3 * Copyright (c) 2001 Fabrice Bellard
4 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
6 * This file is part of FFmpeg.
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.
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.
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
28 #include "libavutil/cpu.h"
32 #include "mpegvideo.h"
34 #include "h263_parser.h"
35 #include "mpeg4video_parser.h"
37 #include "vdpau_internal.h"
39 #include "mpeg4video.h"
42 //#define PRINT_FRAME_TIME
44 av_cold int ff_h263_decode_init(AVCodecContext *avctx)
46 MpegEncContext *s = avctx->priv_data;
49 s->out_format = FMT_H263;
51 s->width = avctx->coded_width;
52 s->height = avctx->coded_height;
53 s->workaround_bugs= avctx->workaround_bugs;
56 MPV_decode_defaults(s);
58 s->decode_mb= ff_h263_decode_mb;
60 avctx->pix_fmt= avctx->get_format(avctx, avctx->codec->pix_fmts);
61 s->unrestricted_mv= 1;
63 /* select sub codec */
64 switch(avctx->codec->id) {
66 s->unrestricted_mv= 0;
67 avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
71 case CODEC_ID_MSMPEG4V1:
76 case CODEC_ID_MSMPEG4V2:
81 case CODEC_ID_MSMPEG4V3:
100 s->msmpeg4_version=6;
101 avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
111 s->codec_id= avctx->codec->id;
112 avctx->hwaccel= ff_find_hwaccel(avctx->codec->id, avctx->pix_fmt);
114 /* for h263, we allocate the images after having read the header */
115 if (avctx->codec->id != CODEC_ID_H263 && avctx->codec->id != CODEC_ID_MPEG4)
116 if (MPV_common_init(s) < 0)
119 h263_decode_init_vlc(s);
124 av_cold int ff_h263_decode_end(AVCodecContext *avctx)
126 MpegEncContext *s = avctx->priv_data;
133 * returns the number of bytes consumed for building the current frame
135 static int get_consumed_bytes(MpegEncContext *s, int buf_size){
136 int pos= (get_bits_count(&s->gb)+7)>>3;
138 if(s->divx_packed || s->avctx->hwaccel){
139 //we would have to scan through the whole buf to handle the weird reordering ...
141 }else if(s->flags&CODEC_FLAG_TRUNCATED){
142 pos -= s->parse_context.last_index;
143 if(pos<0) pos=0; // padding is not really read so this might be -1
146 if(pos==0) pos=1; //avoid infinite loops (i doubt that is needed but ...)
147 if(pos+10>buf_size) pos=buf_size; // oops ;)
153 static int decode_slice(MpegEncContext *s){
154 const int part_mask= s->partitioned_frame ? (AC_END|AC_ERROR) : 0x7F;
155 const int mb_size= 16>>s->avctx->lowres;
156 s->last_resync_gb= s->gb;
157 s->first_slice_line= 1;
159 s->resync_mb_x= s->mb_x;
160 s->resync_mb_y= s->mb_y;
162 ff_set_qscale(s, s->qscale);
164 if (s->avctx->hwaccel) {
165 const uint8_t *start= s->gb.buffer + get_bits_count(&s->gb)/8;
166 const uint8_t *end = ff_h263_find_resync_marker(start + 1, s->gb.buffer_end);
167 skip_bits_long(&s->gb, 8*(end - start));
168 return s->avctx->hwaccel->decode_slice(s->avctx, start, end - start);
171 if(s->partitioned_frame){
172 const int qscale= s->qscale;
174 if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
175 if(ff_mpeg4_decode_partitions(s) < 0)
179 /* restore variables which were modified */
180 s->first_slice_line=1;
181 s->mb_x= s->resync_mb_x;
