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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 "libavutil/avstring.h"
24 #include "libavutil/avassert.h"
25 #include "libavutil/bswap.h"
26 #include "libavutil/dict.h"
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/mathematics.h"
29 #include "libavutil/tree.h"
30 #include "libavcodec/bytestream.h"
31 #include "avio_internal.h"
32 #include "isom.h"
33 #include "nut.h"
34 #include "riff.h"
35 
36 #define NUT_MAX_STREAMS 256    /* arbitrary sanity check value */
37 
38 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index,
39                                   int64_t *pos_arg, int64_t pos_limit);
40 
get_str(AVIOContext * bc,char * string,unsigned int maxlen)41 static int get_str(AVIOContext *bc, char *string, unsigned int maxlen)
42 {
43     unsigned int len = ffio_read_varlen(bc);
44 
45     if (len && maxlen)
46         avio_read(bc, string, FFMIN(len, maxlen));
47     while (len > maxlen) {
48         avio_r8(bc);
49         len--;
50         if (bc->eof_reached)
51             len = maxlen;
52     }
53 
54     if (maxlen)
55         string[FFMIN(len, maxlen - 1)] = 0;
56 
57     if (bc->eof_reached)
58         return AVERROR_EOF;
59     if (maxlen == len)
60         return -1;
61     else
62         return 0;
63 }
64 
get_s(AVIOContext * bc)65 static int64_t get_s(AVIOContext *bc)
66 {
67     int64_t v = ffio_read_varlen(bc) + 1;
68 
69     if (v & 1)
70         return -(v >> 1);
71     else
72         return  (v >> 1);
73 }
74 
get_fourcc(AVIOContext * bc)75 static uint64_t get_fourcc(AVIOContext *bc)
76 {
77     unsigned int len = ffio_read_varlen(bc);
78 
79     if (len == 2)
80         return avio_rl16(bc);
81     else if (len == 4)
82         return avio_rl32(bc);
83     else {
84         av_log(NULL, AV_LOG_ERROR, "Unsupported fourcc length %d\n", len);
85         return -1;
86     }
87 }
88 
get_packetheader(NUTContext * nut,AVIOContext * bc,int calculate_checksum,uint64_t startcode)89 static int get_packetheader(NUTContext *nut, AVIOContext *bc,
90                             int calculate_checksum, uint64_t startcode)
91 {
92     int64_t size;
93 
94     startcode = av_be2ne64(startcode);
95     startcode = ff_crc04C11DB7_update(0, (uint8_t*) &startcode, 8);
96 
97     ffio_init_checksum(bc, ff_crc04C11DB7_update, startcode);
98     size = ffio_read_varlen(bc);
99     if (size > 4096)
100         avio_rb32(bc);
101     if (ffio_get_checksum(bc) && size > 4096)
102         return -1;
103 
104     ffio_init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
105 
106     return size;
107 }
108 
find_any_startcode(AVIOContext * bc,int64_t pos)109 static uint64_t find_any_startcode(AVIOContext *bc, int64_t pos)
110 {
111     uint64_t state = 0;
112 
113     if (pos >= 0)
114         /* Note, this may fail if the stream is not seekable, but that should
115          * not matter, as in this case we simply start where we currently are */
116         avio_seek(bc, pos, SEEK_SET);
117     while (!avio_feof(bc)) {
118         state = (state << 8) | avio_r8(bc);
119         if ((state >> 56) != 'N')
120             continue;
121         switch (state) {
122         case MAIN_STARTCODE:
123         case STREAM_STARTCODE:
124         case SYNCPOINT_STARTCODE:
125         case INFO_STARTCODE:
126         case INDEX_STARTCODE:
127             return state;
128         }
129     }
130 
131     return 0;
132 }
133 
134 /**
135  * Find the given startcode.
