]> git.sesse.net Git - ffmpeg/blob - libavcodec/h263dec.c
AltiVec optimized fdct patch by (James Klicman <james at klicman dot org>)
[ffmpeg] / 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     s->unrestricted_mv= 1;
61
62     /* select sub codec */
63     switch(avctx->codec->id) {
64     case CODEC_ID_H263:
65         s->gob_number = 0;
66         break;
67     case CODEC_ID_MPEG4:
68         s->time_increment_bits = 4; /* default value for broken headers */
69         s->h263_pred = 1;
70         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
71         break;
72     case CODEC_ID_MSMPEG4V1:
73         s->h263_msmpeg4 = 1;
74         s->h263_pred = 1;
75         s->msmpeg4_version=1;
76         break;
77     case CODEC_ID_MSMPEG4V2:
78         s->h263_msmpeg4 = 1;
79         s->h263_pred = 1;
80         s->msmpeg4_version=2;
81         break;
82     case CODEC_ID_MSMPEG4V3:
83         s->h263_msmpeg4 = 1;
84         s->h263_pred = 1;
85         s->msmpeg4_version=3;
86         break;
87     case CODEC_ID_WMV1:
88         s->h263_msmpeg4 = 1;
89         s->h263_pred = 1;
90         s->msmpeg4_version=4;
91         break;
92     case CODEC_ID_WMV2:
93         s->h263_msmpeg4 = 1;
94         s->h263_pred = 1;
95         s->msmpeg4_version=5;
96         break;
97     case CODEC_ID_H263I:
98         s->h263_intel = 1;
99         break;
100     case CODEC_ID_FLV1:
101         s->h263_flv = 1;
102         break;
103     default:
104         return -1;
105     }
106     s->codec_id= avctx->codec->id;
107
108     /* for h263, we allocate the images after having read the header */
109     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
110         if (MPV_common_init(s) < 0)
111             return -1;
112
113     if (s->h263_msmpeg4)
114         ff_msmpeg4_decode_init(s);
115     else
116         h263_decode_init_vlc(s);
117     
118     return 0;
119 }
120
121 int ff_h263_decode_end(AVCodecContext *avctx)
122 {
123     MpegEncContext *s = avctx->priv_data;
124
125     MPV_common_end(s);
126     return 0;
127 }
128
129 /**
130  * retunrs the number of bytes consumed for building the current frame
131  */
132 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
133     int pos= (get_bits_count(&s->gb)+7)>>3;
134     
135     if(s->divx_packed){
136         //we would have to scan through the whole buf to handle the weird reordering ...
137         return buf_size; 
138     }else if(s->flags&CODEC_FLAG_TRUNCATED){
139         pos -= s->parse_context.last_index;
140         if(pos<0) pos=0; // padding is not really read so this might be -1
141         return pos;
142     }else{
143         if(pos==0) pos=1; //avoid infinite loops (i doubt thats needed but ...)
144         if(pos+10>buf_size) pos=buf_size; // oops ;)
145
146         return pos;
147     }
148 }
149
150 static int decode_slice(MpegEncContext *s){
151     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
152     s->last_resync_gb= s->gb;
153     s->first_slice_line= 1;
154         
155     s->resync_mb_x= s->mb_x;
156     s->resync_mb_y= s->mb_y;
157
158     s->y_dc_scale= s->y_dc_scale_table[ s->qscale ];
159     s->c_dc_scale= s->c_dc_scale_table[ s->qscale ];
160     
161     if(s->partitioned_frame){
162         const int qscale= s->qscale;
163
164         if(s->codec_id==CODEC_ID_MPEG4){
165             if(ff_mpeg4_decode_partitions(s) < 0)
166                 return -1; 
167         }
168         
169         /* restore variables which were modified */
170         s->first_slice_line=1;
171         s->mb_x= s->resync_mb_x;
172         s->mb_y= s->resync_mb_y;
173         s->qscale= qscale;
174         s->y_dc_scale= s->y_dc_scale_table[ s->qscale ];
175         s->c_dc_scale= s->c_dc_scale_table[ s->qscale ];
176     }
177
178     for(; s->mb_y < s->mb_height; s->mb_y++) {
179         /* per-row end of slice checks */
180         if(s->msmpeg4_version){
181             if(s->resync_mb_y + s->slice_height == s->mb_y){
182                 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);
183
184                 return 0;
185             }
186         }
187         
188         if(s->msmpeg4_version==1){
189             s->last_dc[0]=
190             s->last_dc[1]=
191             s->last_dc[2]= 128;
192         }
193     
194         ff_init_block_index(s);
195         for(; s->mb_x < s->mb_width; s->mb_x++) {
196             int ret;
197
