closed gop support & flags2 as all bits in flags are used
[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 library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20  
21 /**
22  * @file h263dec.c
23  * H.263 decoder.
24  */
25  
26 #include "avcodec.h"
27 #include "dsputil.h"
28 #include "mpegvideo.h"
29
30 //#define DEBUG
31 //#define PRINT_FRAME_TIME
32
33 int ff_h263_decode_init(AVCodecContext *avctx)
34 {
35     MpegEncContext *s = avctx->priv_data;
36
37     s->avctx = avctx;
38     s->out_format = FMT_H263;
39
40     s->width = avctx->width;
41     s->height = avctx->height;
42     s->workaround_bugs= avctx->workaround_bugs;
43
44     // set defaults
45     s->quant_precision=5;
46     s->progressive_sequence=1;
47     s->decode_mb= ff_h263_decode_mb;
48     s->low_delay= 1;
49     avctx->pix_fmt= PIX_FMT_YUV420P;
50     s->unrestricted_mv= 1;
51
52     /* select sub codec */
53     switch(avctx->codec->id) {
54     case CODEC_ID_H263:
55         s->unrestricted_mv= 0;
56         break;
57     case CODEC_ID_MPEG4:
58         s->decode_mb= ff_mpeg4_decode_mb;
59         s->time_increment_bits = 4; /* default value for broken headers */
60         s->h263_pred = 1;
61         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
62         break;
63     case CODEC_ID_MSMPEG4V1:
64         s->h263_msmpeg4 = 1;
65         s->h263_pred = 1;
66         s->msmpeg4_version=1;
67         break;
68     case CODEC_ID_MSMPEG4V2:
69         s->h263_msmpeg4 = 1;
70         s->h263_pred = 1;
71         s->msmpeg4_version=2;
72         break;
73     case CODEC_ID_MSMPEG4V3:
74         s->h263_msmpeg4 = 1;
75         s->h263_pred = 1;
76         s->msmpeg4_version=3;
77         break;
78     case CODEC_ID_WMV1:
79         s->h263_msmpeg4 = 1;
80         s->h263_pred = 1;
81         s->msmpeg4_version=4;
82         break;
83     case CODEC_ID_WMV2:
84         s->h263_msmpeg4 = 1;
85         s->h263_pred = 1;
86         s->msmpeg4_version=5;
87         break;
88     case CODEC_ID_H263I:
89         break;
90     case CODEC_ID_FLV1:
91         s->h263_flv = 1;
92         break;
93     default:
94         return -1;
95     }
96     s->codec_id= avctx->codec->id;
97
98     /* for h263, we allocate the images after having read the header */
99     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
100         if (MPV_common_init(s) < 0)
101             return -1;
102
103     if (s->h263_msmpeg4)
104         ff_msmpeg4_decode_init(s);
105     else
106         h263_decode_init_vlc(s);
107     
108     return 0;
109 }
110
111 int ff_h263_decode_end(AVCodecContext *avctx)
112 {
113     MpegEncContext *s = avctx->priv_data;
114
115     MPV_common_end(s);
116     return 0;
117 }
118
119 /**
120  * retunrs the number of bytes consumed for building the current frame
121  */
122 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
123     int pos= (get_bits_count(&s->gb)+7)>>3;
124     
125     if(s->divx_packed){
126         //we would have to scan through the whole buf to handle the weird reordering ...
127         return buf_size; 
128     }else if(s->flags&CODEC_FLAG_TRUNCATED){
129         pos -= s->parse_context.last_index;
130         if(pos<0) pos=0; // padding is not really read so this might be -1
131         return pos;
132     }else{
133         if(pos==0) pos=1; //avoid infinite loops (i doubt thats needed but ...)
