get rid of MAX_STREAMS limit in nutdec
[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 <strings.h>
24 #include "libavutil/avstring.h"
25 #include "libavutil/bswap.h"
26 #include "libavutil/tree.h"
27 #include "nut.h"
28
29 #undef NDEBUG
30 #include <assert.h>
31
32 #if LIBAVFORMAT_VERSION_MAJOR < 53
33 #define NUT_MAX_STREAMS MAX_STREAMS
34 #else
35 #define NUT_MAX_STREAMS 256    /* arbitrary sanity check value */
36 #endif
37
38 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
39     unsigned int len= ff_get_v(bc);
40
41     if(len && maxlen)
42         get_buffer(bc, string, FFMIN(len, maxlen));
43     while(len > maxlen){
44         get_byte(bc);
45         len--;
46     }
47
48     if(maxlen)
49         string[FFMIN(len, maxlen-1)]= 0;
50
51     if(maxlen == len)
52         return -1;
53     else
54         return 0;
55 }
56
57 static int64_t get_s(ByteIOContext *bc){
58     int64_t v = ff_get_v(bc) + 1;
59
60     if (v&1) return -(v>>1);
61     else     return  (v>>1);
62 }
63
64 static uint64_t get_fourcc(ByteIOContext *bc){
65     unsigned int len= ff_get_v(bc);
66
67     if     (len==2) return get_le16(bc);
68     else if(len==4) return get_le32(bc);
69     else            return -1;
70 }
71
72 #ifdef TRACE
73 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
74     uint64_t v= ff_get_v(bc);
75
76     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
77     return v;
78 }
79
80 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
81     int64_t v= get_s(bc);
82
83     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
84     return v;
85 }
86
87 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
88     uint64_t v= get_vb(bc);
89
90     av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
91     return v;
92 }
93 #define ff_get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
94 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
95 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
96 #endif
97
98 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
99 {
100     int64_t size;
101 //    start= url_ftell(bc) - 8;
102
103     startcode= av_be2ne64(startcode);
104     startcode= ff_crc04C11DB7_update(0, (uint8_t*)&startcode, 8);
105
106     init_checksum(bc, ff_crc04C11DB7_update, startcode);
107     size= ff_get_v(bc);
108     if(size > 4096)
109         get_be32(bc);
110     if(get_checksum(bc) && size > 4096)
111         return -1;
112
113     init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
114
115     return size;
116 }
117
118 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
119     uint64_t state=0;
120
121     if(pos >= 0)
122         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 currently are
123
124     while(!url_feof(bc)){
125         state= (state<<8) | get_byte(bc);
126         if((state>>56) != 'N')
127             continue;
128         switch(state){
129         case MAIN_STARTCODE:
130         case STREAM_STARTCODE:
131         case SYNCPOINT_STARTCODE:
132         case INFO_STARTCODE:
133         case INDEX_STARTCODE:
134             return state;
135         }
136     }
137
138     return 0;
139 }
140
141 /**
142  * Find the given startcode.