198             ff_update_block_index(s);
199
200             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
201                 s->first_slice_line=0; 
202             }
203
204             /* DCT & quantize */
205             s->dsp.clear_blocks(s->block[0]);
206             
207             s->mv_dir = MV_DIR_FORWARD;
208             s->mv_type = MV_TYPE_16X16;
209 //            s->mb_skiped = 0;
210 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
211             ret= s->decode_mb(s, s->block);
212
213             if (s->pict_type!=B_TYPE)
214                 ff_h263_update_motion_val(s);
215
216             if(ret<0){
217                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
218                 if(ret==SLICE_END){
219                     MPV_decode_mb(s, s->block);
220
221 //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));
222                     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);
223
224                     s->padding_bug_score--;
225                         
226                     if(++s->mb_x >= s->mb_width){
227                         s->mb_x=0;
228                         ff_draw_horiz_band(s, s->mb_y*16, 16);
229                         s->mb_y++;
230                     }
231                     return 0; 
232                 }else if(ret==SLICE_NOEND){
233                     fprintf(stderr,"Slice mismatch at MB: %d\n", xy);
234                     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);
235                     return -1;
236                 }
237                 fprintf(stderr,"Error at MB: %d\n", xy);
238                 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);
239     
240                 return -1;
241             }
242
243             MPV_decode_mb(s, s->block);
244         }
245         
246         ff_draw_horiz_band(s, s->mb_y*16, 16);
247         
248         s->mb_x= 0;
249     }
250     
251     assert(s->mb_x==0 && s->mb_y==s->mb_height);
252
253     /* try to detect the padding bug */
254     if(      s->codec_id==CODEC_ID_MPEG4
255        &&   (s->workaround_bugs&FF_BUG_AUTODETECT) 
256        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
257        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
258 //       &&   !s->resync_marker
259        &&   !s->data_partitioning){
260         
261         const int bits_count= get_bits_count(&s->gb);
262         const int bits_left = s->gb.size_in_bits - bits_count;
263         
264         if(bits_left==0){
265             s->padding_bug_score+=16;
266         }else if(bits_left>8){
267             s->padding_bug_score++;
268         } else if(bits_left != 1){
269             int v= show_bits(&s->gb, 8);
270             v|= 0x7F >> (7-(bits_count&7));
271
272             if(v==0x7F)
273                 s->padding_bug_score--;
274             else
275                 s->padding_bug_score++;            
276         }                          
277     }
278
279     // handle formats which dont have unique end markers
280     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
281         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
282         int max_extra=7;
283         
284         /* no markers in M$ crap */
285         if(s->msmpeg4_version && s->pict_type==I_TYPE)
286             max_extra+= 17;
287         
288         /* buggy padding but the frame should still end approximately at the bitstream end */
289         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
290             max_extra+= 48;
291         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
292             max_extra+= 256*256*256*64;
293         
294         if(left>max_extra){
295             fprintf(stderr, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
296         }
297         else if(left<0){
298             fprintf(stderr, "overreading %d bits\n", -left);
299         }else
300             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);
301         
302         return 0;
303     }
304
305     fprintf(stderr, "slice end not reached but screenspace end (%d left %06X, score= %d)\n", 
306             s->gb.size_in_bits - get_bits_count(&s->gb),
307             show_bits(&s->gb, 24), s->padding_bug_score);
308             
309     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);
310
311     return -1;
312 }
313
314 /**
315  * finds the end of the current frame in the bitstream.
