cbbb9c5065c373851c4fab799bcb6890a3c9235c
[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
33 //#define DEBUG
34 //#define PRINT_FRAME_TIME
35
36 int ff_h263_decode_init(AVCodecContext *avctx)
37 {
38     MpegEncContext *s = avctx->priv_data;
39
40     s->avctx = avctx;
41     s->out_format = FMT_H263;
42
43     s->width  = avctx->coded_width;
44     s->height = avctx->coded_height;
45     s->workaround_bugs= avctx->workaround_bugs;
46
47     // set defaults
48     MPV_decode_defaults(s);
49     s->quant_precision=5;
50     s->decode_mb= ff_h263_decode_mb;
51     s->low_delay= 1;
52     avctx->pix_fmt= PIX_FMT_YUV420P;
53     s->unrestricted_mv= 1;
54
55     /* select sub codec */
56     switch(avctx->codec->id) {
57     case CODEC_ID_H263:
58         s->unrestricted_mv= 0;
59         break;
60     case CODEC_ID_MPEG4:
61         s->decode_mb= ff_mpeg4_decode_mb;
62         s->time_increment_bits = 4; /* default value for broken headers */
63         s->h263_pred = 1;
64         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
65         break;
66     case CODEC_ID_MSMPEG4V1:
67         s->h263_msmpeg4 = 1;
68         s->h263_pred = 1;
69         s->msmpeg4_version=1;
70         break;
71     case CODEC_ID_MSMPEG4V2:
72         s->h263_msmpeg4 = 1;
73         s->h263_pred = 1;
74         s->msmpeg4_version=2;
75         break;
76     case CODEC_ID_MSMPEG4V3:
77         s->h263_msmpeg4 = 1;
78         s->h263_pred = 1;
79         s->msmpeg4_version=3;
80         break;
81     case CODEC_ID_WMV1:
82         s->h263_msmpeg4 = 1;
83         s->h263_pred = 1;
84         s->msmpeg4_version=4;
85         break;
86     case CODEC_ID_WMV2:
87         s->h263_msmpeg4 = 1;
88         s->h263_pred = 1;
89         s->msmpeg4_version=5;
90         break;
91     case CODEC_ID_VC1:
92     case CODEC_ID_WMV3:
93         s->h263_msmpeg4 = 1;
94         s->h263_pred = 1;
95         s->msmpeg4_version=6;
96         break;
97     case CODEC_ID_H263I:
98         break;
99     case CODEC_ID_FLV1:
100         s->h263_flv = 1;
101         break;
102     default:
103         return -1;
104     }
105     s->codec_id= avctx->codec->id;
106
107     /* for h263, we allocate the images after having read the header */
108     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
109         if (MPV_common_init(s) < 0)
110             return -1;
111
112     if (s->h263_msmpeg4)
113         ff_msmpeg4_decode_init(s);
114     else
115         h263_decode_init_vlc(s);
116
117     return 0;
118 }
119
120 int ff_h263_decode_end(AVCodecContext *avctx)
121 {
122     MpegEncContext *s = avctx->priv_data;
123
124     MPV_common_end(s);
125     return 0;
126 }
127
128 /**
129  * returns the number of bytes consumed for building the current frame
130  */
131 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
132     int pos= (get_bits_count(&s->gb)+7)>>3;
133
134     if(s->divx_packed){
135         //we would have to scan through the whole buf to handle the weird reordering ...
136         return buf_size;
137     }else if(s->flags&CODEC_FLAG_TRUNCATED){
138         pos -= s->parse_context.last_index;
139         if(pos<0) pos=0; // padding is not really read so this might be -1
140         return pos;
141     }else{
142         if(pos==0) pos=1; //avoid infinite loops (i doubt thats needed but ...)