134         if(pos+10>buf_size) pos=buf_size; // oops ;)
135
136         return pos;
137     }
138 }
139
140 static int decode_slice(MpegEncContext *s){
141     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
142     s->last_resync_gb= s->gb;
143     s->first_slice_line= 1;
144         
145     s->resync_mb_x= s->mb_x;
146     s->resync_mb_y= s->mb_y;
147
148     ff_set_qscale(s, s->qscale);
149     
150     if(s->partitioned_frame){
151         const int qscale= s->qscale;
152
153         if(s->codec_id==CODEC_ID_MPEG4){
154             if(ff_mpeg4_decode_partitions(s) < 0)
155                 return -1; 
156         }
157         
158         /* restore variables which were modified */
159         s->first_slice_line=1;
160         s->mb_x= s->resync_mb_x;
161         s->mb_y= s->resync_mb_y;
162         ff_set_qscale(s, qscale);
163     }
164
165     for(; s->mb_y < s->mb_height; s->mb_y++) {
166         /* per-row end of slice checks */
167         if(s->msmpeg4_version){
168             if(s->resync_mb_y + s->slice_height == s->mb_y){
169                 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);
170
171                 return 0;
172             }
173         }
174         
175         if(s->msmpeg4_version==1){
176             s->last_dc[0]=
177             s->last_dc[1]=
178             s->last_dc[2]= 128;
179         }
180     
181         ff_init_block_index(s);
182         for(; s->mb_x < s->mb_width; s->mb_x++) {
183             int ret;
184
185             ff_update_block_index(s);
186
187             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
188                 s->first_slice_line=0; 
189             }
190
191             /* DCT & quantize */
192             s->dsp.clear_blocks(s->block[0]);
193             
194             s->mv_dir = MV_DIR_FORWARD;
195             s->mv_type = MV_TYPE_16X16;
196 //            s->mb_skiped = 0;
197 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
198             ret= s->decode_mb(s, s->block);
199
200             if (s->pict_type!=B_TYPE)
201                 ff_h263_update_motion_val(s);
202
203             if(ret<0){
204                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
205                 if(ret==SLICE_END){
206                     MPV_decode_mb(s, s->block);
207                     if(s->loop_filter)
208                         ff_h263_loop_filter(s);
209
210 //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));
211                     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);
212
213                     s->padding_bug_score--;
214                         
215                     if(++s->mb_x >= s->mb_width){
216                         s->mb_x=0;
217                         ff_draw_horiz_band(s, s->mb_y*16, 16);
218                         s->mb_y++;
219                     }
220                     return 0; 
221                 }else if(ret==SLICE_NOEND){
222                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
223                     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);
224                     return -1;
225                 }
226                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
227                 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);
228     
229                 return -1;
230             }
231
232             MPV_decode_mb(s, s->block);
233             if(s->loop_filter)
234                 ff_h263_loop_filter(s);
235         }
236         
237         ff_draw_horiz_band(s, s->mb_y*16, 16);
238         
239         s->mb_x= 0;
240     }
241     
242     assert(s->mb_x==0 && s->mb_y==s->mb_height);
243
244     /* try to detect the padding bug */
245     if(      s->codec_id==CODEC_ID_MPEG4
246        &&   (s->workaround_bugs&FF_BUG_AUTODETECT) 
247        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
248        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
249 //       &&   !s->resync_marker
250        &&   !s->data_partitioning){
251         
252         const int bits_count= get_bits_count(&s->gb);
253         const int bits_left = s->gb.size_in_bits - bits_count;
254         
255         if(bits_left==0){
256             s->padding_bug_score+=16;
257         }else if(bits_left>8){
258             s->padding_bug_score++;
259         } else if(bits_left != 1){
260             int v= show_bits(&s->gb, 8);
261             v|= 0x7F >> (7-(bits_count&7));
262
263             if(v==0x7F)
264                 s->padding_bug_score--;
265             else
266                 s->padding_bug_score++;            
267         }                          
268     }
269
270     // handle formats which dont have unique end markers
271     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
272         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
273         int max_extra=7;
274         
275         /* no markers in M$ crap */
276         if(s->msmpeg4_version && s->pict_type==I_TYPE)
277             max_extra+= 17;
278         
279         /* buggy padding but the frame should still end approximately at the bitstream end */
280         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
281             max_extra+= 48;
282         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
283             max_extra+= 256*256*256*64;
284         
285         if(left>max_extra){
286             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
287         }
288         else if(left<0){
289             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
290         }else
291             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);
292         
293         return 0;
294     }
295
296     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n", 
297             s->gb.size_in_bits - get_bits_count(&s->gb),
298             show_bits(&s->gb, 24), s->padding_bug_score);
299             
300     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);
301
302     return -1;
303 }
304
305 /**
306  * finds the end of the current frame in the bitstream.