143  * @param code the startcode
144  * @param pos the start position of the search, or -1 if the current position
145  * @return the position of the startcode or -1 if not found
146  */
147 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
148     for(;;){
149         uint64_t startcode= find_any_startcode(bc, pos);
150         if(startcode == code)
151             return url_ftell(bc) - 8;
152         else if(startcode == 0)
153             return -1;
154         pos=-1;
155     }
156 }
157
158 static int nut_probe(AVProbeData *p){
159     int i;
160     uint64_t code= 0;
161
162     for (i = 0; i < p->buf_size; i++) {
163         code = (code << 8) | p->buf[i];
164         if (code == MAIN_STARTCODE)
165             return AVPROBE_SCORE_MAX;
166     }
167     return 0;
168 }
169
170 #define GET_V(dst, check) \
171     tmp= ff_get_v(bc);\
172     if(!(check)){\
173         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
174         return -1;\
175     }\
176     dst= tmp;
177
178 static int skip_reserved(ByteIOContext *bc, int64_t pos){
179     pos -= url_ftell(bc);
180     if(pos<0){
181         url_fseek(bc, pos, SEEK_CUR);
182         return -1;
183     }else{
184         while(pos--)
185             get_byte(bc);
186         return 0;
187     }
188 }
189
190 static int decode_main_header(NUTContext *nut){
191     AVFormatContext *s= nut->avf;
192     ByteIOContext *bc = s->pb;
193     uint64_t tmp, end;
194     unsigned int stream_count;
195     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res, tmp_head_idx;
196     int64_t tmp_match;
197
198     end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
199     end += url_ftell(bc);
200
201     GET_V(tmp              , tmp >=2 && tmp <= 3)
202     GET_V(stream_count     , tmp > 0 && tmp <= NUT_MAX_STREAMS)
203
204     nut->max_distance = ff_get_v(bc);
205     if(nut->max_distance > 65536){
206         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
207         nut->max_distance= 65536;
208     }
209
210     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
211     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
212
213     for(i=0; i<nut->time_base_count; i++){
214         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
215         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
216         if(av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
217             av_log(s, AV_LOG_ERROR, "time base invalid\n");
218             return -1;
219         }
220     }
221     tmp_pts=0;
222     tmp_mul=1;
223     tmp_stream=0;
224     tmp_match= 1-(1LL<<62);
225     tmp_head_idx= 0;
226     for(i=0; i<256;){
227         int tmp_flags = ff_get_v(bc);
228         int tmp_fields= ff_get_v(bc);
229         if(tmp_fields>0) tmp_pts   = get_s(bc);
230         if(tmp_fields>1) tmp_mul   = ff_get_v(bc);
231         if(tmp_fields>2) tmp_stream= ff_get_v(bc);
232         if(tmp_fields>3) tmp_size  = ff_get_v(bc);
233         else             tmp_size  = 0;
234         if(tmp_fields>4) tmp_res   = ff_get_v(bc);
235         else             tmp_res   = 0;
236         if(tmp_fields>5) count     = ff_get_v(bc);
237         else             count     = tmp_mul - tmp_size;
238         if(tmp_fields>6) tmp_match = get_s(bc);
239         if(tmp_fields>7) tmp_head_idx= ff_get_v(bc);
240
241         while(tmp_fields-- > 8)
242            ff_get_v(bc);
243
244         if(count == 0 || i+count > 256){
245             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
246             return -1;
247         }
248         if(tmp_stream >= stream_count){
249             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
250             return -1;
251         }
252
253         for(j=0; j<count; j++,i++){
254             if (i == 'N') {
255                 nut->frame_code[i].flags= FLAG_INVALID;
256                 j--;
257                 continue;
258             }
259             nut->frame_code[i].flags           = tmp_flags ;
260             nut->frame_code[i].pts_delta       = tmp_pts   ;
261             nut->frame_code[i].stream_id       = tmp_stream;
262             nut->frame_code[i].size_mul        = tmp_mul   ;
263             nut->frame_code[i].size_lsb        = tmp_size+j;
264             nut->frame_code[i].reserved_count  = tmp_res   ;
265             nut->frame_code[i].header_idx      = tmp_head_idx;
266         }
267     }
268     assert(nut->frame_code['N'].flags == FLAG_INVALID);
269
270     if(end > url_ftell(bc) + 4){
271         int rem= 1024;
272         GET_V(nut->header_count, tmp<128U)
273         nut->header_count++;
274         for(i=1; i<nut->header_count; i++){
275             GET_V(nut->header_len[i], tmp>0 && tmp<256);
276             rem -= nut->header_len[i];
277             if(rem < 0){
278                 av_log(s, AV_LOG_ERROR, "invalid elision header\n");
279                 return -1;