182 s->mb_y= s->resync_mb_y;
183 ff_set_qscale(s, qscale);
186 for(; s->mb_y < s->mb_height; s->mb_y++) {
187 /* per-row end of slice checks */
188 if(s->msmpeg4_version){
189 if(s->resync_mb_y + s->slice_height == s->mb_y){
190 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);
196 if(s->msmpeg4_version==1){
202 ff_init_block_index(s);
203 for(; s->mb_x < s->mb_width; s->mb_x++) {
206 ff_update_block_index(s);
208 if(s->resync_mb_x == s->mb_x && s->resync_mb_y+1 == s->mb_y){
209 s->first_slice_line=0;
214 s->mv_dir = MV_DIR_FORWARD;
215 s->mv_type = MV_TYPE_16X16;
216 // s->mb_skipped = 0;
217 //printf("%d %d %06X\n", ret, get_bits_count(&s->gb), show_bits(&s->gb, 24));
218 ret= s->decode_mb(s, s->block);
220 if (s->pict_type!=FF_B_TYPE)
221 ff_h263_update_motion_val(s);
224 const int xy= s->mb_x + s->mb_y*s->mb_stride;
226 MPV_decode_mb(s, s->block);
228 ff_h263_loop_filter(s);
230 //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));
231 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);
233 s->padding_bug_score--;
235 if(++s->mb_x >= s->mb_width){
237 ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
241 }else if(ret==SLICE_NOEND){
242 av_log(s->avctx, AV_LOG_ERROR, "Slice mismatch at MB: %d\n", xy);
243 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);
246 av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", xy);
247 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);
252 MPV_decode_mb(s, s->block);
254 ff_h263_loop_filter(s);
257 ff_draw_horiz_band(s, s->mb_y*mb_size, mb_size);
262 assert(s->mb_x==0 && s->mb_y==s->mb_height);
264 if(s->codec_id==CODEC_ID_MPEG4
265 && (s->workaround_bugs&FF_BUG_AUTODETECT)
266 && get_bits_left(&s->gb) >= 48
267 && show_bits(&s->gb, 24)==0x4010
268 && !s->data_partitioning)
269 s->padding_bug_score+=32;
271 /* try to detect the padding bug */
272 if( s->codec_id==CODEC_ID_MPEG4
273 && (s->workaround_bugs&FF_BUG_AUTODETECT)
274 && get_bits_left(&s->gb) >=0
275 && get_bits_left(&s->gb) < 48
276 // && !s->resync_marker
277 && !s->data_partitioning){
279 const int bits_count= get_bits_count(&s->gb);
280 const int bits_left = s->gb.size_in_bits - bits_count;
283 s->padding_bug_score+=16;
284 } else if(bits_left != 1){
285 int v= show_bits(&s->gb, 8);
286 v|= 0x7F >> (7-(bits_count&7));
288 if(v==0x7F && bits_left<=8)
289 s->padding_bug_score--;
290 else if(v==0x7F && ((get_bits_count(&s->gb)+8)&8) && bits_left<=16)
291 s->padding_bug_score+= 4;
293 s->padding_bug_score++;
297 if(s->workaround_bugs&FF_BUG_AUTODETECT){
298 if(s->padding_bug_score > -2 && !s->data_partitioning /*&& (s->divx_version>=0 || !s->resync_marker)*/)
299 s->workaround_bugs |= FF_BUG_NO_PADDING;
301 s->workaround_bugs &= ~FF_BUG_NO_PADDING;
304 // handle formats which don't have unique end markers
305 if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
306 int left= get_bits_left(&s->gb);
309 /* no markers in M$ crap */
310 if(s->msmpeg4_version && s->pict_type==FF_I_TYPE)
313 /* buggy padding but the frame should still end approximately at the bitstream end */
314 if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_recognition>=3)
