0){
432  GetBitContext gb;
433 
435  ret = ff_mpeg4_decode_picture_header(s, &gb);
436  }
437  ret = ff_mpeg4_decode_picture_header(s, &s->gb);
438  } else if (CONFIG_H263I_DECODER && s->codec_id == AV_CODEC_ID_H263I) {
440  } else if (CONFIG_FLV_DECODER && s->h263_flv) {
442  } else {
444  }
445 
446  if (ret < 0 || ret==FRAME_SKIPPED) {
447  if ( s->width != avctx->coded_width
448  || s->height != avctx->coded_height) {
449  av_log(s->avctx, AV_LOG_WARNING, "Reverting picture dimensions change due to header decoding failure\n");
450  s->width = avctx->coded_width;
451  s->height= avctx->coded_height;
452  }
453  }
454  if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
455 
456  /* skip if the header was thrashed */
457  if (ret < 0){
458  av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
459  return ret;
460  }
461 
462  avctx->has_b_frames= !s->low_delay;
463 
464  if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
465  if(s->stream_codec_tag == AV_RL32("XVID") ||
466  s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
467  s->codec_tag == AV_RL32("RMP4") || s->codec_tag == AV_RL32("ZMP4") ||
468  s->codec_tag == AV_RL32("SIPP")
469  )
470  s->xvid_build= 0;
471 #if 0
472  if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
473  && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
474  s->xvid_build= 0;
475 #endif
476  }
477 
478  if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
479  if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
480  s->divx_version= 400; //divx 4
481  }
482 
483  if(s->xvid_build>=0 && s->divx_version>=0){
484  s->divx_version=
485  s->divx_build= -1;
486  }
487 
489  if(s->codec_tag == AV_RL32("XVIX"))
491 
492  if(s->codec_tag == AV_RL32("UMP4")){
494  }
495 
496  if(s->divx_version>=500 && s->divx_build<1814){
498  }
499 
500  if(s->divx_version>502 && s->divx_build<1814){
502  }
503 
504  if(s->xvid_build<=3U)
505  s->padding_bug_score= 256*256*256*64;
506 
507  if(s->xvid_build<=1U)
509 
510  if(s->xvid_build<=12U)
512 
513  if(s->xvid_build<=32U)
515 
516 #define SET_QPEL_FUNC(postfix1, postfix2) \
517  s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
518  s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
519  s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
520 
521  if(s->lavc_build<4653U)
523 
524  if(s->lavc_build<4655U)
526 
527  if(s->lavc_build<4670U){
529  }
530 
531  if(s->lavc_build<=4712U)
533 
534  if(s->divx_version>=0)
536  if(s->divx_version==501 && s->divx_build==20020416)
537  s->padding_bug_score= 256*256*256*64;
538 
539  if(s->divx_version<500U){
541  }
542 
543  if(s->divx_version>=0)
545 #if 0
546  if(s->divx_version==500)
547  s->padding_bug_score= 256*256*256*64;
548 
549  /* very ugly XVID padding bug detection FIXME/XXX solve this differently
550  * Let us hope this at least works.
551  */
552  if( s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==-1
553  && s->codec_id==AV_CODEC_ID_MPEG4 && s->vo_type==0)
555 
556  if(s->lavc_build<4609U) //FIXME not sure about the version num but a 4609 file seems ok
558 #endif
559  }
560 
562  SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
563  SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
564  SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
565  SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
566  SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
567  SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
568 
569  SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
570  SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
571  SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
572  SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
573  SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
574  SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
575  }
576 
577  if(avctx->debug & FF_DEBUG_BUGS)
578  av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
580  s->divx_packed ? "p" : "");
581 
582 #if HAVE_MMX
584  avctx->idct_algo= FF_IDCT_XVIDMMX;
586  goto retry;
587  }
588 #endif
589 
590  /* After H263 & mpeg4 header decode we have the height, width,*/
591  /* and other parameters. So then we could init the picture */
592  /* FIXME: By the way H263 decoder is evolving it should have */
593  /* an H263EncContext */
594 
595  if ((!avctx->coded_width || !avctx->coded_height) && 0) {
596  ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
597 
598  s->parse_context.buffer=0;
600  s->parse_context= pc;
601  avcodec_set_dimensions(avctx, s->width, s->height);
602 