280             }
281             nut->header[i]= av_malloc(nut->header_len[i]);
282             get_buffer(bc, nut->header[i], nut->header_len[i]);
283         }
284         assert(nut->header_len[0]==0);
285     }
286
287     if(skip_reserved(bc, end) || get_checksum(bc)){
288         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
289         return -1;
290     }
291
292     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
293     for(i=0; i<stream_count; i++){
294         av_new_stream(s, i);
295     }
296
297     return 0;
298 }
299
300 static int decode_stream_header(NUTContext *nut){
301     AVFormatContext *s= nut->avf;
302     ByteIOContext *bc = s->pb;
303     StreamContext *stc;
304     int class, stream_id;
305     uint64_t tmp, end;
306     AVStream *st;
307
308     end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
309     end += url_ftell(bc);
310
311     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
312     stc= &nut->stream[stream_id];
313
314     st = s->streams[stream_id];
315     if (!st)
316         return AVERROR(ENOMEM);
317
318     class = ff_get_v(bc);
319     tmp = get_fourcc(bc);
320     st->codec->codec_tag= tmp;
321     switch(class)
322     {
323         case 0:
324             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
325             st->codec->codec_id = av_codec_get_id(
326                 (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, 0 },
327                 tmp);
328             break;
329         case 1:
330             st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
331             st->codec->codec_id = ff_codec_get_id(ff_codec_wav_tags, tmp);
332             break;
333         case 2:
334             st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
335             st->codec->codec_id = ff_codec_get_id(ff_nut_subtitle_tags, tmp);
336             break;
337         case 3:
338             st->codec->codec_type = AVMEDIA_TYPE_DATA;
339             break;
340         default:
341             av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
342             return -1;
343     }
344     if(class<3 && st->codec->codec_id == CODEC_ID_NONE)
345         av_log(s, AV_LOG_ERROR, "Unknown codec tag '0x%04x' for stream number %d\n",
346                (unsigned int)tmp, stream_id);
347
348     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
349     GET_V(stc->msb_pts_shift   , tmp < 16);
350     stc->max_pts_distance= ff_get_v(bc);
351     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if Moore's law is true
352     st->codec->has_b_frames= stc->decode_delay;
353     ff_get_v(bc); //stream flags
354
355     GET_V(st->codec->extradata_size, tmp < (1<<30));
356     if(st->codec->extradata_size){
357         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
358         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
359     }
360
361     if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
362         GET_V(st->codec->width , tmp > 0)
363         GET_V(st->codec->height, tmp > 0)
364         st->sample_aspect_ratio.num= ff_get_v(bc);
365         st->sample_aspect_ratio.den= ff_get_v(bc);
366         if((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)){
367             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
368             return -1;
369         }
370         ff_get_v(bc); /* csp type */
371     }else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO){
372         GET_V(st->codec->sample_rate , tmp > 0)
373         ff_get_v(bc); // samplerate_den
374         GET_V(st->codec->channels, tmp > 0)
375     }
376     if(skip_reserved(bc, end) || get_checksum(bc)){
377         av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
378         return -1;
379     }
380     stc->time_base= &nut->time_base[stc->time_base_id];
381     av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
382     return 0;
383 }
384
385 static void set_disposition_bits(AVFormatContext* avf, char* value, int stream_id){
386     int flag = 0, i;
387     for (i=0; ff_nut_dispositions[i].flag; ++i) {
388         if (!strcmp(ff_nut_dispositions[i].str, value))
389             flag = ff_nut_dispositions[i].flag;
390     }
391     if (!flag)
392         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
393     for (i = 0; i < avf->nb_streams; ++i)
394         if (stream_id == i || stream_id == -1)
395             avf->streams[i]->disposition |= flag;
396 }
397
398 static int decode_info_header(NUTContext *nut){
399     AVFormatContext *s= nut->avf;
400     ByteIOContext *bc = s->pb;
401     uint64_t tmp, chapter_start, chapter_len;
402     unsigned int stream_id_plus1, count;
403     int chapter_id, i;
404     int64_t value, end;
405     char name[256], str_value[1024], type_str[256];
406     const char *type;
407     AVChapter *chapter= NULL;
408     AVStream *st= NULL;
409
