Fix warning "passing argument from incompatible pointer type".
[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 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
33     unsigned int len= ff_get_v(bc);
34
35     if(len && maxlen)
36         get_buffer(bc, string, FFMIN(len, maxlen));
37     while(len > maxlen){
38         get_byte(bc);
39         len--;
40     }
41
42     if(maxlen)
43         string[FFMIN(len, maxlen-1)]= 0;
44
45     if(maxlen == len)
46         return -1;
47     else
48         return 0;
49 }
50
51 static int64_t get_s(ByteIOContext *bc){
52     int64_t v = ff_get_v(bc) + 1;
53
54     if (v&1) return -(v>>1);
55     else     return  (v>>1);
56 }
57
58 static uint64_t get_fourcc(ByteIOContext *bc){
59     unsigned int len= ff_get_v(bc);
60
61     if     (len==2) return get_le16(bc);
62     else if(len==4) return get_le32(bc);
63     else            return -1;
64 }
65
66 #ifdef TRACE
67 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
68     uint64_t v= ff_get_v(bc);
69
70     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
71     return v;
72 }
73
74 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
75     int64_t v= get_s(bc);
76
77     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
78     return v;
79 }
80
81 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
82     uint64_t v= get_vb(bc);
83
84     av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
85     return v;
86 }
87 #define ff_get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
88 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
89 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
90 #endif
91
92 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
93 {
94     int64_t size;
95 //    start= url_ftell(bc) - 8;
96
97     startcode= be2me_64(startcode);
98     startcode= ff_crc04C11DB7_update(0, (uint8_t*)&startcode, 8);
99
100     init_checksum(bc, ff_crc04C11DB7_update, startcode);
101     size= ff_get_v(bc);
102     if(size > 4096)
103         get_be32(bc);
104     if(get_checksum(bc) && size > 4096)
105         return -1;
106
107     init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
108
109     return size;
110 }
111
112 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
113     uint64_t state=0;
114
115     if(pos >= 0)
116         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
117
118     while(!url_feof(bc)){
119         state= (state<<8) | get_byte(bc);
120         if((state>>56) != 'N')
121             continue;
122         switch(state){
123         case MAIN_STARTCODE:
124         case STREAM_STARTCODE:
125         case SYNCPOINT_STARTCODE:
126         case INFO_STARTCODE:
127         case INDEX_STARTCODE:
128             return state;
129         }
130     }
131
132     return 0;
133 }
134
135 /**
136  * Find the given startcode.
137  * @param code the startcode
138  * @param pos the start position of the search, or -1 if the current position
139  * @return the position of the startcode or -1 if not found
140  */
141 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
142     for(;;){
143         uint64_t startcode= find_any_startcode(bc, pos);
144         if(startcode == code)
145             return url_ftell(bc) - 8;
146         else if(startcode == 0)
147             return -1;
148         pos=-1;
149     }
150 }
151
152 static int nut_probe(AVProbeData *p){
153     int i;
154     uint64_t code= 0;
155
156     for (i = 0; i < p->buf_size; i++) {
157         code = (code << 8) | p->buf[i];
158         if (code == MAIN_STARTCODE)
159             return AVPROBE_SCORE_MAX;
160     }
161     return 0;
162 }
163
164 #define GET_V(dst, check) \
165     tmp= ff_get_v(bc);\
166     if(!(check)){\
167         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
168         return -1;\
169     }\
170     dst= tmp;
171
172 static int skip_reserved(ByteIOContext *bc, int64_t pos){
173     pos -= url_ftell(bc);
174     if(pos<0){
175         url_fseek(bc, pos, SEEK_CUR);
176         return -1;
177     }else{
178         while(pos--)
179             get_byte(bc);
180         return 0;
181     }
182 }
183
184 static int decode_main_header(NUTContext *nut){
185     AVFormatContext *s= nut->avf;
186     ByteIOContext *bc = s->pb;
187     uint64_t tmp, end;
188     unsigned int stream_count;
189     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res, tmp_head_idx;
190     int64_t tmp_match;
191
192     end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
193     end += url_ftell(bc);
194
195     GET_V(tmp              , tmp >=2 && tmp <= 3)
196     GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
197
198     nut->max_distance = ff_get_v(bc);
199     if(nut->max_distance > 65536){
200         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
201         nut->max_distance= 65536;
202     }
203
204     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
205     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
206
207     for(i=0; i<nut->time_base_count; i++){
208         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
