removed warnings
[ffmpeg.git] / libavcodec / h263dec.c
1 /*
2  * H.263 decoder
3  * Copyright (c) 2001 Fabrice Bellard.
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  */
19  
20 /**
21  * @file h263dec.c
22  * H.263 decoder.
23  */
24  
25 #include "avcodec.h"
26 #include "dsputil.h"
27 #include "mpegvideo.h"
28
29 //#define DEBUG
30 //#define PRINT_FRAME_TIME
31 #ifdef PRINT_FRAME_TIME
32 static inline long long rdtsc()
33 {
34         long long l;
35         asm volatile(   "rdtsc\n\t"
36                 : "=A" (l)
37         );
38 //      printf("%d\n", int(l/1000));
39         return l;
40 }
41 #endif
42
43 int ff_h263_decode_init(AVCodecContext *avctx)
44 {
45     MpegEncContext *s = avctx->priv_data;
46
47     s->avctx = avctx;
48     s->out_format = FMT_H263;
49
50     s->width = avctx->width;
51     s->height = avctx->height;
52     s->workaround_bugs= avctx->workaround_bugs;
53
54     // set defaults
55     s->quant_precision=5;
56     s->progressive_sequence=1;
57     s->decode_mb= ff_h263_decode_mb;
58     s->low_delay= 1;
59     avctx->pix_fmt= PIX_FMT_YUV420P;
60
61     /* select sub codec */
62     switch(avctx->codec->id) {
63     case CODEC_ID_H263:
64         s->gob_number = 0;
65         break;
66     case CODEC_ID_MPEG4:
67         s->time_increment_bits = 4; /* default value for broken headers */
68         s->h263_pred = 1;
69         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
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_H263I:
97         s->h263_intel = 1;
98         break;
99     case CODEC_ID_FLV1:
100         s->h263_flv = 1;
101         break;
102     default:
103         return -1;
104     }
105     s->codec_id= avctx->codec->id;
106
107     /* for h263, we allocate the images after having read the header */
108     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
109         if (MPV_common_init(s) < 0)
110             return -1;
111
112     if (s->h263_msmpeg4)
113         ff_msmpeg4_decode_init(s);
114     else
115         h263_decode_init_vlc(s);
116     
117     return 0;
118 }
119
120 int ff_h263_decode_end(AVCodecContext *avctx)
121 {
122     MpegEncContext *s = avctx->priv_data;
123
124     MPV_common_end(s);
125     return 0;
126 }
127
128 /**
129  * retunrs the number of bytes consumed for building the current frame
130  */
131 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
132     int pos= (get_bits_count(&s->gb)+7)>>3;
133     
134     if(s->divx_packed){
135         //we would have to scan through the whole buf to handle the weird reordering ...
136         return buf_size; 
137     }else if(s->flags&CODEC_FLAG_TRUNCATED){
138         pos -= s->parse_context.last_index;
139         if(pos<0) pos=0; // padding is not really read so this might be -1
140         return pos;
141     }else{
142         if(pos==0) pos=1; //avoid infinite loops (i doubt thats needed but ...)