603  goto retry;
604  }
605 
606  if (s->width != avctx->coded_width ||
607  s->height != avctx->coded_height ||
608  s->context_reinit) {
609  /* H.263 could change picture size any time */
610  s->context_reinit = 0;
611 
612  avcodec_set_dimensions(avctx, s->width, s->height);
613 
614  if ((ret = ff_MPV_common_frame_size_change(s)))
615  return ret;
616  }
617 
620 
621  // for skipping the frame
624 
625  /* skip B-frames if we don't have reference frames */
626  if (s->last_picture_ptr == NULL &&
627  (s->pict_type == AV_PICTURE_TYPE_B || s->droppable))
628  return get_consumed_bytes(s, buf_size);
631  || avctx->skip_frame >= AVDISCARD_ALL)
632  return get_consumed_bytes(s, buf_size);
633 
634  if(s->next_p_frame_damaged){
636  return get_consumed_bytes(s, buf_size);
637  else
639  }
640 
641  if((!s->no_rounding) || s->pict_type==AV_PICTURE_TYPE_B){
644  }else{
647  }
648 
649  if ((ret = ff_MPV_frame_start(s, avctx)) < 0)
650  return ret;
651 
652  if (!s->divx_packed && !avctx->hwaccel)
653  ff_thread_finish_setup(avctx);
654 
655  if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU)) {
657  goto frame_end;
658  }
659 
660  if (avctx->hwaccel) {
661  if ((ret = avctx->hwaccel->start_frame(avctx, s->gb.buffer, s->gb.buffer_end - s->gb.buffer)) < 0)
662  return ret;
663  }
664 
666 
667  //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
668  //which is not available before ff_MPV_frame_start()
669  if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5){
671  if(ret<0) return ret;
672  if(ret==1) goto intrax8_decoded;
673  }
674 
675  /* decode each macroblock */
676  s->mb_x=0;
677  s->mb_y=0;
678 
679  ret = decode_slice(s);
680  while(s->mb_y<s->mb_height){
681  if(s->msmpeg4_version){
682  if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_left(&s->gb)<0)
683  break;
684  }else{
685  int prev_x=s->mb_x, prev_y=s->mb_y;
686  if(ff_h263_resync(s)<0)
687  break;
688  if (prev_y * s->mb_width + prev_x < s->mb_y * s->mb_width + s->mb_x)
689  s->er.error_occurred = 1;
690  }
691 
692  if(s->msmpeg4_version<4 && s->h263_pred)
694 
695  if (decode_slice(s) < 0) ret = AVERROR_INVALIDDATA;
696  }
697 
699  if(!CONFIG_MSMPEG4_DECODER || ff_msmpeg4_decode_ext_header(s, buf_size) < 0){
701  }
702 
704 frame_end:
705  /* divx 5.01+ bitstream reorder stuff */
706  if(s->codec_id==AV_CODEC_ID_MPEG4 && s->divx_packed){
707  int current_pos= s->gb.buffer == s->bitstream_buffer ? 0 : (get_bits_count(&s->gb)>>3);
708  int startcode_found=0;
709 
710  if(buf_size - current_pos > 7){
711  int i;
712  for(i=current_pos; i<buf_size-4; i++){
713  if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
714  startcode_found=!(buf[i+4]&0x40);
715  break;
716  }
717  }
718  }
719 
720  if(startcode_found){
722  &s->bitstream_buffer,
724  buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
725  if (!s->bitstream_buffer)
726  return AVERROR(ENOMEM);
727  memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
728  s->bitstream_buffer_size= buf_size - current_pos;
729  }
730  }
731 
732 intrax8_decoded:
733  ff_er_frame_end(&s->er);
734 
735  if (avctx->hwaccel) {
736  if ((ret = avctx->hwaccel->end_frame(avctx)) < 0)
737  return ret;
738  }
739 
740  ff_MPV_frame_end(s);
741 
742  if (!s->divx_packed && avctx->hwaccel)
743  ff_thread_finish_setup(avctx);
744 
747  if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {
748  if ((ret = av_frame_ref(pict, &s->current_picture_ptr->f)) < 0)
749  return ret;
752  } else if (s->last_picture_ptr != NULL) {
753  if ((ret = av_frame_ref(pict, &s->last_picture_ptr->f)) < 0)
754  return ret;
757  }
758 
759  if(s->last_picture_ptr || s->low_delay){
760  *got_frame = 1;
761  }
762 
763  return (ret && (avctx->err_recognition & AV_EF_EXPLODE))?ret:get_consumed_bytes(s, buf_size);
764 }
765 
767 #if CONFIG_VAAPI
769 #endif
770 #if CONFIG_VDPAU
772 #endif
775 };
776 
778  .name = "h263",
779  .type = AVMEDIA_TYPE_VIDEO,
780  .id = AV_CODEC_ID_H263,
781  .priv_data_size = sizeof(MpegEncContext),
785  .capabilities = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
787  .flush = ff_mpeg_flush,
788  .max_lowres = 3,
789  .long_name = NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
791 };
792 
794  .name = "h263p",
795  .type = AVMEDIA_TYPE_VIDEO,
796  .id = AV_CODEC_ID_H263P,
797  .priv_data_size = sizeof(MpegEncContext),
801  .capabilities = CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 |
803  .flush = ff_mpeg_flush,
804  .max_lowres = 3,
805  .long_name = NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
807 };