209         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
210         if(av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
211             av_log(s, AV_LOG_ERROR, "time base invalid\n");
212             return -1;
213         }
214     }
215     tmp_pts=0;
216     tmp_mul=1;
217     tmp_stream=0;
218     tmp_match= 1-(1LL<<62);
219     tmp_head_idx= 0;
220     for(i=0; i<256;){
221         int tmp_flags = ff_get_v(bc);
222         int tmp_fields= ff_get_v(bc);
223         if(tmp_fields>0) tmp_pts   = get_s(bc);
224         if(tmp_fields>1) tmp_mul   = ff_get_v(bc);
225         if(tmp_fields>2) tmp_stream= ff_get_v(bc);
226         if(tmp_fields>3) tmp_size  = ff_get_v(bc);
227         else             tmp_size  = 0;
228         if(tmp_fields>4) tmp_res   = ff_get_v(bc);
229         else             tmp_res   = 0;
230         if(tmp_fields>5) count     = ff_get_v(bc);
231         else             count     = tmp_mul - tmp_size;
232         if(tmp_fields>6) tmp_match = get_s(bc);
233         if(tmp_fields>7) tmp_head_idx= ff_get_v(bc);
234
235         while(tmp_fields-- > 8)
236            ff_get_v(bc);
237
238         if(count == 0 || i+count > 256){
239             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
240             return -1;
241         }
242         if(tmp_stream >= stream_count){
243             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
244             return -1;
245         }
246
247         for(j=0; j<count; j++,i++){
248             if (i == 'N') {
249                 nut->frame_code[i].flags= FLAG_INVALID;
250                 j--;
251                 continue;
252             }
253             nut->frame_code[i].flags           = tmp_flags ;
254             nut->frame_code[i].pts_delta       = tmp_pts   ;
255             nut->frame_code[i].stream_id       = tmp_stream;
256             nut->frame_code[i].size_mul        = tmp_mul   ;
257             nut->frame_code[i].size_lsb        = tmp_size+j;
258             nut->frame_code[i].reserved_count  = tmp_res   ;
259             nut->frame_code[i].header_idx      = tmp_head_idx;
260         }
261     }
262     assert(nut->frame_code['N'].flags == FLAG_INVALID);
263
264     if(end > url_ftell(bc) + 4){
265         int rem= 1024;
266         GET_V(nut->header_count, tmp<128U)
267         nut->header_count++;
268         for(i=1; i<nut->header_count; i++){
269             GET_V(nut->header_len[i], tmp>0 && tmp<256);
270             rem -= nut->header_len[i];
271             if(rem < 0){
272                 av_log(s, AV_LOG_ERROR, "invalid elision header\n");
273                 return -1;
274             }
275             nut->header[i]= av_malloc(nut->header_len[i]);
276             get_buffer(bc, nut->header[i], nut->header_len[i]);
277         }
278         assert(nut->header_len[0]==0);
279     }
280
281     if(skip_reserved(bc, end) || get_checksum(bc)){
282         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
283         return -1;
284     }
285
286     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
287     for(i=0; i<stream_count; i++){
288         av_new_stream(s, i);
289     }
290
291     return 0;
292 }
293
294 static int decode_stream_header(NUTContext *nut){
295     AVFormatContext *s= nut->avf;
296     ByteIOContext *bc = s->pb;
297     StreamContext *stc;
298     int class, stream_id;
299     uint64_t tmp, end;
300     AVStream *st;
301
302     end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
303     end += url_ftell(bc);
304
305     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
306     stc= &nut->stream[stream_id];
307
308     st = s->streams[stream_id];
309     if (!st)
310         return AVERROR(ENOMEM);
311
312     class = ff_get_v(bc);
313     tmp = get_fourcc(bc);
314     st->codec->codec_tag= tmp;
315     switch(class)
316     {
317         case 0:
318             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
319             st->codec->codec_id = av_codec_get_id(
320                 (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, 0 },
321                 tmp);
322             break;
323         case 1:
324             st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
325             st->codec->codec_id = ff_codec_get_id(ff_codec_wav_tags, tmp);
326             break;
327         case 2:
328             st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
329             st->codec->codec_id = ff_codec_get_id(ff_nut_subtitle_tags, tmp);
330             break;
331         case 3:
332             st->codec->codec_type = AVMEDIA_TYPE_DATA;
333             break;
334         default:
335             av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
336             return -1;
337     }
338     if(class<3 && st->codec->codec_id == CODEC_ID_NONE)
339         av_log(s, AV_LOG_ERROR, "Unknown codec tag '0x%04x' for stream number %d\n",
340                (unsigned int)tmp, stream_id);
341
342     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
343     GET_V(stc->msb_pts_shift   , tmp < 16);
344     stc->max_pts_distance= ff_get_v(bc);
345     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if Moore's law is true
