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1 /*
2  * H.263 decoder
3  * Copyright (c) 2001 Fabrice Bellard.
4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This 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->coded_width;
41     s->height = avctx->coded_height;
42     s->workaround_bugs= avctx->workaround_bugs;
43
44     // set defaults
45     MPV_decode_defaults(s);
46     s->quant_precision=5;
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     const int mb_size= 16>>s->avctx->lowres;
143     s->last_resync_gb= s->gb;
144     s->first_slice_line= 1;
145         
146     s->resync_mb_x= s->mb_x;
147     s->resync_mb_y= s->mb_y;
148
149     ff_set_qscale(s, s->qscale);
150     
151     if(s->partitioned_frame){
152         const int qscale= s->qscale;
153
154         if(s->codec_id==CODEC_ID_MPEG4){
155             if(ff_mpeg4_decode_partitions(s) < 0)
156                 return -1; 
157         }
158         
159         /* restore variables which were modified */
160         s->first_slice_line=1;
161         s->mb_x= s->resync_mb_x;
162         s->mb_y= s->resync_mb_y;
163         ff_set_qscale(s, qscale);
164     }
165
166     for(; s->mb_y < s->mb_height; s->mb_y++) {
167         /* per-row end of slice checks */
168         if(s->msmpeg4_version){
169             if(s->resync_mb_y + s->slice_height == s->mb_y){
170                 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);
171
172                 return 0;
173             }
174         }
175         
176         if(s->msmpeg4_version==1){
177             s->last_dc[0]=
178             s->last_dc[1]=
179             s->last_dc[2]= 128;
180         }
181     
182         ff_init_block_index(s);
183         for(; s->mb_x < s->mb_width; s->mb_x++) {
184             int ret;
185
186             ff_update_block_index(s);
187
188             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
189                 s->first_slice_line=0; 
190             }
191
192             /* DCT & quantize */
193             s->dsp.clear_blocks(s->block[0]);
194             
195             s->mv_dir = MV_DIR_FORWARD;
196             s->mv_type = MV_TYPE_16X16;
197 //            s->mb_skiped = 0;
198 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
199             ret= s->decode_mb(s, s->block);
200
201             if (s->pict_type!=B_TYPE)
202                 ff_h263_update_motion_val(s);
203
204             if(ret<0){
205                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
206                 if(ret==SLICE_END){
207                     MPV_decode_mb(s, s->block);
208                     if(s->loop_filter)
209                         ff_h263_loop_filter(s);
210
211 //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));
212                     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);
213
214                     s->padding_bug_score--;
215                         
216                     if(++s->mb_x >= s->mb_width){
217                         s->mb_x=0;
218                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
219                         s->mb_y++;
220                     }
221                     return 0; 
222                 }else if(ret==SLICE_NOEND){
223                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
224                     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);
225                     return -1;
226                 }
227                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
228                 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);
229     
230                 return -1;
231             }
232
233             MPV_decode_mb(s, s->block);
234             if(s->loop_filter)
235                 ff_h263_loop_filter(s);
236         }
237         
238         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
239         
240         s->mb_x= 0;
241     }
242     
243     assert(s->mb_x==0 && s->mb_y==s->mb_height);
244
245     /* try to detect the padding bug */
246     if(      s->codec_id==CODEC_ID_MPEG4
247        &&   (s->workaround_bugs&FF_BUG_AUTODETECT) 
248        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
249        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
250 //       &&   !s->resync_marker
251        &&   !s->data_partitioning){
252         
253         const int bits_count= get_bits_count(&s->gb);
254         const int bits_left = s->gb.size_in_bits - bits_count;
255         
256         if(bits_left==0){
257             s->padding_bug_score+=16;
258         }else if(bits_left>8){
259             s->padding_bug_score++;
260         } else if(bits_left != 1){
261             int v= show_bits(&s->gb, 8);
262             v|= 0x7F >> (7-(bits_count&7));
263
264             if(v==0x7F)
265                 s->padding_bug_score--;
266             else
267                 s->padding_bug_score++;            
268         }                          
269     }
270
271     // handle formats which dont have unique end markers
272     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
273         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
274         int max_extra=7;
275         
276         /* no markers in M$ crap */
277         if(s->msmpeg4_version && s->pict_type==I_TYPE)
278             max_extra+= 17;
279         
280         /* buggy padding but the frame should still end approximately at the bitstream end */
281         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
282             max_extra+= 48;
283         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
284             max_extra+= 256*256*256*64;
285         
286         if(left>max_extra){
287             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
288         }
289         else if(left<0){
290             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
291         }else
292             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);
293         
294         return 0;
295     }
296
297     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n", 
298             s->gb.size_in_bits - get_bits_count(&s->gb),
299             show_bits(&s->gb, 24), s->padding_bug_score);
300             
301     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);
302
303     return -1;
304 }
305
306 /**
307  * finds the end of the current frame in the bitstream.
