2 * "NUT" Container Format demuxer
3 * Copyright (c) 2004-2006 Michael Niedermayer
4 * Copyright (c) 2003 Alex Beregszaszi
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
30 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
31 unsigned int len= ff_get_v(bc);
34 get_buffer(bc, string, FFMIN(len, maxlen));
41 string[FFMIN(len, maxlen-1)]= 0;
49 static int64_t get_s(ByteIOContext *bc){
50 int64_t v = ff_get_v(bc) + 1;
52 if (v&1) return -(v>>1);
56 static uint64_t get_fourcc(ByteIOContext *bc){
57 unsigned int len= ff_get_v(bc);
59 if (len==2) return get_le16(bc);
60 else if(len==4) return get_le32(bc);
65 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
66 uint64_t v= ff_get_v(bc);
68 av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
72 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
75 av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
79 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
80 uint64_t v= get_vb(bc);
82 av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
85 #define ff_get_v(bc) get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
86 #define get_s(bc) get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
87 #define get_vb(bc) get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
90 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
93 // start= url_ftell(bc) - 8;
95 startcode= be2me_64(startcode);
96 startcode= ff_crc04C11DB7_update(0, &startcode, 8);
98 init_checksum(bc, ff_crc04C11DB7_update, startcode);
102 if(get_checksum(bc) && size > 4096)
105 init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
110 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
114 url_fseek(bc, pos, SEEK_SET); //note, this may fail if the stream is not seekable, but that should not matter, as in this case we simply start where we are currently
116 while(!url_feof(bc)){
117 state= (state<<8) | get_byte(bc);
118 if((state>>56) != 'N')
122 case STREAM_STARTCODE:
123 case SYNCPOINT_STARTCODE:
125 case INDEX_STARTCODE:
134 * Find the given startcode.
135 * @param code the startcode
136 * @param pos the start position of the search, or -1 if the current position
137 * @returns the position of the startcode or -1 if not found
139 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
141 uint64_t startcode= find_any_startcode(bc, pos);
142 if(startcode == code)
143 return url_ftell(bc) - 8;
144 else if(startcode == 0)
150 static int nut_probe(AVProbeData *p){
154 for (i = 0; i < p->buf_size; i++) {
155 code = (code << 8) | p->buf[i];
156 if (code == MAIN_STARTCODE)
157 return AVPROBE_SCORE_MAX;
162 #define GET_V(dst, check) \
165 av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
170 static int skip_reserved(ByteIOContext *bc, int64_t pos){
171 pos -= url_ftell(bc);
173 url_fseek(bc, pos, SEEK_CUR);
182 static int decode_main_header(NUTContext *nut){
183 AVFormatContext *s= nut->avf;
184 ByteIOContext *bc = s->pb;
186 unsigned int stream_count;
187 int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res;
190 end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
191 end += url_ftell(bc);
193 GET_V(tmp , tmp >=2 && tmp <= 3)
194 GET_V(stream_count , tmp > 0 && tmp <=MAX_STREAMS)
196 nut->max_distance = ff_get_v(bc);
197 if(nut->max_distance > 65536){
198 av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
199 nut->max_distance= 65536;
202 GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
203 nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
205 for(i=0; i<nut->time_base_count; i++){
206 GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
207 GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
208 if(ff_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
209 av_log(s, AV_LOG_ERROR, "time base invalid\n");
216 tmp_match= 1-(1LL<<62);
218 int tmp_flags = ff_get_v(bc);
219 int tmp_fields= ff_get_v(bc);
220 if(tmp_fields>0) tmp_pts = get_s(bc);
221 if(tmp_fields>1) tmp_mul = ff_get_v(bc);
222 if(tmp_fields>2) tmp_stream= ff_get_v(bc);
223 if(tmp_fields>3) tmp_size = ff_get_v(bc);
225 if(tmp_fields>4) tmp_res = ff_get_v(bc);
227 if(tmp_fields>5) count = ff_get_v(bc);
228 else count = tmp_mul - tmp_size;
229 if(tmp_fields>6) tmp_match = get_s(bc);
231 while(tmp_fields-- > 7)
234 if(count == 0 || i+count > 256){
235 av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
238 if(tmp_stream >= stream_count){
