819866e62d43fd6fb460696136085df9585383b3
[ffmpeg.git] / libavcodec / h263dec.c
1 /*
2  * H.263 decoder
3  * Copyright (c) 2001 Fabrice Bellard.
4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22
23 /**
24  * @file h263dec.c
25  * H.263 decoder.
26  */
27
28 #include "avcodec.h"
29 #include "dsputil.h"
30 #include "mpegvideo.h"
31 #include "h263_parser.h"
32 #include "mpeg4video_parser.h"
33
34 //#define DEBUG
35 //#define PRINT_FRAME_TIME
36
37 int ff_h263_decode_init(AVCodecContext *avctx)
38 {
39     MpegEncContext *s = avctx->priv_data;
40
41     s->avctx = avctx;
42     s->out_format = FMT_H263;
43
44     s->width  = avctx->coded_width;
45     s->height = avctx->coded_height;
46     s->workaround_bugs= avctx->workaround_bugs;
47
48     // set defaults
49     MPV_decode_defaults(s);
50     s->quant_precision=5;
51     s->decode_mb= ff_h263_decode_mb;
52     s->low_delay= 1;
53     avctx->pix_fmt= PIX_FMT_YUV420P;
54     s->unrestricted_mv= 1;
55
56     /* select sub codec */
57     switch(avctx->codec->id) {
58     case CODEC_ID_H263:
59         s->unrestricted_mv= 0;
60         break;
61     case CODEC_ID_MPEG4:
62         s->decode_mb= ff_mpeg4_decode_mb;
63         s->time_increment_bits = 4; /* default value for broken headers */
64         s->h263_pred = 1;
65         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
66         break;
67     case CODEC_ID_MSMPEG4V1:
68         s->h263_msmpeg4 = 1;
69         s->h263_pred = 1;
70         s->msmpeg4_version=1;
71         break;
72     case CODEC_ID_MSMPEG4V2:
73         s->h263_msmpeg4 = 1;
74         s->h263_pred = 1;
75         s->msmpeg4_version=2;
76         break;
77     case CODEC_ID_MSMPEG4V3:
78         s->h263_msmpeg4 = 1;
79         s->h263_pred = 1;
80         s->msmpeg4_version=3;
81         break;
82     case CODEC_ID_WMV1:
83         s->h263_msmpeg4 = 1;
84         s->h263_pred = 1;
85         s->msmpeg4_version=4;
86         break;
87     case CODEC_ID_WMV2:
88         s->h263_msmpeg4 = 1;
89         s->h263_pred = 1;
90         s->msmpeg4_version=5;
91         break;
92     case CODEC_ID_VC1:
93     case CODEC_ID_WMV3:
94         s->h263_msmpeg4 = 1;
95         s->h263_pred = 1;
96         s->msmpeg4_version=6;
97         break;
98     case CODEC_ID_H263I:
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  * returns 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     const int mb_size= 16>>s->avctx->lowres;
153     s->last_resync_gb= s->gb;
154     s->first_slice_line= 1;
155
156     s->resync_mb_x= s->mb_x;
157     s->resync_mb_y= s->mb_y;
158
159     ff_set_qscale(s, 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         ff_set_qscale(s, qscale);
174     }
175
176     for(; s->mb_y < s->mb_height; s->mb_y++) {
177         /* per-row end of slice checks */
178         if(s->msmpeg4_version){
179             if(s->resync_mb_y + s->slice_height == s->mb_y){
180                 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);
181
182                 return 0;
183             }
184         }
185
186         if(s->msmpeg4_version==1){
187             s->last_dc[0]=
188             s->last_dc[1]=
189             s->last_dc[2]= 128;
190         }
191
192         ff_init_block_index(s);
193         for(; s->mb_x < s->mb_width; s->mb_x++) {
194             int ret;
195
196             ff_update_block_index(s);
197
198             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
199                 s->first_slice_line=0;
200             }
201
202             /* DCT & quantize */
203
204             s->mv_dir = MV_DIR_FORWARD;
205             s->mv_type = MV_TYPE_16X16;
206 //            s->mb_skipped = 0;
207 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
208             ret= s->decode_mb(s, s->block);
209
210             if (s->pict_type!=B_TYPE)
211                 ff_h263_update_motion_val(s);
212
213             if(ret<0){
214                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
215                 if(ret==SLICE_END){
216                     MPV_decode_mb(s, s->block);
217                     if(s->loop_filter)
218                         ff_h263_loop_filter(s);
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*mb_size, mb_size);
228                         s->mb_y++;
229                     }
230                     return 0;
231                 }else if(ret==SLICE_NOEND){
232                     av_log(s->avctx, AV_LOG_ERROR, "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                 av_log(s->avctx, AV_LOG_ERROR, "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             if(s->loop_filter)
244                 ff_h263_loop_filter(s);
245         }
246
247         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
248
249         s->mb_x= 0;
250     }
251
252     assert(s->mb_x==0 && s->mb_y==s->mb_height);
253
