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;
189 end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
190 end += url_ftell(bc);
192 GET_V(tmp , tmp >=2 && tmp <= 3)
193 GET_V(stream_count , tmp > 0 && tmp <=MAX_STREAMS)
195 nut->max_distance = ff_get_v(bc);
196 if(nut->max_distance > 65536){
197 av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
198 nut->max_distance= 65536;
201 GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
202 nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
204 for(i=0; i<nut->time_base_count; i++){
205 GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
206 GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
207 if(ff_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
208 av_log(s, AV_LOG_ERROR, "time base invalid\n");
216 int tmp_flags = ff_get_v(bc);
217 int tmp_fields= ff_get_v(bc);
218 if(tmp_fields>0) tmp_pts = get_s(bc);
219 if(tmp_fields>1) tmp_mul = ff_get_v(bc);
220 if(tmp_fields>2) tmp_stream= ff_get_v(bc);
221 if(tmp_fields>3) tmp_size = ff_get_v(bc);
223 if(tmp_fields>4) tmp_res = ff_get_v(bc);
225 if(tmp_fields>5) count = ff_get_v(bc);
226 else count = tmp_mul - tmp_size;
228 while(tmp_fields-- > 6)
231 if(count == 0 || i+count > 256){
232 av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
235 if(tmp_stream >= stream_count){
236 av_log(s, AV_LOG_ERROR, "illegal stream number\n");
240 for(j=0; j<count; j++,i++){
242 nut->frame_code[i].flags= FLAG_INVALID;
246 nut->frame_code[i].flags = tmp_flags ;
247 nut->frame_code[i].pts_delta = tmp_pts ;
248 nut->frame_code[i].stream_id = tmp_stream;
249 nut->frame_code[i].size_mul = tmp_mul ;
250 nut->frame_code[i].size_lsb = tmp_size+j;
251 nut->frame_code[i].reserved_count = tmp_res ;
254 assert(nut->frame_code['N'].flags == FLAG_INVALID);
256 if(skip_reserved(bc, end) || get_checksum(bc)){
257 av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
261 nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
262 for(i=0; i<stream_count; i++){
269 static int decode_stream_header(NUTContext *nut){
270 AVFormatContext *s= nut->avf;
271 ByteIOContext *bc = s->pb;
273 int class, stream_id;
277 end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
278 end += url_ftell(bc);
280 GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
281 stc= &nut->stream[stream_id];
283 st = s->streams[stream_id];
285 return AVERROR(ENOMEM);
287 class = ff_get_v(bc);
288 tmp = get_fourcc(bc);
289 st->codec->codec_tag= tmp;
293 st->codec->codec_type = CODEC_TYPE_VIDEO;
294 st->codec->codec_id = codec_get_id(codec_bmp_tags, tmp);
295 if (st->codec->codec_id == CODEC_ID_NONE)
296 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
299 st->codec->codec_type = CODEC_TYPE_AUDIO;
300 st->codec->codec_id = codec_get_id(codec_wav_tags, tmp);
301 if (st->codec->codec_id == CODEC_ID_NONE)
302 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
305 // st->codec->codec_type = CODEC_TYPE_TEXT;
308 st->codec->codec_type = CODEC_TYPE_DATA;
311 av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
314 GET_V(stc->time_base_id , tmp < nut->time_base_count);
315 GET_V(stc->msb_pts_shift , tmp < 16);
316 stc->max_pts_distance= ff_get_v(bc);
317 GET_V(stc->decode_delay , tmp < 1000); //sanity limit, raise this if Moore's law is true
318 st->codec->has_b_frames= stc->decode_delay;
319 ff_get_v(bc); //stream flags
321 GET_V(st->codec->extradata_size, tmp < (1<<30));
322 if(st->codec->extradata_size){
323 st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
324 get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
327 if (st->codec->codec_type == CODEC_TYPE_VIDEO){
328 GET_V(st->codec->width , tmp > 0)
329 GET_V(st->codec->height, tmp > 0)
330 st->codec->sample_aspect_ratio.num= ff_get_v(bc);
331 st->codec->sample_aspect_ratio.den= ff_get_v(bc);
332 if((!st->codec->sample_aspect_ratio.num) != (!st->codec->sample_aspect_ratio.den)){
333 av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->codec->sample_aspect_ratio.num, st->codec->sample_aspect_ratio.den);
336 ff_get_v(bc); /* csp type */
337 }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
338 GET_V(st->codec->sample_rate , tmp > 0)
339 tmp= ff_get_v(bc); // samplerate_den
340 if(tmp > st->codec->sample_rate){
341 av_log(s, AV_LOG_ERROR, "Bleh, libnut muxed this ;)\n");
342 st->codec->sample_rate= tmp;
344 GET_V(st->codec->channels, tmp > 0)
346 if(skip_reserved(bc, end) || get_checksum(bc)){
347 av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
350 stc->time_base= &nut->time_base[stc->time_base_id];
351 av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
355 static int decode_info_header(NUTContext *nut){
356 AVFormatContext *s= nut->avf;
357 ByteIOContext *bc = s->pb;
359 unsigned int stream_id_plus1, chapter_start, chapter_len, count;
362 char name[256], str_value[1024], type_str[256];
365 end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
366 end += url_ftell(bc);
368 GET_V(stream_id_plus1, tmp <= s->nb_streams)
369 chapter_id = get_s(bc);
