two more typos spotted by Mike
[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 #include "msmpeg4.h"
34
35 //#define DEBUG
36 //#define PRINT_FRAME_TIME
37
38 int ff_h263_decode_init(AVCodecContext *avctx)
39 {
40     MpegEncContext *s = avctx->priv_data;
41
42     s->avctx = avctx;
43     s->out_format = FMT_H263;
44
45     s->width  = avctx->coded_width;
46     s->height = avctx->coded_height;
47     s->workaround_bugs= avctx->workaround_bugs;
48
49     // set defaults
50     MPV_decode_defaults(s);
51     s->quant_precision=5;
52     s->decode_mb= ff_h263_decode_mb;
53     s->low_delay= 1;
54     avctx->pix_fmt= PIX_FMT_YUV420P;
55     s->unrestricted_mv= 1;
56
57     /* select sub codec */
58     switch(avctx->codec->id) {
59     case CODEC_ID_H263:
60         s->unrestricted_mv= 0;
61         break;
62     case CODEC_ID_MPEG4:
63         s->decode_mb= ff_mpeg4_decode_mb;
64         s->time_increment_bits = 4; /* default value for broken headers */
65         s->h263_pred = 1;
66         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
67         break;
68     case CODEC_ID_MSMPEG4V1:
69         s->h263_msmpeg4 = 1;
70         s->h263_pred = 1;
71         s->msmpeg4_version=1;
72         break;
73     case CODEC_ID_MSMPEG4V2:
74         s->h263_msmpeg4 = 1;
75         s->h263_pred = 1;
76         s->msmpeg4_version=2;
77         break;
78     case CODEC_ID_MSMPEG4V3:
79         s->h263_msmpeg4 = 1;
80         s->h263_pred = 1;
81         s->msmpeg4_version=3;
82         break;
83     case CODEC_ID_WMV1:
84         s->h263_msmpeg4 = 1;
85         s->h263_pred = 1;
86         s->msmpeg4_version=4;
87         break;
88     case CODEC_ID_WMV2:
89         s->h263_msmpeg4 = 1;
90         s->h263_pred = 1;
91         s->msmpeg4_version=5;
92         break;
93     case CODEC_ID_VC1:
94     case CODEC_ID_WMV3:
95         s->h263_msmpeg4 = 1;
96         s->h263_pred = 1;
97         s->msmpeg4_version=6;
98         break;
99     case CODEC_ID_H263I:
100         break;
101     case CODEC_ID_FLV1:
102         s->h263_flv = 1;
103         break;
104     default:
105         return -1;
106     }
107     s->codec_id= avctx->codec->id;
108
109     /* for h263, we allocate the images after having read the header */
110     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
111         if (MPV_common_init(s) < 0)
112             return -1;
113
114     if (ENABLE_MSMPEG4_DECODER && s->h263_msmpeg4)
115         ff_msmpeg4_decode_init(s);
116     else
117         h263_decode_init_vlc(s);
118
119     return 0;
120 }
121
122 int ff_h263_decode_end(AVCodecContext *avctx)
123 {
124     MpegEncContext *s = avctx->priv_data;
125
126     MPV_common_end(s);
127     return 0;
128 }
129
130 /**
131  * returns the number of bytes consumed for building the current frame
132  */
133 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
134     int pos= (get_bits_count(&s->gb)+7)>>3;
135
136     if(s->divx_packed){
137         //we would have to scan through the whole buf to handle the weird reordering ...
