avio: avio_ prefix for url_fseek
[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 FF_API_MAX_STREAMS
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(AVIOContext *bc, char *string, unsigned int maxlen){
39     unsigned int len= ff_get_v(bc);
40
41     if(len && maxlen)
42         avio_read(bc, string, FFMIN(len, maxlen));
43     while(len > maxlen){
44         avio_r8(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(AVIOContext *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(AVIOContext *bc){
65     unsigned int len= ff_get_v(bc);
66
67     if     (len==2) return avio_rl16(bc);
68     else if(len==4) return avio_rl32(bc);
69     else            return -1;
70 }
71
72 #ifdef TRACE
73 static inline uint64_t get_v_trace(AVIOContext *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(AVIOContext *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(AVIOContext *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, AVIOContext *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         avio_rb32(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(AVIOContext *bc, int64_t pos){
119     uint64_t state=0;
120
121     if(pos >= 0)
122         avio_seek(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) | avio_r8(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(AVIOContext *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(AVIOContext *bc, int64_t pos){
179     pos -= url_ftell(bc);
180     if(pos<0){
181         avio_seek(bc, pos, SEEK_CUR);
182         return -1;
183     }else{
184         while(pos--)
185             avio_r8(bc);
186         return 0;
187     }
188 }
189
190 static int decode_main_header(NUTContext *nut){
191     AVFormatContext *s= nut->avf;
192     AVIOContext *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 AVERROR_INVALIDDATA;
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 AVERROR_INVALIDDATA;
247         }
248         if(tmp_stream >= stream_count){
249             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
250             return AVERROR_INVALIDDATA;
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 AVERROR_INVALIDDATA;
280             }
281             nut->header[i]= av_malloc(nut->header_len[i]);
282             avio_read(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 AVERROR_INVALIDDATA;
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     AVIOContext *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         avio_read(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     AVIOContext *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     AVMetadata **metadata = NULL;
410
411     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
412     end += url_ftell(bc);
413
414     GET_V(stream_id_plus1, tmp <= s->nb_streams)
415     chapter_id   = get_s(bc);
416     chapter_start= ff_get_v(bc);
417     chapter_len  = ff_get_v(bc);
418     count        = ff_get_v(bc);
419
420     if(chapter_id && !stream_id_plus1){
421         int64_t start= chapter_start / nut->time_base_count;
422         chapter= ff_new_chapter(s, chapter_id,
423                                 nut->time_base[chapter_start % nut->time_base_count],
424                                 start, start + chapter_len, NULL);
425         metadata = &chapter->metadata;
426     } else if(stream_id_plus1) {
427         st= s->streams[stream_id_plus1 - 1];
428         metadata = &st->metadata;
429     } else
430         metadata = &s->metadata;
431
432     for(i=0; i<count; i++){
433         get_str(bc, name, sizeof(name));
434         value= get_s(bc);
435         if(value == -1){
436             type= "UTF-8";
437             get_str(bc, str_value, sizeof(str_value));
438         }else if(value == -2){
439             get_str(bc, type_str, sizeof(type_str));
440             type= type_str;
441             get_str(bc, str_value, sizeof(str_value));
442         }else if(value == -3){
443             type= "s";
444             value= get_s(bc);
445         }else if(value == -4){
446             type= "t";
447             value= ff_get_v(bc);
448         }else if(value < -4){
449             type= "r";
450             get_s(bc);
451         }else{
452             type= "v";
453         }
454
455         if (stream_id_plus1 > s->nb_streams) {
456             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
457             continue;
458         }
459
460         if(!strcmp(type, "UTF-8")){
461             if(chapter_id==0 && !strcmp(name, "Disposition")) {
462                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
463                 continue;
464             }
465             if(metadata && strcasecmp(name,"Uses")
466                && strcasecmp(name,"Depends") && strcasecmp(name,"Replaces"))
467                 av_metadata_set2(metadata, name, str_value, 0);
468         }
469     }
470
471     if(skip_reserved(bc, end) || get_checksum(bc)){
472         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
473         return -1;
474     }
475     return 0;
476 }
477
478 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
479     AVFormatContext *s= nut->avf;
480     AVIOContext *bc = s->pb;
481     int64_t end, tmp;
482
