3b1cf8c61cf1aadbf9fb26846777af54b2711a9d
[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 libavcodec/h263dec.c
25  * H.263 decoder.
26  */
27
28 #include "internal.h"
29 #include "avcodec.h"
30 #include "dsputil.h"
31 #include "mpegvideo.h"
32 #include "h263_parser.h"
33 #include "mpeg4video_parser.h"
34 #include "msmpeg4.h"
35
36 //#define DEBUG
37 //#define PRINT_FRAME_TIME
38
39 av_cold int ff_h263_decode_init(AVCodecContext *avctx)
40 {
41     MpegEncContext *s = avctx->priv_data;
42
43     s->avctx = avctx;
44     s->out_format = FMT_H263;
45
46     s->width  = avctx->coded_width;
47     s->height = avctx->coded_height;
48     s->workaround_bugs= avctx->workaround_bugs;
49
50     // set defaults
51     MPV_decode_defaults(s);
52     s->quant_precision=5;
53     s->decode_mb= ff_h263_decode_mb;
54     s->low_delay= 1;
55     avctx->pix_fmt= avctx->get_format(avctx, avctx->codec->pix_fmts);
56     s->unrestricted_mv= 1;
57
58     /* select sub codec */
59     switch(avctx->codec->id) {
60     case CODEC_ID_H263:
61         s->unrestricted_mv= 0;
62         break;
63     case CODEC_ID_MPEG4:
64         s->decode_mb= ff_mpeg4_decode_mb;
65         s->time_increment_bits = 4; /* default value for broken headers */
66         s->h263_pred = 1;
67         s->low_delay = 0; //default, might be overriden in the vol header during header parsing
68         break;
69     case CODEC_ID_MSMPEG4V1:
70         s->h263_msmpeg4 = 1;
71         s->h263_pred = 1;
72         s->msmpeg4_version=1;
73         break;
74     case CODEC_ID_MSMPEG4V2:
75         s->h263_msmpeg4 = 1;
76         s->h263_pred = 1;
77         s->msmpeg4_version=2;
78         break;
79     case CODEC_ID_MSMPEG4V3:
80         s->h263_msmpeg4 = 1;
81         s->h263_pred = 1;
82         s->msmpeg4_version=3;
83         break;
84     case CODEC_ID_WMV1:
85         s->h263_msmpeg4 = 1;
86         s->h263_pred = 1;
87         s->msmpeg4_version=4;
88         break;
89     case CODEC_ID_WMV2:
90         s->h263_msmpeg4 = 1;
91         s->h263_pred = 1;
92         s->msmpeg4_version=5;
93         break;
94     case CODEC_ID_VC1:
95     case CODEC_ID_WMV3:
96         s->h263_msmpeg4 = 1;
97         s->h263_pred = 1;
98         s->msmpeg4_version=6;
99         break;
100     case CODEC_ID_H263I:
101         break;
102     case CODEC_ID_FLV1:
103         s->h263_flv = 1;
104         break;
105     default:
106         return -1;
107     }
108     s->codec_id= avctx->codec->id;
109
110     /* for h263, we allocate the images after having read the header */
111     if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
112         if (MPV_common_init(s) < 0)
113             return -1;
114
115     if (CONFIG_MSMPEG4_DECODER && s->h263_msmpeg4)
116         ff_msmpeg4_decode_init(s);
117     else
118         h263_decode_init_vlc(s);
119
120     return 0;
121 }
122
123 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
124 {
125     MpegEncContext *s = avctx->priv_data;
126
127     MPV_common_end(s);
128     return 0;
129 }
130
131 /**
132  * returns the number of bytes consumed for building the current frame
133  */
134 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
135     int pos= (get_bits_count(&s->gb)+7)>>3;
136
137     if(s->divx_packed || s->avctx->hwaccel){
138         //we would have to scan through the whole buf to handle the weird reordering ...