138         return buf_size;
139     }else if(s->flags&CODEC_FLAG_TRUNCATED){
140         pos -= s->parse_context.last_index;
141         if(pos<0) pos=0; // padding is not really read so this might be -1
142         return pos;
143     }else{
144         if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
145         if(pos+10>buf_size) pos=buf_size; // oops ;)
146
147         return pos;
148     }
149 }
150
151 static int decode_slice(MpegEncContext *s){
152     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
153     const int mb_size= 16>>s->avctx->lowres;
154     s->last_resync_gb= s->gb;
155     s->first_slice_line= 1;
156
157     s->resync_mb_x= s->mb_x;
158     s->resync_mb_y= s->mb_y;
159
160     ff_set_qscale(s, s->qscale);
161
162     if(s->partitioned_frame){
163         const int qscale= s->qscale;
164
165         if(s->codec_id==CODEC_ID_MPEG4){
166             if(ff_mpeg4_decode_partitions(s) < 0)
167                 return -1;
168         }
169
170         /* restore variables which were modified */
171         s->first_slice_line=1;
172         s->mb_x= s->resync_mb_x;
173         s->mb_y= s->resync_mb_y;
174         ff_set_qscale(s, qscale);
175     }
176
177     for(; s->mb_y < s->mb_height; s->mb_y++) {
178         /* per-row end of slice checks */
179         if(s->msmpeg4_version){
180             if(s->resync_mb_y + s->slice_height == s->mb_y){
181                 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);
182
183                 return 0;
184             }
185         }
186
187         if(s->msmpeg4_version==1){
188             s->last_dc[0]=
189             s->last_dc[1]=
190             s->last_dc[2]= 128;
191         }
192
193         ff_init_block_index(s);
194         for(; s->mb_x < s->mb_width; s->mb_x++) {
195             int ret;
196
197             ff_update_block_index(s);
198
199             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
200                 s->first_slice_line=0;
201             }
202
203             /* DCT & quantize */
204
205             s->mv_dir = MV_DIR_FORWARD;
206             s->mv_type = MV_TYPE_16X16;
207 //            s->mb_skipped = 0;
208 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
209             ret= s->decode_mb(s, s->block);
210
211             if (s->pict_type!=FF_B_TYPE)
212                 ff_h263_update_motion_val(s);
213
214             if(ret<0){
215                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
216                 if(ret==SLICE_END){
217                     MPV_decode_mb(s, s->block);
218                     if(s->loop_filter)
219                         ff_h263_loop_filter(s);
220
221 //printf("%d %d %d %06X\n", s->mb_x, s->mb_y, s->gb.size*8 - get_bits_count(&s->gb), show_bits(&s->gb, 24));
222                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
223
224                     s->padding_bug_score--;
225
226                     if(++s->mb_x >= s->mb_width){
227                         s->mb_x=0;
228                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
229                         s->mb_y++;
230                     }
231                     return 0;
232                 }else if(ret==SLICE_NOEND){
233                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
234                     ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x+1, s->mb_y, (AC_END|DC_END|MV_END)&part_mask);
235                     return -1;
236                 }
237                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
238                 ff_er_add_slice(s, s->resync_mb_x, s->resync_mb_y, s->mb_x, s->mb_y, (AC_ERROR|DC_ERROR|MV_ERROR)&part_mask);
239
240                 return -1;
241             }
242
243             MPV_decode_mb(s, s->block);
244             if(s->loop_filter)
245                 ff_h263_loop_filter(s);
246         }
247
248         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
249
250         s->mb_x= 0;
251     }
252
253     assert(s->mb_x==0 && s->mb_y==s->mb_height);
254
255     /* try to detect the padding bug */
256     if(      s->codec_id==CODEC_ID_MPEG4
257        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
258        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
259        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
260 //       &&   !s->resync_marker
261        &&   !s->data_partitioning){
262
263         const int bits_count= get_bits_count(&s->gb);
264         const int bits_left = s->gb.size_in_bits - bits_count;
265
266         if(bits_left==0){
267             s->padding_bug_score+=16;
268         } else if(bits_left != 1){
269             int v= show_bits(&s->gb, 8);