239 av_log(s, AV_LOG_ERROR, "illegal stream number\n");
243 for(j=0; j<count; j++,i++){
245 nut->frame_code[i].flags= FLAG_INVALID;
249 nut->frame_code[i].flags = tmp_flags ;
250 nut->frame_code[i].pts_delta = tmp_pts ;
251 nut->frame_code[i].stream_id = tmp_stream;
252 nut->frame_code[i].size_mul = tmp_mul ;
253 nut->frame_code[i].size_lsb = tmp_size+j;
254 nut->frame_code[i].reserved_count = tmp_res ;
257 assert(nut->frame_code['N'].flags == FLAG_INVALID);
259 if(skip_reserved(bc, end) || get_checksum(bc)){
260 av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
264 nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
265 for(i=0; i<stream_count; i++){
272 static int decode_stream_header(NUTContext *nut){
273 AVFormatContext *s= nut->avf;
274 ByteIOContext *bc = s->pb;
276 int class, stream_id;
280 end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
281 end += url_ftell(bc);
283 GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
284 stc= &nut->stream[stream_id];
286 st = s->streams[stream_id];
288 return AVERROR(ENOMEM);
290 class = ff_get_v(bc);
291 tmp = get_fourcc(bc);
292 st->codec->codec_tag= tmp;
296 st->codec->codec_type = CODEC_TYPE_VIDEO;
297 st->codec->codec_id = codec_get_id(codec_bmp_tags, tmp);
298 if (st->codec->codec_id == CODEC_ID_NONE)
299 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
302 st->codec->codec_type = CODEC_TYPE_AUDIO;
303 st->codec->codec_id = codec_get_id(codec_wav_tags, tmp);
304 if (st->codec->codec_id == CODEC_ID_NONE)
305 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
308 // st->codec->codec_type = CODEC_TYPE_TEXT;
311 st->codec->codec_type = CODEC_TYPE_DATA;
314 av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
317 GET_V(stc->time_base_id , tmp < nut->time_base_count);
318 GET_V(stc->msb_pts_shift , tmp < 16);
319 stc->max_pts_distance= ff_get_v(bc);
320 GET_V(stc->decode_delay , tmp < 1000); //sanity limit, raise this if Moore's law is true
321 st->codec->has_b_frames= stc->decode_delay;
322 ff_get_v(bc); //stream flags
324 GET_V(st->codec->extradata_size, tmp < (1<<30));
325 if(st->codec->extradata_size){
326 st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
327 get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
330 if (st->codec->codec_type == CODEC_TYPE_VIDEO){
331 GET_V(st->codec->width , tmp > 0)
332 GET_V(st->codec->height, tmp > 0)
333 st->codec->sample_aspect_ratio.num= ff_get_v(bc);
334 st->codec->sample_aspect_ratio.den= ff_get_v(bc);
335 if((!st->codec->sample_aspect_ratio.num) != (!st->codec->sample_aspect_ratio.den)){
336 av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->codec->sample_aspect_ratio.num, st->codec->sample_aspect_ratio.den);
339 ff_get_v(bc); /* csp type */
340 }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
341 GET_V(st->codec->sample_rate , tmp > 0)
342 ff_get_v(bc); // samplerate_den
343 GET_V(st->codec->channels, tmp > 0)
345 if(skip_reserved(bc, end) || get_checksum(bc)){
346 av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
349 stc->time_base= &nut->time_base[stc->time_base_id];
350 av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
354 static int decode_info_header(NUTContext *nut){
355 AVFormatContext *s= nut->avf;
356 ByteIOContext *bc = s->pb;
358 unsigned int stream_id_plus1, chapter_start, chapter_len, count;
361 char name[256], str_value[1024], type_str[256];
364 end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
365 end += url_ftell(bc);
367 GET_V(stream_id_plus1, tmp <= s->nb_streams)
368 chapter_id = get_s(bc);
369 chapter_start= ff_get_v(bc);
370 chapter_len = ff_get_v(bc);
371 count = ff_get_v(bc);
372 for(i=0; i<count; i++){
373 get_str(bc, name, sizeof(name));
377 get_str(bc, str_value, sizeof(str_value));
378 }else if(value == -2){
379 get_str(bc, type_str, sizeof(type_str));
381 get_str(bc, str_value, sizeof(str_value));
382 }else if(value == -3){
385 }else if(value == -4){
388 }else if(value < -4){
395 if(chapter_id==0 && !strcmp(type, "UTF-8")){
396 if (!strcmp(name, "Author"))
397 av_strlcpy(s->author , str_value, sizeof(s->author));
398 else if(!strcmp(name, "Title"))
399 av_strlcpy(s->title , str_value, sizeof(s->title));
400 else if(!strcmp(name, "Copyright"))
401 av_strlcpy(s->copyright, str_value, sizeof(s->copyright));
402 else if(!strcmp(name, "Description"))
403 av_strlcpy(s->comment , str_value, sizeof(s->comment));