483     nut->last_syncpoint_pos= url_ftell(bc)-8;
484
485     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
486     end += url_ftell(bc);
487
488     tmp= ff_get_v(bc);
489     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
490     if(*back_ptr < 0)
491         return -1;
492
493     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
494
495     if(skip_reserved(bc, end) || get_checksum(bc)){
496         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
497         return -1;
498     }
499
500     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
501     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
502
503     return 0;
504 }
505
506 static int find_and_decode_index(NUTContext *nut){
507     AVFormatContext *s= nut->avf;
508     AVIOContext *bc = s->pb;
509     uint64_t tmp, end;
510     int i, j, syncpoint_count;
511     int64_t filesize= url_fsize(bc);
512     int64_t *syncpoints;
513     int8_t *has_keyframe;
514     int ret= -1;
515
516     avio_seek(bc, filesize-12, SEEK_SET);
517     avio_seek(bc, filesize-avio_rb64(bc), SEEK_SET);
518     if(avio_rb64(bc) != INDEX_STARTCODE){
519         av_log(s, AV_LOG_ERROR, "no index at the end\n");
520         return -1;
521     }
522
523     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
524     end += url_ftell(bc);
525
526     ff_get_v(bc); //max_pts
527     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
528     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
529     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
530     for(i=0; i<syncpoint_count; i++){
531         syncpoints[i] = ff_get_v(bc);
532         if(syncpoints[i] <= 0)
533             goto fail;
534         if(i)
535             syncpoints[i] += syncpoints[i-1];
536     }
537
538     for(i=0; i<s->nb_streams; i++){
539         int64_t last_pts= -1;
540         for(j=0; j<syncpoint_count;){
541             uint64_t x= ff_get_v(bc);
542             int type= x&1;
543             int n= j;
544             x>>=1;
545             if(type){
546                 int flag= x&1;
547                 x>>=1;
548                 if(n+x >= syncpoint_count + 1){
549                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
550                     goto fail;
551                 }
552                 while(x--)
553                     has_keyframe[n++]= flag;
554                 has_keyframe[n++]= !flag;
555             }else{
556                 while(x != 1){
557                     if(n>=syncpoint_count + 1){
558                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
559                         goto fail;
560                     }
561                     has_keyframe[n++]= x&1;
562                     x>>=1;
563                 }
564             }
565             if(has_keyframe[0]){
566                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
567                 goto fail;
568             }
569             assert(n<=syncpoint_count+1);
570             for(; j<n && j<syncpoint_count; j++){
571                 if(has_keyframe[j]){
572                     uint64_t B, A= ff_get_v(bc);
573                     if(!A){
574                         A= ff_get_v(bc);
575                         B= ff_get_v(bc);
576                         //eor_pts[j][i] = last_pts + A + B
577                     }else
578                         B= 0;
579                     av_add_index_entry(
580                         s->streams[i],
581                         16*syncpoints[j-1],
582                         last_pts + A,
583                         0,
584                         0,
585                         AVINDEX_KEYFRAME);
586                     last_pts += A + B;
587                 }
588             }
589         }
590     }
591
592     if(skip_reserved(bc, end) || get_checksum(bc)){
593         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
594         goto fail;
595     }
596     ret= 0;
597 fail:
598     av_free(syncpoints);
599     av_free(has_keyframe);
600     return ret;
601 }
602
603 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
604 {
605     NUTContext *nut = s->priv_data;
606     AVIOContext *bc = s->pb;
607     int64_t pos;
608     int initialized_stream_count;
609
610     nut->avf= s;
611
612     /* main header */
613     pos=0;
614     do{
615         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
616         if (pos<0+1){
617             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
618             return AVERROR_INVALIDDATA;
619         }
620     }while(decode_main_header(nut) < 0);
621
622     /* stream headers */
623     pos=0;
624     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
625         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
626         if (pos<0+1){
627             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
628             return AVERROR_INVALIDDATA;
629         }
630         if(decode_stream_header(nut) >= 0)
631             initialized_stream_count++;
632     }
633
634     /* info headers */
635     pos=0;
636     for(;;){
637         uint64_t startcode= find_any_startcode(bc, pos);
638         pos= url_ftell(bc);
639
640         if(startcode==0){