143         if(pos+10>buf_size) pos=buf_size; // oops ;)
144
145         return pos;
146     }
147 }
148
149 static int decode_slice(MpegEncContext *s){
150     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
151     const int mb_size= 16>>s->avctx->lowres;
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     ff_set_qscale(s, s->qscale);
159
160     if(s->partitioned_frame){
161         const int qscale= s->qscale;
162
163         if(s->codec_id==CODEC_ID_MPEG4){
164             if(ff_mpeg4_decode_partitions(s) < 0)
165                 return -1;
166         }
167
168         /* restore variables which were modified */
169         s->first_slice_line=1;
170         s->mb_x= s->resync_mb_x;
171         s->mb_y= s->resync_mb_y;
172         ff_set_qscale(s, qscale);
173     }
174
175     for(; s->mb_y < s->mb_height; s->mb_y++) {
176         /* per-row end of slice checks */
177         if(s->msmpeg4_version){
178             if(s->resync_mb_y + s->slice_height == s->mb_y){
179                 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);
180
181                 return 0;
182             }
183         }
184
185         if(s->msmpeg4_version==1){
186             s->last_dc[0]=
187             s->last_dc[1]=
188             s->last_dc[2]= 128;
189         }
190
191         ff_init_block_index(s);
192         for(; s->mb_x < s->mb_width; s->mb_x++) {
193             int ret;
194
195             ff_update_block_index(s);
196
197             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
198                 s->first_slice_line=0;
199             }
200
201             /* DCT & quantize */
202
203             s->mv_dir = MV_DIR_FORWARD;
204             s->mv_type = MV_TYPE_16X16;
205 //            s->mb_skipped = 0;
206 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
207             ret= s->decode_mb(s, s->block);
208
209             if (s->pict_type!=B_TYPE)
210                 ff_h263_update_motion_val(s);
211
212             if(ret<0){
213                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
214                 if(ret==SLICE_END){
215                     MPV_decode_mb(s, s->block);
216                     if(s->loop_filter)
217                         ff_h263_loop_filter(s);
218
219 //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));
220                     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);
221
222                     s->padding_bug_score--;
223
224                     if(++s->mb_x >= s->mb_width){
225                         s->mb_x=0;
226                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
227                         s->mb_y++;
228                     }
229                     return 0;
230                 }else if(ret==SLICE_NOEND){
231                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
232                     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);
233                     return -1;
234                 }
235                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
236                 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);
237
238                 return -1;
239             }
240
241             MPV_decode_mb(s, s->block);
242             if(s->loop_filter)
243                 ff_h263_loop_filter(s);
244         }
245
246         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
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 != 1){
267             int v= show_bits(&s->gb, 8);
268             v|= 0x7F >> (7-(bits_count&7));
269
270             if(v==0x7F && bits_left<=8)
271                 s->padding_bug_score--;
272             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
273                 s->padding_bug_score+= 4;
274             else
275                 s->padding_bug_score++;
276         }
277     }
278
279     if(s->workaround_bugs&FF_BUG_AUTODETECT){
280         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version || !s->resync_marker)*/)
281             s->workaround_bugs |=  FF_BUG_NO_PADDING;
282         else
283             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
284     }
285
286     // handle formats which don't have unique end markers
287     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
288         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
289         int max_extra=7;
290
291         /* no markers in M$ crap */
292         if(s->msmpeg4_version && s->pict_type==I_TYPE)
293             max_extra+= 17;
294
295         /* buggy padding but the frame should still end approximately at the bitstream end */
296         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
297             max_extra+= 48;
298         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
299             max_extra+= 256*256*256*64;
300
301         if(left>max_extra){
302             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
303         }
304         else if(left<0){
305             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
306         }else
307             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);
308
309         return 0;
310     }
311
312     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
313             s->gb.size_in_bits - get_bits_count(&s->gb),
314             show_bits(&s->gb, 24), s->padding_bug_score);
315
316     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);
317
318     return -1;
319 }
320
321 /**
322  * finds the end of the current frame in the bitstream.
323  * @return the position of the first byte of the next frame, or -1
324  */
325 int ff_mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
326     int vop_found, i;
327     uint32_t state;
328
329     vop_found= pc->frame_start_found;
330     state= pc->state;