143         if(pos+10>buf_size) pos=buf_size; // oops ;)
144
145         return pos;
146     }
147 }
148
149 static int decode_slice(MpegEncContext *s){
150     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
151     s->last_resync_gb= s->gb;
152     s->first_slice_line= 1;
153         
154     s->resync_mb_x= s->mb_x;
155     s->resync_mb_y= s->mb_y;
156
157     s->y_dc_scale= s->y_dc_scale_table[ s->qscale ];
158     s->c_dc_scale= s->c_dc_scale_table[ s->qscale ];
159     
160     if(s->partitioned_frame){
161         const int qscale= s->qscale;
162
163         if(s->codec_id==CODEC_ID_MPEG4){
164             if(ff_mpeg4_decode_partitions(s) < 0)
165                 return -1; 
166         }
167         
168         /* restore variables which were modified */
169         s->first_slice_line=1;
170         s->mb_x= s->resync_mb_x;
171         s->mb_y= s->resync_mb_y;
172         s->qscale= qscale;
173         s->y_dc_scale= s->y_dc_scale_table[ s->qscale ];
174         s->c_dc_scale= s->c_dc_scale_table[ s->qscale ];
175     }
176
177     for(; s->mb_y < s->mb_height; s->mb_y++) {
178         /* per-row end of slice checks */
179         if(s->msmpeg4_version){
180             if(s->resync_mb_y + s->slice_height == s->mb_y){
181                 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);
182
183                 return 0;
184             }
185         }
186         
187         if(s->msmpeg4_version==1){
188             s->last_dc[0]=
189             s->last_dc[1]=
190             s->last_dc[2]= 128;
191         }
192     
193         ff_init_block_index(s);
194         for(; s->mb_x < s->mb_width; s->mb_x++) {
195             int ret;
196
197             ff_update_block_index(s);
198
199             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
200                 s->first_slice_line=0; 
201             }
202
203             /* DCT & quantize */
204             s->dsp.clear_blocks(s->block[0]);
205             
206             s->mv_dir = MV_DIR_FORWARD;
207             s->mv_type = MV_TYPE_16X16;
208 //            s->mb_skiped = 0;
209 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
210             ret= s->decode_mb(s, s->block);
211
212             if (s->pict_type!=B_TYPE)
213                 ff_h263_update_motion_val(s);
214
215             if(ret<0){
216                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
217                 if(ret==SLICE_END){
218                     MPV_decode_mb(s, s->block);
219
220 //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));
221                     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);
222
223                     s->padding_bug_score--;
224                         
225                     if(++s->mb_x >= s->mb_width){
226                         s->mb_x=0;
227                         ff_draw_horiz_band(s, s->mb_y*16, 16);
228                         s->mb_y++;
229                     }
230                     return 0; 
231                 }else if(ret==SLICE_NOEND){
232                     fprintf(stderr,"Slice mismatch at MB: %d\n", xy);
233                     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);
234                     return -1;
235                 }
236                 fprintf(stderr,"Error at MB: %d\n", xy);
237                 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);
238     
239                 return -1;
240             }
241
242             MPV_decode_mb(s, s->block);
243         }
244         
245         ff_draw_horiz_band(s, s->mb_y*16, 16);
246         
247         s->mb_x= 0;
248     }
249     
250     assert(s->mb_x==0 && s->mb_y==s->mb_height);
251
252     /* try to detect the padding bug */
253     if(      s->codec_id==CODEC_ID_MPEG4
254        &&   (s->workaround_bugs&FF_BUG_AUTODETECT) 
255        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
256        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
257 //       &&   !s->resync_marker
258        &&   !s->data_partitioning){
259         
260         const int bits_count= get_bits_count(&s->gb);
261         const int bits_left = s->gb.size_in_bits - bits_count;
262         
263         if(bits_left==0){
264             s->padding_bug_score+=16;
265         }else if(bits_left>8){
266             s->padding_bug_score++;
267         } else if(bits_left != 1){
268             int v= show_bits(&s->gb, 8);
269             v|= 0x7F >> (7-(bits_count&7));
270
271             if(v==0x7F)
272                 s->padding_bug_score--;
273             else
274                 s->padding_bug_score++;            
275         }                          
276     }
277
278     // handle formats which dont have unique end markers
279     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
280         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
281         int max_extra=7;
282         
283         /* no markers in M$ crap */
284         if(s->msmpeg4_version && s->pict_type==I_TYPE)
285             max_extra+= 17;
286         
287         /* buggy padding but the frame should still end approximately at the bitstream end */
288         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
289             max_extra+= 48;
290         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
291             max_extra+= 256*256*256*64;
292         
293         if(left>max_extra){
294             fprintf(stderr, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
295         }
296         else if(left<0){
297             fprintf(stderr, "overreading %d bits\n", -left);
298         }else
299             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);
300         
301         return 0;
302     }
303
304     fprintf(stderr, "slice end not reached but screenspace end (%d left %06X, score= %d)\n", 
305             s->gb.size_in_bits - get_bits_count(&s->gb),
306             show_bits(&s->gb, 24), s->padding_bug_score);
307             
308     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);
309
310     return -1;
311 }
312
313 /**
314  * finds the end of the current frame in the bitstream.
