Move CODEC_FLAG_LOW_DELAY into ff_mpeg4_decode_picture_header().
[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 av_cold 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 av_cold 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_recognition>=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     } else if (s->codec_id == CODEC_ID_H263I) {
406         ret = intel_h263_decode_picture_header(s);
407     } else if (s->h263_flv) {
408         ret = flv_h263_decode_picture_header(s);
409     } else {
410         ret = h263_decode_picture_header(s);
411     }
412
413     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
414
415     /* skip if the header was thrashed */
416     if (ret < 0){
417         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
418         return -1;
419     }
420
421     avctx->has_b_frames= !s->low_delay;
422
423     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
424         if(s->stream_codec_tag == ff_get_fourcc("XVID") ||
425            s->codec_tag == ff_get_fourcc("XVID") || s->codec_tag == ff_get_fourcc("XVIX") ||
426            s->codec_tag == ff_get_fourcc("RMP4"))
427             s->xvid_build= -1;
428 #if 0
429         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
430            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
431             s->xvid_build= -1;
432 #endif
433     }
434
435     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
436         if(s->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
437             s->divx_version= 400; //divx 4
438     }
439
440     if(s->xvid_build && s->divx_version){
441         s->divx_version=
442         s->divx_build= 0;
443     }
444
445     if(s->workaround_bugs&FF_BUG_AUTODETECT){
446         if(s->codec_tag == ff_get_fourcc("XVIX"))
447             s->workaround_bugs|= FF_BUG_XVID_ILACE;
448
449         if(s->codec_tag == ff_get_fourcc("UMP4")){
450             s->workaround_bugs|= FF_BUG_UMP4;
451         }
452
453         if(s->divx_version>=500 && s->divx_build<1814){
454             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
455         }
456
457         if(s->divx_version>502 && s->divx_build<1814){
458             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
459         }
460
461         if(s->xvid_build && s->xvid_build<=3)
462             s->padding_bug_score= 256*256*256*64;
463
464         if(s->xvid_build && s->xvid_build<=1)
465             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
466
467         if(s->xvid_build && s->xvid_build<=12)
468             s->workaround_bugs|= FF_BUG_EDGE;
469
470         if(s->xvid_build && s->xvid_build<=32)
471             s->workaround_bugs|= FF_BUG_DC_CLIP;
472
473 #define SET_QPEL_FUNC(postfix1, postfix2) \
474     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
475     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
476     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
477
478         if(s->lavc_build && s->lavc_build<4653)
479             s->workaround_bugs|= FF_BUG_STD_QPEL;
480
481         if(s->lavc_build && s->lavc_build<4655)
482             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
483
484         if(s->lavc_build && s->lavc_build<4670){
485             s->workaround_bugs|= FF_BUG_EDGE;
486         }
487
488         if(s->lavc_build && s->lavc_build<=4712)
489             s->workaround_bugs|= FF_BUG_DC_CLIP;
490
491         if(s->divx_version)
492             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
493 //printf("padding_bug_score: %d\n", s->padding_bug_score);
494         if(s->divx_version==501 && s->divx_build==20020416)
495             s->padding_bug_score= 256*256*256*64;
496
497         if(s->divx_version && s->divx_version<500){
498             s->workaround_bugs|= FF_BUG_EDGE;
499         }
500
501         if(s->divx_version)
502             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
503 #if 0
504         if(s->divx_version==500)
505             s->padding_bug_score= 256*256*256*64;
506
507         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
508          * Let us hope this at least works.
509          */
510         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
511            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
512             s->workaround_bugs|= FF_BUG_NO_PADDING;
513
514         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
515             s->workaround_bugs|= FF_BUG_NO_PADDING;
516 #endif
517     }
518
519     if(s->workaround_bugs& FF_BUG_STD_QPEL){
520         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
521         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
522         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
523         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
524         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
525         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
526
527         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
528         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
529         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
530         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
531         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
532         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
533     }
534
535     if(avctx->debug & FF_DEBUG_BUGS)
536         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
537                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
538                s->divx_packed ? "p" : "");
539
540 #if 0 // dump bits per frame / qp / complexity
541 {
542     static FILE *f=NULL;
543     if(!f) f=fopen("rate_qp_cplx.txt", "w");
544     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
545 }
546 #endif
547
548 #if defined(HAVE_MMX)
549     if(s->codec_id == CODEC_ID_MPEG4 && s->xvid_build && avctx->idct_algo == FF_IDCT_AUTO && (mm_flags & FF_MM_MMX)){
550         avctx->idct_algo= FF_IDCT_XVIDMMX;
551         avctx->coded_width= 0; // force reinit
552 //        dsputil_init(&s->dsp, avctx);
553         s->picture_number=0;
554     }
555 #endif
556
557         /* After H263 & mpeg4 header decode we have the height, width,*/
558         /* and other parameters. So then we could init the picture   */
559         /* FIXME: By the way H263 decoder is evolving it should have */
560         /* an H263EncContext                                         */
561
562     if (   s->width  != avctx->coded_width