270             v|= 0x7F >> (7-(bits_count&7));
271
272             if(v==0x7F && bits_left<=8)
273                 s->padding_bug_score--;
274             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
275                 s->padding_bug_score+= 4;
276             else
277                 s->padding_bug_score++;
278         }
279     }
280
281     if(s->workaround_bugs&FF_BUG_AUTODETECT){
282         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version || !s->resync_marker)*/)
283             s->workaround_bugs |=  FF_BUG_NO_PADDING;
284         else
285             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
286     }
287
288     // handle formats which don't have unique end markers
289     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
290         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
291         int max_extra=7;
292
293         /* no markers in M$ crap */
294         if(s->msmpeg4_version && s->pict_type==FF_I_TYPE)
295             max_extra+= 17;
296
297         /* buggy padding but the frame should still end approximately at the bitstream end */
298         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
299             max_extra+= 48;
300         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
301             max_extra+= 256*256*256*64;
302
303         if(left>max_extra){
304             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
305         }
306         else if(left<0){
307             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
308         }else
309             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);
310
311         return 0;
312     }
313
314     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
315             s->gb.size_in_bits - get_bits_count(&s->gb),
316             show_bits(&s->gb, 24), s->padding_bug_score);
317
318     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);
319
320     return -1;
321 }
322
323 int ff_h263_decode_frame(AVCodecContext *avctx,
324                              void *data, int *data_size,
325                              const uint8_t *buf, int buf_size)
326 {
327     MpegEncContext *s = avctx->priv_data;
328     int ret;
329     AVFrame *pict = data;
330
331 #ifdef PRINT_FRAME_TIME
332 uint64_t time= rdtsc();
333 #endif
334 #ifdef DEBUG
335     av_log(avctx, AV_LOG_DEBUG, "*****frame %d size=%d\n", avctx->frame_number, buf_size);
336     if(buf_size>0)
337         av_log(avctx, AV_LOG_DEBUG, "bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
338 #endif
339     s->flags= avctx->flags;
340     s->flags2= avctx->flags2;
341
342     /* no supplementary picture */
343     if (buf_size == 0) {
344         /* special case for last picture */
345         if (s->low_delay==0 && s->next_picture_ptr) {
346             *pict= *(AVFrame*)s->next_picture_ptr;
347             s->next_picture_ptr= NULL;
348
349             *data_size = sizeof(AVFrame);
350         }
351
352         return 0;
353     }
354
355     if(s->flags&CODEC_FLAG_TRUNCATED){
356         int next;
357
358         if(ENABLE_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
359             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
360         }else if(ENABLE_H263_DECODER && s->codec_id==CODEC_ID_H263){
361             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
362         }else{
363             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
364             return -1;
365         }
366
367         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
368             return buf_size;
369     }
370
371
372 retry:
373
374     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
375         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
376     }else
377         init_get_bits(&s->gb, buf, buf_size*8);
378     s->bitstream_buffer_size=0;
379
380     if (!s->context_initialized) {
381         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
382             return -1;
383     }
384
385     /* We need to set current_picture_ptr before reading the header,
386      * otherwise we cannot store anyting in there */
387     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
388         int i= ff_find_unused_picture(s, 0);
389         s->current_picture_ptr= &s->picture[i];
390     }
391
392     /* let's go :-) */
393     if (ENABLE_WMV2_DECODER && s->msmpeg4_version==5) {
394         ret= ff_wmv2_decode_picture_header(s);
395     } else if (ENABLE_MSMPEG4_DECODER && s->msmpeg4_version) {
396         ret = msmpeg4_decode_picture_header(s);
397     } else if (s->h263_pred) {
398         if(s->avctx->extradata_size && s->picture_number==0){
399             GetBitContext gb;