307  * @return the position of the first byte of the next frame, or -1
308  */
309 static int mpeg4_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
310     ParseContext *pc= &s->parse_context;
311     int vop_found, i;
312     uint32_t state;
313     
314     vop_found= pc->frame_start_found;
315     state= pc->state;
316     
317     i=0;
318     if(!vop_found){
319         for(i=0; i<buf_size; i++){
320             state= (state<<8) | buf[i];
321             if(state == 0x1B6){
322                 i++;
323                 vop_found=1;
324                 break;
325             }
326         }
327     }
328
329     if(vop_found){    
330       for(; i<buf_size; i++){
331         state= (state<<8) | buf[i];
332         if((state&0xFFFFFF00) == 0x100){
333             pc->frame_start_found=0;
334             pc->state=-1; 
335             return i-3;
336         }
337       }
338     }
339     pc->frame_start_found= vop_found;
340     pc->state= state;
341     return END_NOT_FOUND;
342 }
343
344 static int h263_find_frame_end(MpegEncContext *s, uint8_t *buf, int buf_size){
345     ParseContext *pc= &s->parse_context;
346     int vop_found, i;
347     uint32_t state;
348     
349     vop_found= pc->frame_start_found;
350     state= pc->state;
351     
352     i=0;
353     if(!vop_found){
354         for(i=0; i<buf_size; i++){
355             state= (state<<8) | buf[i];
356             if(state>>(32-22) == 0x20){
357                 i++;
358                 vop_found=1;
359                 break;
360             }
361         }
362     }
363
364     if(vop_found){    
365       for(; i<buf_size; i++){
366         state= (state<<8) | buf[i];
367         if(state>>(32-22) == 0x20){
368             pc->frame_start_found=0;
369             pc->state=-1; 
370             return i-3;
371         }
372       }
373     }
374     pc->frame_start_found= vop_found;
375     pc->state= state;
376     
377     return END_NOT_FOUND;
378 }
379
380 int ff_h263_decode_frame(AVCodecContext *avctx, 
381                              void *data, int *data_size,
382                              uint8_t *buf, int buf_size)
383 {
384     MpegEncContext *s = avctx->priv_data;
385     int ret;
386     AVFrame *pict = data; 
387     
388 #ifdef PRINT_FRAME_TIME
389 uint64_t time= rdtsc();
390 #endif
391 #ifdef DEBUG
392     printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);
393     printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
394 #endif
395     s->flags= avctx->flags;
396     s->flags2= avctx->flags2;
397
398     *data_size = 0;
399
400     /* no supplementary picture */
401     if (buf_size == 0) {
402         /* special case for last picture */
403         if (s->low_delay==0 && s->next_picture_ptr) {
404             *pict= *(AVFrame*)s->next_picture_ptr;
405             s->next_picture_ptr= NULL;
406
407             *data_size = sizeof(AVFrame);
408         }
409
410         return 0;
411     }
412
413     if(s->flags&CODEC_FLAG_TRUNCATED){
414         int next;
415         
416         if(s->codec_id==CODEC_ID_MPEG4){
417             next= mpeg4_find_frame_end(s, buf, buf_size);
418         }else if(s->codec_id==CODEC_ID_H263){
419             next= h263_find_frame_end(s, buf, buf_size);
420         }else{
421             av_log(s->avctx, AV_LOG_ERROR, "this codec doesnt support truncated bitstreams\n");
422             return -1;
423         }
424         
425         if( ff_combine_frame(s, next, &buf, &buf_size) < 0 )
426             return buf_size;
427     }
428
429     
430 retry:
431     
432     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
433         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
434     }else
435         init_get_bits(&s->gb, buf, buf_size*8);
436     s->bitstream_buffer_size=0;
437
438     if (!s->context_initialized) {
439         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
440             return -1;
441     }
442     
443     //we need to set current_picture_ptr before reading the header, otherwise we cant store anyting im there
444     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
445         int i= ff_find_unused_picture(s, 0);
446         s->current_picture_ptr= &s->picture[i];