315  * @return the position of the first byte of the next frame, or -1
316  */
317 static int mpeg4_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
318     ParseContext *pc= &s->parse_context;
319     int vop_found, i;
320     uint32_t state;
321     
322     vop_found= pc->frame_start_found;
323     state= pc->state;
324     
325     i=0;
326     if(!vop_found){
327         for(i=0; i<buf_size; i++){
328             state= (state<<8) | buf[i];
329             if(state == 0x1B6){
330                 i++;
331                 vop_found=1;
332                 break;
333             }
334         }
335     }
336
337     if(vop_found){    
338       for(; i<buf_size; i++){
339         state= (state<<8) | buf[i];
340         if((state&0xFFFFFF00) == 0x100){
341             pc->frame_start_found=0;
342             pc->state=-1; 
343             return i-3;
344         }
345       }
346     }
347     pc->frame_start_found= vop_found;
348     pc->state= state;
349     return END_NOT_FOUND;
350 }
351
352 static int h263_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
353     ParseContext *pc= &s->parse_context;
354     int vop_found, i;
355     uint32_t state;
356     
357     vop_found= pc->frame_start_found;
358     state= pc->state;
359     
360     i=0;
361     if(!vop_found){
362         for(i=0; i<buf_size; i++){
363             state= (state<<8) | buf[i];
364             if(state>>(32-22) == 0x20){
365                 i++;
366                 vop_found=1;
367                 break;
368             }
369         }
370     }
371
372     if(vop_found){    
373       for(; i<buf_size; i++){
374         state= (state<<8) | buf[i];
375         if(state>>(32-22) == 0x20){
376             pc->frame_start_found=0;
377             pc->state=-1; 
378             return i-3;
379         }
380       }
381     }
382     pc->frame_start_found= vop_found;
383     pc->state= state;
384     
385     return END_NOT_FOUND;
386 }
387
388 int ff_h263_decode_frame(AVCodecContext *avctx, 
389                              void *data, int *data_size,
390                              uint8_t *buf, int buf_size)
391 {
392     MpegEncContext *s = avctx->priv_data;
393     int ret;
394     AVFrame *pict = data; 
395     float new_aspect;
396     
397 #ifdef PRINT_FRAME_TIME
398 uint64_t time= rdtsc();
399 #endif
400 #ifdef DEBUG
401     printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);
402     printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
403 #endif
404     s->flags= avctx->flags;
405
406     *data_size = 0;
407
408     /* no supplementary picture */
409     if (buf_size == 0) {
410         /* special case for last picture */
411         if (s->low_delay==0 && s->next_picture_ptr) {
412             *pict= *(AVFrame*)s->next_picture_ptr;
413             s->next_picture_ptr= NULL;
414
415             *data_size = sizeof(AVFrame);
416         }
417
418         return 0;
419     }
420
421     if(s->flags&CODEC_FLAG_TRUNCATED){
422         int next;
423         
424         if(s->codec_id==CODEC_ID_MPEG4){
425             next= mpeg4_find_frame_end(s, buf, buf_size);
426         }else if(s->codec_id==CODEC_ID_H263){
427             next= h263_find_frame_end(s, buf, buf_size);
428         }else{
429             fprintf(stderr, "this codec doesnt support truncated bitstreams\n");
430             return -1;
431         }
432         
433         if( ff_combine_frame(s, next, &buf, &buf_size) < 0 )
434             return buf_size;
435     }
436
437 retry:
438     
439     if(s->bitstream_buffer_size && buf_size<20){ //divx 5.01+ frame reorder
440         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
441     }else
442         init_get_bits(&s->gb, buf, buf_size*8);
443     s->bitstream_buffer_size=0;
444
445     if (!s->context_initialized) {
446         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
447             return -1;
448     }
449       
450     /* let's go :-) */
451     if (s->msmpeg4_version==5) {
452         ret= ff_wmv2_decode_picture_header(s);
453     } else if (s->msmpeg4_version) {
454         ret = msmpeg4_decode_picture_header(s);
455     } else if (s->h263_pred) {
456         if(s->avctx->extradata_size && s->picture_number==0){