400
401             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
402             ret = ff_mpeg4_decode_picture_header(s, &gb);
403         }
404         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
405
406         if(s->flags& CODEC_FLAG_LOW_DELAY)
407             s->low_delay=1;
408     } else if (s->codec_id == CODEC_ID_H263I) {
409         ret = intel_h263_decode_picture_header(s);
410     } else if (s->h263_flv) {
411         ret = flv_h263_decode_picture_header(s);
412     } else {
413         ret = h263_decode_picture_header(s);
414     }
415
416     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
417
418     /* skip if the header was thrashed */
419     if (ret < 0){
420         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
421         return -1;
422     }
423
424     avctx->has_b_frames= !s->low_delay;
425
426     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
427         if(s->stream_codec_tag == ff_get_fourcc("XVID") ||
428            s->codec_tag == ff_get_fourcc("XVID") || s->codec_tag == ff_get_fourcc("XVIX") ||
429            s->codec_tag == ff_get_fourcc("RMP4"))
430             s->xvid_build= -1;
431 #if 0
432         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
433            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
434             s->xvid_build= -1;
435 #endif
436     }
437
438     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
439         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
440             s->divx_version= 400; //divx 4
441     }
442
443     if(s->xvid_build && s->divx_version){
444         s->divx_version=
445         s->divx_build= 0;
446     }
447
448     if(s->workaround_bugs&FF_BUG_AUTODETECT){
449         if(s->codec_tag == ff_get_fourcc("XVIX"))
450             s->workaround_bugs|= FF_BUG_XVID_ILACE;
451
452         if(s->codec_tag == ff_get_fourcc("UMP4")){
453             s->workaround_bugs|= FF_BUG_UMP4;
454         }
455
456         if(s->divx_version>=500 && s->divx_build<1814){
457             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
458         }
459
460         if(s->divx_version>502 && s->divx_build<1814){
461             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
462         }
463
464         if(s->xvid_build && s->xvid_build<=3)
465             s->padding_bug_score= 256*256*256*64;
466
467         if(s->xvid_build && s->xvid_build<=1)
468             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
469
470         if(s->xvid_build && s->xvid_build<=12)
471             s->workaround_bugs|= FF_BUG_EDGE;
472
473         if(s->xvid_build && s->xvid_build<=32)
474             s->workaround_bugs|= FF_BUG_DC_CLIP;
475
476 #define SET_QPEL_FUNC(postfix1, postfix2) \
477     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
478     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
479     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
480
481         if(s->lavc_build && s->lavc_build<4653)
482             s->workaround_bugs|= FF_BUG_STD_QPEL;
483
484         if(s->lavc_build && s->lavc_build<4655)
485             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
486
487         if(s->lavc_build && s->lavc_build<4670){
488             s->workaround_bugs|= FF_BUG_EDGE;
489         }
490
491         if(s->lavc_build && s->lavc_build<=4712)
492             s->workaround_bugs|= FF_BUG_DC_CLIP;
493
494         if(s->divx_version)
495             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
496 //printf("padding_bug_score: %d\n", s->padding_bug_score);
497         if(s->divx_version==501 && s->divx_build==20020416)
498             s->padding_bug_score= 256*256*256*64;
499
500         if(s->divx_version && s->divx_version<500){
501             s->workaround_bugs|= FF_BUG_EDGE;
502         }
503
504         if(s->divx_version)
505             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
506 #if 0
507         if(s->divx_version==500)
508             s->padding_bug_score= 256*256*256*64;
509
510         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
511          * lets hope this at least works
512          */
513         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
514            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
515             s->workaround_bugs|= FF_BUG_NO_PADDING;
516
517         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
518             s->workaround_bugs|= FF_BUG_NO_PADDING;
519 #endif
520     }
521
522     if(s->workaround_bugs& FF_BUG_STD_QPEL){
523         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
524         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