447     }
448       
449     /* let's go :-) */
450     if (s->msmpeg4_version==5) {
451         ret= ff_wmv2_decode_picture_header(s);
452     } else if (s->msmpeg4_version) {
453         ret = msmpeg4_decode_picture_header(s);
454     } else if (s->h263_pred) {
455         if(s->avctx->extradata_size && s->picture_number==0){
456             GetBitContext gb;
457             
458             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
459             ret = ff_mpeg4_decode_picture_header(s, &gb);
460         }
461         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
462
463         if(s->flags& CODEC_FLAG_LOW_DELAY)
464             s->low_delay=1;
465     } else if (s->codec_id == CODEC_ID_H263I) {
466         ret = intel_h263_decode_picture_header(s);
467     } else if (s->h263_flv) {
468         ret = flv_h263_decode_picture_header(s);
469     } else {
470         ret = h263_decode_picture_header(s);
471     }
472     
473     if(ret==FRAME_SKIPED) return get_consumed_bytes(s, buf_size);
474
475     /* skip if the header was thrashed */
476     if (ret < 0){
477         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
478         return -1;
479     }
480     
481     avctx->has_b_frames= !s->low_delay;
482     
483     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
484         if(s->avctx->stream_codec_tag == ff_get_fourcc("XVID") || 
485            s->avctx->codec_tag == ff_get_fourcc("XVID") || s->avctx->codec_tag == ff_get_fourcc("XVIX"))
486             s->xvid_build= -1;
487 #if 0
488         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
489            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc 
490             s->xvid_build= -1;
491 #endif
492     }
493
494     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
495         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
496             s->divx_version= 400; //divx 4
497     }
498
499     if(s->workaround_bugs&FF_BUG_AUTODETECT){
500         s->workaround_bugs &= ~FF_BUG_NO_PADDING;
501         
502         if(s->padding_bug_score > -2 && !s->data_partitioning && (s->divx_version || !s->resync_marker))
503             s->workaround_bugs |=  FF_BUG_NO_PADDING;
504
505         if(s->avctx->codec_tag == ff_get_fourcc("XVIX")) 
506             s->workaround_bugs|= FF_BUG_XVID_ILACE;
507
508         if(s->avctx->codec_tag == ff_get_fourcc("UMP4")){
509             s->workaround_bugs|= FF_BUG_UMP4;
510         }
511
512         if(s->divx_version>=500){
513             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
514         }
515
516         if(s->divx_version>502){
517             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
518         }
519
520         if(s->xvid_build && s->xvid_build<=3)
521             s->padding_bug_score= 256*256*256*64;
522         
523         if(s->xvid_build && s->xvid_build<=1)
524             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
525
526         if(s->xvid_build && s->xvid_build<=12)
527             s->workaround_bugs|= FF_BUG_EDGE;
528
529 #define SET_QPEL_FUNC(postfix1, postfix2) \
530     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
531     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
532     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
533
534         if(s->lavc_build && s->lavc_build<4653)
535             s->workaround_bugs|= FF_BUG_STD_QPEL;
536         
537         if(s->lavc_build && s->lavc_build<4655)
538             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
539
540         if(s->lavc_build && s->lavc_build<4670){
541             s->workaround_bugs|= FF_BUG_EDGE;
542         }
543
544         if(s->divx_version)
545             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
546 //printf("padding_bug_score: %d\n", s->padding_bug_score);
547         if(s->divx_version==501 && s->divx_build==20020416)
548             s->padding_bug_score= 256*256*256*64;
549
550         if(s->divx_version && s->divx_version<500){
551             s->workaround_bugs|= FF_BUG_EDGE;
552         }
553         
554 #if 0
555         if(s->divx_version==500)
556             s->padding_bug_score= 256*256*256*64;
557