641             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
642             return AVERROR_INVALIDDATA;
643         }else if(startcode == SYNCPOINT_STARTCODE){
644             nut->next_startcode= startcode;
645             break;
646         }else if(startcode != INFO_STARTCODE){
647             continue;
648         }
649
650         decode_info_header(nut);
651     }
652
653     s->data_offset= pos-8;
654
655     if(!url_is_streamed(bc)){
656         int64_t orig_pos= url_ftell(bc);
657         find_and_decode_index(nut);
658         avio_seek(bc, orig_pos, SEEK_SET);
659     }
660     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
661
662     ff_metadata_conv_ctx(s, NULL, ff_nut_metadata_conv);
663
664     return 0;
665 }
666
667 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, uint8_t *header_idx, int frame_code){
668     AVFormatContext *s= nut->avf;
669     AVIOContext *bc = s->pb;
670     StreamContext *stc;
671     int size, flags, size_mul, pts_delta, i, reserved_count;
672     uint64_t tmp;
673
674     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
675         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);
676         return AVERROR_INVALIDDATA;
677     }
678
679     flags          = nut->frame_code[frame_code].flags;
680     size_mul       = nut->frame_code[frame_code].size_mul;
681     size           = nut->frame_code[frame_code].size_lsb;
682     *stream_id     = nut->frame_code[frame_code].stream_id;
683     pts_delta      = nut->frame_code[frame_code].pts_delta;
684     reserved_count = nut->frame_code[frame_code].reserved_count;
685     *header_idx    = nut->frame_code[frame_code].header_idx;
686
687     if(flags & FLAG_INVALID)
688         return AVERROR_INVALIDDATA;
689     if(flags & FLAG_CODED)
690         flags ^= ff_get_v(bc);
691     if(flags & FLAG_STREAM_ID){
692         GET_V(*stream_id, tmp < s->nb_streams)
693     }
694     stc= &nut->stream[*stream_id];
695     if(flags&FLAG_CODED_PTS){
696         int coded_pts= ff_get_v(bc);
697 //FIXME check last_pts validity?
698         if(coded_pts < (1<<stc->msb_pts_shift)){
699             *pts=ff_lsb2full(stc, coded_pts);
700         }else
701             *pts=coded_pts - (1<<stc->msb_pts_shift);
702     }else
703         *pts= stc->last_pts + pts_delta;
704     if(flags&FLAG_SIZE_MSB){
705         size += size_mul*ff_get_v(bc);
706     }
707     if(flags&FLAG_MATCH_TIME)
708         get_s(bc);
709     if(flags&FLAG_HEADER_IDX)
710         *header_idx= ff_get_v(bc);
711     if(flags&FLAG_RESERVED)
712         reserved_count= ff_get_v(bc);
713     for(i=0; i<reserved_count; i++)
714         ff_get_v(bc);
715
716     if(*header_idx >= (unsigned)nut->header_count){
717         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
718         return AVERROR_INVALIDDATA;
719     }
720     if(size > 4096)
721         *header_idx=0;
722     size -= nut->header_len[*header_idx];
723
724     if(flags&FLAG_CHECKSUM){
725         avio_rb32(bc); //FIXME check this
726     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
727         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
728         return AVERROR_INVALIDDATA;
729     }
730
731     stc->last_pts= *pts;
732     stc->last_flags= flags;
733
734     return size;
735 }
736
737 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
738     AVFormatContext *s= nut->avf;
739     AVIOContext *bc = s->pb;
740     int size, stream_id, discard;
741     int64_t pts, last_IP_pts;
742     StreamContext *stc;
743     uint8_t header_idx;
744
745     size= decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
746     if(size < 0)
747         return size;
748
749     stc= &nut->stream[stream_id];
750
751     if (stc->last_flags & FLAG_KEY)
752         stc->skip_until_key_frame=0;
753
754     discard= s->streams[ stream_id ]->discard;
755     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
756     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
757        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
758        || discard >= AVDISCARD_ALL
759        || stc->skip_until_key_frame){
760         url_fskip(bc, size);
761         return 1;
762     }
763
764     av_new_packet(pkt, size + nut->header_len[header_idx]);
765     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
766     pkt->pos= url_ftell(bc); //FIXME
767     avio_read(bc, pkt->data + nut->header_len[header_idx], size);
768
769     pkt->stream_index = stream_id;
770     if (stc->last_flags & FLAG_KEY)
771         pkt->flags |= AV_PKT_FLAG_KEY;
772     pkt->pts = pts;
773
774     return 0;
775 }
776
777 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
778 {
779     NUTContext *nut = s->priv_data;
780     AVIOContext *bc = s->pb;
781     int i, frame_code=0, ret, skip;
782     int64_t ts, back_ptr;
783
784     for(;;){
785         int64_t pos= url_ftell(bc);
786         uint64_t tmp= nut->next_startcode;
787         nut->next_startcode=0;
788
789         if(tmp){
790             pos-=8;
791         }else{
792             frame_code = avio_r8(bc);
793             if(url_feof(bc))
794                 return -1;
795             if(frame_code == 'N'){
796                 tmp= frame_code;