316  * @return the position of the first byte of the next frame, or -1
317  */
318 static int mpeg4_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
319     ParseContext *pc= &s->parse_context;
320     int vop_found, i;
321     uint32_t state;
322     
323     vop_found= pc->frame_start_found;
324     state= pc->state;
325     
326     i=0;
327     if(!vop_found){
328         for(i=0; i<buf_size; i++){
329             state= (state<<8) | buf[i];
330             if(state == 0x1B6){
331                 i++;
332                 vop_found=1;
333                 break;
334             }
335         }
336     }
337
338     if(vop_found){    
339       for(; i<buf_size; i++){
340         state= (state<<8) | buf[i];
341         if((state&0xFFFFFF00) == 0x100){
342             pc->frame_start_found=0;
343             pc->state=-1; 
344             return i-3;
345         }
346       }
347     }
348     pc->frame_start_found= vop_found;
349     pc->state= state;
350     return END_NOT_FOUND;
351 }
352
353 static int h263_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
354     ParseContext *pc= &s->parse_context;
355     int vop_found, i;
356     uint32_t state;
357     
358     vop_found= pc->frame_start_found;
359     state= pc->state;
360     
361     i=0;
362     if(!vop_found){
363         for(i=0; i<buf_size; i++){
364             state= (state<<8) | buf[i];
365             if(state>>(32-22) == 0x20){
366                 i++;
367                 vop_found=1;
368                 break;
369             }
370         }
371     }
372
373     if(vop_found){    
374       for(; i<buf_size; i++){
375         state= (state<<8) | buf[i];
376         if(state>>(32-22) == 0x20){
377             pc->frame_start_found=0;
378             pc->state=-1; 
379             return i-3;
380         }
381       }
382     }
383     pc->frame_start_found= vop_found;
384     pc->state= state;
385     
386     return END_NOT_FOUND;
387 }
388
389 int ff_h263_decode_frame(AVCodecContext *avctx, 
390                              void *data, int *data_size,
391                              uint8_t *buf, int buf_size)
392 {
393     MpegEncContext *s = avctx->priv_data;
394     int ret;
395     AVFrame *pict = data; 
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->stream_codec_tag == ff_get_fourcc("XVID") || 
486            s->avctx->codec_tag == ff_get_fourcc("XVID") || s->avctx->codec_tag == ff_get_fourcc("XVIX"))
487             s->xvid_build= -1;
488 #if 0
489         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
490            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc 
491             s->xvid_build= -1;
492 #endif
493     }
494
495     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
496         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
497             s->divx_version= 400; //divx 4
498     }
499
500     if(s->workaround_bugs&FF_BUG_AUTODETECT){
501         s->workaround_bugs &= ~FF_BUG_NO_PADDING;
502         
503         if(s->padding_bug_score > -2 && !s->data_partitioning && (s->divx_version || !s->resync_marker))
504             s->workaround_bugs |=  FF_BUG_NO_PADDING;
505
506         if(s->avctx->codec_tag == ff_get_fourcc("XVIX")) 
507             s->workaround_bugs|= FF_BUG_XVID_ILACE;
508
509         if(s->avctx->codec_tag == ff_get_fourcc("UMP4")){
510             s->workaround_bugs|= FF_BUG_UMP4;
511         }
512
513         if(s->divx_version>=500){
514             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
515         }
516
517         if(s->divx_version>502){
518             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
519         }
520
521         if(s->xvid_build && s->xvid_build<=3)
522             s->padding_bug_score= 256*256*256*64;
523         
524         if(s->xvid_build && s->xvid_build<=1)
525             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
526
527         if(s->xvid_build && s->xvid_build<=12)
528             s->workaround_bugs|= FF_BUG_EDGE;
529
530 #define SET_QPEL_FUNC(postfix1, postfix2) \
531     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
532     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
533     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
534
535         if(s->lavc_build && s->lavc_build<4653)
536             s->workaround_bugs|= FF_BUG_STD_QPEL;
537         
538         if(s->lavc_build && s->lavc_build<4655)
539             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
540
541         if(s->lavc_build && s->lavc_build<4670){
542             s->workaround_bugs|= FF_BUG_EDGE;
543         }
544
545         if(s->divx_version)
546             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