407 if(skip_reserved(bc, end) || get_checksum(bc)){
408 av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
414 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
415 AVFormatContext *s= nut->avf;
416 ByteIOContext *bc = s->pb;
419 nut->last_syncpoint_pos= url_ftell(bc)-8;
421 end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
422 end += url_ftell(bc);
425 *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
429 ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
431 if(skip_reserved(bc, end) || get_checksum(bc)){
432 av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
436 *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
437 ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
442 static int find_and_decode_index(NUTContext *nut){
443 AVFormatContext *s= nut->avf;
444 ByteIOContext *bc = s->pb;
446 int i, j, syncpoint_count;
447 int64_t filesize= url_fsize(bc);
449 int8_t *has_keyframe;
451 url_fseek(bc, filesize-12, SEEK_SET);
452 url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
453 if(get_be64(bc) != INDEX_STARTCODE){
454 av_log(s, AV_LOG_ERROR, "no index at the end\n");
458 end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
459 end += url_ftell(bc);
461 ff_get_v(bc); //max_pts
462 GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
463 syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
464 has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
465 for(i=0; i<syncpoint_count; i++){
466 GET_V(syncpoints[i], tmp>0)
468 syncpoints[i] += syncpoints[i-1];
471 for(i=0; i<s->nb_streams; i++){
472 int64_t last_pts= -1;
473 for(j=0; j<syncpoint_count;){
474 uint64_t x= ff_get_v(bc);
481 if(n+x >= syncpoint_count + 1){
482 av_log(s, AV_LOG_ERROR, "index overflow A\n");
486 has_keyframe[n++]= flag;
487 has_keyframe[n++]= !flag;
490 if(n>=syncpoint_count + 1){
491 av_log(s, AV_LOG_ERROR, "index overflow B\n");
494 has_keyframe[n++]= x&1;
499 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
502 assert(n<=syncpoint_count+1);
503 for(; j<n && j<syncpoint_count; j++){
505 uint64_t B, A= ff_get_v(bc);
509 //eor_pts[j][i] = last_pts + A + B
525 if(skip_reserved(bc, end) || get_checksum(bc)){
526 av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
532 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
534 NUTContext *nut = s->priv_data;
535 ByteIOContext *bc = s->pb;
537 int initialized_stream_count;
544 pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
546 av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
549 }while(decode_main_header(nut) < 0);
553 for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
554 pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
556 av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
559 if(decode_stream_header(nut) >= 0)
560 initialized_stream_count++;
566 uint64_t startcode= find_any_startcode(bc, pos);
570 av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
572 }else if(startcode == SYNCPOINT_STARTCODE){
573 nut->next_startcode= startcode;
575 }else if(startcode != INFO_STARTCODE){
579 decode_info_header(nut);
582 s->data_offset= pos-8;
584 if(!url_is_streamed(bc)){
585 int64_t orig_pos= url_ftell(bc);
586 find_and_decode_index(nut);
587 url_fseek(bc, orig_pos, SEEK_SET);
589 assert(nut->next_startcode == SYNCPOINT_STARTCODE);
594 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, int frame_code){
595 AVFormatContext *s= nut->avf;
596 ByteIOContext *bc = s->pb;
598 int size, flags, size_mul, pts_delta, i, reserved_count;
601 if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
602 av_log(s, AV_LOG_ERROR, "Last frame must have been damaged %"PRId64" > %"PRId64" + %d\n", url_ftell(bc), nut->last_syncpoint_pos, nut->max_distance);
606 flags = nut->frame_code[frame_code].flags;
607 size_mul = nut->frame_code[frame_code].size_mul;
608 size = nut->frame_code[frame_code].size_lsb;
609 *stream_id = nut->frame_code[frame_code].stream_id;
610 pts_delta = nut->frame_code[frame_code].pts_delta;
611 reserved_count = nut->frame_code[frame_code].reserved_count;
613 if(flags & FLAG_INVALID)
615 if(flags & FLAG_CODED)
616 flags ^= ff_get_v(bc);
617 if(flags & FLAG_STREAM_ID){
618 GET_V(*stream_id, tmp < s->nb_streams)
620 stc= &nut->stream[*stream_id];
621 if(flags&FLAG_CODED_PTS){
622 int coded_pts= ff_get_v(bc);
623 //FIXME check last_pts validity?