136  * @param code the startcode
137  * @param pos the start position of the search, or -1 if the current position
138  * @return the position of the startcode or -1 if not found
139  */
find_startcode(AVIOContext * bc,uint64_t code,int64_t pos)140 static int64_t find_startcode(AVIOContext *bc, uint64_t code, int64_t pos)
141 {
142     for (;;) {
143         uint64_t startcode = find_any_startcode(bc, pos);
144         if (startcode == code)
145             return avio_tell(bc) - 8;
146         else if (startcode == 0)
147             return -1;
148         pos = -1;
149     }
150 }
151 
nut_probe(const AVProbeData * p)152 static int nut_probe(const AVProbeData *p)
153 {
154     int i;
155 
156     for (i = 0; i < p->buf_size-8; i++) {
157         if (AV_RB32(p->buf+i) != MAIN_STARTCODE>>32)
158             continue;
159         if (AV_RB32(p->buf+i+4) == (MAIN_STARTCODE & 0xFFFFFFFF))
160             return AVPROBE_SCORE_MAX;
161     }
162     return 0;
163 }
164 
165 #define GET_V(dst, check)                                                     \
166     do {                                                                      \
167         tmp = ffio_read_varlen(bc);                                           \
168         if (!(check)) {                                                       \
169             av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);  \
170             ret = AVERROR_INVALIDDATA;                                        \
171             goto fail;                                                        \
172         }                                                                     \
173         dst = tmp;                                                            \
174     } while (0)
175 
skip_reserved(AVIOContext * bc,int64_t pos)176 static int skip_reserved(AVIOContext *bc, int64_t pos)
177 {
178     pos -= avio_tell(bc);
179     if (pos < 0) {
180         avio_seek(bc, pos, SEEK_CUR);
181         return AVERROR_INVALIDDATA;
182     } else {
183         while (pos--) {
184             if (bc->eof_reached)
185                 return AVERROR_INVALIDDATA;
186             avio_r8(bc);
187         }
188         return 0;
189     }
190 }
191 
decode_main_header(NUTContext * nut)192 static int decode_main_header(NUTContext *nut)
193 {
194     AVFormatContext *s = nut->avf;
195     AVIOContext *bc    = s->pb;
196     uint64_t tmp, end, length;
197     unsigned int stream_count;
198     int i, j, count, ret;
199     int tmp_stream, tmp_mul, tmp_pts, tmp_size, tmp_res, tmp_head_idx;
200 
201     length = get_packetheader(nut, bc, 1, MAIN_STARTCODE);
202     end = length + avio_tell(bc);
203 
204     nut->version = ffio_read_varlen(bc);
205     if (nut->version < NUT_MIN_VERSION ||
206         nut->version > NUT_MAX_VERSION) {
207         av_log(s, AV_LOG_ERROR, "Version %d not supported.\n",
208                nut->version);
209         return AVERROR(ENOSYS);
210     }
211     if (nut->version > 3)
212         nut->minor_version = ffio_read_varlen(bc);
213 
214     GET_V(stream_count, tmp > 0 && tmp <= NUT_MAX_STREAMS);
215 
216     nut->max_distance = ffio_read_varlen(bc);
217     if (nut->max_distance > 65536) {
218         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
219         nut->max_distance = 65536;
220     }
221 
222     GET_V(nut->time_base_count, tmp > 0 && tmp < INT_MAX / sizeof(AVRational) && tmp < length/2);
223     nut->time_base = av_malloc_array(nut->time_base_count, sizeof(AVRational));
224     if (!nut->time_base)
225         return AVERROR(ENOMEM);
226 
227     for (i = 0; i < nut->time_base_count; i++) {
228         GET_V(nut->time_base[i].num, tmp > 0 && tmp < (1ULL << 31));
229         GET_V(nut->time_base[i].den, tmp > 0 && tmp < (1ULL << 31));
230         if (av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1) {
231             av_log(s, AV_LOG_ERROR, "invalid time base %d/%d\n",
232                    nut->time_base[i].num,
233                    nut->time_base[i].den);
234             ret = AVERROR_INVALIDDATA;
235             goto fail;
236         }
237     }
238     tmp_pts      = 0;
239     tmp_mul      = 1;
240     tmp_stream   = 0;
241     tmp_head_idx = 0;
242     for (i = 0; i < 256;) {
243         int tmp_flags  = ffio_read_varlen(bc);
244         int tmp_fields = ffio_read_varlen(bc);
245 
246         if (tmp_fields > 0)
247             tmp_pts = get_s(bc);
248         if (tmp_fields > 1)
249             tmp_mul = ffio_read_varlen(bc);
250         if (tmp_fields > 2)