316 else if((s->workaround_bugs&FF_BUG_NO_PADDING))
317 max_extra+= 256*256*256*64;
320 av_log(s->avctx, AV_LOG_ERROR, "discarding %d junk bits at end, next would be %X\n", left, show_bits(&s->gb, 24));
323 av_log(s->avctx, AV_LOG_ERROR, "overreading %d bits\n", -left);
325 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);
330 av_log(s->avctx, AV_LOG_ERROR, "slice end not reached but screenspace end (%d left %06X, score= %d)\n",
331 get_bits_left(&s->gb),
332 show_bits(&s->gb, 24), s->padding_bug_score);
334 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);
339 int ff_h263_decode_frame(AVCodecContext *avctx,
340 void *data, int *data_size,
343 const uint8_t *buf = avpkt->data;
344 int buf_size = avpkt->size;
345 MpegEncContext *s = avctx->priv_data;
347 AVFrame *pict = data;
349 #ifdef PRINT_FRAME_TIME
350 uint64_t time= rdtsc();
352 s->flags= avctx->flags;
353 s->flags2= avctx->flags2;
355 /* no supplementary picture */
357 /* special case for last picture */
358 if (s->low_delay==0 && s->next_picture_ptr) {
359 *pict= *(AVFrame*)s->next_picture_ptr;
360 s->next_picture_ptr= NULL;
362 *data_size = sizeof(AVFrame);
368 if(s->flags&CODEC_FLAG_TRUNCATED){
371 if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4){
372 next= ff_mpeg4_find_frame_end(&s->parse_context, buf, buf_size);
373 }else if(CONFIG_H263_DECODER && s->codec_id==CODEC_ID_H263){
374 next= ff_h263_find_frame_end(&s->parse_context, buf, buf_size);
376 av_log(s->avctx, AV_LOG_ERROR, "this codec does not support truncated bitstreams\n");
380 if( ff_combine_frame(&s->parse_context, next, (const uint8_t **)&buf, &buf_size) < 0 )
387 if(s->bitstream_buffer_size && (s->divx_packed || buf_size<20)){ //divx 5.01+/xvid frame reorder
388 init_get_bits(&s->gb, s->bitstream_buffer, s->bitstream_buffer_size*8);
390 init_get_bits(&s->gb, buf, buf_size*8);
391 s->bitstream_buffer_size=0;
393 if (!s->context_initialized) {
394 if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix
398 /* We need to set current_picture_ptr before reading the header,
399 * otherwise we cannot store anyting in there */
400 if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){
401 int i= ff_find_unused_picture(s, 0);
402 s->current_picture_ptr= &s->picture[i];
406 if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5) {
407 ret= ff_wmv2_decode_picture_header(s);
408 } else if (CONFIG_MSMPEG4_DECODER && s->msmpeg4_version) {
409 ret = msmpeg4_decode_picture_header(s);
410 } else if (CONFIG_MPEG4_DECODER && s->h263_pred) {
411 if(s->avctx->extradata_size && s->picture_number==0){
414 init_get_bits(&gb, s->avctx->extradata, s->avctx->extradata_size*8);
415 ret = ff_mpeg4_decode_picture_header(s, &gb);
417 ret = ff_mpeg4_decode_picture_header(s, &s->gb);
418 } else if (CONFIG_H263I_DECODER && s->codec_id == CODEC_ID_H263I) {
419 ret = ff_intel_h263_decode_picture_header(s);
420 } else if (CONFIG_FLV_DECODER && s->h263_flv) {
421 ret = ff_flv_decode_picture_header(s);
423 ret = h263_decode_picture_header(s);
426 if(ret==FRAME_SKIPPED) return get_consumed_bytes(s, buf_size);