410     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
411     end += url_ftell(bc);
412
413     GET_V(stream_id_plus1, tmp <= s->nb_streams)
414     chapter_id   = get_s(bc);
415     chapter_start= ff_get_v(bc);
416     chapter_len  = ff_get_v(bc);
417     count        = ff_get_v(bc);
418
419     if(chapter_id && !stream_id_plus1){
420         int64_t start= chapter_start / nut->time_base_count;
421         chapter= ff_new_chapter(s, chapter_id,
422                                 nut->time_base[chapter_start % nut->time_base_count],
423                                 start, start + chapter_len, NULL);
424     } else if(stream_id_plus1)
425         st= s->streams[stream_id_plus1 - 1];
426
427     for(i=0; i<count; i++){
428         get_str(bc, name, sizeof(name));
429         value= get_s(bc);
430         if(value == -1){
431             type= "UTF-8";
432             get_str(bc, str_value, sizeof(str_value));
433         }else if(value == -2){
434             get_str(bc, type_str, sizeof(type_str));
435             type= type_str;
436             get_str(bc, str_value, sizeof(str_value));
437         }else if(value == -3){
438             type= "s";
439             value= get_s(bc);
440         }else if(value == -4){
441             type= "t";
442             value= ff_get_v(bc);
443         }else if(value < -4){
444             type= "r";
445             get_s(bc);
446         }else{
447             type= "v";
448         }
449
450         if (stream_id_plus1 > s->nb_streams) {
451             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
452             continue;
453         }
454
455         if(!strcmp(type, "UTF-8")){
456             AVMetadata **metadata = NULL;
457             if(chapter_id==0 && !strcmp(name, "Disposition"))
458                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
459             else if(chapter)          metadata= &chapter->metadata;
460             else if(stream_id_plus1)  metadata= &st->metadata;
461             else                      metadata= &s->metadata;
462             if(metadata && strcasecmp(name,"Uses")
463                && strcasecmp(name,"Depends") && strcasecmp(name,"Replaces"))
464                 av_metadata_set2(metadata, name, str_value, 0);
465         }
466     }
467
468     if(skip_reserved(bc, end) || get_checksum(bc)){
469         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
470         return -1;
471     }
472     return 0;
473 }
474
475 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
476     AVFormatContext *s= nut->avf;
477     ByteIOContext *bc = s->pb;
478     int64_t end, tmp;
479
480     nut->last_syncpoint_pos= url_ftell(bc)-8;
481
482     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
483     end += url_ftell(bc);
484
485     tmp= ff_get_v(bc);
486     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
487     if(*back_ptr < 0)
488         return -1;
489
490     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
491
492     if(skip_reserved(bc, end) || get_checksum(bc)){
493         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
494         return -1;
495     }
496
497     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
498     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
499
500     return 0;
501 }
502
503 static int find_and_decode_index(NUTContext *nut){
504     AVFormatContext *s= nut->avf;
505     ByteIOContext *bc = s->pb;
506     uint64_t tmp, end;
507     int i, j, syncpoint_count;
508     int64_t filesize= url_fsize(bc);
509     int64_t *syncpoints;
510     int8_t *has_keyframe;
511     int ret= -1;
512
513     url_fseek(bc, filesize-12, SEEK_SET);
514     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
515     if(get_be64(bc) != INDEX_STARTCODE){
516         av_log(s, AV_LOG_ERROR, "no index at the end\n");
517         return -1;
518     }
519
520     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
521     end += url_ftell(bc);
522
523     ff_get_v(bc); //max_pts
524     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
525     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
526     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
527     for(i=0; i<syncpoint_count; i++){
528         syncpoints[i] = ff_get_v(bc);
529         if(syncpoints[i] <= 0)
530             goto fail;
531         if(i)
532             syncpoints[i] += syncpoints[i-1];
533     }
534
535     for(i=0; i<s->nb_streams; i++){
536         int64_t last_pts= -1;
537         for(j=0; j<syncpoint_count;){
538             uint64_t x= ff_get_v(bc);
539             int type= x&1;
540             int n= j;
541             x>>=1;
542             if(type){
543                 int flag= x&1;
544                 x>>=1;
545                 if(n+x >= syncpoint_count + 1){
546                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
547                     goto fail;