563         || s->height != avctx->coded_height) {
564         /* H.263 could change picture size any time */
565         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
566         s->parse_context.buffer=0;
567         MPV_common_end(s);
568         s->parse_context= pc;
569     }
570     if (!s->context_initialized) {
571         avcodec_set_dimensions(avctx, s->width, s->height);
572
573         goto retry;
574     }
575
576     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P))
577         s->gob_index = ff_h263_get_gob_height(s);
578
579     // for hurry_up==5
580     s->current_picture.pict_type= s->pict_type;
581     s->current_picture.key_frame= s->pict_type == FF_I_TYPE;
582
583     /* skip B-frames if we don't have reference frames */
584     if(s->last_picture_ptr==NULL && (s->pict_type==FF_B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
585     /* skip b frames if we are in a hurry */
586     if(avctx->hurry_up && s->pict_type==FF_B_TYPE) return get_consumed_bytes(s, buf_size);
587     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==FF_B_TYPE)
588        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=FF_I_TYPE)
589        ||  avctx->skip_frame >= AVDISCARD_ALL)
590         return get_consumed_bytes(s, buf_size);
591     /* skip everything if we are in a hurry>=5 */
592     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
593
594     if(s->next_p_frame_damaged){
595         if(s->pict_type==FF_B_TYPE)
596             return get_consumed_bytes(s, buf_size);
597         else
598             s->next_p_frame_damaged=0;
599     }
600
601     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==FF_B_TYPE){
602         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
603         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
604     }else if((!s->no_rounding) || s->pict_type==FF_B_TYPE){
605         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
606         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
607     }else{
608         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
609         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
610     }
611
612     if(MPV_frame_start(s, avctx) < 0)
613         return -1;
614
615 #ifdef DEBUG
616     av_log(avctx, AV_LOG_DEBUG, "qscale=%d\n", s->qscale);
617 #endif
618
619     ff_er_frame_start(s);
620
621     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
622     //which is not available before MPV_frame_start()
623     if (ENABLE_WMV2_DECODER && s->msmpeg4_version==5){
624         ret = ff_wmv2_decode_secondary_picture_header(s);
625         if(ret<0) return ret;
626         if(ret==1) goto intrax8_decoded;
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==FF_I_TYPE)
650         if(!ENABLE_MSMPEG4_DECODER || 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 intrax8_decoded:
684     ff_er_frame_end(s);
685
686     MPV_frame_end(s);
687
688 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
689 assert(s->current_picture.pict_type == s->pict_type);
690     if (s->pict_type == FF_B_TYPE || s->low_delay) {
691         *pict= *(AVFrame*)s->current_picture_ptr;
692     } else if (s->last_picture_ptr != NULL) {
693         *pict= *(AVFrame*)s->last_picture_ptr;
694     }
695
696     if(s->last_picture_ptr || s->low_delay){
697         *data_size = sizeof(AVFrame);
698         ff_print_debug_info(s, pict);
699     }
700
701     /* Return the Picture timestamp as the frame number */
702     /* we subtract 1 because it is added on utils.c     */
703     avctx->frame_number = s->picture_number - 1;
704
705 #ifdef PRINT_FRAME_TIME
706 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
707 #endif
708
709     return get_consumed_bytes(s, buf_size);
710 }
711
712 AVCodec mpeg4_decoder = {
713     "mpeg4",
714     CODEC_TYPE_VIDEO,
715     CODEC_ID_MPEG4,
716     sizeof(MpegEncContext),
717     ff_h263_decode_init,
718     NULL,
719     ff_h263_decode_end,
720     ff_h263_decode_frame,
721     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
722     .flush= ff_mpeg_flush,
723     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
724 };
725
726 AVCodec h263_decoder = {
727     "h263",
728     CODEC_TYPE_VIDEO,
729     CODEC_ID_H263,
730     sizeof(MpegEncContext),
731     ff_h263_decode_init,
732     NULL,
733     ff_h263_decode_end,
734     ff_h263_decode_frame,
735     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
736     .flush= ff_mpeg_flush,
737     .long_name= NULL_IF_CONFIG_SMALL("H.263"),
738 };
739
740 AVCodec msmpeg4v1_decoder = {
741     "msmpeg4v1",
742     CODEC_TYPE_VIDEO,
743     CODEC_ID_MSMPEG4V1,
744     sizeof(MpegEncContext),
745     ff_h263_decode_init,
746     NULL,
747     ff_h263_decode_end,
748     ff_h263_decode_frame,
749     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
750     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 1"),
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     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 2"),
764 };
765
766 AVCodec msmpeg4v3_decoder = {
767     "msmpeg4",
768     CODEC_TYPE_VIDEO,
769     CODEC_ID_MSMPEG4V3,
770     sizeof(MpegEncContext),
771     ff_h263_decode_init,
772     NULL,
773     ff_h263_decode_end,
774     ff_h263_decode_frame,
775     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
776     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 3"),
777 };
778
779 AVCodec wmv1_decoder = {
780     "wmv1",
781     CODEC_TYPE_VIDEO,
782     CODEC_ID_WMV1,
783     sizeof(MpegEncContext),
784     ff_h263_decode_init,
785     NULL,
786     ff_h263_decode_end,
787     ff_h263_decode_frame,
788     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
789     .long_name= NULL_IF_CONFIG_SMALL("Windows Media Video 7"),
790 };
791
792 AVCodec h263i_decoder = {
793     "h263i",
794     CODEC_TYPE_VIDEO,
795     CODEC_ID_H263I,
796     sizeof(MpegEncContext),
797     ff_h263_decode_init,
798     NULL,
799     ff_h263_decode_end,
800     ff_h263_decode_frame,
801     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
802     .long_name = NULL_IF_CONFIG_SMALL("H.263i"),
803 };
804
805 AVCodec flv_decoder = {
806     "flv",
807     CODEC_TYPE_VIDEO,
808     CODEC_ID_FLV1,
809     sizeof(MpegEncContext),
810     ff_h263_decode_init,
811     NULL,
812     ff_h263_decode_end,
813     ff_h263_decode_frame,
814     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
815     .long_name= NULL_IF_CONFIG_SMALL("Flash Video"),
816 };