331
332     i=0;
333     if(!vop_found){
334         for(i=0; i<buf_size; i++){
335             state= (state<<8) | buf[i];
336             if(state == 0x1B6){
337                 i++;
338                 vop_found=1;
339                 break;
340             }
341         }
342     }
343
344     if(vop_found){
345         /* EOF considered as end of frame */
346         if (buf_size == 0)
347             return 0;
348         for(; i<buf_size; i++){
349             state= (state<<8) | buf[i];
350             if((state&0xFFFFFF00) == 0x100){
351                 pc->frame_start_found=0;
352                 pc->state=-1;
353                 return i-3;
354             }
355         }
356     }
357     pc->frame_start_found= vop_found;
358     pc->state= state;
359     return END_NOT_FOUND;
360 }
361
362 int ff_h263_decode_frame(AVCodecContext *avctx,
363                              void *data, int *data_size,
364                              uint8_t *buf, int buf_size)
365 {
366     MpegEncContext *s = avctx->priv_data;
367     int ret;
368     AVFrame *pict = data;
369
370 #ifdef PRINT_FRAME_TIME
371 uint64_t time= rdtsc();
372 #endif
373 #ifdef DEBUG
374     av_log(avctx, AV_LOG_DEBUG, "*****frame %d size=%d\n", avctx->frame_number, buf_size);
375     if(buf_size>0)
376         av_log(avctx, AV_LOG_DEBUG, "bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
377 #endif
378     s->flags= avctx->flags;
379     s->flags2= avctx->flags2;
380
381     /* no supplementary picture */
382     if (buf_size == 0) {
383         /* special case for last picture */
384         if (s->low_delay==0 && s->next_picture_ptr) {
385             *pict= *(AVFrame*)s->next_picture_ptr;
386             s->next_picture_ptr= NULL;
387
388             *data_size = sizeof(AVFrame);
389         }
390
391         return 0;
392     }
393
394     if(s->flags&CODEC_FLAG_TRUNCATED){
395         int next;
396
397         if(s->codec_id==CODEC_ID_MPEG4){
398             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
399         }else if(s->codec_id==CODEC_ID_H263){
400             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
401         }else{
402             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
403             return -1;
404         }
405
406         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
407             return buf_size;
408     }
409
410
411 retry:
412
413     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
414         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
415     }else
416         init_get_bits(&s->gb, buf, buf_size*8);
417     s->bitstream_buffer_size=0;
418
419     if (!s->context_initialized) {
420         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
421             return -1;
422     }
423
424     //we need to set current_picture_ptr before reading the header, otherwise we cant store anyting im there
425     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
426         int i= ff_find_unused_picture(s, 0);
427         s->current_picture_ptr= &s->picture[i];
428     }
429
430     /* let's go :-) */
431     if (s->msmpeg4_version==5) {
432         ret= ff_wmv2_decode_picture_header(s);
433     } else if (s->msmpeg4_version) {
434         ret = msmpeg4_decode_picture_header(s);
435     } else if (s->h263_pred) {
436         if(s->avctx->extradata_size && s->picture_number==0){
437             GetBitContext gb;
438
439             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
440             ret = ff_mpeg4_decode_picture_header(s, &gb);
441         }
442         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
443
444         if(s->flags& CODEC_FLAG_LOW_DELAY)
445             s->low_delay=1;
446     } else if (s->codec_id == CODEC_ID_H263I) {
447         ret = intel_h263_decode_picture_header(s);
448     } else if (s->h263_flv) {
449         ret = flv_h263_decode_picture_header(s);
450     } else {
451         ret = h263_decode_picture_header(s);
452     }
453
454     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
455
456     /* skip if the header was thrashed */
457     if (ret < 0){
458         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
459         return -1;
460     }
461
462     avctx->has_b_frames= !s->low_delay;
463
464     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
465         if(s->stream_codec_tag == ff_get_fourcc("XVID") ||
466            s->codec_tag == ff_get_fourcc("XVID") || s->codec_tag == ff_get_fourcc("XVIX") ||
467            s->codec_tag == ff_get_fourcc("RMP4"))
468             s->xvid_build= -1;
469 #if 0
470         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
471            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
472             s->xvid_build= -1;
473 #endif
474     }
475
476     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
477         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
478             s->divx_version= 400; //divx 4
479     }
480
481     if(s->xvid_build && s->divx_version){
482         s->divx_version=
483         s->divx_build= 0;
484     }
485
486     if(s->workaround_bugs&FF_BUG_AUTODETECT){
487         if(s->codec_tag == ff_get_fourcc("XVIX"))
488             s->workaround_bugs|= FF_BUG_XVID_ILACE;
489
490         if(s->codec_tag == ff_get_fourcc("UMP4")){
491             s->workaround_bugs|= FF_BUG_UMP4;
492         }
493
494         if(s->divx_version>=500){
495             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
496         }
497
498         if(s->divx_version>502){
499             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
500         }
501
502         if(s->xvid_build && s->xvid_build<=3)
503             s->padding_bug_score= 256*256*256*64;
504
505         if(s->xvid_build && s->xvid_build<=1)