457             GetBitContext gb;
458             
459             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
460             ret = ff_mpeg4_decode_picture_header(s, &gb);
461         }
462         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
463
464         if(s->flags& CODEC_FLAG_LOW_DELAY)
465             s->low_delay=1;
466     } else if (s->h263_intel) {
467         ret = intel_h263_decode_picture_header(s);
468     } else if (s->h263_flv) {
469         ret = flv_h263_decode_picture_header(s);
470     } else {
471         ret = h263_decode_picture_header(s);
472     }
473     
474     if(ret==FRAME_SKIPED) return get_consumed_bytes(s, buf_size);
475
476     /* skip if the header was thrashed */
477     if (ret < 0){
478         fprintf(stderr, "header damaged\n");
479         return -1;
480     }
481     
482     avctx->has_b_frames= !s->low_delay;
483     
484     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
485         if(s->avctx->codec_tag == ff_get_fourcc("XVID") || s->avctx->codec_tag == ff_get_fourcc("XVIX"))
486             s->xvid_build= -1;
487
488         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
489             s->divx_version= 400; //divx 4
490     }
491
492     if(s->workaround_bugs&FF_BUG_AUTODETECT){
493         s->workaround_bugs &= ~FF_BUG_NO_PADDING;
494         
495         if(s->padding_bug_score > -2 && !s->data_partitioning && (s->divx_version || !s->resync_marker))
496             s->workaround_bugs |=  FF_BUG_NO_PADDING;
497
498         if(s->avctx->codec_tag == ff_get_fourcc("XVIX")) 
499             s->workaround_bugs|= FF_BUG_XVID_ILACE;
500
501         if(s->avctx->codec_tag == ff_get_fourcc("UMP4")){
502             s->workaround_bugs|= FF_BUG_UMP4;
503             s->workaround_bugs|= FF_BUG_AC_VLC;
504         }
505
506         if(s->divx_version>=500){
507             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
508         }
509
510         if(s->divx_version>502){
511             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
512         }
513
514         if(s->xvid_build && s->xvid_build<=3)
515             s->padding_bug_score= 256*256*256*64;
516         
517         if(s->xvid_build && s->xvid_build<=1)
518             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
519
520         if(s->xvid_build && s->xvid_build<=12)
521             s->workaround_bugs|= FF_BUG_EDGE;
522
523 #define SET_QPEL_FUNC(postfix1, postfix2) \
524     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
525     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
526     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
527
528         if(s->lavc_build && s->lavc_build<4653)
529             s->workaround_bugs|= FF_BUG_STD_QPEL;
530         
531         if(s->lavc_build && s->lavc_build<4655)
532             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
533
534         if(s->lavc_build && s->lavc_build<4618){
535             s->workaround_bugs|= FF_BUG_EDGE;
536         }
537
538         if(s->divx_version)
539             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
540 //printf("padding_bug_score: %d\n", s->padding_bug_score);
541         if(s->divx_version==501 && s->divx_build==20020416)
542             s->padding_bug_score= 256*256*256*64;
543
544         if(s->divx_version && s->divx_version<500){
545             s->workaround_bugs|= FF_BUG_EDGE;
546         }
547         
548 #if 0
549         if(s->divx_version==500)
550             s->padding_bug_score= 256*256*256*64;
551
552         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
553          * lets hope this at least works
554          */
555         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
556            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
557             s->workaround_bugs|= FF_BUG_NO_PADDING;
558         
559         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
560             s->workaround_bugs|= FF_BUG_NO_PADDING;
561 #endif
562     }
563     
564     if(s->workaround_bugs& FF_BUG_STD_QPEL){
565         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
566         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