370 chapter_start= ff_get_v(bc);
371 chapter_len = ff_get_v(bc);
372 count = ff_get_v(bc);
373 for(i=0; i<count; i++){
374 get_str(bc, name, sizeof(name));
378 get_str(bc, str_value, sizeof(str_value));
379 }else if(value == -2){
380 get_str(bc, type_str, sizeof(type_str));
382 get_str(bc, str_value, sizeof(str_value));
383 }else if(value == -3){
386 }else if(value == -4){
389 }else if(value < -4){
396 if(chapter_id==0 && !strcmp(type, "UTF-8")){
397 if (!strcmp(name, "Author"))
398 av_strlcpy(s->author , str_value, sizeof(s->author));
399 else if(!strcmp(name, "Title"))
400 av_strlcpy(s->title , str_value, sizeof(s->title));
401 else if(!strcmp(name, "Copyright"))
402 av_strlcpy(s->copyright, str_value, sizeof(s->copyright));
403 else if(!strcmp(name, "Description"))
404 av_strlcpy(s->comment , str_value, sizeof(s->comment));
408 if(skip_reserved(bc, end) || get_checksum(bc)){
409 av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
415 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
416 AVFormatContext *s= nut->avf;
417 ByteIOContext *bc = s->pb;
420 nut->last_syncpoint_pos= url_ftell(bc)-8;
422 end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
423 end += url_ftell(bc);
426 *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
430 ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp);
432 if(skip_reserved(bc, end) || get_checksum(bc)){
433 av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
437 *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
438 ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
443 static int find_and_decode_index(NUTContext *nut){
444 AVFormatContext *s= nut->avf;
445 ByteIOContext *bc = s->pb;
447 int i, j, syncpoint_count;
448 int64_t filesize= url_fsize(bc);
450 int8_t *has_keyframe;
452 url_fseek(bc, filesize-12, SEEK_SET);
453 url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
454 if(get_be64(bc) != INDEX_STARTCODE){
455 av_log(s, AV_LOG_ERROR, "no index at the end\n");
459 end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
460 end += url_ftell(bc);
462 ff_get_v(bc); //max_pts
463 GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
464 syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
465 has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
466 for(i=0; i<syncpoint_count; i++){
467 GET_V(syncpoints[i], tmp>0)
469 syncpoints[i] += syncpoints[i-1];
472 for(i=0; i<s->nb_streams; i++){
473 int64_t last_pts= -1;
474 for(j=0; j<syncpoint_count;){
475 uint64_t x= ff_get_v(bc);
482 if(n+x >= syncpoint_count + 1){
483 av_log(s, AV_LOG_ERROR, "index overflow A\n");
487 has_keyframe[n++]= flag;
488 has_keyframe[n++]= !flag;
491 if(n>=syncpoint_count + 1){
492 av_log(s, AV_LOG_ERROR, "index overflow B\n");
495 has_keyframe[n++]= x&1;
500 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
503 assert(n<=syncpoint_count+1);
506 uint64_t B, A= ff_get_v(bc);
510 //eor_pts[j][i] = last_pts + A + B
526 if(skip_reserved(bc, end) || get_checksum(bc)){
527 av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
533 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
535 NUTContext *nut = s->priv_data;
536 ByteIOContext *bc = s->pb;
538 int inited_stream_count;
545 pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
547 av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
550 }while(decode_main_header(nut) < 0);
554 for(inited_stream_count=0; inited_stream_count < s->nb_streams;){
555 pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
557 av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
560 if(decode_stream_header(nut) >= 0)
561 inited_stream_count++;
567 uint64_t startcode= find_any_startcode(bc, pos);
571 av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
573 }else if(startcode == SYNCPOINT_STARTCODE){
574 nut->next_startcode= startcode;
576 }else if(startcode != INFO_STARTCODE){
580 decode_info_header(nut);
583 s->data_offset= pos-8;
585 if(!url_is_streamed(bc)){
586 int64_t orig_pos= url_ftell(bc);
587 find_and_decode_index(nut);
588 url_fseek(bc, orig_pos, SEEK_SET);
590 assert(nut->next_startcode == SYNCPOINT_STARTCODE);
595 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, int frame_code){
596 AVFormatContext *s= nut->avf;
597 ByteIOContext *bc = s->pb;
599 int size, flags, size_mul, pts_delta, i, reserved_count;
602 if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
603 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);
607 flags = nut->frame_code[frame_code].flags;
608 size_mul = nut->frame_code[frame_code].size_mul;
609 size = nut->frame_code[frame_code].size_lsb;
610 *stream_id = nut->frame_code[frame_code].stream_id;
611 pts_delta = nut->frame_code[frame_code].pts_delta;
612 reserved_count = nut->frame_code[frame_code].reserved_count;
614 if(flags & FLAG_INVALID)
616 if(flags & FLAG_CODED)
617 flags ^= ff_get_v(bc);
618 if(flags & FLAG_STREAM_ID){
619 GET_V(*stream_id, tmp < s->nb_streams)
621 stc= &nut->stream[*stream_id];
622 if(flags&FLAG_CODED_PTS){
623 int coded_pts= ff_get_v(bc);
624 //FIXME check last_pts validity?