139         return buf_size;
140     }else if(s->flags&CODEC_FLAG_TRUNCATED){
141         pos -= s->parse_context.last_index;
142         if(pos<0) pos=0; // padding is not really read so this might be -1
143         return pos;
144     }else{
145         if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
146         if(pos+10>buf_size) pos=buf_size; // oops ;)
147
148         return pos;
149     }
150 }
151
152 static int decode_slice(MpegEncContext *s){
153     const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
154     const int mb_size= 16>>s->avctx->lowres;
155     s->last_resync_gb= s->gb;
156     s->first_slice_line= 1;
157
158     s->resync_mb_x= s->mb_x;
159     s->resync_mb_y= s->mb_y;
160
161     ff_set_qscale(s, s->qscale);
162
163     if (s->avctx->hwaccel)
164         return 0;
165
166     if(s->partitioned_frame){
167         const int qscale= s->qscale;
168
169         if(s->codec_id==CODEC_ID_MPEG4){
170             if(ff_mpeg4_decode_partitions(s) < 0)
171                 return -1;
172         }
173
174         /* restore variables which were modified */
175         s->first_slice_line=1;
176         s->mb_x= s->resync_mb_x;
177         s->mb_y= s->resync_mb_y;
178         ff_set_qscale(s, qscale);
179     }
180
181     for(; s->mb_y < s->mb_height; s->mb_y++) {
182         /* per-row end of slice checks */
183         if(s->msmpeg4_version){
184             if(s->resync_mb_y + s->slice_height == s->mb_y){
185                 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);
186
187                 return 0;
188             }
189         }
190
191         if(s->msmpeg4_version==1){
192             s->last_dc[0]=
193             s->last_dc[1]=
194             s->last_dc[2]= 128;
195         }
196
197         ff_init_block_index(s);
198         for(; s->mb_x < s->mb_width; s->mb_x++) {
199             int ret;
200
201             ff_update_block_index(s);
202
203             if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
204                 s->first_slice_line=0;
205             }
206
207             /* DCT & quantize */
208
209             s->mv_dir = MV_DIR_FORWARD;
210             s->mv_type = MV_TYPE_16X16;
211 //            s->mb_skipped = 0;
212 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
213             ret= s->decode_mb(s, s->block);
214
215             if (s->pict_type!=FF_B_TYPE)
216                 ff_h263_update_motion_val(s);
217
218             if(ret<0){
219                 const int xy= s->mb_x + s->mb_y*s->mb_stride;
220                 if(ret==SLICE_END){
221                     MPV_decode_mb(s, s->block);
222                     if(s->loop_filter)
223                         ff_h263_loop_filter(s);
224
225 //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));
226                     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);
227
228                     s->padding_bug_score--;
229
230                     if(++s->mb_x >= s->mb_width){
231                         s->mb_x=0;
232                         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
233                         s->mb_y++;
234                     }
235                     return 0;
236                 }else if(ret==SLICE_NOEND){
237                     av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
238                     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);
239                     return -1;
240                 }
241                 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
242                 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);
243
244                 return -1;
245             }
246
247             MPV_decode_mb(s, s->block);
248             if(s->loop_filter)
249                 ff_h263_loop_filter(s);
250         }
251
252         ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
253
254         s->mb_x= 0;
255     }
256
257     assert(s->mb_x==0 && s->mb_y==s->mb_height);
258
259     /* try to detect the padding bug */
260     if(      s->codec_id==CODEC_ID_MPEG4
261        &&   (s->workaround_bugs&FF_BUG_AUTODETECT)
262        &&    s->gb.size_in_bits - get_bits_count(&s->gb) >=0
263        &&    s->gb.size_in_bits - get_bits_count(&s->gb) < 48
264 //       &&   !s->resync_marker
265        &&   !s->data_partitioning){
266
267         const int bits_count= get_bits_count(&s->gb);
268         const int bits_left = s->gb.size_in_bits - bits_count;
269
270         if(bits_left==0){
271             s->padding_bug_score+=16;
272         } else if(bits_left != 1){
273             int v= show_bits(&s->gb, 8);
274             v|= 0x7F >> (7-(bits_count&7));
275
276             if(v==0x7F && bits_left<=8)
277                 s->padding_bug_score--;
278             else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
279                 s->padding_bug_score+= 4;
280             else
281                 s->padding_bug_score++;
282         }
283     }