506             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
507
508         if(s->xvid_build && s->xvid_build<=12)
509             s->workaround_bugs|= FF_BUG_EDGE;
510
511         if(s->xvid_build && s->xvid_build<=32)
512             s->workaround_bugs|= FF_BUG_DC_CLIP;
513
514 #define SET_QPEL_FUNC(postfix1, postfix2) \
515     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
516     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
517     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
518
519         if(s->lavc_build && s->lavc_build<4653)
520             s->workaround_bugs|= FF_BUG_STD_QPEL;
521
522         if(s->lavc_build && s->lavc_build<4655)
523             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
524
525         if(s->lavc_build && s->lavc_build<4670){
526             s->workaround_bugs|= FF_BUG_EDGE;
527         }
528
529         if(s->lavc_build && s->lavc_build<=4712)
530             s->workaround_bugs|= FF_BUG_DC_CLIP;
531
532         if(s->divx_version)
533             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
534 //printf("padding_bug_score: %d\n", s->padding_bug_score);
535         if(s->divx_version==501 && s->divx_build==20020416)
536             s->padding_bug_score= 256*256*256*64;
537
538         if(s->divx_version && s->divx_version<500){
539             s->workaround_bugs|= FF_BUG_EDGE;
540         }
541
542         if(s->divx_version)
543             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
544 #if 0
545         if(s->divx_version==500)
546             s->padding_bug_score= 256*256*256*64;
547
548         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
549          * lets hope this at least works
550          */
551         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
552            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
553             s->workaround_bugs|= FF_BUG_NO_PADDING;
554
555         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
556             s->workaround_bugs|= FF_BUG_NO_PADDING;
557 #endif
558     }
559
560     if(s->workaround_bugs& FF_BUG_STD_QPEL){
561         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
562         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
563         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
564         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
565         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
566         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
567
568         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
569         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
570         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
571         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
572         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
573         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
574     }
575
576     if(avctx->debug & FF_DEBUG_BUGS)
577         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
578                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
579                s->divx_packed ? "p" : "");
580
581 #if 0 // dump bits per frame / qp / complexity
582 {
583     static FILE *f=NULL;
584     if(!f) f=fopen("rate_qp_cplx.txt", "w");
585     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
586 }
587 #endif
588
589 #if defined(HAVE_MMX) && defined(CONFIG_GPL)
590     if(s->codec_id == CODEC_ID_MPEG4 && s->xvid_build && avctx->idct_algo == FF_IDCT_AUTO && (mm_flags & MM_MMX)){
591         avctx->idct_algo= FF_IDCT_XVIDMMX;
592         avctx->coded_width= 0; // force reinit
593 //        dsputil_init(&s->dsp, avctx);
594         s->picture_number=0;
595     }
596 #endif
597
598         /* After H263 & mpeg4 header decode we have the height, width,*/
599         /* and other parameters. So then we could init the picture   */
600         /* FIXME: By the way H263 decoder is evolving it should have */
601         /* an H263EncContext                                         */
602
603     if (   s->width  != avctx->coded_width
604         || s->height != avctx->coded_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         avcodec_set_dimensions(avctx, s->width, s->height);
613
614         goto retry;
615     }
616
617     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
618         s->gob_index = ff_h263_get_gob_height(s);
619
620     // for hurry_up==5
621     s->current_picture.pict_type= s->pict_type;
622     s->current_picture.key_frame= s->pict_type == I_TYPE;
623
624     /* skip B-frames if we don't have reference frames */
625     if(s->last_picture_ptr==NULL && (s->pict_type==B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
626     /* skip b frames if we are in a hurry */
627     if(avctx->hurry_up && s->pict_type==B_TYPE) return get_consumed_bytes(s, buf_size);
628     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==B_TYPE)
629        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=I_TYPE)
630        ||  avctx->skip_frame >= AVDISCARD_ALL)
631         return get_consumed_bytes(s, buf_size);
632     /* skip everything if we are in a hurry>=5 */
633     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
634
635     if(s->next_p_frame_damaged){
636         if(s->pict_type==B_TYPE)
637             return get_consumed_bytes(s, buf_size);
638         else
639             s->next_p_frame_damaged=0;
640     }
641
642     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==B_TYPE){
643         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
644         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
645     }else if((!s->no_rounding) || s->pict_type==B_TYPE){
646         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