346     st->codec->has_b_frames= stc->decode_delay;
347     ff_get_v(bc); //stream flags
348
349     GET_V(st->codec->extradata_size, tmp < (1<<30));
350     if(st->codec->extradata_size){
351         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
352         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
353     }
354
355     if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
356         GET_V(st->codec->width , tmp > 0)
357         GET_V(st->codec->height, tmp > 0)
358         st->sample_aspect_ratio.num= ff_get_v(bc);
359         st->sample_aspect_ratio.den= ff_get_v(bc);
360         if((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)){
361             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
362             return -1;
363         }
364         ff_get_v(bc); /* csp type */
365     }else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO){
366         GET_V(st->codec->sample_rate , tmp > 0)
367         ff_get_v(bc); // samplerate_den
368         GET_V(st->codec->channels, tmp > 0)
369     }
370     if(skip_reserved(bc, end) || get_checksum(bc)){
371         av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
372         return -1;
373     }
374     stc->time_base= &nut->time_base[stc->time_base_id];
375     av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
376     return 0;
377 }
378
379 static void set_disposition_bits(AVFormatContext* avf, char* value, int stream_id){
380     int flag = 0, i;
381     for (i=0; ff_nut_dispositions[i].flag; ++i) {
382         if (!strcmp(ff_nut_dispositions[i].str, value))
383             flag = ff_nut_dispositions[i].flag;
384     }
385     if (!flag)
386         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
387     for (i = 0; i < avf->nb_streams; ++i)
388         if (stream_id == i || stream_id == -1)
389             avf->streams[i]->disposition |= flag;
390 }
391
392 static int decode_info_header(NUTContext *nut){
393     AVFormatContext *s= nut->avf;
394     ByteIOContext *bc = s->pb;
395     uint64_t tmp, chapter_start, chapter_len;
396     unsigned int stream_id_plus1, count;
397     int chapter_id, i;
398     int64_t value, end;
399     char name[256], str_value[1024], type_str[256];
400     const char *type;
401     AVChapter *chapter= NULL;
402     AVStream *st= NULL;
403
404     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
405     end += url_ftell(bc);
406
407     GET_V(stream_id_plus1, tmp <= s->nb_streams)
408     chapter_id   = get_s(bc);
409     chapter_start= ff_get_v(bc);
410     chapter_len  = ff_get_v(bc);
411     count        = ff_get_v(bc);
412
413     if(chapter_id && !stream_id_plus1){
414         int64_t start= chapter_start / nut->time_base_count;
415         chapter= ff_new_chapter(s, chapter_id,
416                                 nut->time_base[chapter_start % nut->time_base_count],
417                                 start, start + chapter_len, NULL);
418     } else if(stream_id_plus1)
419         st= s->streams[stream_id_plus1 - 1];
420
421     for(i=0; i<count; i++){
422         get_str(bc, name, sizeof(name));
423         value= get_s(bc);
424         if(value == -1){
425             type= "UTF-8";
426             get_str(bc, str_value, sizeof(str_value));
427         }else if(value == -2){
428             get_str(bc, type_str, sizeof(type_str));
429             type= type_str;
430             get_str(bc, str_value, sizeof(str_value));
431         }else if(value == -3){
432             type= "s";
433             value= get_s(bc);
434         }else if(value == -4){
435             type= "t";
436             value= ff_get_v(bc);
437         }else if(value < -4){
438             type= "r";
439             get_s(bc);
440         }else{
441             type= "v";
442         }
443
444         if (stream_id_plus1 > s->nb_streams) {
445             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
446             continue;
447         }
448
449         if(!strcmp(type, "UTF-8")){
450             AVMetadata **metadata = NULL;
451             if(chapter_id==0 && !strcmp(name, "Disposition"))
452                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
453             else if(chapter)          metadata= &chapter->metadata;
454             else if(stream_id_plus1)  metadata= &st->metadata;
455             else                      metadata= &s->metadata;
456             if(metadata && strcasecmp(name,"Uses")
457                && strcasecmp(name,"Depends") && strcasecmp(name,"Replaces"))
458                 av_metadata_set2(metadata, name, str_value, 0);
459         }
460     }
461
462     if(skip_reserved(bc, end) || get_checksum(bc)){
463         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
464         return -1;
465     }
466     return 0;
467 }
468
469 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
470     AVFormatContext *s= nut->avf;
471     ByteIOContext *bc = s->pb;
472     int64_t end, tmp;
473
474     nut->last_syncpoint_pos= url_ftell(bc)-8;
475
476     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
477     end += url_ftell(bc);