547 //printf("padding_bug_score: %d\n", s->padding_bug_score);
548         if(s->divx_version==501 && s->divx_build==20020416)
549             s->padding_bug_score= 256*256*256*64;
550
551         if(s->divx_version && s->divx_version<500){
552             s->workaround_bugs|= FF_BUG_EDGE;
553         }
554         
555 #if 0
556         if(s->divx_version==500)
557             s->padding_bug_score= 256*256*256*64;
558
559         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
560          * lets hope this at least works
561          */
562         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
563            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
564             s->workaround_bugs|= FF_BUG_NO_PADDING;
565         
566         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
567             s->workaround_bugs|= FF_BUG_NO_PADDING;
568 #endif
569     }
570     
571     if(s->workaround_bugs& FF_BUG_STD_QPEL){
572         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
573         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
574         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
575         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
576         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
577         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
578
579         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
580         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
581         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
582         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
583         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
584         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
585     }
586
587     if(avctx->debug & FF_DEBUG_BUGS)
588         printf("bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n", 
589                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
590                s->divx_packed ? "p" : "");
591     
592 #if 0 // dump bits per frame / qp / complexity
593 {
594     static FILE *f=NULL;
595     if(!f) f=fopen("rate_qp_cplx.txt", "w");
596     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
597 }
598 #endif
599        
600         /* After H263 & mpeg4 header decode we have the height, width,*/
601         /* and other parameters. So then we could init the picture   */
602         /* FIXME: By the way H263 decoder is evolving it should have */
603         /* an H263EncContext                                         */
604     
605     if (   s->width != avctx->width || s->height != avctx->height) {
606         /* H.263 could change picture size any time */
607         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
608         s->parse_context.buffer=0;
609         MPV_common_end(s);
610         s->parse_context= pc;
611     }
612     if (!s->context_initialized) {
613         avctx->width = s->width;
614         avctx->height = s->height;
615
616         goto retry;
617     }
618
619     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
620         s->gob_index = ff_h263_get_gob_height(s);
621     
622     // for hurry_up==5
623     s->current_picture.pict_type= s->pict_type;
624     s->current_picture.key_frame= s->pict_type == I_TYPE;
625
626     /* skip b frames if we dont have reference frames */
627     if(s->last_picture_ptr==NULL && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
628     /* skip b frames if we are in a hurry */
629     if(avctx->hurry_up && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
630     /* skip everything if we are in a hurry>=5 */
631     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
632     
633     if(s->next_p_frame_damaged){
634         if(s->pict_type==B_TYPE)
635             return get_consumed_bytes(s, buf_size);
636         else
637             s->next_p_frame_damaged=0;
638     }
639
640     if(MPV_frame_start(s, avctx) < 0)
641         return -1;
642
643 #ifdef DEBUG
644     printf("qscale=%d\n", s->qscale);
645 #endif
646
647     ff_er_frame_start(s);
648     
649     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
650     //which isnt available before MPV_frame_start()
651     if (s->msmpeg4_version==5){
652         if(ff_wmv2_decode_secondary_picture_header(s) < 0)
653             return -1;
654     }
655
656     /* decode each macroblock */
657     s->mb_x=0; 
658     s->mb_y=0;
659     
660     decode_slice(s);
661     while(s->mb_y<s->mb_height){
662         if(s->msmpeg4_version){
663             if(s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
664                 break;
665         }else{
666             if(ff_h263_resync(s)<0)
667                 break;
668         }
669         