251             tmp_stream = ffio_read_varlen(bc);
252         if (tmp_fields > 3)
253             tmp_size = ffio_read_varlen(bc);
254         else
255             tmp_size = 0;
256         if (tmp_fields > 4)
257             tmp_res = ffio_read_varlen(bc);
258         else
259             tmp_res = 0;
260         if (tmp_fields > 5)
261             count = ffio_read_varlen(bc);
262         else
263             count = tmp_mul - (unsigned)tmp_size;
264         if (tmp_fields > 6)
265             get_s(bc);
266         if (tmp_fields > 7)
267             tmp_head_idx = ffio_read_varlen(bc);
268 
269         while (tmp_fields-- > 8) {
270             if (bc->eof_reached) {
271                 av_log(s, AV_LOG_ERROR, "reached EOF while decoding main header\n");
272                 ret = AVERROR_INVALIDDATA;
273                 goto fail;
274             }
275             ffio_read_varlen(bc);
276         }
277 
278         if (count <= 0 || count > 256 - (i <= 'N') - i) {
279             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
280             ret = AVERROR_INVALIDDATA;
281             goto fail;
282         }
283         if (tmp_stream >= stream_count) {
284             av_log(s, AV_LOG_ERROR, "illegal stream number %d >= %d\n",
285                    tmp_stream, stream_count);
286             ret = AVERROR_INVALIDDATA;
287             goto fail;
288         }
289         if (tmp_size < 0 || tmp_size > INT_MAX - count) {
290             av_log(s, AV_LOG_ERROR, "illegal size\n");
291             ret = AVERROR_INVALIDDATA;
292             goto fail;
293         }
294 
295         for (j = 0; j < count; j++, i++) {
296             if (i == 'N') {
297                 nut->frame_code[i].flags = FLAG_INVALID;
298                 j--;
299                 continue;
300             }
301             nut->frame_code[i].flags          = tmp_flags;
302             nut->frame_code[i].pts_delta      = tmp_pts;
303             nut->frame_code[i].stream_id      = tmp_stream;
304             nut->frame_code[i].size_mul       = tmp_mul;
305             nut->frame_code[i].size_lsb       = tmp_size + j;
306             nut->frame_code[i].reserved_count = tmp_res;
307             nut->frame_code[i].header_idx     = tmp_head_idx;
308         }
309     }
310     av_assert0(nut->frame_code['N'].flags == FLAG_INVALID);
311 
312     if (end > avio_tell(bc) + 4) {
313         int rem = 1024;
314         GET_V(nut->header_count, tmp < 128U);
315         nut->header_count++;
316         for (i = 1; i < nut->header_count; i++) {
317             uint8_t *hdr;
318             GET_V(nut->header_len[i], tmp > 0 && tmp < 256);
319             if (rem < nut->header_len[i]) {
320                 av_log(s, AV_LOG_ERROR,
321                        "invalid elision header %d : %d > %d\n",
322                        i, nut->header_len[i], rem);
323                 ret = AVERROR_INVALIDDATA;
324                 goto fail;
325             }
326             rem -= nut->header_len[i];
327             hdr = av_malloc(nut->header_len[i]);
328             if (!hdr) {
329                 ret = AVERROR(ENOMEM);
330                 goto fail;
331             }
332             avio_read(bc, hdr, nut->header_len[i]);
333             nut->header[i] = hdr;
334         }
335         av_assert0(nut->header_len[0] == 0);
336     }
337 
338     // flags had been effectively introduced in version 4
339     if (nut->version > 3 && end > avio_tell(bc) + 4) {
340         nut->flags = ffio_read_varlen(bc);
341     }
342 
343     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
344         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
345         ret = AVERROR_INVALIDDATA;
346         goto fail;
347     }
348 
349     nut->stream = av_calloc(stream_count, sizeof(StreamContext));
350     if (!nut->stream) {
351         ret = AVERROR(ENOMEM);
352         goto fail;
353     }
354     for (i = 0; i < stream_count; i++) {
355         if (!avformat_new_stream(s, NULL)) {
356             ret = AVERROR(ENOMEM);
357             goto fail;
358         }
359     }
360 
361     return 0;
362 fail:
363     av_freep(&nut->time_base);
364     for (i = 1; i < nut->header_count; i++) {
365         av_freep(&nut->header[i]);
366     }
367     nut->header_count = 0;
368     return ret;
369 }
370 
decode_stream_header(NUTContext * nut)371 static int decode_stream_header(NUTContext *nut)
372 {
373     AVFormatContext *s = nut->avf;
374     AVIOContext *bc    = s->pb;
375     StreamContext *stc;
376     int class, stream_id, ret;