254     /* try to detect the padding bug */
255     if(      s->codec_id==CODEC_ID_MPEG4
256        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
257        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
258        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
259 //       &&   !s->resync_marker
260        &&   !s->data_partitioning){
261
262         const int bits_count= get_bits_count(&s->gb);
263         const int bits_left = s->gb.size_in_bits - bits_count;
264
265         if(bits_left==0){
266             s->padding_bug_score+=16;
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 && bits_left<=8)
272                 s->padding_bug_score--;
273             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
274                 s->padding_bug_score+= 4;
275             else
276                 s->padding_bug_score++;
277         }
278     }
279
280     if(s->workaround_bugs&FF_BUG_AUTODETECT){
281         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version || !s->resync_marker)*/)
282             s->workaround_bugs |=  FF_BUG_NO_PADDING;
283         else
284             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
285     }
286
287     // handle formats which don't have unique end markers
288     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
289         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
290         int max_extra=7;
291
292         /* no markers in M$ crap */
293         if(s->msmpeg4_version && s->pict_type==I_TYPE)
294             max_extra+= 17;
295
296         /* buggy padding but the frame should still end approximately at the bitstream end */
297         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
298             max_extra+= 48;
299         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
300             max_extra+= 256*256*256*64;
301
302         if(left>max_extra){
303             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
304         }
305         else if(left<0){
306             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
307         }else
308             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);
309
310         return 0;
311     }
312
313     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
314             s->gb.size_in_bits - get_bits_count(&s->gb),
315             show_bits(&s->gb, 24), s->padding_bug_score);
316
317     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);
318
319     return -1;
320 }
321
322 int ff_h263_decode_frame(AVCodecContext *avctx,
323                              void *data, int *data_size,
324                              uint8_t *buf, int buf_size)
325 {
326     MpegEncContext *s = avctx->priv_data;
327     int ret;
328     AVFrame *pict = data;
329
330 #ifdef PRINT_FRAME_TIME
331 uint64_t time= rdtsc();
332 #endif
333 #ifdef DEBUG
334     av_log(avctx, AV_LOG_DEBUG, "*****frame %d size=%d\n", avctx->frame_number, buf_size);
335     if(buf_size>0)
336         av_log(avctx, AV_LOG_DEBUG, "bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
337 #endif
338     s->flags= avctx->flags;
339     s->flags2= avctx->flags2;
340
341     /* no supplementary picture */
342     if (buf_size == 0) {
343         /* special case for last picture */
344         if (s->low_delay==0 && s->next_picture_ptr) {
345             *pict= *(AVFrame*)s->next_picture_ptr;
346             s->next_picture_ptr= NULL;
347
348             *data_size = sizeof(AVFrame);
349         }
350
351         return 0;
352     }
353
354     if(s->flags&CODEC_FLAG_TRUNCATED){
355         int next;
356
357         if(s->codec_id==CODEC_ID_MPEG4){
358             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
359         }else if(s->codec_id==CODEC_ID_H263){
360             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
361         }else{
362             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
363             return -1;
364         }
365
366         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
367             return buf_size;
368     }
369
370
371 retry:
372
373     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
374         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
375     }else
376         init_get_bits(&s->gb, buf, buf_size*8);
377     s->bitstream_buffer_size=0;
378
379     if (!s->context_initialized) {
380         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
381             return -1;
382     }
383
384     //we need to set current_picture_ptr before reading the header, otherwise we cant store anyting im there
385     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
386         int i= ff_find_unused_picture(s, 0);
387         s->current_picture_ptr= &s->picture[i];
388     }
389
390     /* let's go :-) */
391     if (s->msmpeg4_version==5) {
392         ret= ff_wmv2_decode_picture_header(s);