428 /* skip if the header was thrashed */
430 av_log(s->avctx, AV_LOG_ERROR, "header damaged\n");
434 avctx->has_b_frames= !s->low_delay;
436 if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
437 if(s->stream_codec_tag == AV_RL32("XVID") ||
438 s->codec_tag == AV_RL32("XVID") || s->codec_tag == AV_RL32("XVIX") ||
439 s->codec_tag == AV_RL32("RMP4") ||
440 s->codec_tag == AV_RL32("SIPP")
444 if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
445 && s->padding_bug_score > 0 && s->low_delay) // XVID with modified fourcc
450 if(s->xvid_build==-1 && s->divx_version==-1 && s->lavc_build==-1){
451 if(s->codec_tag == AV_RL32("DIVX") && s->vo_type==0 && s->vol_control_parameters==0)
452 s->divx_version= 400; //divx 4
455 if(s->xvid_build>=0 && s->divx_version>=0){
460 if(s->workaround_bugs&FF_BUG_AUTODETECT){
461 if(s->codec_tag == AV_RL32("XVIX"))
462 s->workaround_bugs|= FF_BUG_XVID_ILACE;
464 if(s->codec_tag == AV_RL32("UMP4")){
465 s->workaround_bugs|= FF_BUG_UMP4;
468 if(s->divx_version>=500 && s->divx_build<1814){
469 s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
472 if(s->divx_version>502 && s->divx_build<1814){
473 s->workaround_bugs|= FF_BUG_QPEL_CHROMA2;
476 if(s->xvid_build<=3U)
477 s->padding_bug_score= 256*256*256*64;
479 if(s->xvid_build<=1U)
480 s->workaround_bugs|= FF_BUG_QPEL_CHROMA;
482 if(s->xvid_build<=12U)
483 s->workaround_bugs|= FF_BUG_EDGE;
485 if(s->xvid_build<=32U)
486 s->workaround_bugs|= FF_BUG_DC_CLIP;
488 #define SET_QPEL_FUNC(postfix1, postfix2) \
489 s->dsp.put_ ## postfix1 = ff_put_ ## postfix2;\
490 s->dsp.put_no_rnd_ ## postfix1 = ff_put_no_rnd_ ## postfix2;\
491 s->dsp.avg_ ## postfix1 = ff_avg_ ## postfix2;
493 if(s->lavc_build<4653U)
494 s->workaround_bugs|= FF_BUG_STD_QPEL;
496 if(s->lavc_build<4655U)
497 s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
499 if(s->lavc_build<4670U){
500 s->workaround_bugs|= FF_BUG_EDGE;
503 if(s->lavc_build<=4712U)
504 s->workaround_bugs|= FF_BUG_DC_CLIP;
506 if(s->divx_version>=0)
507 s->workaround_bugs|= FF_BUG_DIRECT_BLOCKSIZE;
508 //printf("padding_bug_score: %d\n", s->padding_bug_score);
509 if(s->divx_version==501 && s->divx_build==20020416)
510 s->padding_bug_score= 256*256*256*64;
512 if(s->divx_version<500U){
513 s->workaround_bugs|= FF_BUG_EDGE;
516 if(s->divx_version>=0)
517 s->workaround_bugs|= FF_BUG_HPEL_CHROMA;
519 if(s->divx_version==500)
520 s->padding_bug_score= 256*256*256*64;
522 /* very ugly XVID padding bug detection FIXME/XXX solve this differently
523 * Let us hope this at least works.
525 if( s->resync_marker==0 && s->data_partitioning==0 && s->divx_version==-1
526 && s->codec_id==CODEC_ID_MPEG4 && s->vo_type==0)
527 s->workaround_bugs|= FF_BUG_NO_PADDING;
529 if(s->lavc_build<4609U) //FIXME not sure about the version num but a 4609 file seems ok
530 s->workaround_bugs|= FF_BUG_NO_PADDING;
534 if(s->workaround_bugs& FF_BUG_STD_QPEL){
535 SET_QPEL_FUNC(qpel_pixels_tab[0][ 5], qpel16_mc11_old_c)
536 SET_QPEL_FUNC(qpel_pixels_tab[0][ 7], qpel16_mc31_old_c)
537 SET_QPEL_FUNC(qpel_pixels_tab[0][ 9], qpel16_mc12_old_c)