308  * @return the position of the first byte of the next frame, or -1
309  */
310 int ff_mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
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         /* EOF considered as end of frame */
331         if (buf_size == 0)
332             return 0;
333         for(; i<buf_size; i++){
334             state= (state<<8) | buf[i];
335             if((state&0xFFFFFF00) == 0x100){
336                 pc->frame_start_found=0;
337                 pc->state=-1; 
338                 return i-3;
339             }
340         }
341     }
342     pc->frame_start_found= vop_found;
343     pc->state= state;
344     return END_NOT_FOUND;
345 }
346
347 static int h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
348     int vop_found, i;
349     uint32_t state;
350     
351     vop_found= pc->frame_start_found;
352     state= pc->state;
353     
354     i=0;
355     if(!vop_found){
356         for(i=0; i<buf_size; i++){
357             state= (state<<8) | buf[i];
358             if(state>>(32-22) == 0x20){
359                 i++;
360                 vop_found=1;
361                 break;
362             }
363         }
364     }
365
366     if(vop_found){    
367       for(; i<buf_size; i++){
368         state= (state<<8) | buf[i];
369         if(state>>(32-22) == 0x20){
370             pc->frame_start_found=0;
371             pc->state=-1; 
372             return i-3;
373         }
374       }
375     }
376     pc->frame_start_found= vop_found;
377     pc->state= state;
378     
379     return END_NOT_FOUND;
380 }
381
382 static int h263_parse(AVCodecParserContext *s,
383                            AVCodecContext *avctx,
384                            uint8_t **poutbuf, int *poutbuf_size, 
385                            const uint8_t *buf, int buf_size)
386 {
387     ParseContext *pc = s->priv_data;
388     int next;
389     
390     next= h263_find_frame_end(pc, buf, buf_size);
391
392     if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) {
393         *poutbuf = NULL;
394         *poutbuf_size = 0;
395         return buf_size;
396     }
397
398     *poutbuf = (uint8_t *)buf;
399     *poutbuf_size = buf_size;
400     return next;
401 }
402
403 int ff_h263_decode_frame(AVCodecContext *avctx, 
404                              void *data, int *data_size,
405                              uint8_t *buf, int buf_size)
406 {
407     MpegEncContext *s = avctx->priv_data;
408     int ret;
409     AVFrame *pict = data; 
410     
411 #ifdef PRINT_FRAME_TIME
412 uint64_t time= rdtsc();
413 #endif
414 #ifdef DEBUG
415     printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);
416     printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
417 #endif
418     s->flags= avctx->flags;
419     s->flags2= avctx->flags2;
420
421     /* no supplementary picture */
422     if (buf_size == 0) {
423         /* special case for last picture */
424         if (s->low_delay==0 && s->next_picture_ptr) {
425             *pict= *(AVFrame*)s->next_picture_ptr;
426             s->next_picture_ptr= NULL;
427
428             *data_size = sizeof(AVFrame);
429         }
430
431         return 0;
432     }
433
434     if(s->flags&CODEC_FLAG_TRUNCATED){
435         int next;
436         
437         if(s->codec_id==CODEC_ID_MPEG4){
438             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
439         }else if(s->codec_id==CODEC_ID_H263){
440             next= h263_find_frame_end(&s->parse_context, buf, buf_size);
441         }else{
442             av_log(s->avctx, AV_LOG_ERROR, "this codec doesnt support truncated bitstreams\n");
443             return -1;
444         }
445         
446         if( ff_combine_frame(&s->parse_context, next, &buf, &buf_size) < 0 )
447             return buf_size;
448     }
449
450     
451 retry:
452     
453     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
454         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
455     }else
456         init_get_bits(&s->gb, buf, buf_size*8);
457     s->bitstream_buffer_size=0;
458
459     if (!s->context_initialized) {
460         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
461             return -1;
462     }
463     
464     //we need to set current_picture_ptr before reading the header, otherwise we cant store anyting im there
465     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
466         int i= ff_find_unused_picture(s, 0);
467         s->current_picture_ptr= &s->picture[i];
468     }
469       
470     /* let's go :-) */
471     if (s->msmpeg4_version==5) {
472         ret= ff_wmv2_decode_picture_header(s);
473     } else if (s->msmpeg4_version) {
474         ret = msmpeg4_decode_picture_header(s);
475     } else if (s->h263_pred) {
