h263dec: produce a warning when excessive bitstream is discarded
[ffmpeg.git] / libavcodec / h263dec.c
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 #include "libavutil/cpu.h"
29 #include "internal.h"
30 #include "avcodec.h"
31 #include "dsputil.h"
32 #include "mpegvideo.h"
33 #include "h263.h"
34 #include "h263_parser.h"
35 #include "mpeg4video_parser.h"
36 #include "msmpeg4.h"
37 #include "vdpau_internal.h"
38 #include "flv.h"
39 #include "mpeg4video.h"
40
41 //#define DEBUG
42 //#define PRINT_FRAME_TIME
43
44 av_cold int ff_h263_decode_init(AVCodecContext *avctx)
45 {
46     MpegEncContext *s = avctx->priv_data;
47
48     s->avctx = avctx;
49     s->out_format = FMT_H263;
50
51     s->width  = avctx->coded_width;
52     s->height = avctx->coded_height;
53     s->workaround_bugs= avctx->workaround_bugs;
54
55     // set defaults
56     MPV_decode_defaults(s);
57     s->quant_precision=5;
58     s->decode_mb= ff_h263_decode_mb;
59     s->low_delay= 1;
60     avctx->pix_fmt= avctx->get_format(avctx, avctx->codec->pix_fmts);
61     s->unrestricted_mv= 1;
62
63     /* select sub codec */
64     switch(avctx->codec->id) {
65     case CODEC_ID_H263:
66         s->unrestricted_mv= 0;
67         avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
68         break;
69     case CODEC_ID_MPEG4:
70         break;
71     case CODEC_ID_MSMPEG4V1:
72         s->h263_msmpeg4 = 1;
73         s->h263_pred = 1;
74         s->msmpeg4_version=1;
75         break;
76     case CODEC_ID_MSMPEG4V2:
77         s->h263_msmpeg4 = 1;
78         s->h263_pred = 1;
79         s->msmpeg4_version=2;
80         break;
81     case CODEC_ID_MSMPEG4V3:
82         s->h263_msmpeg4 = 1;
83         s->h263_pred = 1;
84         s->msmpeg4_version=3;
85         break;
86     case CODEC_ID_WMV1:
87         s->h263_msmpeg4 = 1;
88         s->h263_pred = 1;
89         s->msmpeg4_version=4;
90         break;
91     case CODEC_ID_WMV2:
92         s->h263_msmpeg4 = 1;
93         s->h263_pred = 1;
94         s->msmpeg4_version=5;
95         break;
96     case CODEC_ID_VC1:
97     case CODEC_ID_WMV3:
98         s->h263_msmpeg4 = 1;
99         s->h263_pred = 1;
100         s->msmpeg4_version=6;
101         avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
102         break;
103     case CODEC_ID_H263I:
104         break;
105     case CODEC_ID_FLV1:
106         s->h263_flv = 1;
107         break;
108     default:
109         return -1;
110     }
111     s->codec_id= avctx->codec->id;
112     avctx->hwaccel= ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);
113
114     /* for h263, we allocate the images after having read the header */
115     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
116         if (MPV_common_init(s) < 0)
117             return -1;
118
119         h263_decode_init_vlc(s);
120
121     return 0;
122 }
123
124 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
125 {
126     MpegEncContext *s = avctx->priv_data;
127
128     MPV_common_end(s);
129     return 0;
130 }
131
132 /**
133  * returns the number of bytes consumed for building the current frame
134  */
135 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
136     int pos= (get_bits_count(&s->gb)+7)>>3;
137
138     if(s->divx_packed || s->avctx->hwaccel){
139         //we would have to scan through the whole buf to handle the weird reordering ...