525         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
526         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
527         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
528         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
529
530         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
531         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
532         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
533         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
534         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
535         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
536     }
537
538     if(avctx->debug & FF_DEBUG_BUGS)
539         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
540                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
541                s->divx_packed ? "p" : "");
542
543 #if 0 // dump bits per frame / qp / complexity
544 {
545     static FILE *f=NULL;
546     if(!f) f=fopen("rate_qp_cplx.txt", "w");
547     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
548 }
549 #endif
550
551 #if defined(HAVE_MMX) && defined(CONFIG_GPL)
552     if(s->codec_id == CODEC_ID_MPEG4 && s->xvid_build && avctx->idct_algo == FF_IDCT_AUTO && (mm_flags & MM_MMX)){
553         avctx->idct_algo= FF_IDCT_XVIDMMX;
554         avctx->coded_width= 0; // force reinit
555 //        dsputil_init(&s->dsp, avctx);
556         s->picture_number=0;
557     }
558 #endif
559
560         /* After H263 & mpeg4 header decode we have the height, width,*/
561         /* and other parameters. So then we could init the picture   */
562         /* FIXME: By the way H263 decoder is evolving it should have */
563         /* an H263EncContext                                         */
564
565     if (   s->width  != avctx->coded_width
566         || s->height != avctx->coded_height) {
567         /* H.263 could change picture size any time */
568         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
569         s->parse_context.buffer=0;
570         MPV_common_end(s);
571         s->parse_context= pc;
572     }
573     if (!s->context_initialized) {
574         avcodec_set_dimensions(avctx, s->width, s->height);
575
576         goto retry;
577     }
578
579     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
580         s->gob_index = ff_h263_get_gob_height(s);
581
582     // for hurry_up==5
583     s->current_picture.pict_type= s->pict_type;
584     s->current_picture.key_frame= s->pict_type == FF_I_TYPE;
585
586     /* skip B-frames if we don't have reference frames */
587     if(s->last_picture_ptr==NULL && (s->pict_type==FF_B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
588     /* skip b frames if we are in a hurry */
589     if(avctx->hurry_up && s->pict_type==FF_B_TYPE) return get_consumed_bytes(s, buf_size);
590     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==FF_B_TYPE)
591        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=FF_I_TYPE)
592        ||  avctx->skip_frame >= AVDISCARD_ALL)
593         return get_consumed_bytes(s, buf_size);
594     /* skip everything if we are in a hurry>=5 */
595     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
596
597     if(s->next_p_frame_damaged){
598         if(s->pict_type==FF_B_TYPE)
599             return get_consumed_bytes(s, buf_size);
600         else
601             s->next_p_frame_damaged=0;
602     }
603
604     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==FF_B_TYPE){
605         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
606         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
607     }else if((!s->no_rounding) || s->pict_type==FF_B_TYPE){
608         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
609         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
610     }else{
611         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
612         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
613     }
614
615     if(MPV_frame_start(s, avctx) < 0)
616         return -1;
617
618 #ifdef DEBUG
619     av_log(avctx, AV_LOG_DEBUG, "qscale=%d\n", s->qscale);
620 #endif
621
622     ff_er_frame_start(s);
623
624     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
625     //which is not available before MPV_frame_start()
626     if (ENABLE_WMV2_DECODER && s->msmpeg4_version==5){
627         ret = ff_wmv2_decode_secondary_picture_header(s);
628         if(ret<0) return ret;
629         if(ret==1) goto intrax8_decoded;
630     }
631
632     /* decode each macroblock */
633     s->mb_x=0;
634     s->mb_y=0;
635
636     decode_slice(s);
637     while(s->mb_y<s->mb_height){