476         if(s->avctx->extradata_size && s->picture_number==0){
477             GetBitContext gb;
478             
479             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
480             ret = ff_mpeg4_decode_picture_header(s, &gb);
481         }
482         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
483
484         if(s->flags& CODEC_FLAG_LOW_DELAY)
485             s->low_delay=1;
486     } else if (s->codec_id == CODEC_ID_H263I) {
487         ret = intel_h263_decode_picture_header(s);
488     } else if (s->h263_flv) {
489         ret = flv_h263_decode_picture_header(s);
490     } else {
491         ret = h263_decode_picture_header(s);
492     }
493     
494     if(ret==FRAME_SKIPED) return get_consumed_bytes(s, buf_size);
495
496     /* skip if the header was thrashed */
497     if (ret < 0){
498         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
499         return -1;
500     }
501     
502     avctx->has_b_frames= !s->low_delay;
503     
504     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
505         if(s->avctx->stream_codec_tag == ff_get_fourcc("XVID") || 
506            s->avctx->codec_tag == ff_get_fourcc("XVID") || s->avctx->codec_tag == ff_get_fourcc("XVIX"))
507             s->xvid_build= -1;
508 #if 0
509         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
510            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc 
511             s->xvid_build= -1;
512 #endif
513     }
514
515     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
516         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
517             s->divx_version= 400; //divx 4
518     }
519     
520     if(s->xvid_build && s->divx_version){
521         s->divx_version=
522         s->divx_build= 0;
523     }
524
525     if(s->workaround_bugs&FF_BUG_AUTODETECT){
526         s->workaround_bugs &= ~FF_BUG_NO_PADDING;
527         
528         if(s->padding_bug_score > -2 && !s->data_partitioning && (s->divx_version || !s->resync_marker))
529             s->workaround_bugs |=  FF_BUG_NO_PADDING;
530
531         if(s->avctx->codec_tag == ff_get_fourcc("XVIX")) 
532             s->workaround_bugs|= FF_BUG_XVID_ILACE;
533
534         if(s->avctx->codec_tag == ff_get_fourcc("UMP4")){
535             s->workaround_bugs|= FF_BUG_UMP4;
536         }
537
538         if(s->divx_version>=500){
539             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
540         }
541
542         if(s->divx_version>502){
543             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
544         }
545
546         if(s->xvid_build && s->xvid_build<=3)
547             s->padding_bug_score= 256*256*256*64;
548         
549         if(s->xvid_build && s->xvid_build<=1)
550             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
551
552         if(s->xvid_build && s->xvid_build<=12)
553             s->workaround_bugs|= FF_BUG_EDGE;
554
555         if(s->xvid_build && s->xvid_build<=32)
556             s->workaround_bugs|= FF_BUG_DC_CLIP;
557
558 #define SET_QPEL_FUNC(postfix1, postfix2) \
559     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
560     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
561     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
562
563         if(s->lavc_build && s->lavc_build<4653)
564             s->workaround_bugs|= FF_BUG_STD_QPEL;
565         
566         if(s->lavc_build && s->lavc_build<4655)
567             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
568
569         if(s->lavc_build && s->lavc_build<4670){
570             s->workaround_bugs|= FF_BUG_EDGE;
571         }
572         
573         if(s->lavc_build && s->lavc_build<=4712)
574             s->workaround_bugs|= FF_BUG_DC_CLIP;
575
576         if(s->divx_version)
577             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
578 //printf("padding_bug_score: %d\n", s->padding_bug_score);
579         if(s->divx_version==501 && s->divx_build==20020416)
580             s->padding_bug_score= 256*256*256*64;
581
582         if(s->divx_version && s->divx_version<500){
583             s->workaround_bugs|= FF_BUG_EDGE;
584         }
585         
586         if(s->divx_version)
587             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
588 #if 0
589         if(s->divx_version==500)
590             s->padding_bug_score= 256*256*256*64;
591
592         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
593          * lets hope this at least works
594          */
595         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
596            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
597             s->workaround_bugs|= FF_BUG_NO_PADDING;
598         
