ce3746e5fdf488755a2d80fce2f37cfffdb1a0ce
[ffmpeg.git] / libavformat / nutdec.c
1 /*
2  * "NUT" Container Format demuxer
3  * Copyright (c) 2004-2006 Michael Niedermayer
4  * Copyright (c) 2003 Alex Beregszaszi
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 #include "tree.h"
24 #include "nut.h"
25 #include "avstring.h"
26
27 #undef NDEBUG
28 #include <assert.h>
29
30 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
31     unsigned int len= ff_get_v(bc);
32
33     if(len && maxlen)
34         get_buffer(bc, string, FFMIN(len, maxlen));
35     while(len > maxlen){
36         get_byte(bc);
37         len--;
38     }
39
40     if(maxlen)
41         string[FFMIN(len, maxlen-1)]= 0;
42
43     if(maxlen == len)
44         return -1;
45     else
46         return 0;
47 }
48
49 static int64_t get_s(ByteIOContext *bc){
50     int64_t v = ff_get_v(bc) + 1;
51
52     if (v&1) return -(v>>1);
53     else     return  (v>>1);
54 }
55
56 static uint64_t get_fourcc(ByteIOContext *bc){
57     unsigned int len= ff_get_v(bc);
58
59     if     (len==2) return get_le16(bc);
60     else if(len==4) return get_le32(bc);
61     else            return -1;
62 }
63
64 #ifdef TRACE
65 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
66     uint64_t v= ff_get_v(bc);
67
68     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
69     return v;
70 }
71
72 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
73     int64_t v= get_s(bc);
74
75     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
76     return v;
77 }
78
79 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
80     uint64_t v= get_vb(bc);
81
82     av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
83     return v;
84 }
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__)
88 #endif
89
90 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
91 {
92     int64_t size;
93 //    start= url_ftell(bc) - 8;
94
95     startcode= be2me_64(startcode);
96     startcode= ff_crc04C11DB7_update(0, &startcode, 8);
97
98     init_checksum(bc, ff_crc04C11DB7_update, startcode);
99     size= ff_get_v(bc);
100     if(size > 4096)
101         get_be32(bc);
102     if(get_checksum(bc) && size > 4096)
103         return -1;
104
105     init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
106
107     return size;
108 }
109
110 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
111     uint64_t state=0;
112
113     if(pos >= 0)
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
115
116     while(!url_feof(bc)){
117         state= (state<<8) | get_byte(bc);
118         if((state>>56) != 'N')
119             continue;
120         switch(state){
121         case MAIN_STARTCODE:
122         case STREAM_STARTCODE:
123         case SYNCPOINT_STARTCODE:
124         case INFO_STARTCODE:
125         case INDEX_STARTCODE:
126             return state;
127         }
128     }
129
130     return 0;
131 }
132
133 /**
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
138  */
139 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
140     for(;;){
141         uint64_t startcode= find_any_startcode(bc, pos);
142         if(startcode == code)
143             return url_ftell(bc) - 8;
144         else if(startcode == 0)
145             return -1;
146         pos=-1;
147     }
148 }
149
150 static int nut_probe(AVProbeData *p){
151     int i;
152     uint64_t code= 0;
153
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;
158     }
159     return 0;
160 }
161
162 #define GET_V(dst, check) \
163     tmp= ff_get_v(bc);\
164     if(!(check)){\
165         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
166         return -1;\
167     }\
168     dst= tmp;
169
170 static int skip_reserved(ByteIOContext *bc, int64_t pos){
171     pos -= url_ftell(bc);
172     if(pos<0){
173         url_fseek(bc, pos, SEEK_CUR);
174         return -1;
175     }else{
176         while(pos--)
177             get_byte(bc);
178         return 0;
179     }
180 }
181
182 static int decode_main_header(NUTContext *nut){
183     AVFormatContext *s= nut->avf;
184     ByteIOContext *bc = s->pb;
185     uint64_t tmp, end;
186     unsigned int stream_count;
187     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res;
188     int64_t tmp_match;
189
190     end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
191     end += url_ftell(bc);
192
193     GET_V(tmp              , tmp >=2 && tmp <= 3)
194     GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
195
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;
200     }
201
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));
204
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");
210             return -1;
211         }
212     }
213     tmp_pts=0;
214     tmp_mul=1;
215     tmp_stream=0;
216     tmp_match= 1-(1LL<<62);
217     for(i=0; i<256;){
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);
224         else             tmp_size  = 0;
225         if(tmp_fields>4) tmp_res   = ff_get_v(bc);
226         else             tmp_res   = 0;