140         return buf_size;
141     }else if(s->flags&CODEC_FLAG_TRUNCATED){
142         pos -= s->parse_context.last_index;
143         if(pos<0) pos=0; // padding is not really read so this might be -1
144         return pos;
145     }else{
146         if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
147         if(pos+10>buf_size) pos=buf_size; // oops ;)
148
149         return pos;
150     }
151 }
152
153 static int decode_slice(MpegEncContext *s){
154     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
155     const int mb_size= 16>>s->avctx->lowres;
156     s->last_resync_gb= s->gb;
157     s->first_slice_line= 1;
158
159     s->resync_mb_x= s->mb_x;
160     s->resync_mb_y= s->mb_y;
161
162     ff_set_qscale(s, s->qscale);
163
164     if (s->avctx->hwaccel) {
165         const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
166         const uint8_t *end  = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end);
167         skip_bits_long(&s->gb, 8*(end - start));
168         return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
169     }
170
171     if(s->partitioned_frame){
172         const int qscale= s->qscale;
173
174         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
175             if(ff_mpeg4_decode_partitions(s) < 0)
176                 return -1;
177         }
178
179         /* restore variables which were modified */
180         s->first_slice_line=1;
181         s->mb_x= s->resync_mb_x;
182         s->mb_y= s->resync_mb_y;
183         ff_set_qscale(s, qscale);
184     }
185
186     for(; s->mb_y < s->mb_height; s->mb_y++) {
187         /* per-row end of slice checks */
188         if(s->msmpeg4_version){
189             if(s->resync_mb_y + s->slice_height == s->mb_y){
190                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, AC_END|DC_END|MV_END);
191
192                 return 0;
193             }
194         }
195
196         if(s->msmpeg4_version==1){
197             s->last_dc[0]=
198             s->last_dc[1]=
199             s->last_dc[2]= 128;
200         }
201
202         ff_init_block_index(s);
203         for(; s->mb_x < s->mb_width; s->mb_x++) {
204             int ret;
205
206             ff_update_block_index(s);
207
208             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
209                 s->first_slice_line=0;
210             }
211
212             /* DCT & quantize */
213
214             s->mv_dir = MV_DIR_FORWARD;
215             s->mv_type = MV_TYPE_16X16;
216 //            s->mb_skipped = 0;
217 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
218             ret= s->decode_mb(s, s->block);
219
220             if (s->pict_type!=FF_B_TYPE)
221                 ff_h263_update_motion_val(s);
222
223             if(ret<0){
224                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
225                 if(ret==SLICE_END){
226                     MPV_decode_mb(s, s->block);
227                     if(s->loop_filter)
228                         ff_h263_loop_filter(s);
229
230 //printf("%d %d %d %06X\n", s->mb_x, s->mb_y, s->gb.size*8 - get_bits_count(&s->gb), show_bits(&s->gb, 24));
231                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
232
233                     s->padding_bug_score--;
234
235                     if(++s->mb_x >= s->mb_width){
236                         s->mb_x=0;
237                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
238                         s->mb_y++;
239                     }
240                     return 0;
241                 }else if(ret==SLICE_NOEND){
242                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
243                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x+1, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
244                     return -1;
245                 }
246                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
247                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_ERROR|DC_ERROR|MV_ERROR)&part_mask);
248
249                 return -1;
250             }
251
252             MPV_decode_mb(s, s->block);
253             if(s->loop_filter)
254                 ff_h263_loop_filter(s);
255         }
256
257         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
258
259         s->mb_x= 0;
260     }
261
262     assert(s->mb_x==0 && s->mb_y==s->mb_height);
263
264     if(s->codec_id==CODEC_ID_MPEG4
265        && (s->workaround_bugs&FF_BUG_AUTODETECT)
266        && get_bits_left(&s->gb) >= 48
267        && show_bits(&s->gb, 24)==0x4010
268        && !s->data_partitioning)
269         s->padding_bug_score+=32;
270
271     /* try to detect the padding bug */
272     if(      s->codec_id==CODEC_ID_MPEG4
273        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
274        &&    get_bits_left(&s->gb) >=0
275        &&    get_bits_left(&s->gb) < 48
276 //       &&   !s->resync_marker
277        &&   !s->data_partitioning){
278
279         const int bits_count= get_bits_count(&s->gb);
280         const int bits_left = s->gb.size_in_bits - bits_count;
281
282         if(bits_left==0){
283             s->padding_bug_score+=16;
284         } else if(bits_left != 1){
285             int v= show_bits(&s->gb, 8);
286             v|= 0x7F >> (7-(bits_count&7));
287
288             if(v==0x7F && bits_left<=8)
289                 s->padding_bug_score--;
290             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
291                 s->padding_bug_score+= 4;
292             else
293                 s->padding_bug_score++;
294         }
295     }
296
297     if(s->workaround_bugs&FF_BUG_AUTODETECT){
298         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version>=0 || !s->resync_marker)*/)