599         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
600             s->workaround_bugs|= FF_BUG_NO_PADDING;
601 #endif
602     }
603     
604     if(s->workaround_bugs& FF_BUG_STD_QPEL){
605         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
606         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
607         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
608         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
609         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
610         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
611
612         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
613         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
614         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
615         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
616         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
617         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
618     }
619
620     if(avctx->debug & FF_DEBUG_BUGS)
621         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n", 
622                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
623                s->divx_packed ? "p" : "");
624     
625 #if 0 // dump bits per frame / qp / complexity
626 {
627     static FILE *f=NULL;
628     if(!f) f=fopen("rate_qp_cplx.txt", "w");
629     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
630 }
631 #endif
632
633 #ifdef HAVE_MMX
634     if(s->codec_id == CODEC_ID_MPEG4 && s->xvid_build && avctx->idct_algo == FF_IDCT_AUTO && (mm_flags & MM_MMX) && !(s->flags&CODEC_FLAG_BITEXACT)){
635         avctx->idct_algo= FF_IDCT_LIBMPEG2MMX;
636         avctx->coded_width= 0; // force reinit
637     }
638 #endif
639
640         /* After H263 & mpeg4 header decode we have the height, width,*/
641         /* and other parameters. So then we could init the picture   */
642         /* FIXME: By the way H263 decoder is evolving it should have */
643         /* an H263EncContext                                         */
644     
645     if (   s->width  != avctx->coded_width 
646         || s->height != avctx->coded_height) {
647         /* H.263 could change picture size any time */
648         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
649         s->parse_context.buffer=0;
650         MPV_common_end(s);
651         s->parse_context= pc;
652     }
653     if (!s->context_initialized) {
654         avcodec_set_dimensions(avctx, s->width, s->height);
655
656         goto retry;
657     }
658
659     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
660         s->gob_index = ff_h263_get_gob_height(s);
661     
662     // for hurry_up==5
663     s->current_picture.pict_type= s->pict_type;
664     s->current_picture.key_frame= s->pict_type == I_TYPE;
665
666     /* skip b frames if we dont have reference frames */
667     if(s->last_picture_ptr==NULL && (s->pict_type==B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
668     /* skip b frames if we are in a hurry */
669     if(avctx->hurry_up && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
670     /* skip everything if we are in a hurry>=5 */
671     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
672     
673     if(s->next_p_frame_damaged){
674         if(s->pict_type==B_TYPE)
675             return get_consumed_bytes(s, buf_size);
676         else
677             s->next_p_frame_damaged=0;
678     }
679
680     if(MPV_frame_start(s, avctx) < 0)
681         return -1;
682
683 #ifdef DEBUG
684     printf("qscale=%d\n", s->qscale);
685 #endif
686
687     ff_er_frame_start(s);
688     
689     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
690     //which isnt available before MPV_frame_start()
691     if (s->msmpeg4_version==5){
692         if(ff_wmv2_decode_secondary_picture_header(s) < 0)
693             return -1;
694     }
695
696     /* decode each macroblock */
697     s->mb_x=0; 
698     s->mb_y=0;
699     
700     decode_slice(s);
701     while(s->mb_y<s->mb_height){
702         if(s->msmpeg4_version){
703             if(s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
704                 break;
705         }else{
706             if(ff_h263_resync(s)<0)
707                 break;
708         }
709         
710         if(s->msmpeg4_version<4 && s->h263_pred)
711             ff_mpeg4_clean_buffers(s);
712
713         decode_slice(s);
714     }
715
716     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
717         if(msmpeg4_decode_ext_header(s, buf_size) < 0){
718             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
719         }
720     
721     /* divx 5.01+ bistream reorder stuff */
722     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