624 if(coded_pts < (1<<stc->msb_pts_shift)){
625 *pts=ff_lsb2full(stc, coded_pts);
627 *pts=coded_pts - (1<<stc->msb_pts_shift);
629 *pts= stc->last_pts + pts_delta;
630 if(flags&FLAG_SIZE_MSB){
631 size += size_mul*ff_get_v(bc);
633 if(flags&FLAG_MATCH_TIME)
635 if(flags&FLAG_RESERVED)
636 reserved_count= ff_get_v(bc);
637 for(i=0; i<reserved_count; i++)
639 if(flags&FLAG_CHECKSUM){
640 get_be32(bc); //FIXME check this
641 }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
642 av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
647 stc->last_flags= flags;
652 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
653 AVFormatContext *s= nut->avf;
654 ByteIOContext *bc = s->pb;
655 int size, stream_id, discard;
656 int64_t pts, last_IP_pts;
659 size= decode_frame_header(nut, &pts, &stream_id, frame_code);
663 stc= &nut->stream[stream_id];
665 if (stc->last_flags & FLAG_KEY)
666 stc->skip_until_key_frame=0;
668 discard= s->streams[ stream_id ]->discard;
669 last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
670 if( (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
671 ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
672 || discard >= AVDISCARD_ALL
673 || stc->skip_until_key_frame){
678 av_get_packet(bc, pkt, size);
679 pkt->stream_index = stream_id;
680 if (stc->last_flags & FLAG_KEY)
681 pkt->flags |= PKT_FLAG_KEY;
687 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
689 NUTContext *nut = s->priv_data;
690 ByteIOContext *bc = s->pb;
691 int i, frame_code=0, ret, skip;
692 int64_t ts, back_ptr;
695 int64_t pos= url_ftell(bc);
696 uint64_t tmp= nut->next_startcode;
697 nut->next_startcode=0;
702 frame_code = get_byte(bc);
705 if(frame_code == 'N'){
708 tmp = (tmp<<8) + get_byte(bc);
713 case STREAM_STARTCODE:
714 case INDEX_STARTCODE:
715 skip= get_packetheader(nut, bc, 0, tmp);
716 url_fseek(bc, skip, SEEK_CUR);
719 if(decode_info_header(nut)<0)
722 case SYNCPOINT_STARTCODE:
723 if(decode_syncpoint(nut, &ts, &back_ptr)<0)
725 frame_code = get_byte(bc);
727 ret= decode_frame(nut, pkt, frame_code);
730 else if(ret==1) //ok but discard packet
734 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
735 tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
738 av_log(s, AV_LOG_DEBUG, "sync\n");
739 nut->next_startcode= tmp;
744 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
745 NUTContext *nut = s->priv_data;
746 ByteIOContext *bc = s->pb;
747 int64_t pos, pts, back_ptr;
748 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
752 pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
754 assert(nut->next_startcode == 0);
755 av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
756 return AV_NOPTS_VALUE;
758 }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
760 assert(nut->last_syncpoint_pos == *pos_arg);
762 av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
763 if (stream_index == -1) return pts;
764 else if(stream_index == -2) return back_ptr;
769 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
770 NUTContext *nut = s->priv_data;
771 AVStream *st= s->streams[stream_index];
772 syncpoint_t dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
773 syncpoint_t nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
774 syncpoint_t *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
775 int64_t pos, pos2, ts;
778 if(st->index_entries){
779 int index= av_index_search_timestamp(st, pts, flags);
783 pos2= st->index_entries[index].pos;
784 ts = st->index_entries[index].timestamp;
786 av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pts_cmp, next_node);
787 av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
788 next_node[0]->ts , next_node[1]->ts);
789 pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
790 next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
792 if(!(flags & AVSEEK_FLAG_BACKWARD)){
794 next_node[1]= &nopts_sp;
795 av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, next_node);
796 pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos , next_node[1]->pos, next_node[1]->pos,
797 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
800 //FIXME dir but i think it does not matter
803 sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
806 pos2= sp->back_ptr - 15;
808 av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
809 pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
810 url_fseek(s->pb, pos, SEEK_SET);
811 av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
812 if(pos2 > pos || pos2 + 15 < pos){
813 av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
815 for(i=0; i<s->nb_streams; i++)
816 nut->stream[i].skip_until_key_frame=1;
821 static int nut_read_close(AVFormatContext *s)
823 NUTContext *nut = s->priv_data;
825 av_freep(&nut->time_base);
826 av_freep(&nut->stream);
831 #ifdef CONFIG_NUT_DEMUXER
832 AVInputFormat nut_demuxer = {