558         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
559          * lets hope this at least works
560          */
561         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
562            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
563             s->workaround_bugs|= FF_BUG_NO_PADDING;
564         
565         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
566             s->workaround_bugs|= FF_BUG_NO_PADDING;
567 #endif
568     }
569     
570     if(s->workaround_bugs& FF_BUG_STD_QPEL){
571         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
572         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
573         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
574         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
575         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
576         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
577
578         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
579         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
580         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
581         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
582         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
583         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
584     }
585
586     if(avctx->debug & FF_DEBUG_BUGS)
587         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n", 
588                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
589                s->divx_packed ? "p" : "");
590     
591 #if 0 // dump bits per frame / qp / complexity
592 {
593     static FILE *f=NULL;
594     if(!f) f=fopen("rate_qp_cplx.txt", "w");
595     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
596 }
597 #endif
598        
599         /* After H263 & mpeg4 header decode we have the height, width,*/
600         /* and other parameters. So then we could init the picture   */
601         /* FIXME: By the way H263 decoder is evolving it should have */
602         /* an H263EncContext                                         */
603     
604     if (   s->width != avctx->width || s->height != avctx->height) {
605         /* H.263 could change picture size any time */
606         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
607         s->parse_context.buffer=0;
608         MPV_common_end(s);
609         s->parse_context= pc;
610     }
611     if (!s->context_initialized) {
612         avctx->width = s->width;
613         avctx->height = s->height;
614
615         goto retry;
616     }
617
618     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
619         s->gob_index = ff_h263_get_gob_height(s);
620     
621     // for hurry_up==5
622     s->current_picture.pict_type= s->pict_type;
623     s->current_picture.key_frame= s->pict_type == I_TYPE;
624
625     /* skip b frames if we dont have reference frames */
626     if(s->last_picture_ptr==NULL && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
627     /* skip b frames if we are in a hurry */
628     if(avctx->hurry_up && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
629     /* skip everything if we are in a hurry>=5 */
630     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
631     
632     if(s->next_p_frame_damaged){
633         if(s->pict_type==B_TYPE)
634             return get_consumed_bytes(s, buf_size);
635         else
636             s->next_p_frame_damaged=0;
637     }
638
639     if(MPV_frame_start(s, avctx) < 0)
640         return -1;
641
642 #ifdef DEBUG
643     printf("qscale=%d\n", s->qscale);
644 #endif
645
646     ff_er_frame_start(s);
647     
648     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
649     //which isnt available before MPV_frame_start()
650     if (s->msmpeg4_version==5){
651         if(ff_wmv2_decode_secondary_picture_header(s) < 0)
652             return -1;
653     }
654
655     /* decode each macroblock */
656     s->mb_x=0; 
657     s->mb_y=0;
658     
659     decode_slice(s);
660     while(s->mb_y<s->mb_height){
661         if(s->msmpeg4_version){
662             if(s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
663                 break;