538 SET_QPEL_FUNC(qpel_pixels_tab[0][11], qpel16_mc32_old_c)
539 SET_QPEL_FUNC(qpel_pixels_tab[0][13], qpel16_mc13_old_c)
540 SET_QPEL_FUNC(qpel_pixels_tab[0][15], qpel16_mc33_old_c)
542 SET_QPEL_FUNC(qpel_pixels_tab[1][ 5], qpel8_mc11_old_c)
543 SET_QPEL_FUNC(qpel_pixels_tab[1][ 7], qpel8_mc31_old_c)
544 SET_QPEL_FUNC(qpel_pixels_tab[1][ 9], qpel8_mc12_old_c)
545 SET_QPEL_FUNC(qpel_pixels_tab[1][11], qpel8_mc32_old_c)
546 SET_QPEL_FUNC(qpel_pixels_tab[1][13], qpel8_mc13_old_c)
547 SET_QPEL_FUNC(qpel_pixels_tab[1][15], qpel8_mc33_old_c)
550 if(avctx->debug & FF_DEBUG_BUGS)
551 av_log(s->avctx, AV_LOG_DEBUG, "bugs: %X lavc_build:%d xvid_build:%d divx_version:%d divx_build:%d %s\n",
552 s->workaround_bugs, s->lavc_build, s->xvid_build, s->divx_version, s->divx_build,
553 s->divx_packed ? "p" : "");
555 #if 0 // dump bits per frame / qp / complexity
558 if(!f) f=fopen("rate_qp_cplx.txt", "w");
559 fprintf(f, "%d %d %f\n", buf_size, s->qscale, buf_size*(double)s->qscale);
564 if (s->codec_id == CODEC_ID_MPEG4 && s->xvid_build>=0 && avctx->idct_algo == FF_IDCT_AUTO && (av_get_cpu_flags() & AV_CPU_FLAG_MMX)) {
565 avctx->idct_algo= FF_IDCT_XVIDMMX;
566 avctx->coded_width= 0; // force reinit
567 // dsputil_init(&s->dsp, avctx);
572 /* After H263 & mpeg4 header decode we have the height, width,*/
573 /* and other parameters. So then we could init the picture */
574 /* FIXME: By the way H263 decoder is evolving it should have */
575 /* an H263EncContext */
577 if ( s->width != avctx->coded_width
578 || s->height != avctx->coded_height) {
579 /* H.263 could change picture size any time */
580 ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat
581 s->parse_context.buffer=0;
583 s->parse_context= pc;
585 if (!s->context_initialized) {
586 avcodec_set_dimensions(avctx, s->width, s->height);
591 if((s->codec_id==CODEC_ID_H263 || s->codec_id==CODEC_ID_H263P || s->codec_id == CODEC_ID_H263I))
592 s->gob_index = ff_h263_get_gob_height(s);
595 s->current_picture.pict_type= s->pict_type;
596 s->current_picture.key_frame= s->pict_type == FF_I_TYPE;
598 /* skip B-frames if we don't have reference frames */
599 if(s->last_picture_ptr==NULL && (s->pict_type==FF_B_TYPE || s->dropable)) return get_consumed_bytes(s, buf_size);
600 /* skip b frames if we are in a hurry */
601 if(avctx->hurry_up && s->pict_type==FF_B_TYPE) return get_consumed_bytes(s, buf_size);
602 if( (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==FF_B_TYPE)
603 || (avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=FF_I_TYPE)
604 || avctx->skip_frame >= AVDISCARD_ALL)
605 return get_consumed_bytes(s, buf_size);
606 /* skip everything if we are in a hurry>=5 */
607 if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size);
609 if(s->next_p_frame_damaged){
610 if(s->pict_type==FF_B_TYPE)
611 return get_consumed_bytes(s, buf_size);
613 s->next_p_frame_damaged=0;
616 if((s->avctx->flags2 & CODEC_FLAG2_FAST) && s->pict_type==FF_B_TYPE){
617 s->me.qpel_put= s->dsp.put_2tap_qpel_pixels_tab;
618 s->me.qpel_avg= s->dsp.avg_2tap_qpel_pixels_tab;
619 }else if((!s->no_rounding) || s->pict_type==FF_B_TYPE){