284
285     if(s->workaround_bugs&FF_BUG_AUTODETECT){
286         if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version || !s->resync_marker)*/)
287             s->workaround_bugs |=  FF_BUG_NO_PADDING;
288         else
289             s->workaround_bugs &= ~FF_BUG_NO_PADDING;
290     }
291
292     // handle formats which don't have unique end markers
293     if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
294         int left= s->gb.size_in_bits - get_bits_count(&s->gb);
295         int max_extra=7;
296
297         /* no markers in M$ crap */
298         if(s->msmpeg4_version && s->pict_type==FF_I_TYPE)
299             max_extra+= 17;
300
301         /* buggy padding but the frame should still end approximately at the bitstream end */
302         if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_recognition>=3)
303             max_extra+= 48;
304         else if((s->workaround_bugs&FF_BUG_NO_PADDING))
305             max_extra+= 256*256*256*64;
306
307         if(left>max_extra){
308             av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
309         }
310         else if(left<0){
311             av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
312         }else
313             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);
314
315         return 0;
316     }
317
318     av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
319             s->gb.size_in_bits - get_bits_count(&s->gb),
320             show_bits(&s->gb, 24), s->padding_bug_score);
321
322     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);
323
324     return -1;
325 }
326
327 int ff_h263_decode_frame(AVCodecContext *avctx,
328                              void *data, int *data_size,
329                              const uint8_t *buf, int buf_size)
330 {
331     MpegEncContext *s = avctx->priv_data;
332     int ret;
333     AVFrame *pict = data;
334
335 #ifdef PRINT_FRAME_TIME
336 uint64_t time= rdtsc();
337 #endif
338 #ifdef DEBUG
339     av_log(avctx, AV_LOG_DEBUG, "*****frame %d size=%d\n", avctx->frame_number, buf_size);
340     if(buf_size>0)
341         av_log(avctx, AV_LOG_DEBUG, "bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);
342 #endif
343     s->flags= avctx->flags;
344     s->flags2= avctx->flags2;
345
346     /* no supplementary picture */
347     if (buf_size == 0) {
348         /* special case for last picture */
349         if (s->low_delay==0 && s->next_picture_ptr) {
350             *pict= *(AVFrame*)s->next_picture_ptr;
351             s->next_picture_ptr= NULL;
352
353             *data_size = sizeof(AVFrame);
354         }
355
356         return 0;
357     }
358
359     if(s->flags&CODEC_FLAG_TRUNCATED){
360         int next;
361
362         if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
363             next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
364         }else if(CONFIG_H263_DECODER && s->codec_id==CODEC_ID_H263){
365             next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
366         }else{
367             av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
368             return -1;
369         }
370
371         if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
372             return buf_size;
373     }
374
375
376 retry:
377
378     if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
379         init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
380     }else
381         init_get_bits(&s->gb, buf, buf_size*8);
382     s->bitstream_buffer_size=0;
383
384     if (!s->context_initialized) {
385         if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
386             return -1;
387     }
388
389     /* We need to set current_picture_ptr before reading the header,
390      * otherwise we cannot store anyting in there */
391     if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
392         int i= ff_find_unused_picture(s, 0);
393         s->current_picture_ptr= &s->picture[i];
394     }
395
396     /* let's go :-) */
397     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
398         ret= ff_wmv2_decode_picture_header(s);
399     } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
400         ret = msmpeg4_decode_picture_header(s);
401     } else if (s->h263_pred) {
402         if(s->avctx->extradata_size && s->picture_number==0){
403             GetBitContext gb;
404
405             init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
406             ret = ff_mpeg4_decode_picture_header(s, &gb);
407         }
408         ret = ff_mpeg4_decode_picture_header(s, &s->gb);
409     } else if (s->codec_id == CODEC_ID_H263I) {
410         ret = intel_h263_decode_picture_header(s);
411     } else if (s->h263_flv) {
412         ret = flv_h263_decode_picture_header(s);
413     } else {
414         ret = h263_decode_picture_header(s);
415     }
416
417     if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
418