478
479     tmp= ff_get_v(bc);
480     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
481     if(*back_ptr < 0)
482         return -1;
483
484     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
485
486     if(skip_reserved(bc, end) || get_checksum(bc)){
487         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
488         return -1;
489     }
490
491     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
492     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
493
494     return 0;
495 }
496
497 static int find_and_decode_index(NUTContext *nut){
498     AVFormatContext *s= nut->avf;
499     ByteIOContext *bc = s->pb;
500     uint64_t tmp, end;
501     int i, j, syncpoint_count;
502     int64_t filesize= url_fsize(bc);
503     int64_t *syncpoints;
504     int8_t *has_keyframe;
505     int ret= -1;
506
507     url_fseek(bc, filesize-12, SEEK_SET);
508     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
509     if(get_be64(bc) != INDEX_STARTCODE){
510         av_log(s, AV_LOG_ERROR, "no index at the end\n");
511         return -1;
512     }
513
514     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
515     end += url_ftell(bc);
516
517     ff_get_v(bc); //max_pts
518     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
519     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
520     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
521     for(i=0; i<syncpoint_count; i++){
522         syncpoints[i] = ff_get_v(bc);
523         if(syncpoints[i] <= 0)
524             goto fail;
525         if(i)
526             syncpoints[i] += syncpoints[i-1];
527     }
528
529     for(i=0; i<s->nb_streams; i++){
530         int64_t last_pts= -1;
531         for(j=0; j<syncpoint_count;){
532             uint64_t x= ff_get_v(bc);
533             int type= x&1;
534             int n= j;
535             x>>=1;
536             if(type){
537                 int flag= x&1;
538                 x>>=1;
539                 if(n+x >= syncpoint_count + 1){
540                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
541                     goto fail;
542                 }
543                 while(x--)
544                     has_keyframe[n++]= flag;
545                 has_keyframe[n++]= !flag;
546             }else{
547                 while(x != 1){
548                     if(n>=syncpoint_count + 1){
549                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
550                         goto fail;
551                     }
552                     has_keyframe[n++]= x&1;
553                     x>>=1;
554                 }
555             }
556             if(has_keyframe[0]){
557                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
558                 goto fail;
559             }
560             assert(n<=syncpoint_count+1);
561             for(; j<n && j<syncpoint_count; j++){
562                 if(has_keyframe[j]){
563                     uint64_t B, A= ff_get_v(bc);
564                     if(!A){
565                         A= ff_get_v(bc);
566                         B= ff_get_v(bc);
567                         //eor_pts[j][i] = last_pts + A + B
568                     }else
569                         B= 0;
570                     av_add_index_entry(
571                         s->streams[i],
572                         16*syncpoints[j-1],
573                         last_pts + A,
574                         0,
575                         0,
576                         AVINDEX_KEYFRAME);
577                     last_pts += A + B;
578                 }
579             }
580         }
581     }
582
583     if(skip_reserved(bc, end) || get_checksum(bc)){
584         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
585         goto fail;
586     }
587     ret= 0;
588 fail:
589     av_free(syncpoints);
590     av_free(has_keyframe);
591     return ret;
592 }
593
594 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
595 {
596     NUTContext *nut = s->priv_data;
597     ByteIOContext *bc = s->pb;
598     int64_t pos;
599     int initialized_stream_count;
600
601     nut->avf= s;
602
603     /* main header */
604     pos=0;
605     do{
606         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
607         if (pos<0+1){
608             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
609             return -1;
610         }
611     }while(decode_main_header(nut) < 0);
612
613     /* stream headers */
614     pos=0;
615     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
616         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
617         if (pos<0+1){
618             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
619             return -1;
620         }
621         if(decode_stream_header(nut) >= 0)
622             initialized_stream_count++;
623     }
624
625     /* info headers */
626     pos=0;
627     for(;;){
628         uint64_t startcode= find_any_startcode(bc, pos);
629         pos= url_ftell(bc);
630
631         if(startcode==0){
632             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