567         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
568         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
569         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
570         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
571
572         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
573         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
574         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
575         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
576         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
577         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
578     }
579
580 #if 0 // dump bits per frame / qp / complexity
581 {
582     static FILE *f=NULL;
583     if(!f) f=fopen("rate_qp_cplx.txt", "w");
584     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
585 }
586 #endif
587        
588         /* After H263 & mpeg4 header decode we have the height, width,*/
589         /* and other parameters. So then we could init the picture   */
590         /* FIXME: By the way H263 decoder is evolving it should have */
591         /* an H263EncContext                                         */
592     if(s->aspected_height)
593         new_aspect= s->aspected_width*s->width / (float)(s->height*s->aspected_height);
594     else
595         new_aspect=0;
596     
597     if (   s->width != avctx->width || s->height != avctx->height 
598         || ABS(new_aspect - avctx->aspect_ratio) > 0.001) {
599         /* H.263 could change picture size any time */
600         MPV_common_end(s);
601     }
602     if (!s->context_initialized) {
603         avctx->width = s->width;
604         avctx->height = s->height;
605         avctx->aspect_ratio= new_aspect;
606
607         goto retry;
608     }
609
610     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
611         s->gob_index = ff_h263_get_gob_height(s);
612     
613     // for hurry_up==5
614     s->current_picture.pict_type= s->pict_type;
615     s->current_picture.key_frame= s->pict_type == I_TYPE;
616
617     /* skip b frames if we dont have reference frames */
618     if(s->last_picture_ptr==NULL && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
619     /* skip b frames if we are in a hurry */
620     if(avctx->hurry_up && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
621     /* skip everything if we are in a hurry>=5 */
622     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
623     
624     if(s->next_p_frame_damaged){
625         if(s->pict_type==B_TYPE)
626             return get_consumed_bytes(s, buf_size);
627         else
628             s->next_p_frame_damaged=0;
629     }
630
631     if(MPV_frame_start(s, avctx) < 0)
632         return -1;
633
634 #ifdef DEBUG
635     printf("qscale=%d\n", s->qscale);
636 #endif
637
638     ff_er_frame_start(s);
639     
640     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
641     //which isnt available before MPV_frame_start()
642     if (s->msmpeg4_version==5){
643         if(ff_wmv2_decode_secondary_picture_header(s) < 0)
644             return -1;
645     }
646
647     /* decode each macroblock */
648     s->mb_x=0; 
649     s->mb_y=0;
650     
651     decode_slice(s);
652     while(s->mb_y<s->mb_height){
653         if(s->msmpeg4_version){
654             if(s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
655                 break;
656         }else{
657             if(ff_h263_resync(s)<0)
658                 break;
659         }
660         
661         if(s->msmpeg4_version<4 && s->h263_pred)
662             ff_mpeg4_clean_buffers(s);
663
664         decode_slice(s);
665     }
666
667     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
668         if(msmpeg4_decode_ext_header(s, buf_size) < 0){
669             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
670         }
671     
672     /* divx 5.01+ bistream reorder stuff */
673     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
674         int current_pos= get_bits_count(&s->gb)>>3;
675
676         if(   buf_size - current_pos > 5 
677            && buf_size - current_pos < BITSTREAM_BUFFER_SIZE){
678             int i;
679             int startcode_found=0;