299             s->workaround_bugs |=  FF_BUG_NO_PADDING;
300         else
301             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
302     }
303
304     // handle formats which don't have unique end markers
305     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
306         int left= get_bits_left(&s->gb);
307         int max_extra=7;
308
309         /* no markers in M$ crap */
310         if(s->msmpeg4_version && s->pict_type==FF_I_TYPE)
311             max_extra+= 17;
312
313         /* buggy padding but the frame should still end approximately at the bitstream end */
314         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_recognition>=3)
315             max_extra+= 48;
316         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
317             max_extra+= 256*256*256*64;
318
319         if(left>max_extra){
320             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
321         }
322         else if(left<0){
323             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
324         }else
325             ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x-1, s->mb_y, AC_END|DC_END|MV_END);
326
327         return 0;
328     }
329
330     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
331             get_bits_left(&s->gb),
332             show_bits(&s->gb, 24), s->padding_bug_score);
333
334     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
335
336     return -1;
337 }
338
339 int ff_h263_decode_frame(AVCodecContext *avctx,
340                              void *data, int *data_size,
341                              AVPacket *avpkt)
342 {
343     const uint8_t *buf = avpkt->data;
344     int buf_size = avpkt->size;
345     MpegEncContext *s = avctx->priv_data;
346     int ret;
347     AVFrame *pict = data;
348
349 #ifdef PRINT_FRAME_TIME
350 uint64_t time= rdtsc();
351 #endif
352     s->flags= avctx->flags;
353     s->flags2= avctx->flags2;
354
355     /* no supplementary picture */
356     if (buf_size == 0) {
357         /* special case for last picture */
358         if (s->low_delay==0 && s->next_picture_ptr) {
359             *pict= *(AVFrame*)s->next_picture_ptr;
360             s->next_picture_ptr= NULL;
361
362             *data_size = sizeof(AVFrame);
363         }
364
365         return 0;
366     }
367
368     if(s->flags&CODEC_FLAG_TRUNCATED){
369         int next;
370
371         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
372             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
373         }else if(CONFIG_H263_DECODER && s->codec_id==CODEC_ID_H263){
374             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
375         }else{
376             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
377             return -1;
378         }
379
380         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
381             return buf_size;
382     }
383
384
385 retry:
386     if(s->divx_packed && s->xvid_build>=0 && s->bitstream_buffer_size){
387         int i;
388         for(i=0; i<buf_size-3; i++){
389             if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1){
390                 if(buf[i+3]==0xB0){
391                     av_log(s->avctx, AV_LOG_WARNING, "Discarding excessive bitstream in packed xvid\n");
392                     s->bitstream_buffer_size=0;
393                 }
394                 break;
395             }
396         }
397     }
398
399     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
400         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
401     }else
402         init_get_bits(&s->gb, buf, buf_size*8);
403     s->bitstream_buffer_size=0;
404
405     if (!s->context_initialized) {
406         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
407             return -1;
408     }
409
410     /* We need to set current_picture_ptr before reading the header,
411      * otherwise we cannot store anyting in there */
412     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
413         int i= ff_find_unused_picture(s, 0);
414         s->current_picture_ptr= &s->picture[i];
415     }
416
417     /* let's go :-) */
418     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
419         ret= ff_wmv2_decode_picture_header(s);
420     } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
421         ret = msmpeg4_decode_picture_header(s);
422     } else if (CONFIG_MPEG4_DECODER && s->h263_pred) {
423         if(s->avctx->extradata_size && s->picture_number==0){
424             GetBitContext gb;
425
426             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
427             ret = ff_mpeg4_decode_picture_header(s, &gb);
428         }
429         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
430     } else if (CONFIG_H263I_DECODER && s->codec_id == CODEC_ID_H263I) {
431         ret = ff_intel_h263_decode_picture_header(s);
432     } else if (CONFIG_FLV_DECODER && s->h263_flv) {
433         ret = ff_flv_decode_picture_header(s);
434     } else {
435         ret = h263_decode_picture_header(s);
436     }
437
438     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
439
440     /* skip if the header was thrashed */
441     if (ret < 0){
442         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
443         return -1;
444     }
445
446     avctx->has_b_frames= !s->low_delay;
447
448     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
449         if(s->stream_codec_tag == AV_RL32("XVID") ||
450            s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
451            s->codec_tag == AV_RL32("RMP4") ||
452            s->codec_tag == AV_RL32("SIPP")
453            )
454             s->xvid_build= 0;
455 #if 0
456         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