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);
230
231         while(tmp_fields-- > 7)
232            ff_get_v(bc);
233
234         if(count == 0 || i+count > 256){
235             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
236             return -1;
237         }
238         if(tmp_stream >= stream_count){
239             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
240             return -1;
241         }
242
243         for(j=0; j<count; j++,i++){
244             if (i == 'N') {
245                 nut->frame_code[i].flags= FLAG_INVALID;
246                 j--;
247                 continue;
248             }
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   ;
255         }
256     }
257     assert(nut->frame_code['N'].flags == FLAG_INVALID);
258
259     if(skip_reserved(bc, end) || get_checksum(bc)){
260         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
261         return -1;
262     }
263
264     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
265     for(i=0; i<stream_count; i++){
266         av_new_stream(s, i);
267     }
268
269     return 0;
270 }
271
272 static int decode_stream_header(NUTContext *nut){
273     AVFormatContext *s= nut->avf;
274     ByteIOContext *bc = s->pb;
275     StreamContext *stc;
276     int class, stream_id;
277     uint64_t tmp, end;
278     AVStream *st;
279
280     end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
281     end += url_ftell(bc);
282
283     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
284     stc= &nut->stream[stream_id];
285
286     st = s->streams[stream_id];
287     if (!st)
288         return AVERROR(ENOMEM);
289
290     class = ff_get_v(bc);
291     tmp = get_fourcc(bc);
292     st->codec->codec_tag= tmp;
293     switch(class)
294     {
295         case 0:
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");
300             break;
301         case 1:
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");
306             break;
307         case 2:
308 //            st->codec->codec_type = CODEC_TYPE_TEXT;
309 //            break;
310         case 3:
311             st->codec->codec_type = CODEC_TYPE_DATA;
312             break;
313         default:
314             av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
315             return -1;
316     }
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
323
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);
328     }
329
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);
337             return -1;
338         }
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)
344     }
345     if(skip_reserved(bc, end) || get_checksum(bc)){
346         av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
347         return -1;
348     }
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);
351     return 0;
352 }
353
354 static int decode_info_header(NUTContext *nut){
355     AVFormatContext *s= nut->avf;
356     ByteIOContext *bc = s->pb;
357     uint64_t tmp;
358     unsigned int stream_id_plus1, chapter_start, chapter_len, count;
359     int chapter_id, i;
360     int64_t value, end;
361     char name[256], str_value[1024], type_str[256];
362     const char *type;
363
364     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
365     end += url_ftell(bc);
366
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));
374         value= get_s(bc);
375         if(value == -1){
376             type= "UTF-8";
377             get_str(bc, str_value, sizeof(str_value));
378         }else if(value == -2){
379             get_str(bc, type_str, sizeof(type_str));
380             type= type_str;
381             get_str(bc, str_value, sizeof(str_value));
382         }else if(value == -3){
383             type= "s";
384             value= get_s(bc);
385         }else if(value == -4){
386             type= "t";
387             value= ff_get_v(bc);
388         }else if(value < -4){
389             type= "r";
390             get_s(bc);
391         }else{
392             type= "v";
393         }
394
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));
404         }
405     }
406
407     if(skip_reserved(bc, end) || get_checksum(bc)){
408         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
409         return -1;
410     }
411     return 0;
412 }
413
414 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
415     AVFormatContext *s= nut->avf;
416     ByteIOContext *bc = s->pb;
417     int64_t end, tmp;
418
419     nut->last_syncpoint_pos= url_ftell(bc)-8;
420
421     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
422     end += url_ftell(bc);
423
424     tmp= ff_get_v(bc);
425     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
426     if(*back_ptr < 0)
427         return -1;
428
429     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
430
431     if(skip_reserved(bc, end) || get_checksum(bc)){
432         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
433         return -1;
434     }
435