638         if(s->msmpeg4_version){
639             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)
640                 break;
641         }else{
642             if(ff_h263_resync(s)<0)
643                 break;
644         }
645
646         if(s->msmpeg4_version<4 && s->h263_pred)
647             ff_mpeg4_clean_buffers(s);
648
649         decode_slice(s);
650     }
651
652     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==FF_I_TYPE)
653         if(!ENABLE_MSMPEG4_DECODER || msmpeg4_decode_ext_header(s, buf_size) < 0){
654             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
655         }
656
657     /* divx 5.01+ bistream reorder stuff */
658     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
659         int current_pos= get_bits_count(&s->gb)>>3;
660         int startcode_found=0;
661
662         if(buf_size - current_pos > 5){
663             int i;
664             for(i=current_pos; i<buf_size-3; i++){
665                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
666                     startcode_found=1;
667                     break;
668                 }
669             }
670         }
671         if(s->gb.buffer == s->bitstream_buffer && buf_size>20){ //xvid style
672             startcode_found=1;
673             current_pos=0;
674         }
675
676         if(startcode_found){
677             s->bitstream_buffer= av_fast_realloc(
678                 s->bitstream_buffer,
679                 &s->allocated_bitstream_buffer_size,
680                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
681             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
682             s->bitstream_buffer_size= buf_size - current_pos;
683         }
684     }
685
686 intrax8_decoded:
687     ff_er_frame_end(s);
688
689     MPV_frame_end(s);
690
691 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
692 assert(s->current_picture.pict_type == s->pict_type);
693     if (s->pict_type == FF_B_TYPE || s->low_delay) {
694         *pict= *(AVFrame*)s->current_picture_ptr;
695     } else if (s->last_picture_ptr != NULL) {
696         *pict= *(AVFrame*)s->last_picture_ptr;
697     }
698
699     if(s->last_picture_ptr || s->low_delay){
700         *data_size = sizeof(AVFrame);
701         ff_print_debug_info(s, pict);
702     }
703
704     /* Return the Picture timestamp as the frame number */
705     /* we subtract 1 because it is added on utils.c     */
706     avctx->frame_number = s->picture_number - 1;
707
708 #ifdef PRINT_FRAME_TIME
709 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
710 #endif
711
712     return get_consumed_bytes(s, buf_size);
713 }
714
715 AVCodec mpeg4_decoder = {
716     "mpeg4",
717     CODEC_TYPE_VIDEO,
718     CODEC_ID_MPEG4,
719     sizeof(MpegEncContext),
720     ff_h263_decode_init,
721     NULL,
722     ff_h263_decode_end,
723     ff_h263_decode_frame,
724     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
725     .flush= ff_mpeg_flush,
726 };
727
728 AVCodec h263_decoder = {
729     "h263",
730     CODEC_TYPE_VIDEO,
731     CODEC_ID_H263,
732     sizeof(MpegEncContext),
733     ff_h263_decode_init,
734     NULL,
735     ff_h263_decode_end,
736     ff_h263_decode_frame,
737     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
738     .flush= ff_mpeg_flush,
739 };
740
741 AVCodec msmpeg4v1_decoder = {
742     "msmpeg4v1",
743     CODEC_TYPE_VIDEO,
744     CODEC_ID_MSMPEG4V1,
745     sizeof(MpegEncContext),
746     ff_h263_decode_init,
747     NULL,
748     ff_h263_decode_end,
749     ff_h263_decode_frame,
750     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
751 };
752
753 AVCodec msmpeg4v2_decoder = {
754     "msmpeg4v2",
755     CODEC_TYPE_VIDEO,
756     CODEC_ID_MSMPEG4V2,
757     sizeof(MpegEncContext),
758     ff_h263_decode_init,
759     NULL,
760     ff_h263_decode_end,
761     ff_h263_decode_frame,
762     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
763 };
764
765 AVCodec msmpeg4v3_decoder = {
766     "msmpeg4",
767     CODEC_TYPE_VIDEO,
768     CODEC_ID_MSMPEG4V3,
769     sizeof(MpegEncContext),
770     ff_h263_decode_init,
771     NULL,
772     ff_h263_decode_end,
773     ff_h263_decode_frame,
774     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
775 };
776
777 AVCodec wmv1_decoder = {
778     "wmv1",
779     CODEC_TYPE_VIDEO,
780     CODEC_ID_WMV1,
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 h263i_decoder = {
790     "h263i",
791     CODEC_TYPE_VIDEO,
792     CODEC_ID_H263I,
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 flv_decoder = {
802     "flv",
803     CODEC_TYPE_VIDEO,
804     CODEC_ID_FLV1,
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 };