633             return -1;
634         }else if(startcode == SYNCPOINT_STARTCODE){
635             nut->next_startcode= startcode;
636             break;
637         }else if(startcode != INFO_STARTCODE){
638             continue;
639         }
640
641         decode_info_header(nut);
642     }
643
644     s->data_offset= pos-8;
645
646     if(!url_is_streamed(bc)){
647         int64_t orig_pos= url_ftell(bc);
648         find_and_decode_index(nut);
649         url_fseek(bc, orig_pos, SEEK_SET);
650     }
651     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
652
653     return 0;
654 }
655
656 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, uint8_t *header_idx, int frame_code){
657     AVFormatContext *s= nut->avf;
658     ByteIOContext *bc = s->pb;
659     StreamContext *stc;
660     int size, flags, size_mul, pts_delta, i, reserved_count;
661     uint64_t tmp;
662
663     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
664         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);
665         return -1;
666     }
667
668     flags          = nut->frame_code[frame_code].flags;
669     size_mul       = nut->frame_code[frame_code].size_mul;
670     size           = nut->frame_code[frame_code].size_lsb;
671     *stream_id     = nut->frame_code[frame_code].stream_id;
672     pts_delta      = nut->frame_code[frame_code].pts_delta;
673     reserved_count = nut->frame_code[frame_code].reserved_count;
674     *header_idx    = nut->frame_code[frame_code].header_idx;
675
676     if(flags & FLAG_INVALID)
677         return -1;
678     if(flags & FLAG_CODED)
679         flags ^= ff_get_v(bc);
680     if(flags & FLAG_STREAM_ID){
681         GET_V(*stream_id, tmp < s->nb_streams)
682     }
683     stc= &nut->stream[*stream_id];
684     if(flags&FLAG_CODED_PTS){
685         int coded_pts= ff_get_v(bc);
686 //FIXME check last_pts validity?
687         if(coded_pts < (1<<stc->msb_pts_shift)){
688             *pts=ff_lsb2full(stc, coded_pts);
689         }else
690             *pts=coded_pts - (1<<stc->msb_pts_shift);
691     }else
692         *pts= stc->last_pts + pts_delta;
693     if(flags&FLAG_SIZE_MSB){
694         size += size_mul*ff_get_v(bc);
695     }
696     if(flags&FLAG_MATCH_TIME)
697         get_s(bc);
698     if(flags&FLAG_HEADER_IDX)
699         *header_idx= ff_get_v(bc);
700     if(flags&FLAG_RESERVED)
701         reserved_count= ff_get_v(bc);
702     for(i=0; i<reserved_count; i++)
703         ff_get_v(bc);
704
705     if(*header_idx >= (unsigned)nut->header_count){
706         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
707         return -1;
708     }
709     if(size > 4096)
710         *header_idx=0;
711     size -= nut->header_len[*header_idx];
712
713     if(flags&FLAG_CHECKSUM){
714         get_be32(bc); //FIXME check this
715     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
716         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
717         return -1;
718     }
719
720     stc->last_pts= *pts;
721     stc->last_flags= flags;
722
723     return size;
724 }
725
726 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
727     AVFormatContext *s= nut->avf;
728     ByteIOContext *bc = s->pb;
729     int size, stream_id, discard;
730     int64_t pts, last_IP_pts;
731     StreamContext *stc;
732     uint8_t header_idx;
733
734     size= decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
735     if(size < 0)
736         return -1;
737
738     stc= &nut->stream[stream_id];
739
740     if (stc->last_flags & FLAG_KEY)
741         stc->skip_until_key_frame=0;
742
743     discard= s->streams[ stream_id ]->discard;
744     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
745     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
746        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
747        || discard >= AVDISCARD_ALL
748        || stc->skip_until_key_frame){
749         url_fskip(bc, size);
750         return 1;
751     }
752
753     av_new_packet(pkt, size + nut->header_len[header_idx]);
754     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
755     pkt->pos= url_ftell(bc); //FIXME
756     get_buffer(bc, pkt->data + nut->header_len[header_idx], size);
757
758     pkt->stream_index = stream_id;
759     if (stc->last_flags & FLAG_KEY)
760         pkt->flags |= AV_PKT_FLAG_KEY;
761     pkt->pts = pts;
762
763     return 0;
764 }
765
766 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
767 {
768     NUTContext *nut = s->priv_data;
769     ByteIOContext *bc = s->pb;
770     int i, frame_code=0, ret, skip;
771     int64_t ts, back_ptr;
772
773     for(;;){
774         int64_t pos= url_ftell(bc);
775         uint64_t tmp= nut->next_startcode;
776         nut->next_startcode=0;
777
778         if(tmp){
779             pos-=8;
780         }else{
781             frame_code = get_byte(bc);
782             if(url_feof(bc))
783                 return -1;
784             if(frame_code == 'N'){
785                 tmp= frame_code;
786                 for(i=1; i<8; i++)
787                     tmp = (tmp<<8) + get_byte(bc);
788             }