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);
438
439     return 0;
440 }
441
442 static int find_and_decode_index(NUTContext *nut){
443     AVFormatContext *s= nut->avf;
444     ByteIOContext *bc = s->pb;
445     uint64_t tmp, end;
446     int i, j, syncpoint_count;
447     int64_t filesize= url_fsize(bc);
448     int64_t *syncpoints;
449     int8_t *has_keyframe;
450
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");
455         return -1;
456     }
457
458     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
459     end += url_ftell(bc);
460
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)
467         if(i)
468             syncpoints[i] += syncpoints[i-1];
469     }
470
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);
475             int type= x&1;
476             int n= j;
477             x>>=1;
478             if(type){
479                 int flag= x&1;
480                 x>>=1;
481                 if(n+x >= syncpoint_count + 1){
482                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
483                     return -1;
484                 }
485                 while(x--)
486                     has_keyframe[n++]= flag;
487                 has_keyframe[n++]= !flag;
488             }else{
489                 while(x != 1){
490                     if(n>=syncpoint_count + 1){
491                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
492                         return -1;
493                     }
494                     has_keyframe[n++]= x&1;
495                     x>>=1;
496                 }
497             }
498             if(has_keyframe[0]){
499                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
500                 return -1;
501             }
502             assert(n<=syncpoint_count+1);
503             for(; j<n && j<syncpoint_count; j++){
504                 if(has_keyframe[j]){
505                     uint64_t B, A= ff_get_v(bc);
506                     if(!A){
507                         A= ff_get_v(bc);
508                         B= ff_get_v(bc);
509                         //eor_pts[j][i] = last_pts + A + B
510                     }else
511                         B= 0;
512                     av_add_index_entry(
513                         s->streams[i],
514                         16*syncpoints[j-1],
515                         last_pts + A,
516                         0,
517                         0,
518                         AVINDEX_KEYFRAME);
519                     last_pts += A + B;
520                 }
521             }
522         }
523     }
524
525     if(skip_reserved(bc, end) || get_checksum(bc)){
526         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
527         return -1;
528     }
529     return 0;
530 }
531
532 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
533 {
534     NUTContext *nut = s->priv_data;
535     ByteIOContext *bc = s->pb;
536     int64_t pos;
537     int initialized_stream_count;
538
539     nut->avf= s;
540
541     /* main header */
542     pos=0;
543     do{
544         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
545         if (pos<0+1){
546             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
547             return -1;
548         }
549     }while(decode_main_header(nut) < 0);
550
551     /* stream headers */
552     pos=0;
553     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
554         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
555         if (pos<0+1){
556             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
557             return -1;
558         }
559         if(decode_stream_header(nut) >= 0)
560             initialized_stream_count++;
561     }
562
563     /* info headers */
564     pos=0;
565     for(;;){
566         uint64_t startcode= find_any_startcode(bc, pos);
567         pos= url_ftell(bc);
568
569         if(startcode==0){
570             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
571             return -1;
572         }else if(startcode == SYNCPOINT_STARTCODE){
573             nut->next_startcode= startcode;
574             break;
575         }else if(startcode != INFO_STARTCODE){
576             continue;
577         }
578
579         decode_info_header(nut);
580     }
581
582     s->data_offset= pos-8;
583
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);
588     }
589     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
590
591     return 0;
592 }
593
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;
597     StreamContext *stc;
598     int size, flags, size_mul, pts_delta, i, reserved_count;
599     uint64_t tmp;
600
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);
603         return -1;
604     }
605
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;
612
613     if(flags & FLAG_INVALID)
614         return -1;
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)
619     }
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);
626         }else