680             for(i=current_pos; i<buf_size-3; i++){
681                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
682                     startcode_found=1;
683                     break;
684                 }
685             }
686             if(startcode_found){
687                 memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
688                 s->bitstream_buffer_size= buf_size - current_pos;
689             }
690         }
691     }
692
693     ff_er_frame_end(s);
694
695     MPV_frame_end(s);
696
697 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
698 assert(s->current_picture.pict_type == s->pict_type);
699     if(s->pict_type==B_TYPE || s->low_delay){
700         *pict= *(AVFrame*)&s->current_picture;
701         ff_print_debug_info(s, s->current_picture_ptr);
702     } else {
703         *pict= *(AVFrame*)&s->last_picture;
704         ff_print_debug_info(s, s->last_picture_ptr);
705     }
706
707     /* Return the Picture timestamp as the frame number */
708     /* we substract 1 because it is added on utils.c    */
709     avctx->frame_number = s->picture_number - 1;
710
711     /* dont output the last pic after seeking */
712     if(s->last_picture_ptr || s->low_delay)
713         *data_size = sizeof(AVFrame);
714 #ifdef PRINT_FRAME_TIME
715 printf("%Ld\n", rdtsc()-time);
716 #endif
717
718     return get_consumed_bytes(s, buf_size);
719 }
720
721 static const AVOption mpeg4_decoptions[] =
722 {
723     AVOPTION_SUB(avoptions_workaround_bug),
724     AVOPTION_END()
725 };
726
727 AVCodec mpeg4_decoder = {
728     "mpeg4",
729     CODEC_TYPE_VIDEO,
730     CODEC_ID_MPEG4,
731     sizeof(MpegEncContext),
732     ff_h263_decode_init,
733     NULL,
734     ff_h263_decode_end,
735     ff_h263_decode_frame,
736     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
737     .options = mpeg4_decoptions,
738     .flush= ff_mpeg_flush,
739 };
740
741 AVCodec h263_decoder = {
742     "h263",
743     CODEC_TYPE_VIDEO,
744     CODEC_ID_H263,
745     sizeof(MpegEncContext),
746     ff_h263_decode_init,
747     NULL,
748     ff_h263_decode_end,
749     ff_h263_decode_frame,
750     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
751     .flush= ff_mpeg_flush,
752 };
753
754 AVCodec msmpeg4v1_decoder = {
755     "msmpeg4v1",
756     CODEC_TYPE_VIDEO,
757     CODEC_ID_MSMPEG4V1,
758     sizeof(MpegEncContext),
759     ff_h263_decode_init,
760     NULL,
761     ff_h263_decode_end,
762     ff_h263_decode_frame,
763     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
764     mpeg4_decoptions,
765 };
766
767 AVCodec msmpeg4v2_decoder = {
768     "msmpeg4v2",
769     CODEC_TYPE_VIDEO,
770     CODEC_ID_MSMPEG4V2,
771     sizeof(MpegEncContext),
772     ff_h263_decode_init,
773     NULL,
774     ff_h263_decode_end,
775     ff_h263_decode_frame,
776     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
777     mpeg4_decoptions,
778 };
779
780 AVCodec msmpeg4v3_decoder = {
781     "msmpeg4",
782     CODEC_TYPE_VIDEO,
783     CODEC_ID_MSMPEG4V3,
784     sizeof(MpegEncContext),
785     ff_h263_decode_init,
786     NULL,
787     ff_h263_decode_end,
788     ff_h263_decode_frame,
789     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
790     .options = mpeg4_decoptions,
791 };
792
793 AVCodec wmv1_decoder = {
794     "wmv1",
795     CODEC_TYPE_VIDEO,
796     CODEC_ID_WMV1,
797     sizeof(MpegEncContext),
798     ff_h263_decode_init,
799     NULL,
800     ff_h263_decode_end,
801     ff_h263_decode_frame,
802     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
803     mpeg4_decoptions,
804 };
805
806 AVCodec h263i_decoder = {
807     "h263i",
808     CODEC_TYPE_VIDEO,
809     CODEC_ID_H263I,
810     sizeof(MpegEncContext),
811     ff_h263_decode_init,
812     NULL,
813     ff_h263_decode_end,
814     ff_h263_decode_frame,
815     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
816     mpeg4_decoptions,
817 };
818
819 AVCodec flv_decoder = {
820     "flv",
821     CODEC_TYPE_VIDEO,
822     CODEC_ID_FLV1,
823     sizeof(MpegEncContext),
824     ff_h263_decode_init,
825     NULL,
826     ff_h263_decode_end,
827     ff_h263_decode_frame,
828     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1
829 };