457            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
458             s->xvid_build= 0;
459 #endif
460     }
461
462     if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
463         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
464             s->divx_version= 400; //divx 4
465     }
466
467     if(s->xvid_build>=0 && s->divx_version>=0){
468         s->divx_version=
469         s->divx_build= -1;
470     }
471
472     if(s->workaround_bugs&FF_BUG_AUTODETECT){
473         if(s->codec_tag == AV_RL32("XVIX"))
474             s->workaround_bugs|= FF_BUG_XVID_ILACE;
475
476         if(s->codec_tag == AV_RL32("UMP4")){
477             s->workaround_bugs|= FF_BUG_UMP4;
478         }
479
480         if(s->divx_version>=500 && s->divx_build<1814){
481             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
482         }
483
484         if(s->divx_version>502 && s->divx_build<1814){
485             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
486         }
487
488         if(s->xvid_build<=3U)
489             s->padding_bug_score= 256*256*256*64;
490
491         if(s->xvid_build<=1U)
492             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
493
494         if(s->xvid_build<=12U)
495             s->workaround_bugs|= FF_BUG_EDGE;
496
497         if(s->xvid_build<=32U)
498             s->workaround_bugs|= FF_BUG_DC_CLIP;
499
500 #define SET_QPEL_FUNC(postfix1, postfix2) \
501     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
502     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
503     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
504
505         if(s->lavc_build<4653U)
506             s->workaround_bugs|= FF_BUG_STD_QPEL;
507
508         if(s->lavc_build<4655U)
509             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
510
511         if(s->lavc_build<4670U){
512             s->workaround_bugs|= FF_BUG_EDGE;
513         }
514
515         if(s->lavc_build<=4712U)
516             s->workaround_bugs|= FF_BUG_DC_CLIP;
517
518         if(s->divx_version>=0)
519             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
520 //printf("padding_bug_score: %d\n", s->padding_bug_score);
521         if(s->divx_version==501 && s->divx_build==20020416)
522             s->padding_bug_score= 256*256*256*64;
523
524         if(s->divx_version<500U){
525             s->workaround_bugs|= FF_BUG_EDGE;
526         }
527
528         if(s->divx_version>=0)
529             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
530 #if 0
531         if(s->divx_version==500)
532             s->padding_bug_score= 256*256*256*64;
533
534         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
535          * Let us hope this at least works.
536          */
537         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==-1
538            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
539             s->workaround_bugs|= FF_BUG_NO_PADDING;
540
541         if(s->lavc_build<4609U) //FIXME not sure about the version num but a 4609 file seems ok
542             s->workaround_bugs|= FF_BUG_NO_PADDING;
543 #endif
544     }
545
546     if(s->workaround_bugs& FF_BUG_STD_QPEL){
547         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
548         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
549         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
550         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
551         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
552         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
553
554         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
555         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
556         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
557         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
558         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
559         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
560     }
561
562     if(avctx->debug & FF_DEBUG_BUGS)
563         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
564                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
565                s->divx_packed ? "p" : "");
566
567 #if 0 // dump bits per frame / qp / complexity
568 {
569     static FILE *f=NULL;
570     if(!f) f=fopen("rate_qp_cplx.txt", "w");
571     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
572 }
573 #endif
574
575 #if HAVE_MMX
576     if (s->codec_id == CODEC_ID_MPEG4 && s->xvid_build>=0 && avctx->idct_algo == FF_IDCT_AUTO && (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
577         avctx->idct_algo= FF_IDCT_XVIDMMX;
578         avctx->coded_width= 0; // force reinit
579 //        dsputil_init(&s->dsp, avctx);
580         s->picture_number=0;
581     }
582 #endif
583
584         /* After H263 & mpeg4 header decode we have the height, width,*/
585         /* and other parameters. So then we could init the picture   */
586         /* FIXME: By the way H263 decoder is evolving it should have */
587         /* an H263EncContext                                         */
588
589     if (   s->width  != avctx->coded_width
590         || s->height != avctx->coded_height) {
591         /* H.263 could change picture size any time */
592         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
593         s->parse_context.buffer=0;
594         MPV_common_end(s);
595         s->parse_context= pc;
596     }
597     if (!s->context_initialized) {
598         avcodec_set_dimensions(avctx, s->width, s->height);
599
600         goto retry;
601     }
602
603     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P || s->codec_id == CODEC_ID_H263I))
604         s->gob_index = ff_h263_get_gob_height(s);
605
606     // for hurry_up==5