377     uint64_t tmp, end;
378     AVStream *st = NULL;
379 
380     end  = get_packetheader(nut, bc, 1, STREAM_STARTCODE);
381     end += avio_tell(bc);
382 
383     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
384     stc = &nut->stream[stream_id];
385     st  = s->streams[stream_id];
386     if (!st)
387         return AVERROR(ENOMEM);
388 
389     class                = ffio_read_varlen(bc);
390     tmp                  = get_fourcc(bc);
391     st->codecpar->codec_tag = tmp;
392     switch (class) {
393     case 0:
394         st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
395         st->codecpar->codec_id   = av_codec_get_id((const AVCodecTag * const []) {
396                                                     ff_nut_video_tags,
397                                                     ff_codec_bmp_tags,
398                                                     ff_codec_movvideo_tags,
399                                                     0
400                                                 },
401                                                 tmp);
402         break;
403     case 1:
404         st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
405         st->codecpar->codec_id   = av_codec_get_id((const AVCodecTag * const []) {
406                                                     ff_nut_audio_tags,
407                                                     ff_codec_wav_tags,
408                                                     ff_nut_audio_extra_tags,
409                                                     0
410                                                 },
411                                                 tmp);
412         break;
413     case 2:
414         st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
415         st->codecpar->codec_id   = ff_codec_get_id(ff_nut_subtitle_tags, tmp);
416         break;
417     case 3:
418         st->codecpar->codec_type = AVMEDIA_TYPE_DATA;
419         st->codecpar->codec_id   = ff_codec_get_id(ff_nut_data_tags, tmp);
420         break;
421     default:
422         av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
423         return AVERROR(ENOSYS);
424     }
425     if (class < 3 && st->codecpar->codec_id == AV_CODEC_ID_NONE)
426         av_log(s, AV_LOG_ERROR,
427                "Unknown codec tag '0x%04x' for stream number %d\n",
428                (unsigned int) tmp, stream_id);
429 
430     GET_V(stc->time_base_id, tmp < nut->time_base_count);
431     GET_V(stc->msb_pts_shift, tmp < 16);
432     stc->max_pts_distance = ffio_read_varlen(bc);
433     GET_V(stc->decode_delay, tmp < 1000); // sanity limit, raise this if Moore's law is true
434     st->codecpar->video_delay = stc->decode_delay;
435     ffio_read_varlen(bc); // stream flags
436 
437     GET_V(st->codecpar->extradata_size, tmp < (1 << 30));
438     if (st->codecpar->extradata_size) {
439         ret = ff_get_extradata(s, st->codecpar, bc,
440                                st->codecpar->extradata_size);
441         if (ret < 0)
442             return ret;
443     }
444 
445     if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
446         GET_V(st->codecpar->width,  tmp > 0);
447         GET_V(st->codecpar->height, tmp > 0);
448         st->sample_aspect_ratio.num = ffio_read_varlen(bc);
449         st->sample_aspect_ratio.den = ffio_read_varlen(bc);
450         if ((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)) {
451             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n",
452                    st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
453             ret = AVERROR_INVALIDDATA;
454             goto fail;
455         }
456         ffio_read_varlen(bc); /* csp type */
457     } else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
458         GET_V(st->codecpar->sample_rate, tmp > 0);
459         ffio_read_varlen(bc); // samplerate_den
460         GET_V(st->codecpar->channels, tmp > 0);
461     }
462     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
463         av_log(s, AV_LOG_ERROR,
464                "stream header %d checksum mismatch\n", stream_id);
465         ret = AVERROR_INVALIDDATA;
466         goto fail;
467     }
468     stc->time_base = &nut->time_base[stc->time_base_id];
469     avpriv_set_pts_info(s->streams[stream_id], 63, stc->time_base->num,
470                         stc->time_base->den);
471     return 0;
472 fail:
473     if (st && st->codecpar) {
474         av_freep(&st->codecpar->extradata);
475         st->codecpar->extradata_size = 0;
476     }