548                 }
549                 while(x--)
550                     has_keyframe[n++]= flag;
551                 has_keyframe[n++]= !flag;
552             }else{
553                 while(x != 1){
554                     if(n>=syncpoint_count + 1){
555                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
556                         goto fail;
557                     }
558                     has_keyframe[n++]= x&1;
559                     x>>=1;
560                 }
561             }
562             if(has_keyframe[0]){
563                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
564                 goto fail;
565             }
566             assert(n<=syncpoint_count+1);
567             for(; j<n && j<syncpoint_count; j++){
568                 if(has_keyframe[j]){
569                     uint64_t B, A= ff_get_v(bc);
570                     if(!A){
571                         A= ff_get_v(bc);
572                         B= ff_get_v(bc);
573                         //eor_pts[j][i] = last_pts + A + B
574                     }else
575                         B= 0;
576                     av_add_index_entry(
577                         s->streams[i],
578                         16*syncpoints[j-1],
579                         last_pts + A,
580                         0,
581                         0,
582                         AVINDEX_KEYFRAME);
583                     last_pts += A + B;
584                 }
585             }
586         }
587     }
588
589     if(skip_reserved(bc, end) || get_checksum(bc)){
590         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
591         goto fail;
592     }
593     ret= 0;
594 fail:
595     av_free(syncpoints);
596     av_free(has_keyframe);
597     return ret;
598 }
599
600 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
601 {
602     NUTContext *nut = s->priv_data;
603     ByteIOContext *bc = s->pb;
604     int64_t pos;
605     int initialized_stream_count;
606
607     nut->avf= s;
608
609     /* main header */
610     pos=0;
611     do{
612         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
613         if (pos<0+1){
614             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
615             return -1;
616         }
617     }while(decode_main_header(nut) < 0);
618
619     /* stream headers */
620     pos=0;
621     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
622         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
623         if (pos<0+1){
624             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
625             return -1;
626         }
627         if(decode_stream_header(nut) >= 0)
628             initialized_stream_count++;
629     }
630
631     /* info headers */
632     pos=0;
633     for(;;){
634         uint64_t startcode= find_any_startcode(bc, pos);
635         pos= url_ftell(bc);
636
637         if(startcode==0){
638             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
639             return -1;
640         }else if(startcode == SYNCPOINT_STARTCODE){
641             nut->next_startcode= startcode;
642             break;
643         }else if(startcode != INFO_STARTCODE){
644             continue;
645         }
646
647         decode_info_header(nut);
648     }
649
650     s->data_offset= pos-8;
651
652     if(!url_is_streamed(bc)){
653         int64_t orig_pos= url_ftell(bc);
654         find_and_decode_index(nut);
655         url_fseek(bc, orig_pos, SEEK_SET);
656     }
657     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
658
659     return 0;
660 }
661
662 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, uint8_t *header_idx, int frame_code){
663     AVFormatContext *s= nut->avf;
664     ByteIOContext *bc = s->pb;
665     StreamContext *stc;
666     int size, flags, size_mul, pts_delta, i, reserved_count;
667     uint64_t tmp;
668
669     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
670         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);
671         return -1;
672     }
673
674     flags          = nut->frame_code[frame_code].flags;
675     size_mul       = nut->frame_code[frame_code].size_mul;
676     size           = nut->frame_code[frame_code].size_lsb;
677     *stream_id     = nut->frame_code[frame_code].stream_id;
678     pts_delta      = nut->frame_code[frame_code].pts_delta;
679     reserved_count = nut->frame_code[frame_code].reserved_count;
680     *header_idx    = nut->frame_code[frame_code].header_idx;
681
682     if(flags & FLAG_INVALID)
683         return -1;
684     if(flags & FLAG_CODED)
685         flags ^= ff_get_v(bc);
686     if(flags & FLAG_STREAM_ID){
687         GET_V(*stream_id, tmp < s->nb_streams)
688     }
689     stc= &nut->stream[*stream_id];
690     if(flags&FLAG_CODED_PTS){
691         int coded_pts= ff_get_v(bc);
692 //FIXME check last_pts validity?