664         }else{
665             if(ff_h263_resync(s)<0)
666                 break;
667         }
668         
669         if(s->msmpeg4_version<4 && s->h263_pred)
670             ff_mpeg4_clean_buffers(s);
671
672         decode_slice(s);
673     }
674
675     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
676         if(msmpeg4_decode_ext_header(s, buf_size) < 0){
677             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
678         }
679     
680     /* divx 5.01+ bistream reorder stuff */
681     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
682         int current_pos= get_bits_count(&s->gb)>>3;
683         int startcode_found=0;
684
685         if(   buf_size - current_pos > 5 
686            && buf_size - current_pos < BITSTREAM_BUFFER_SIZE){
687             int i;
688             for(i=current_pos; i<buf_size-3; i++){
689                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
690                     startcode_found=1;
691                     break;
692                 }
693             }
694         }
695         if(s->gb.buffer == s->bitstream_buffer && buf_size>20){ //xvid style
696             startcode_found=1;
697             current_pos=0;
698         }
699
700         if(startcode_found){
701             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
702             s->bitstream_buffer_size= buf_size - current_pos;
703         }
704     }
705
706     ff_er_frame_end(s);
707
708     MPV_frame_end(s);
709
710 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
711 assert(s->current_picture.pict_type == s->pict_type);
712     if(s->pict_type==B_TYPE || s->low_delay){
713         *pict= *(AVFrame*)&s->current_picture;
714         ff_print_debug_info(s, pict);
715     } else {
716         *pict= *(AVFrame*)&s->last_picture;
717         ff_print_debug_info(s, pict);
718     }
719
720     /* Return the Picture timestamp as the frame number */
721     /* we substract 1 because it is added on utils.c    */
722     avctx->frame_number = s->picture_number - 1;
723
724     /* dont output the last pic after seeking */
725     if(s->last_picture_ptr || s->low_delay)
726         *data_size = sizeof(AVFrame);
727 #ifdef PRINT_FRAME_TIME
728 printf("%Ld\n", rdtsc()-time);
729 #endif
730
731     return get_consumed_bytes(s, buf_size);
732 }
733
734 static const AVOption mpeg4_decoptions[] =
735 {
736     AVOPTION_SUB(avoptions_workaround_bug),
737     AVOPTION_END()
738 };
739
740 AVCodec mpeg4_decoder = {
741     "mpeg4",
742     CODEC_TYPE_VIDEO,
743     CODEC_ID_MPEG4,
744     sizeof(MpegEncContext),
745     ff_h263_decode_init,
746     NULL,
747     ff_h263_decode_end,
748     ff_h263_decode_frame,
749     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
750     .options = mpeg4_decoptions,
751     .flush= ff_mpeg_flush,
752 };
753
754 AVCodec h263_decoder = {
755     "h263",
756     CODEC_TYPE_VIDEO,
757     CODEC_ID_H263,
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 | CODEC_CAP_TRUNCATED,
764     .flush= ff_mpeg_flush,
765 };
766
767 AVCodec msmpeg4v1_decoder = {
768     "msmpeg4v1",
769     CODEC_TYPE_VIDEO,
770     CODEC_ID_MSMPEG4V1,
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 msmpeg4v2_decoder = {
781     "msmpeg4v2",
782     CODEC_TYPE_VIDEO,
783     CODEC_ID_MSMPEG4V2,
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     mpeg4_decoptions,
791 };
792
793 AVCodec msmpeg4v3_decoder = {
794     "msmpeg4",
795     CODEC_TYPE_VIDEO,
796     CODEC_ID_MSMPEG4V3,
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     .options = mpeg4_decoptions,
804 };
805
806 AVCodec wmv1_decoder = {
807     "wmv1",
808     CODEC_TYPE_VIDEO,
809     CODEC_ID_WMV1,
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 h263i_decoder = {
820     "h263i",
821     CODEC_TYPE_VIDEO,
822     CODEC_ID_H263I,
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     mpeg4_decoptions,
830 };
831
832 AVCodec flv_decoder = {
833     "flv",
834     CODEC_TYPE_VIDEO,
835     CODEC_ID_FLV1,
836     sizeof(MpegEncContext),
837     ff_h263_decode_init,
838     NULL,
839     ff_h263_decode_end,
840     ff_h263_decode_frame,
841     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1
842 };