625 if(coded_pts < (1<<stc->msb_pts_shift)){
626 *pts=ff_lsb2full(stc, coded_pts);
628 *pts=coded_pts - (1<<stc->msb_pts_shift);
630 *pts= stc->last_pts + pts_delta;
631 if(flags&FLAG_SIZE_MSB){
632 size += size_mul*ff_get_v(bc);
634 if(flags&FLAG_RESERVED)
635 reserved_count= ff_get_v(bc);
636 for(i=0; i<reserved_count; i++)
638 if(flags&FLAG_CHECKSUM){
639 get_be32(bc); //FIXME check this
640 }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
641 av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
646 stc->last_flags= flags;
651 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
652 AVFormatContext *s= nut->avf;
653 ByteIOContext *bc = s->pb;
654 int size, stream_id, discard;
655 int64_t pts, last_IP_pts;
658 size= decode_frame_header(nut, &pts, &stream_id, frame_code);
662 stc= &nut->stream[stream_id];
664 if (stc->last_flags & FLAG_KEY)
665 stc->skip_until_key_frame=0;
667 discard= s->streams[ stream_id ]->discard;
668 last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
669 if( (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
670 ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
671 || discard >= AVDISCARD_ALL
672 || stc->skip_until_key_frame){
677 av_get_packet(bc, pkt, size);
678 pkt->stream_index = stream_id;
679 if (stc->last_flags & FLAG_KEY)
680 pkt->flags |= PKT_FLAG_KEY;
686 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
688 NUTContext *nut = s->priv_data;
689 ByteIOContext *bc = s->pb;
690 int i, frame_code=0, ret, skip;
691 int64_t ts, back_ptr;
694 int64_t pos= url_ftell(bc);
695 uint64_t tmp= nut->next_startcode;
696 nut->next_startcode=0;
701 frame_code = get_byte(bc);
704 if(frame_code == 'N'){
707 tmp = (tmp<<8) + get_byte(bc);
712 case STREAM_STARTCODE:
713 case INDEX_STARTCODE:
714 skip= get_packetheader(nut, bc, 0, tmp);
715 url_fseek(bc, skip, SEEK_CUR);
718 if(decode_info_header(nut)<0)
721 case SYNCPOINT_STARTCODE:
722 if(decode_syncpoint(nut, &ts, &back_ptr)<0)
724 frame_code = get_byte(bc);
726 ret= decode_frame(nut, pkt, frame_code);
729 else if(ret==1) //ok but discard packet
733 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
734 tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
737 av_log(s, AV_LOG_DEBUG, "sync\n");
738 nut->next_startcode= tmp;
743 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
744 NUTContext *nut = s->priv_data;
745 ByteIOContext *bc = s->pb;
746 int64_t pos, pts, back_ptr;
747 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
751 pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
753 assert(nut->next_startcode == 0);
754 av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
755 return AV_NOPTS_VALUE;
757 }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
759 assert(nut->last_syncpoint_pos == *pos_arg);
761 av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
762 if (stream_index == -1) return pts;
763 else if(stream_index == -2) return back_ptr;
768 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
769 NUTContext *nut = s->priv_data;
770 AVStream *st= s->streams[stream_index];
771 syncpoint_t dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
772 syncpoint_t nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
773 syncpoint_t *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
774 int64_t pos, pos2, ts;
777 if(st->index_entries){
778 int index= av_index_search_timestamp(st, pts, flags);
782 pos2= st->index_entries[index].pos;
783 ts = st->index_entries[index].timestamp;
785 av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pts_cmp, next_node);
786 av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
787 next_node[0]->ts , next_node[1]->ts);
788 pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
789 next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
791 if(!(flags & AVSEEK_FLAG_BACKWARD)){
793 next_node[1]= &nopts_sp;
794 av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, next_node);
795 pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos , next_node[1]->pos, next_node[1]->pos,
796 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
799 //FIXME dir but i think it does not matter
802 sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
805 pos2= sp->back_ptr - 15;
807 av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
808 pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
809 url_fseek(s->pb, pos, SEEK_SET);
810 av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
811 if(pos2 > pos || pos2 + 15 < pos){
812 av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
814 for(i=0; i<s->nb_streams; i++)
815 nut->stream[i].skip_until_key_frame=1;
820 static int nut_read_close(AVFormatContext *s)
822 NUTContext *nut = s->priv_data;
824 av_freep(&nut->time_base);
825 av_freep(&nut->stream);
830 #ifdef CONFIG_NUT_DEMUXER
831 AVInputFormat nut_demuxer = {