693         if(coded_pts < (1<<stc->msb_pts_shift)){
694             *pts=ff_lsb2full(stc, coded_pts);
695         }else
696             *pts=coded_pts - (1<<stc->msb_pts_shift);
697     }else
698         *pts= stc->last_pts + pts_delta;
699     if(flags&FLAG_SIZE_MSB){
700         size += size_mul*ff_get_v(bc);
701     }
702     if(flags&FLAG_MATCH_TIME)
703         get_s(bc);
704     if(flags&FLAG_HEADER_IDX)
705         *header_idx= ff_get_v(bc);
706     if(flags&FLAG_RESERVED)
707         reserved_count= ff_get_v(bc);
708     for(i=0; i<reserved_count; i++)
709         ff_get_v(bc);
710
711     if(*header_idx >= (unsigned)nut->header_count){
712         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
713         return -1;
714     }
715     if(size > 4096)
716         *header_idx=0;
717     size -= nut->header_len[*header_idx];
718
719     if(flags&FLAG_CHECKSUM){
720         get_be32(bc); //FIXME check this
721     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
722         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
723         return -1;
724     }
725
726     stc->last_pts= *pts;
727     stc->last_flags= flags;
728
729     return size;
730 }
731
732 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
733     AVFormatContext *s= nut->avf;
734     ByteIOContext *bc = s->pb;
735     int size, stream_id, discard;
736     int64_t pts, last_IP_pts;
737     StreamContext *stc;
738     uint8_t header_idx;
739
740     size= decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
741     if(size < 0)
742         return -1;
743
744     stc= &nut->stream[stream_id];
745
746     if (stc->last_flags & FLAG_KEY)
747         stc->skip_until_key_frame=0;
748
749     discard= s->streams[ stream_id ]->discard;
750     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
751     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
752        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
753        || discard >= AVDISCARD_ALL
754        || stc->skip_until_key_frame){
755         url_fskip(bc, size);
756         return 1;
757     }
758
759     av_new_packet(pkt, size + nut->header_len[header_idx]);
760     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
761     pkt->pos= url_ftell(bc); //FIXME
762     get_buffer(bc, pkt->data + nut->header_len[header_idx], size);
763
764     pkt->stream_index = stream_id;
765     if (stc->last_flags & FLAG_KEY)
766         pkt->flags |= AV_PKT_FLAG_KEY;
767     pkt->pts = pts;
768
769     return 0;
770 }
771
772 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
773 {
774     NUTContext *nut = s->priv_data;
775     ByteIOContext *bc = s->pb;
776     int i, frame_code=0, ret, skip;
777     int64_t ts, back_ptr;
778
779     for(;;){
780         int64_t pos= url_ftell(bc);
781         uint64_t tmp= nut->next_startcode;
782         nut->next_startcode=0;
783
784         if(tmp){
785             pos-=8;
786         }else{
787             frame_code = get_byte(bc);
788             if(url_feof(bc))
789                 return -1;
790             if(frame_code == 'N'){
791                 tmp= frame_code;
792                 for(i=1; i<8; i++)
793                     tmp = (tmp<<8) + get_byte(bc);
794             }
795         }
796         switch(tmp){
797         case MAIN_STARTCODE:
798         case STREAM_STARTCODE:
799         case INDEX_STARTCODE:
800             skip= get_packetheader(nut, bc, 0, tmp);
801             url_fseek(bc, skip, SEEK_CUR);
802             break;
803         case INFO_STARTCODE:
804             if(decode_info_header(nut)<0)
805                 goto resync;
806             break;
807         case SYNCPOINT_STARTCODE:
808             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
809                 goto resync;
810             frame_code = get_byte(bc);
811         case 0:
812             ret= decode_frame(nut, pkt, frame_code);
813             if(ret==0)
814                 return 0;
815             else if(ret==1) //ok but discard packet
816                 break;
817         default:
818 resync:
819 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
820             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