393     } else if (s->msmpeg4_version) {
394         ret = msmpeg4_decode_picture_header(s);
395     } else if (s->h263_pred) {
396         if(s->avctx->extradata_size && s->picture_number==0){
397             GetBitContext gb;
398
399             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
400             ret = ff_mpeg4_decode_picture_header(s, &gb);
401         }
402         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
403
404         if(s->flags& CODEC_FLAG_LOW_DELAY)
405             s->low_delay=1;
406     } else if (s->codec_id == CODEC_ID_H263I) {
407         ret = intel_h263_decode_picture_header(s);
408     } else if (s->h263_flv) {
409         ret = flv_h263_decode_picture_header(s);
410     } else {
411         ret = h263_decode_picture_header(s);
412     }
413
414     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
415
416     /* skip if the header was thrashed */
417     if (ret < 0){
418         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
419         return -1;
420     }
421
422     avctx->has_b_frames= !s->low_delay;
423
424     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
425         if(s->stream_codec_tag == ff_get_fourcc("XVID") ||
426            s->codec_tag == ff_get_fourcc("XVID") || s->codec_tag == ff_get_fourcc("XVIX") ||
427            s->codec_tag == ff_get_fourcc("RMP4"))
428             s->xvid_build= -1;
429 #if 0
430         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
431            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
432             s->xvid_build= -1;
433 #endif
434     }
435
436     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
437         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
438             s->divx_version= 400; //divx 4
439     }
440
441     if(s->xvid_build && s->divx_version){
442         s->divx_version=
443         s->divx_build= 0;
444     }
445
446     if(s->workaround_bugs&FF_BUG_AUTODETECT){
447         if(s->codec_tag == ff_get_fourcc("XVIX"))
448             s->workaround_bugs|= FF_BUG_XVID_ILACE;
449
450         if(s->codec_tag == ff_get_fourcc("UMP4")){
451             s->workaround_bugs|= FF_BUG_UMP4;
452         }
453
454         if(s->divx_version>=500){
455             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
456         }
457
458         if(s->divx_version>502){
459             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
460         }
461
462         if(s->xvid_build && s->xvid_build<=3)
463             s->padding_bug_score= 256*256*256*64;
464
465         if(s->xvid_build && s->xvid_build<=1)
466             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
467
468         if(s->xvid_build && s->xvid_build<=12)
469             s->workaround_bugs|= FF_BUG_EDGE;
470
471         if(s->xvid_build && s->xvid_build<=32)
472             s->workaround_bugs|= FF_BUG_DC_CLIP;
473
474 #define SET_QPEL_FUNC(postfix1, postfix2) \
475     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
476     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
477     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
478
479         if(s->lavc_build && s->lavc_build<4653)
480             s->workaround_bugs|= FF_BUG_STD_QPEL;
481
482         if(s->lavc_build && s->lavc_build<4655)
483             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
484
485         if(s->lavc_build && s->lavc_build<4670){
486             s->workaround_bugs|= FF_BUG_EDGE;
487         }
488
489         if(s->lavc_build && s->lavc_build<=4712)
490             s->workaround_bugs|= FF_BUG_DC_CLIP;
491
492         if(s->divx_version)
493             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
494 //printf("padding_bug_score: %d\n", s->padding_bug_score);
495         if(s->divx_version==501 && s->divx_build==20020416)
496             s->padding_bug_score= 256*256*256*64;
497
498         if(s->divx_version && s->divx_version<500){
499             s->workaround_bugs|= FF_BUG_EDGE;
500         }
501
502         if(s->divx_version)
503             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
504 #if 0
505         if(s->divx_version==500)
506             s->padding_bug_score= 256*256*256*64;
507
508         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
509          * lets hope this at least works
510          */
511         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
512            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
513             s->workaround_bugs|= FF_BUG_NO_PADDING;
514
515         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
516             s->workaround_bugs|= FF_BUG_NO_PADDING;
517 #endif
518     }
519
520     if(s->workaround_bugs& FF_BUG_STD_QPEL){
521         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
522         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