627             *pts=coded_pts - (1<<stc->msb_pts_shift);
628     }else
629         *pts= stc->last_pts + pts_delta;
630     if(flags&FLAG_SIZE_MSB){
631         size += size_mul*ff_get_v(bc);
632     }
633     if(flags&FLAG_MATCH_TIME)
634         get_s(bc);
635     if(flags&FLAG_RESERVED)
636         reserved_count= ff_get_v(bc);
637     for(i=0; i<reserved_count; i++)
638         ff_get_v(bc);
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");
643         return -1;
644     }
645
646     stc->last_pts= *pts;
647     stc->last_flags= flags;
648
649     return size;
650 }
651
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;
657     StreamContext *stc;
658
659     size= decode_frame_header(nut, &pts, &stream_id, frame_code);
660     if(size < 0)
661         return -1;
662
663     stc= &nut->stream[stream_id];
664
665     if (stc->last_flags & FLAG_KEY)
666         stc->skip_until_key_frame=0;
667
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){
674         url_fskip(bc, size);
675         return 1;
676     }
677
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;
682     pkt->pts = pts;
683
684     return 0;
685 }
686
687 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
688 {
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;
693
694     for(;;){
695         int64_t pos= url_ftell(bc);
696         uint64_t tmp= nut->next_startcode;
697         nut->next_startcode=0;
698
699         if(tmp){
700             pos-=8;
701         }else{
702             frame_code = get_byte(bc);
703             if(url_feof(bc))
704                 return -1;
705             if(frame_code == 'N'){
706                 tmp= frame_code;
707                 for(i=1; i<8; i++)
708                     tmp = (tmp<<8) + get_byte(bc);
709             }
710         }
711         switch(tmp){
712         case MAIN_STARTCODE:
713         case STREAM_STARTCODE:
714         case INDEX_STARTCODE:
715             skip= get_packetheader(nut, bc, 0, tmp);
716             url_fseek(bc, skip, SEEK_CUR);
717             break;
718         case INFO_STARTCODE:
719             if(decode_info_header(nut)<0)
720                 goto resync;
721             break;
722         case SYNCPOINT_STARTCODE:
723             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
724                 goto resync;
725             frame_code = get_byte(bc);
726         case 0:
727             ret= decode_frame(nut, pkt, frame_code);
728             if(ret==0)
729                 return 0;
730             else if(ret==1) //ok but discard packet
731                 break;
732         default:
733 resync:
734 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
735             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
736             if(tmp==0)
737                 return -1;
738 av_log(s, AV_LOG_DEBUG, "sync\n");
739             nut->next_startcode= tmp;
740         }
741     }
742 }
743
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);
749
750     pos= *pos_arg;
751     do{
752         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
753         if(pos < 1){
754             assert(nut->next_startcode == 0);
755             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
756             return AV_NOPTS_VALUE;
757         }
758     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
759     *pos_arg = pos-1;
760     assert(nut->last_syncpoint_pos == *pos_arg);
761
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;
765
766 assert(0);
767 }
768
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;
776     int i;
777
778     if(st->index_entries){
779         int index= av_index_search_timestamp(st, pts, flags);
780         if(index<0)
781             return -1;
782
783         pos2= st->index_entries[index].pos;
784         ts  = st->index_entries[index].timestamp;
785     }else{
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);
791
792         if(!(flags & AVSEEK_FLAG_BACKWARD)){
793             dummy.pos= pos+16;
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);
798             if(pos2>=0)
799                 pos= pos2;
800             //FIXME dir but i think it does not matter
801         }
802         dummy.pos= pos;
803         sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
804
805         assert(sp);
806         pos2= sp->back_ptr  - 15;
807     }
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");
814     }
815     for(i=0; i<s->nb_streams; i++)
816         nut->stream[i].skip_until_key_frame=1;
817
818     return 0;
819 }
820
821 static int nut_read_close(AVFormatContext *s)
822 {
823     NUTContext *nut = s->priv_data;
824
825     av_freep(&nut->time_base);
826     av_freep(&nut->stream);
827
828     return 0;
829 }
830
831 #ifdef CONFIG_NUT_DEMUXER
832 AVInputFormat nut_demuxer = {
833     "nut",
834     "nut format",
835     sizeof(NUTContext),
836     nut_probe,
837     nut_read_header,
838     nut_read_packet,
839     nut_read_close,
840     read_seek,
841     .extensions = "nut",
842 };
843 #endif