789         }
790         switch(tmp){
791         case MAIN_STARTCODE:
792         case STREAM_STARTCODE:
793         case INDEX_STARTCODE:
794             skip= get_packetheader(nut, bc, 0, tmp);
795             url_fseek(bc, skip, SEEK_CUR);
796             break;
797         case INFO_STARTCODE:
798             if(decode_info_header(nut)<0)
799                 goto resync;
800             break;
801         case SYNCPOINT_STARTCODE:
802             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
803                 goto resync;
804             frame_code = get_byte(bc);
805         case 0:
806             ret= decode_frame(nut, pkt, frame_code);
807             if(ret==0)
808                 return 0;
809             else if(ret==1) //ok but discard packet
810                 break;
811         default:
812 resync:
813 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
814             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
815             if(tmp==0)
816                 return -1;
817 av_log(s, AV_LOG_DEBUG, "sync\n");
818             nut->next_startcode= tmp;
819         }
820     }
821 }
822
823 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
824     NUTContext *nut = s->priv_data;
825     ByteIOContext *bc = s->pb;
826     int64_t pos, pts, back_ptr;
827 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
828
829     pos= *pos_arg;
830     do{
831         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
832         if(pos < 1){
833             assert(nut->next_startcode == 0);
834             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
835             return AV_NOPTS_VALUE;
836         }
837     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
838     *pos_arg = pos-1;
839     assert(nut->last_syncpoint_pos == *pos_arg);
840
841     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
842     if     (stream_index == -1) return pts;
843     else if(stream_index == -2) return back_ptr;
844
845 assert(0);
846 }
847
848 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
849     NUTContext *nut = s->priv_data;
850     AVStream *st= s->streams[stream_index];
851     Syncpoint dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
852     Syncpoint nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
853     Syncpoint *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
854     int64_t pos, pos2, ts;
855     int i;
856
857     if(st->index_entries){
858         int index= av_index_search_timestamp(st, pts, flags);
859         if(index<0)
860             return -1;
861
862         pos2= st->index_entries[index].pos;
863         ts  = st->index_entries[index].timestamp;
864     }else{
865         av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pts_cmp,
866                      (void **) next_node);
867         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
868                                                     next_node[0]->ts , next_node[1]->ts);
869         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
870                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
871
872         if(!(flags & AVSEEK_FLAG_BACKWARD)){
873             dummy.pos= pos+16;
874             next_node[1]= &nopts_sp;
875             av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
876                          (void **) next_node);
877             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
878                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
879             if(pos2>=0)
880                 pos= pos2;
881             //FIXME dir but I think it does not matter
882         }
883         dummy.pos= pos;
884         sp= av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
885                          NULL);
886
887         assert(sp);
888         pos2= sp->back_ptr  - 15;
889     }
890     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
891     pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
892     url_fseek(s->pb, pos, SEEK_SET);
893     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
894     if(pos2 > pos || pos2 + 15 < pos){
895         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
896     }
897     for(i=0; i<s->nb_streams; i++)
898         nut->stream[i].skip_until_key_frame=1;
899
900     return 0;
901 }
902
903 static int nut_read_close(AVFormatContext *s)
904 {
905     NUTContext *nut = s->priv_data;
906     int i;
907
908     av_freep(&nut->time_base);
909     av_freep(&nut->stream);
910     ff_nut_free_sp(nut);
911     for(i = 1; i < nut->header_count; i++)
912         av_freep(&nut->header[i]);
913
914     return 0;
915 }
916
917 #if CONFIG_NUT_DEMUXER
918 AVInputFormat nut_demuxer = {
919     "nut",
920     NULL_IF_CONFIG_SMALL("NUT format"),
921     sizeof(NUTContext),
922     nut_probe,
923     nut_read_header,
924     nut_read_packet,
925     nut_read_close,
926     read_seek,
927     .extensions = "nut",
928     .metadata_conv = ff_nut_metadata_conv,
929     .codec_tag = (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, ff_codec_wav_tags, ff_nut_subtitle_tags, 0 },
930 };
931 #endif