647         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
648     }else{
649         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
650         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
651     }
652
653     if(MPV_frame_start(s, avctx) < 0)
654         return -1;
655
656 #ifdef DEBUG
657     av_log(avctx, AV_LOG_DEBUG, "qscale=%d\n", s->qscale);
658 #endif
659
660     ff_er_frame_start(s);
661
662     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
663     //which isnt available before MPV_frame_start()
664     if (s->msmpeg4_version==5){
665         if(ff_wmv2_decode_secondary_picture_header(s) < 0)
666             return -1;
667     }
668
669     /* decode each macroblock */
670     s->mb_x=0;
671     s->mb_y=0;
672
673     decode_slice(s);
674     while(s->mb_y<s->mb_height){
675         if(s->msmpeg4_version){
676             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)
677                 break;
678         }else{
679             if(ff_h263_resync(s)<0)
680                 break;
681         }
682
683         if(s->msmpeg4_version<4 && s->h263_pred)
684             ff_mpeg4_clean_buffers(s);
685
686         decode_slice(s);
687     }
688
689     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==I_TYPE)
690         if(msmpeg4_decode_ext_header(s, buf_size) < 0){
691             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
692         }
693
694     /* divx 5.01+ bistream reorder stuff */
695     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
696         int current_pos= get_bits_count(&s->gb)>>3;
697         int startcode_found=0;
698
699         if(buf_size - current_pos > 5){
700             int i;
701             for(i=current_pos; i<buf_size-3; i++){
702                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
703                     startcode_found=1;
704                     break;
705                 }
706             }
707         }
708         if(s->gb.buffer == s->bitstream_buffer && buf_size>20){ //xvid style
709             startcode_found=1;
710             current_pos=0;
711         }
712
713         if(startcode_found){
714             s->bitstream_buffer= av_fast_realloc(
715                 s->bitstream_buffer,
716                 &s->allocated_bitstream_buffer_size,
717                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
718             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
719             s->bitstream_buffer_size= buf_size - current_pos;
720         }
721     }
722
723     ff_er_frame_end(s);
724
725     MPV_frame_end(s);
726
727 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
728 assert(s->current_picture.pict_type == s->pict_type);
729     if (s->pict_type == B_TYPE || s->low_delay) {
730         *pict= *(AVFrame*)s->current_picture_ptr;
731     } else if (s->last_picture_ptr != NULL) {
732         *pict= *(AVFrame*)s->last_picture_ptr;
733     }
734
735     if(s->last_picture_ptr || s->low_delay){
736         *data_size = sizeof(AVFrame);
737         ff_print_debug_info(s, pict);
738     }
739
740     /* Return the Picture timestamp as the frame number */
741     /* we substract 1 because it is added on utils.c    */
742     avctx->frame_number = s->picture_number - 1;
743
744 #ifdef PRINT_FRAME_TIME
745 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
746 #endif
747
748     return get_consumed_bytes(s, buf_size);
749 }
750
751 AVCodec mpeg4_decoder = {
752     "mpeg4",
753     CODEC_TYPE_VIDEO,
754     CODEC_ID_MPEG4,
755     sizeof(MpegEncContext),
756     ff_h263_decode_init,
757     NULL,
758     ff_h263_decode_end,
759     ff_h263_decode_frame,
760     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
761     .flush= ff_mpeg_flush,
762 };
763
764 AVCodec h263_decoder = {
765     "h263",
766     CODEC_TYPE_VIDEO,
767     CODEC_ID_H263,
768     sizeof(MpegEncContext),
769     ff_h263_decode_init,
770     NULL,
771     ff_h263_decode_end,
772     ff_h263_decode_frame,
773     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
774     .flush= ff_mpeg_flush,
775 };
776
777 AVCodec msmpeg4v1_decoder = {
778     "msmpeg4v1",
779     CODEC_TYPE_VIDEO,
780     CODEC_ID_MSMPEG4V1,
781     sizeof(MpegEncContext),
782     ff_h263_decode_init,
783     NULL,
784     ff_h263_decode_end,
785     ff_h263_decode_frame,
786     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
787 };
788
789 AVCodec msmpeg4v2_decoder = {
790     "msmpeg4v2",
791     CODEC_TYPE_VIDEO,
792     CODEC_ID_MSMPEG4V2,
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 };
800
801 AVCodec msmpeg4v3_decoder = {
802     "msmpeg4",
803     CODEC_TYPE_VIDEO,
804     CODEC_ID_MSMPEG4V3,
805     sizeof(MpegEncContext),
806     ff_h263_decode_init,
807     NULL,
808     ff_h263_decode_end,
809     ff_h263_decode_frame,
810     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
811 };
812
813 AVCodec wmv1_decoder = {
814     "wmv1",
815     CODEC_TYPE_VIDEO,
816     CODEC_ID_WMV1,
817     sizeof(MpegEncContext),
818     ff_h263_decode_init,
819     NULL,
820     ff_h263_decode_end,
821     ff_h263_decode_frame,
822     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
823 };
824
825 AVCodec h263i_decoder = {
826     "h263i",
827     CODEC_TYPE_VIDEO,
828     CODEC_ID_H263I,
829     sizeof(MpegEncContext),
830     ff_h263_decode_init,
831     NULL,
832     ff_h263_decode_end,
833     ff_h263_decode_frame,
834     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
835 };
836
837 AVCodec flv_decoder = {
838     "flv",
839     CODEC_TYPE_VIDEO,
840     CODEC_ID_FLV1,
841     sizeof(MpegEncContext),
842     ff_h263_decode_init,
843     NULL,
844     ff_h263_decode_end,
845     ff_h263_decode_frame,
846     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1
847 };