821             if(tmp==0)
822                 return -1;
823 av_log(s, AV_LOG_DEBUG, "sync\n");
824             nut->next_startcode= tmp;
825         }
826     }
827 }
828
829 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
830     NUTContext *nut = s->priv_data;
831     ByteIOContext *bc = s->pb;
832     int64_t pos, pts, back_ptr;
833 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
834
835     pos= *pos_arg;
836     do{
837         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
838         if(pos < 1){
839             assert(nut->next_startcode == 0);
840             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
841             return AV_NOPTS_VALUE;
842         }
843     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
844     *pos_arg = pos-1;
845     assert(nut->last_syncpoint_pos == *pos_arg);
846
847     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
848     if     (stream_index == -1) return pts;
849     else if(stream_index == -2) return back_ptr;
850
851 assert(0);
852 }
853
854 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
855     NUTContext *nut = s->priv_data;
856     AVStream *st= s->streams[stream_index];
857     Syncpoint dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
858     Syncpoint nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
859     Syncpoint *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
860     int64_t pos, pos2, ts;
861     int i;
862
863     if(st->index_entries){
864         int index= av_index_search_timestamp(st, pts, flags);
865         if(index<0)
866             return -1;
867
868         pos2= st->index_entries[index].pos;
869         ts  = st->index_entries[index].timestamp;
870     }else{
871         av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pts_cmp,
872                      (void **) next_node);
873         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
874                                                     next_node[0]->ts , next_node[1]->ts);
875         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
876                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
877
878         if(!(flags & AVSEEK_FLAG_BACKWARD)){
879             dummy.pos= pos+16;
880             next_node[1]= &nopts_sp;
881             av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
882                          (void **) next_node);
883             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
884                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
885             if(pos2>=0)
886                 pos= pos2;
887             //FIXME dir but I think it does not matter
888         }
889         dummy.pos= pos;
890         sp= av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
891                          NULL);
892
893         assert(sp);
894         pos2= sp->back_ptr  - 15;
895     }
896     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
897     pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
898     url_fseek(s->pb, pos, SEEK_SET);
899     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
900     if(pos2 > pos || pos2 + 15 < pos){
901         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
902     }
903     for(i=0; i<s->nb_streams; i++)
904         nut->stream[i].skip_until_key_frame=1;
905
906     return 0;
907 }
908
909 static int nut_read_close(AVFormatContext *s)
910 {
911     NUTContext *nut = s->priv_data;
912     int i;
913
914     av_freep(&nut->time_base);
915     av_freep(&nut->stream);
916     ff_nut_free_sp(nut);
917     for(i = 1; i < nut->header_count; i++)
918         av_freep(&nut->header[i]);
919
920     return 0;
921 }
922
923 #if CONFIG_NUT_DEMUXER
924 AVInputFormat nut_demuxer = {
925     "nut",
926     NULL_IF_CONFIG_SMALL("NUT format"),
927     sizeof(NUTContext),
928     nut_probe,
929     nut_read_header,
930     nut_read_packet,
931     nut_read_close,
932     read_seek,
933     .extensions = "nut",
934     .metadata_conv = ff_nut_metadata_conv,
935     .codec_tag = (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, ff_codec_wav_tags, ff_nut_subtitle_tags, 0 },
936 };
937 #endif