797                 for(i=1; i<8; i++)
798                     tmp = (tmp<<8) + avio_r8(bc);
799             }
800         }
801         switch(tmp){
802         case MAIN_STARTCODE:
803         case STREAM_STARTCODE:
804         case INDEX_STARTCODE:
805             skip= get_packetheader(nut, bc, 0, tmp);
806             avio_seek(bc, skip, SEEK_CUR);
807             break;
808         case INFO_STARTCODE:
809             if(decode_info_header(nut)<0)
810                 goto resync;
811             break;
812         case SYNCPOINT_STARTCODE:
813             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
814                 goto resync;
815             frame_code = avio_r8(bc);
816         case 0:
817             ret= decode_frame(nut, pkt, frame_code);
818             if(ret==0)
819                 return 0;
820             else if(ret==1) //ok but discard packet
821                 break;
822         default:
823 resync:
824 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
825             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
826             if(tmp==0)
827                 return AVERROR_INVALIDDATA;
828 av_log(s, AV_LOG_DEBUG, "sync\n");
829             nut->next_startcode= tmp;
830         }
831     }
832 }
833
834 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
835     NUTContext *nut = s->priv_data;
836     AVIOContext *bc = s->pb;
837     int64_t pos, pts, back_ptr;
838 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
839
840     pos= *pos_arg;
841     do{
842         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
843         if(pos < 1){
844             assert(nut->next_startcode == 0);
845             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
846             return AV_NOPTS_VALUE;
847         }
848     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
849     *pos_arg = pos-1;
850     assert(nut->last_syncpoint_pos == *pos_arg);
851
852     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
853     if     (stream_index == -1) return pts;
854     else if(stream_index == -2) return back_ptr;
855
856 assert(0);
857 }
858
859 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
860     NUTContext *nut = s->priv_data;
861     AVStream *st= s->streams[stream_index];
862     Syncpoint dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
863     Syncpoint nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
864     Syncpoint *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
865     int64_t pos, pos2, ts;
866     int i;
867
868     if(st->index_entries){
869         int index= av_index_search_timestamp(st, pts, flags);
870         if(index<0)
871             return -1;
872
873         pos2= st->index_entries[index].pos;
874         ts  = st->index_entries[index].timestamp;
875     }else{
876         av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pts_cmp,
877                      (void **) next_node);
878         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
879                                                     next_node[0]->ts , next_node[1]->ts);
880         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
881                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
882
883         if(!(flags & AVSEEK_FLAG_BACKWARD)){
884             dummy.pos= pos+16;
885             next_node[1]= &nopts_sp;
886             av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
887                          (void **) next_node);
888             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
889                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
890             if(pos2>=0)
891                 pos= pos2;
892             //FIXME dir but I think it does not matter
893         }
894         dummy.pos= pos;
895         sp= av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
896                          NULL);
897
898         assert(sp);
899         pos2= sp->back_ptr  - 15;
900     }
901     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
902     pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
903     avio_seek(s->pb, pos, SEEK_SET);
904     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
905     if(pos2 > pos || pos2 + 15 < pos){
906         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
907     }
908     for(i=0; i<s->nb_streams; i++)
909         nut->stream[i].skip_until_key_frame=1;
910
911     return 0;
912 }
913
914 static int nut_read_close(AVFormatContext *s)
915 {
916     NUTContext *nut = s->priv_data;
917     int i;
918
919     av_freep(&nut->time_base);
920     av_freep(&nut->stream);
921     ff_nut_free_sp(nut);
922     for(i = 1; i < nut->header_count; i++)
923         av_freep(&nut->header[i]);
924
925     return 0;
926 }
927
928 #if CONFIG_NUT_DEMUXER
929 AVInputFormat ff_nut_demuxer = {
930     "nut",
931     NULL_IF_CONFIG_SMALL("NUT format"),
932     sizeof(NUTContext),
933     nut_probe,
934     nut_read_header,
935     nut_read_packet,
936     nut_read_close,
937     read_seek,
938     .extensions = "nut",
939     .codec_tag = (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, ff_codec_wav_tags, ff_nut_subtitle_tags, 0 },
940 };
941 #endif