419     /* skip if the header was thrashed */
420     if (ret < 0){
421         av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
422         return -1;
423     }
424
425     avctx->has_b_frames= !s->low_delay;
426
427     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
428         if(s->stream_codec_tag == AV_RL32("XVID") ||
429            s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
430            s->codec_tag == AV_RL32("RMP4"))
431             s->xvid_build= -1;
432 #if 0
433         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
434            && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
435             s->xvid_build= -1;
436 #endif
437     }
438
439     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
440         if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
441             s->divx_version= 400; //divx 4
442     }
443
444     if(s->xvid_build && s->divx_version){
445         s->divx_version=
446         s->divx_build= 0;
447     }
448
449     if(s->workaround_bugs&FF_BUG_AUTODETECT){
450         if(s->codec_tag == AV_RL32("XVIX"))
451             s->workaround_bugs|= FF_BUG_XVID_ILACE;
452
453         if(s->codec_tag == AV_RL32("UMP4")){
454             s->workaround_bugs|= FF_BUG_UMP4;
455         }
456
457         if(s->divx_version>=500 && s->divx_build<1814){
458             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
459         }
460
461         if(s->divx_version>502 && s->divx_build<1814){
462             s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
463         }
464
465         if(s->xvid_build && s->xvid_build<=3)
466             s->padding_bug_score= 256*256*256*64;
467
468         if(s->xvid_build && s->xvid_build<=1)
469             s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
470
471         if(s->xvid_build && s->xvid_build<=12)
472             s->workaround_bugs|= FF_BUG_EDGE;
473
474         if(s->xvid_build && s->xvid_build<=32)
475             s->workaround_bugs|= FF_BUG_DC_CLIP;
476
477 #define SET_QPEL_FUNC(postfix1, postfix2) \
478     s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
479     s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
480     s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
481
482         if(s->lavc_build && s->lavc_build<4653)
483             s->workaround_bugs|= FF_BUG_STD_QPEL;
484
485         if(s->lavc_build && s->lavc_build<4655)
486             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
487
488         if(s->lavc_build && s->lavc_build<4670){
489             s->workaround_bugs|= FF_BUG_EDGE;
490         }
491
492         if(s->lavc_build && s->lavc_build<=4712)
493             s->workaround_bugs|= FF_BUG_DC_CLIP;
494
495         if(s->divx_version)
496             s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
497 //printf("padding_bug_score: %d\n", s->padding_bug_score);
498         if(s->divx_version==501 && s->divx_build==20020416)
499             s->padding_bug_score= 256*256*256*64;
500
501         if(s->divx_version && s->divx_version<500){
502             s->workaround_bugs|= FF_BUG_EDGE;
503         }
504
505         if(s->divx_version)
506             s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
507 #if 0
508         if(s->divx_version==500)
509             s->padding_bug_score= 256*256*256*64;
510
511         /* very ugly XVID padding bug detection FIXME/XXX solve this differently
512          * Let us hope this at least works.
513          */
514         if(   s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==0
515            && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
516             s->workaround_bugs|= FF_BUG_NO_PADDING;
517
518         if(s->lavc_build && s->lavc_build<4609) //FIXME not sure about the version num but a 4609 file seems ok
519             s->workaround_bugs|= FF_BUG_NO_PADDING;
520 #endif
521     }
522
523     if(s->workaround_bugs& FF_BUG_STD_QPEL){
524         SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
525         SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
526         SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
527         SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
528         SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
529         SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
530
531         SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
532         SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
533         SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
534         SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
535         SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
536         SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
537     }
538
539     if(avctx->debug & FF_DEBUG_BUGS)
540         av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
541                s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