670         if(s->msmpeg4_version<4 && s->h263_pred)
671             ff_mpeg4_clean_buffers(s);
672
673         decode_slice(s);
674     }
675
676     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
677         if(msmpeg4_decode_ext_header(s, buf_size) < 0){
678             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
679         }
680     
681     /* divx 5.01+ bistream reorder stuff */
682     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
683         int current_pos= get_bits_count(&s->gb)>>3;
684
685         if(   buf_size - current_pos > 5 
686            && buf_size - current_pos < BITSTREAM_BUFFER_SIZE){
687             int i;
688             int startcode_found=0;
689             for(i=current_pos; i<buf_size-3; i++){
690                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
691                     startcode_found=1;
692                     break;
693                 }
694             }
695             if(startcode_found){
696                 memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
697                 s->bitstream_buffer_size= buf_size - current_pos;
698             }
699         }
700     }
701
702     ff_er_frame_end(s);
703
704     MPV_frame_end(s);
705
706 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
707 assert(s->current_picture.pict_type == s->pict_type);
708     if(s->pict_type==B_TYPE || s->low_delay){
709         *pict= *(AVFrame*)&s->current_picture;
710         ff_print_debug_info(s, s->current_picture_ptr);
711     } else {
712         *pict= *(AVFrame*)&s->last_picture;
713         ff_print_debug_info(s, s->last_picture_ptr);
714     }
715
716     /* Return the Picture timestamp as the frame number */
717     /* we substract 1 because it is added on utils.c    */
718     avctx->frame_number = s->picture_number - 1;
719
720     /* dont output the last pic after seeking */
721     if(s->last_picture_ptr || s->low_delay)
722         *data_size = sizeof(AVFrame);
723 #ifdef PRINT_FRAME_TIME
724 printf("%Ld\n", rdtsc()-time);
725 #endif
726
727     return get_consumed_bytes(s, buf_size);
728 }
729
730 static const AVOption mpeg4_decoptions[] =
731 {
732     AVOPTION_SUB(avoptions_workaround_bug),
733     AVOPTION_END()
734 };
735
736 AVCodec mpeg4_decoder = {
737     "mpeg4",
738     CODEC_TYPE_VIDEO,
739     CODEC_ID_MPEG4,
740     sizeof(MpegEncContext),
741     ff_h263_decode_init,
742     NULL,
743     ff_h263_decode_end,
744     ff_h263_decode_frame,
745     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
746     .options = mpeg4_decoptions,
747     .flush= ff_mpeg_flush,
748 };
749
750 AVCodec h263_decoder = {
751     "h263",
752     CODEC_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,
760     .flush= ff_mpeg_flush,
761 };
762
763 AVCodec msmpeg4v1_decoder = {
764     "msmpeg4v1",
765     CODEC_TYPE_VIDEO,
766     CODEC_ID_MSMPEG4V1,
767     sizeof(MpegEncContext),
768     ff_h263_decode_init,
769     NULL,
770     ff_h263_decode_end,
771     ff_h263_decode_frame,
772     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
773     mpeg4_decoptions,
774 };
775
776 AVCodec msmpeg4v2_decoder = {
777     "msmpeg4v2",
778     CODEC_TYPE_VIDEO,
779     CODEC_ID_MSMPEG4V2,
780     sizeof(MpegEncContext),
781     ff_h263_decode_init,
782     NULL,
783     ff_h263_decode_end,
784     ff_h263_decode_frame,
785     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
786     mpeg4_decoptions,
787 };
788
789 AVCodec msmpeg4v3_decoder = {
790     "msmpeg4",
791     CODEC_TYPE_VIDEO,
792     CODEC_ID_MSMPEG4V3,
793     sizeof(MpegEncContext),
794     ff_h263_decode_init,
795     NULL,
796     ff_h263_decode_end,
797     ff_h263_decode_frame,
798     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
799     .options = mpeg4_decoptions,
800 };
801
802 AVCodec wmv1_decoder = {
803     "wmv1",
804     CODEC_TYPE_VIDEO,
805     CODEC_ID_WMV1,
806     sizeof(MpegEncContext),
807     ff_h263_decode_init,
808     NULL,
809     ff_h263_decode_end,
810     ff_h263_decode_frame,
811     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
812     mpeg4_decoptions,
813 };
814
815 AVCodec h263i_decoder = {
816     "h263i",
817     CODEC_TYPE_VIDEO,
818     CODEC_ID_H263I,
819     sizeof(MpegEncContext),
820     ff_h263_decode_init,
821     NULL,
822     ff_h263_decode_end,
823     ff_h263_decode_frame,
824     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
825     mpeg4_decoptions,
826 };
827
828 AVCodec flv_decoder = {
829     "flv",
830     CODEC_TYPE_VIDEO,
831     CODEC_ID_FLV1,
832     sizeof(MpegEncContext),
833     ff_h263_decode_init,
834     NULL,
835     ff_h263_decode_end,
836     ff_h263_decode_frame,
837     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1
838 };