607     s->current_picture.pict_type= s->pict_type;
608     s->current_picture.key_frame= s->pict_type == FF_I_TYPE;
609
610     /* skip B-frames if we don't have reference frames */
611     if(s->last_picture_ptr==NULL && (s->pict_type==FF_B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
612     /* skip b frames if we are in a hurry */
613     if(avctx->hurry_up && s->pict_type==FF_B_TYPE) return get_consumed_bytes(s, buf_size);
614     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==FF_B_TYPE)
615        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=FF_I_TYPE)
616        ||  avctx->skip_frame >= AVDISCARD_ALL)
617         return get_consumed_bytes(s, buf_size);
618     /* skip everything if we are in a hurry>=5 */
619     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
620
621     if(s->next_p_frame_damaged){
622         if(s->pict_type==FF_B_TYPE)
623             return get_consumed_bytes(s, buf_size);
624         else
625             s->next_p_frame_damaged=0;
626     }
627
628     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==FF_B_TYPE){
629         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
630         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
631     }else if((!s->no_rounding) || s->pict_type==FF_B_TYPE){
632         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
633         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
634     }else{
635         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
636         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
637     }
638
639     if(MPV_frame_start(s, avctx) < 0)
640         return -1;
641
642     if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU)) {
643         ff_vdpau_mpeg4_decode_picture(s, s->gb.buffer, s->gb.buffer_end - s->gb.buffer);
644         goto frame_end;
645     }
646
647     if (avctx->hwaccel) {
648         if (avctx->hwaccel->start_frame(avctx, s->gb.buffer, s->gb.buffer_end - s->gb.buffer) < 0)
649             return -1;
650     }
651
652     ff_er_frame_start(s);
653
654     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
655     //which is not available before MPV_frame_start()
656     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5){
657         ret = ff_wmv2_decode_secondary_picture_header(s);
658         if(ret<0) return ret;
659         if(ret==1) goto intrax8_decoded;
660     }
661
662     /* decode each macroblock */
663     s->mb_x=0;
664     s->mb_y=0;
665
666     decode_slice(s);
667     while(s->mb_y<s->mb_height){
668         if(s->msmpeg4_version){
669             if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
670                 break;
671         }else{
672             if(ff_h263_resync(s)<0)
673                 break;
674         }
675
676         if(s->msmpeg4_version<4 && s->h263_pred)
677             ff_mpeg4_clean_buffers(s);
678
679         decode_slice(s);
680     }
681
682     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==FF_I_TYPE)
683         if(!CONFIG_MSMPEG4_DECODER || msmpeg4_decode_ext_header(s, buf_size) < 0){
684             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
685         }
686
687     assert(s->bitstream_buffer_size==0);
688 frame_end:
689     /* divx 5.01+ bistream reorder stuff */
690     if(s->codec_id==CODEC_ID_MPEG4 && s->divx_packed){
691         int current_pos= get_bits_count(&s->gb)>>3;
692         int startcode_found=0;
693
694         if(buf_size - current_pos > 5){
695             int i;
696             for(i=current_pos; i<buf_size-3; i++){
697                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
698                     startcode_found=1;
699                     break;
700                 }
701             }
702         }
703         if(s->gb.buffer == s->bitstream_buffer && buf_size>7 && s->xvid_build>=0){ //xvid style
704             startcode_found=1;
705             current_pos=0;
706         }
707
708         if(startcode_found){
709             av_fast_malloc(
710                 &s->bitstream_buffer,
711                 &s->allocated_bitstream_buffer_size,
712                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
713             if (!s->bitstream_buffer)
714                 return AVERROR(ENOMEM);
715             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
716             s->bitstream_buffer_size= buf_size - current_pos;
717         }
718     }
719
720 intrax8_decoded:
721     ff_er_frame_end(s);
722
723     if (avctx->hwaccel) {
724         if (avctx->hwaccel->end_frame(avctx) < 0)
725             return -1;
726     }
727
728     MPV_frame_end(s);
729
730 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
731 assert(s->current_picture.pict_type == s->pict_type);
732     if (s->pict_type == FF_B_TYPE || s->low_delay) {
733         *pict= *(AVFrame*)s->current_picture_ptr;
734     } else if (s->last_picture_ptr != NULL) {
735         *pict= *(AVFrame*)s->last_picture_ptr;
736     }
737
738     if(s->last_picture_ptr || s->low_delay){
739         *data_size = sizeof(AVFrame);
740         ff_print_debug_info(s, pict);
741     }
742
743 #ifdef PRINT_FRAME_TIME
744 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
745 #endif
746
747     return get_consumed_bytes(s, buf_size);
748 }
749
750 AVCodec ff_h263_decoder = {
751     "h263",
752     AVMEDIA_TYPE_VIDEO,
753     CODEC_ID_H263,
754     sizeof(MpegEncContext),
755     ff_h263_decode_init,
756     NULL,
757     ff_h263_decode_end,
758     ff_h263_decode_frame,
759     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
760     .flush= ff_mpeg_flush,
761     .max_lowres= 3,
762     .long_name= NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
763     .pix_fmts= ff_hwaccel_pixfmt_list_420,
764 };