542                s->divx_packed ? "p" : "");
543
544 #if 0 // dump bits per frame / qp / complexity
545 {
546     static FILE *f=NULL;
547     if(!f) f=fopen("rate_qp_cplx.txt", "w");
548     fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
549 }
550 #endif
551
552 #if HAVE_MMX
553     if(s->codec_id == CODEC_ID_MPEG4 && s->xvid_build && avctx->idct_algo == FF_IDCT_AUTO && (mm_flags & FF_MM_MMX)){
554         avctx->idct_algo= FF_IDCT_XVIDMMX;
555         avctx->coded_width= 0; // force reinit
556 //        dsputil_init(&s->dsp, avctx);
557         s->picture_number=0;
558     }
559 #endif
560
561         /* After H263 & mpeg4 header decode we have the height, width,*/
562         /* and other parameters. So then we could init the picture   */
563         /* FIXME: By the way H263 decoder is evolving it should have */
564         /* an H263EncContext                                         */
565
566     if (   s->width  != avctx->coded_width
567         || s->height != avctx->coded_height) {
568         /* H.263 could change picture size any time */
569         ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
570         s->parse_context.buffer=0;
571         MPV_common_end(s);
572         s->parse_context= pc;
573     }
574     if (!s->context_initialized) {
575         avcodec_set_dimensions(avctx, s->width, s->height);
576
577         goto retry;
578     }
579
580     if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P || s->codec_id == CODEC_ID_H263I))
581         s->gob_index = ff_h263_get_gob_height(s);
582
583     // for hurry_up==5
584     s->current_picture.pict_type= s->pict_type;
585     s->current_picture.key_frame= s->pict_type == FF_I_TYPE;
586
587     /* skip B-frames if we don't have reference frames */
588     if(s->last_picture_ptr==NULL && (s->pict_type==FF_B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
589     /* skip b frames if we are in a hurry */
590     if(avctx->hurry_up && s->pict_type==FF_B_TYPE) return get_consumed_bytes(s, buf_size);
591     if(   (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==FF_B_TYPE)
592        || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=FF_I_TYPE)
593        ||  avctx->skip_frame >= AVDISCARD_ALL)
594         return get_consumed_bytes(s, buf_size);
595     /* skip everything if we are in a hurry>=5 */
596     if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
597
598     if(s->next_p_frame_damaged){
599         if(s->pict_type==FF_B_TYPE)
600             return get_consumed_bytes(s, buf_size);
601         else
602             s->next_p_frame_damaged=0;
603     }
604
605     if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==FF_B_TYPE){
606         s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
607         s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
608     }else if((!s->no_rounding) || s->pict_type==FF_B_TYPE){
609         s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
610         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
611     }else{
612         s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
613         s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
614     }
615
616     if(MPV_frame_start(s, avctx) < 0)
617         return -1;
618
619 #ifdef DEBUG
620     av_log(avctx, AV_LOG_DEBUG, "qscale=%d\n", s->qscale);
621 #endif
622
623     ff_er_frame_start(s);
624
625     //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
626     //which is not available before MPV_frame_start()
627     if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5){
628         ret = ff_wmv2_decode_secondary_picture_header(s);
629         if(ret<0) return ret;
630         if(ret==1) goto intrax8_decoded;
631     }
632
633     /* decode each macroblock */
634     s->mb_x=0;
635     s->mb_y=0;
636
637     decode_slice(s);
638     while(s->mb_y<s->mb_height){
639         if(s->msmpeg4_version){
640             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)
641                 break;
642         }else{
643             if(ff_h263_resync(s)<0)
644                 break;
645         }
646
647         if(s->msmpeg4_version<4 && s->h263_pred)
648             ff_mpeg4_clean_buffers(s);
649
650         decode_slice(s);
651     }
652
653     if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==FF_I_TYPE)
654         if(!CONFIG_MSMPEG4_DECODER || msmpeg4_decode_ext_header(s, buf_size) < 0){
655             s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
656         }
657
658     /* divx 5.01+ bistream reorder stuff */
659     if(s->codec_id==CODEC_ID_MPEG4 && s->bitstream_buffer_size==0 && s->divx_packed){
660         int current_pos= get_bits_count(&s->gb)>>3;
661         int startcode_found=0;
662
663         if(buf_size - current_pos > 5){
664             int i;
665             for(i=current_pos; i<buf_size-3; i++){
666                 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
667                     startcode_found=1;