523         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
524         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
525         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
526         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
527
528         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
529         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
530         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
531         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
532         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
533         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
534     }
535
536     if(avctx->debug & FF_DEBUG_BUGS)
537         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
538                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
539                s->divx_packed ? "p" : "");
540
541 #if 0 // dump bits per frame / qp / complexity
542 {
543     static FILE *f=NULL;
544     if(!f) f=fopen("rate_qp_cplx.txt", "w");
545     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
546 }
547 #endif
548
549 #if defined(HAVE_MMX) && defined(CONFIG_GPL)
550     if(s->codec_id == CODEC_ID_MPEG4 && s->xvid_build && avctx->idct_algo == FF_IDCT_AUTO && (mm_flags & MM_MMX)){
551         avctx->idct_algo= FF_IDCT_XVIDMMX;
552         avctx->coded_width= 0; // force reinit
553 //        dsputil_init(&s->dsp, avctx);
554         s->picture_number=0;
555     }
556 #endif
557
558         /* After H263 & mpeg4 header decode we have the height, width,*/
559         /* and other parameters. So then we could init the picture   */
560         /* FIXME: By the way H263 decoder is evolving it should have */
561         /* an H263EncContext                                         */
562
563     if (   s->width  != avctx->coded_width
564         || s->height != avctx->coded_height) {
565         /* H.263 could change picture size any time */
566         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
567         s->parse_context.buffer=0;
568         MPV_common_end(s);
569         s->parse_context= pc;
570     }
571     if (!s->context_initialized) {
572         avcodec_set_dimensions(avctx, s->width, s->height);
573
574         goto retry;
575     }
576
577     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
578         s->gob_index = ff_h263_get_gob_height(s);
579
580     // for hurry_up==5
581     s->current_picture.pict_type= s->pict_type;
582     s->current_picture.key_frame= s->pict_type == I_TYPE;
583
584     /* skip B-frames if we don't have reference frames */
585     if(s->last_picture_ptr==NULL && (s->pict_type==B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
586     /* skip b frames if we are in a hurry */
587     if(avctx->hurry_up && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
588     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==B_TYPE)
589        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=I_TYPE)
590        ||  avctx->skip_frame >= AVDISCARD_ALL)
591         return get_consumed_bytes(s, buf_size);
592     /* skip everything if we are in a hurry>=5 */
593     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
594
595     if(s->next_p_frame_damaged){
596         if(s->pict_type==B_TYPE)
597             return get_consumed_bytes(s, buf_size);
598         else
599             s->next_p_frame_damaged=0;
600     }
601
602     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==B_TYPE){
603         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
604         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
605     }else if((!s->no_rounding) || s->pict_type==B_TYPE){
606         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
607         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
608     }else{
609         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
610         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
611     }
612
613     if(MPV_frame_start(s, avctx) < 0)
614         return -1;
615
616 #ifdef DEBUG
617     av_log(avctx, AV_LOG_DEBUG, "qscale=%d\n", s->qscale);
618 #endif
619
620     ff_er_frame_start(s);
621
622     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
623     //which isnt available before MPV_frame_start()
624     if (s->msmpeg4_version==5){
625         if(ff_wmv2_decode_secondary_picture_header(s) < 0)
626             return -1;
627     }
628
629     /* decode each macroblock */
630     s->mb_x=0;
631     s->mb_y=0;
632
633     decode_slice(s);
634     while(s->mb_y<s->mb_height){
635         if(s->msmpeg4_version){
636             if(s->slice_height==0 || s->mb_x!=0 || (s->mb_y%s->slice_height)!=0 || get_bits_count(&s->gb) > s->gb.size_in_bits)
637                 break;
638         }else{
639             if(ff_h263_resync(s)<0)
640                 break;
641         }