723         int current_pos= get_bits_count(&s->gb)>>3;
724         int startcode_found=0;
725
726         if(   buf_size - current_pos > 5 
727            && buf_size - current_pos < BITSTREAM_BUFFER_SIZE){
728             int i;
729             for(i=current_pos; i<buf_size-3; i++){
730                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
731                     startcode_found=1;
732                     break;
733                 }
734             }
735         }
736         if(s->gb.buffer == s->bitstream_buffer && buf_size>20){ //xvid style
737             startcode_found=1;
738             current_pos=0;
739         }
740
741         if(startcode_found){
742             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
743             s->bitstream_buffer_size= buf_size - current_pos;
744         }
745     }
746
747     ff_er_frame_end(s);
748
749     MPV_frame_end(s);
750
751 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
752 assert(s->current_picture.pict_type == s->pict_type);
753     if(s->pict_type==B_TYPE || s->low_delay){
754         *pict= *(AVFrame*)&s->current_picture;
755         ff_print_debug_info(s, pict);
756     } else {
757         *pict= *(AVFrame*)&s->last_picture;
758         if(pict)
759             ff_print_debug_info(s, pict);
760     }
761
762     /* Return the Picture timestamp as the frame number */
763     /* we substract 1 because it is added on utils.c    */
764     avctx->frame_number = s->picture_number - 1;
765
766     /* dont output the last pic after seeking */
767     if(s->last_picture_ptr || s->low_delay)
768         *data_size = sizeof(AVFrame);
769 #ifdef PRINT_FRAME_TIME
770 printf("%Ld\n", rdtsc()-time);
771 #endif
772
773     return get_consumed_bytes(s, buf_size);
774 }
775
776 static const AVOption mpeg4_decoptions[] =
777 {
778     AVOPTION_SUB(avoptions_workaround_bug),
779     AVOPTION_END()
780 };
781
782 AVCodec mpeg4_decoder = {
783     "mpeg4",
784     CODEC_TYPE_VIDEO,
785     CODEC_ID_MPEG4,
786     sizeof(MpegEncContext),
787     ff_h263_decode_init,
788     NULL,
789     ff_h263_decode_end,
790     ff_h263_decode_frame,
791     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
792     .options = mpeg4_decoptions,
793     .flush= ff_mpeg_flush,
794 };
795
796 AVCodec h263_decoder = {
797     "h263",
798     CODEC_TYPE_VIDEO,
799     CODEC_ID_H263,
800     sizeof(MpegEncContext),
801     ff_h263_decode_init,
802     NULL,
803     ff_h263_decode_end,
804     ff_h263_decode_frame,
805     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED,
806     .flush= ff_mpeg_flush,
807 };
808
809 AVCodec msmpeg4v1_decoder = {
810     "msmpeg4v1",
811     CODEC_TYPE_VIDEO,
812     CODEC_ID_MSMPEG4V1,
813     sizeof(MpegEncContext),
814     ff_h263_decode_init,
815     NULL,
816     ff_h263_decode_end,
817     ff_h263_decode_frame,
818     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
819     mpeg4_decoptions,
820 };
821
822 AVCodec msmpeg4v2_decoder = {
823     "msmpeg4v2",
824     CODEC_TYPE_VIDEO,
825     CODEC_ID_MSMPEG4V2,
826     sizeof(MpegEncContext),
827     ff_h263_decode_init,
828     NULL,
829     ff_h263_decode_end,
830     ff_h263_decode_frame,
831     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
832     mpeg4_decoptions,
833 };
834
835 AVCodec msmpeg4v3_decoder = {
836     "msmpeg4",
837     CODEC_TYPE_VIDEO,
838     CODEC_ID_MSMPEG4V3,
839     sizeof(MpegEncContext),
840     ff_h263_decode_init,
841     NULL,
842     ff_h263_decode_end,
843     ff_h263_decode_frame,
844     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
845     .options = mpeg4_decoptions,
846 };
847
848 AVCodec wmv1_decoder = {
849     "wmv1",
850     CODEC_TYPE_VIDEO,
851     CODEC_ID_WMV1,
852     sizeof(MpegEncContext),
853     ff_h263_decode_init,
854     NULL,
855     ff_h263_decode_end,
856     ff_h263_decode_frame,
857     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
858     mpeg4_decoptions,
859 };
860
861 AVCodec h263i_decoder = {
862     "h263i",
863     CODEC_TYPE_VIDEO,
864     CODEC_ID_H263I,
865     sizeof(MpegEncContext),
866     ff_h263_decode_init,
867     NULL,
868     ff_h263_decode_end,
869     ff_h263_decode_frame,
870     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
871     mpeg4_decoptions,
872 };
873
874 AVCodec flv_decoder = {
875     "flv",
876     CODEC_TYPE_VIDEO,
877     CODEC_ID_FLV1,
878     sizeof(MpegEncContext),
879     ff_h263_decode_init,
880     NULL,
881     ff_h263_decode_end,
882     ff_h263_decode_frame,
883     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1
884 };
885
886 AVCodecParser h263_parser = {
887     { CODEC_ID_H263 },
888     sizeof(ParseContext),
889     NULL,
890     h263_parse,
891     ff_parse_close,
892 };