668                     break;
669                 }
670             }
671         }
672         if(s->gb.buffer == s->bitstream_buffer && buf_size>20){ //xvid style
673             startcode_found=1;
674             current_pos=0;
675         }
676
677         if(startcode_found){
678             s->bitstream_buffer= av_fast_realloc(
679                 s->bitstream_buffer,
680                 &s->allocated_bitstream_buffer_size,
681                 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
682             memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
683             s->bitstream_buffer_size= buf_size - current_pos;
684         }
685     }
686
687 intrax8_decoded:
688     ff_er_frame_end(s);
689
690     MPV_frame_end(s);
691
692 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
693 assert(s->current_picture.pict_type == s->pict_type);
694     if (s->pict_type == FF_B_TYPE || s->low_delay) {
695         *pict= *(AVFrame*)s->current_picture_ptr;
696     } else if (s->last_picture_ptr != NULL) {
697         *pict= *(AVFrame*)s->last_picture_ptr;
698     }
699
700     if(s->last_picture_ptr || s->low_delay){
701         *data_size = sizeof(AVFrame);
702         ff_print_debug_info(s, pict);
703     }
704
705     /* Return the Picture timestamp as the frame number */
706     /* we subtract 1 because it is added on utils.c     */
707     avctx->frame_number = s->picture_number - 1;
708
709 #ifdef PRINT_FRAME_TIME
710 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
711 #endif
712
713     return get_consumed_bytes(s, buf_size);
714 }
715
716 AVCodec mpeg4_decoder = {
717     "mpeg4",
718     CODEC_TYPE_VIDEO,
719     CODEC_ID_MPEG4,
720     sizeof(MpegEncContext),
721     ff_h263_decode_init,
722     NULL,
723     ff_h263_decode_end,
724     ff_h263_decode_frame,
725     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
726     .flush= ff_mpeg_flush,
727     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2"),
728     .pix_fmts= ff_pixfmt_list_420,
729 };
730
731 AVCodec h263_decoder = {
732     "h263",
733     CODEC_TYPE_VIDEO,
734     CODEC_ID_H263,
735     sizeof(MpegEncContext),
736     ff_h263_decode_init,
737     NULL,
738     ff_h263_decode_end,
739     ff_h263_decode_frame,
740     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
741     .flush= ff_mpeg_flush,
742     .long_name= NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998"),
743     .pix_fmts= ff_pixfmt_list_420,
744 };
745
746 AVCodec msmpeg4v1_decoder = {
747     "msmpeg4v1",
748     CODEC_TYPE_VIDEO,
749     CODEC_ID_MSMPEG4V1,
750     sizeof(MpegEncContext),
751     ff_h263_decode_init,
752     NULL,
753     ff_h263_decode_end,
754     ff_h263_decode_frame,
755     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
756     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 1"),
757     .pix_fmts= ff_pixfmt_list_420,
758 };
759
760 AVCodec msmpeg4v2_decoder = {
761     "msmpeg4v2",
762     CODEC_TYPE_VIDEO,
763     CODEC_ID_MSMPEG4V2,
764     sizeof(MpegEncContext),
765     ff_h263_decode_init,
766     NULL,
767     ff_h263_decode_end,
768     ff_h263_decode_frame,
769     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
770     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 2"),
771     .pix_fmts= ff_pixfmt_list_420,
772 };
773
774 AVCodec msmpeg4v3_decoder = {
775     "msmpeg4",
776     CODEC_TYPE_VIDEO,
777     CODEC_ID_MSMPEG4V3,
778     sizeof(MpegEncContext),
779     ff_h263_decode_init,
780     NULL,
781     ff_h263_decode_end,
782     ff_h263_decode_frame,
783     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
784     .long_name= NULL_IF_CONFIG_SMALL("MPEG-4 part 2 Microsoft variant version 3"),
785     .pix_fmts= ff_pixfmt_list_420,
786 };
787
788 AVCodec wmv1_decoder = {
789     "wmv1",
790     CODEC_TYPE_VIDEO,
791     CODEC_ID_WMV1,
792     sizeof(MpegEncContext),
793     ff_h263_decode_init,
794     NULL,
795     ff_h263_decode_end,
796     ff_h263_decode_frame,
797     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
798     .long_name= NULL_IF_CONFIG_SMALL("Windows Media Video 7"),
799     .pix_fmts= ff_pixfmt_list_420,
800 };
801
802 AVCodec h263i_decoder = {
803     "h263i",
804     CODEC_TYPE_VIDEO,
805     CODEC_ID_H263I,
806     sizeof(MpegEncContext),
807     ff_h263_decode_init,
808     NULL,
809     ff_h263_decode_end,
810     ff_h263_decode_frame,
811     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
812     .long_name = NULL_IF_CONFIG_SMALL("Intel H.263"),
813     .pix_fmts= ff_pixfmt_list_420,
814 };
815
816 AVCodec flv_decoder = {
817     "flv",
818     CODEC_TYPE_VIDEO,
819     CODEC_ID_FLV1,
820     sizeof(MpegEncContext),
821     ff_h263_decode_init,
822     NULL,
823     ff_h263_decode_end,
824     ff_h263_decode_frame,
825     CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1,
826     .long_name= NULL_IF_CONFIG_SMALL("Flash Video"),
827     .pix_fmts= ff_pixfmt_list_420,
828 };