642
643         if(s->msmpeg4_version<4 && s->h263_pred)
644             ff_mpeg4_clean_buffers(s);
645
646         decode_slice(s);
647     }
648
649     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
650         if(msmpeg4_decode_ext_header(s, buf_size) < 0){
651             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
652         }
653
654     /* divx 5.01+ bistream reorder stuff */
655     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
656         int current_pos= get_bits_count(&s->gb)>>3;
657         int startcode_found=0;
658
659         if(buf_size - current_pos > 5){
660             int i;
661             for(i=current_pos; i<buf_size-3; i++){
662                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
663                     startcode_found=1;
664                     break;
665                 }
666             }
667         }
668         if(s->gb.buffer == s->bitstream_buffer && buf_size>20){ //xvid style
669             startcode_found=1;
670             current_pos=0;
671         }
672
673         if(startcode_found){
674             s->bitstream_buffer= av_fast_realloc(
675                 s->bitstream_buffer,
676                 &s->allocated_bitstream_buffer_size,
677                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
678             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
679             s->bitstream_buffer_size= buf_size - current_pos;
680         }
681     }
682
683     ff_er_frame_end(s);
684
685     MPV_frame_end(s);
686
687 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
688 assert(s->current_picture.pict_type == s->pict_type);
689     if (s->pict_type == B_TYPE || s->low_delay) {
690         *pict= *(AVFrame*)s->current_picture_ptr;
691     } else if (s->last_picture_ptr != NULL) {
692         *pict= *(AVFrame*)s->last_picture_ptr;
693     }
694
695     if(s->last_picture_ptr || s->low_delay){
696         *data_size = sizeof(AVFrame);
697         ff_print_debug_info(s, pict);
698     }
699
700     /* Return the Picture timestamp as the frame number */
701     /* we substract 1 because it is added on utils.c    */
702     avctx->frame_number = s->picture_number - 1;
703
704 #ifdef PRINT_FRAME_TIME
705 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
706 #endif
707
708     return get_consumed_bytes(s, buf_size);
709 }
710
711 AVCodec mpeg4_decoder = {
712     "mpeg4",
713     CODEC_TYPE_VIDEO,
714     CODEC_ID_MPEG4,
715     sizeof(MpegEncContext),
716     ff_h263_decode_init,
717     NULL,
718     ff_h263_decode_end,
719     ff_h263_decode_frame,
720     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
721     .flush= ff_mpeg_flush,
722 };
723
724 AVCodec h263_decoder = {
725     "h263",
726     CODEC_TYPE_VIDEO,
727     CODEC_ID_H263,
728     sizeof(MpegEncContext),
729     ff_h263_decode_init,
730     NULL,
731     ff_h263_decode_end,
732     ff_h263_decode_frame,
733     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
734     .flush= ff_mpeg_flush,
735 };
736
737 AVCodec msmpeg4v1_decoder = {
738     "msmpeg4v1",
739     CODEC_TYPE_VIDEO,
740     CODEC_ID_MSMPEG4V1,
741     sizeof(MpegEncContext),
742     ff_h263_decode_init,
743     NULL,
744     ff_h263_decode_end,
745     ff_h263_decode_frame,
746     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
747 };
748
749 AVCodec msmpeg4v2_decoder = {
750     "msmpeg4v2",
751     CODEC_TYPE_VIDEO,
752     CODEC_ID_MSMPEG4V2,
753     sizeof(MpegEncContext),
754     ff_h263_decode_init,
755     NULL,
756     ff_h263_decode_end,
757     ff_h263_decode_frame,
758     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
759 };
760
761 AVCodec msmpeg4v3_decoder = {
762     "msmpeg4",
763     CODEC_TYPE_VIDEO,
764     CODEC_ID_MSMPEG4V3,
765     sizeof(MpegEncContext),
766     ff_h263_decode_init,
767     NULL,
768     ff_h263_decode_end,
769     ff_h263_decode_frame,
770     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
771 };
772
773 AVCodec wmv1_decoder = {
774     "wmv1",
775     CODEC_TYPE_VIDEO,
776     CODEC_ID_WMV1,
777     sizeof(MpegEncContext),
778     ff_h263_decode_init,
779     NULL,
780     ff_h263_decode_end,
781     ff_h263_decode_frame,
782     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
783 };
784
785 AVCodec h263i_decoder = {
786     "h263i",
787     CODEC_TYPE_VIDEO,
788     CODEC_ID_H263I,
789     sizeof(MpegEncContext),
790     ff_h263_decode_init,
791     NULL,
792     ff_h263_decode_end,
793     ff_h263_decode_frame,
794     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
795 };
796
797 AVCodec flv_decoder = {
798     "flv",
799     CODEC_TYPE_VIDEO,
800     CODEC_ID_FLV1,
801     sizeof(MpegEncContext),
802     ff_h263_decode_init,
803     NULL,
804     ff_h263_decode_end,
805     ff_h263_decode_frame,
806     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1
807 };