620 s->me.qpel_put= s->dsp.put_qpel_pixels_tab;
621 s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
623 s->me.qpel_put= s->dsp.put_no_rnd_qpel_pixels_tab;
624 s->me.qpel_avg= s->dsp.avg_qpel_pixels_tab;
627 if(MPV_frame_start(s, avctx) < 0)
630 if (CONFIG_MPEG4_VDPAU_DECODER && (s->avctx->codec->capabilities & CODEC_CAP_HWACCEL_VDPAU)) {
631 ff_vdpau_mpeg4_decode_picture(s, s->gb.buffer, s->gb.buffer_end - s->gb.buffer);
635 if (avctx->hwaccel) {
636 if (avctx->hwaccel->start_frame(avctx, s->gb.buffer, s->gb.buffer_end - s->gb.buffer) < 0)
640 ff_er_frame_start(s);
642 //the second part of the wmv2 header contains the MB skip bits which are stored in current_picture->mb_type
643 //which is not available before MPV_frame_start()
644 if (CONFIG_WMV2_DECODER && s->msmpeg4_version==5){
645 ret = ff_wmv2_decode_secondary_picture_header(s);
646 if(ret<0) return ret;
647 if(ret==1) goto intrax8_decoded;
650 /* decode each macroblock */
655 while(s->mb_y<s->mb_height){
656 if(s->msmpeg4_version){
657 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)
660 if(ff_h263_resync(s)<0)
664 if(s->msmpeg4_version<4 && s->h263_pred)
665 ff_mpeg4_clean_buffers(s);
670 if (s->h263_msmpeg4 && s->msmpeg4_version<4 && s->pict_type==FF_I_TYPE)
671 if(!CONFIG_MSMPEG4_DECODER || msmpeg4_decode_ext_header(s, buf_size) < 0){
672 s->error_status_table[s->mb_num-1]= AC_ERROR|DC_ERROR|MV_ERROR;
675 assert(s->bitstream_buffer_size==0);
677 /* divx 5.01+ bistream reorder stuff */
678 if(s->codec_id==CODEC_ID_MPEG4 && s->divx_packed){
679 int current_pos= get_bits_count(&s->gb)>>3;
680 int startcode_found=0;
682 if(buf_size - current_pos > 5){
684 for(i=current_pos; i<buf_size-3; i++){
685 if(buf[i]==0 && buf[i+1]==0 && buf[i+2]==1 && buf[i+3]==0xB6){
691 if(s->gb.buffer == s->bitstream_buffer && buf_size>7 && s->xvid_build>=0){ //xvid style
698 &s->bitstream_buffer,
699 &s->allocated_bitstream_buffer_size,
700 buf_size - current_pos + FF_INPUT_BUFFER_PADDING_SIZE);
701 if (!s->bitstream_buffer)
702 return AVERROR(ENOMEM);
703 memcpy(s->bitstream_buffer, buf + current_pos, buf_size - current_pos);
704 s->bitstream_buffer_size= buf_size - current_pos;
711 if (avctx->hwaccel) {
712 if (avctx->hwaccel->end_frame(avctx) < 0)
718 assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type);
719 assert(s->current_picture.pict_type == s->pict_type);
720 if (s->pict_type == FF_B_TYPE || s->low_delay) {
721 *pict= *(AVFrame*)s->current_picture_ptr;
722 } else if (s->last_picture_ptr != NULL) {
723 *pict= *(AVFrame*)s->last_picture_ptr;
726 if(s->last_picture_ptr || s->low_delay){
727 *data_size = sizeof(AVFrame);
728 ff_print_debug_info(s, pict);
731 #ifdef PRINT_FRAME_TIME
732 av_log(avctx, AV_LOG_DEBUG, "%"PRId64"\n", rdtsc()-time);
735 return get_consumed_bytes(s, buf_size);
738 AVCodec h263_decoder = {
742 sizeof(MpegEncContext),
746 ff_h263_decode_frame,
747 CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED | CODEC_CAP_DELAY,
748 .flush= ff_mpeg_flush,
750 .long_name= NULL_IF_CONFIG_SMALL("H.263 / H.263-1996, H.263+ / H.263-1998 / H.263 version 2"),
751 .pix_fmts= ff_hwaccel_pixfmt_list_420,