477     return ret;
478 }
479 
set_disposition_bits(AVFormatContext * avf,char * value,int stream_id)480 static void set_disposition_bits(AVFormatContext *avf, char *value,
481                                  int stream_id)
482 {
483     int flag = 0, i;
484 
485     for (i = 0; ff_nut_dispositions[i].flag; ++i)
486         if (!strcmp(ff_nut_dispositions[i].str, value))
487             flag = ff_nut_dispositions[i].flag;
488     if (!flag)
489         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
490     for (i = 0; i < avf->nb_streams; ++i)
491         if (stream_id == i || stream_id == -1)
492             avf->streams[i]->disposition |= flag;
493 }
494 
decode_info_header(NUTContext * nut)495 static int decode_info_header(NUTContext *nut)
496 {
497     AVFormatContext *s = nut->avf;
498     AVIOContext *bc    = s->pb;
499     uint64_t tmp, chapter_start, chapter_len;
500     unsigned int stream_id_plus1, count;
501     int i, ret = 0;
502     int64_t chapter_id, value, end;
503     char name[256], str_value[1024], type_str[256];
504     const char *type;
505     int *event_flags        = NULL;
506     AVChapter *chapter      = NULL;
507     AVStream *st            = NULL;
508     AVDictionary **metadata = NULL;
509     int metadata_flag       = 0;
510 
511     end  = get_packetheader(nut, bc, 1, INFO_STARTCODE);
512     end += avio_tell(bc);
513 
514     GET_V(stream_id_plus1, tmp <= s->nb_streams);
515     chapter_id    = get_s(bc);
516     chapter_start = ffio_read_varlen(bc);
517     chapter_len   = ffio_read_varlen(bc);
518     count         = ffio_read_varlen(bc);
519 
520     if (chapter_id && !stream_id_plus1) {
521         int64_t start = chapter_start / nut->time_base_count;
522         chapter = avpriv_new_chapter(s, chapter_id,
523                                      nut->time_base[chapter_start %
524                                                     nut->time_base_count],
525                                      start, start + chapter_len, NULL);
526         if (!chapter) {
527             av_log(s, AV_LOG_ERROR, "Could not create chapter.\n");
528             return AVERROR(ENOMEM);
529         }
530         metadata = &chapter->metadata;
531     } else if (stream_id_plus1) {
532         st       = s->streams[stream_id_plus1 - 1];
533         metadata = &st->metadata;
534         event_flags = &st->event_flags;
535         metadata_flag = AVSTREAM_EVENT_FLAG_METADATA_UPDATED;
536     } else {
537         metadata = &s->metadata;
538         event_flags = &s->event_flags;
539         metadata_flag = AVFMT_EVENT_FLAG_METADATA_UPDATED;
540     }
541 
542     for (i = 0; i < count; i++) {
543         ret = get_str(bc, name, sizeof(name));
544         if (ret < 0) {
545             av_log(s, AV_LOG_ERROR, "get_str failed while decoding info header\n");
546             return ret;
547         }
548         value = get_s(bc);
549         str_value[0] = 0;
550 
551         if (value == -1) {
552             type = "UTF-8";
553             ret = get_str(bc, str_value, sizeof(str_value));
554         } else if (value == -2) {
555             ret = get_str(bc, type_str, sizeof(type_str));
556             if (ret < 0) {
557                 av_log(s, AV_LOG_ERROR, "get_str failed while decoding info header\n");
558                 return ret;
559             }
560             type = type_str;
561             ret = get_str(bc, str_value, sizeof(str_value));
562         } else if (value == -3) {
563             type  = "s";
564             value = get_s(bc);
565         } else if (value == -4) {
566             type  = "t";
567             value = ffio_read_varlen(bc);
568         } else if (value < -4) {
569             type = "r";
570             get_s(bc);
571         } else {
572             type = "v";
573         }
574 
575         if (ret < 0) {
576             av_log(s, AV_LOG_ERROR, "get_str failed while decoding info header\n");
577             return ret;
578         }
579 
580         if (stream_id_plus1 > s->nb_streams) {
581             av_log(s, AV_LOG_WARNING,
582                    "invalid stream id %d for info packet\n",
583                    stream_id_plus1);
584             continue;
585         }
586 
587         if (!strcmp(type, "UTF-8")) {
588             if (chapter_id == 0 && !strcmp(name, "Disposition")) {
589                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
590                 continue;
591             }
592 
593             if (stream_id_plus1 && !strcmp(name, "r_frame_rate")) {
594                 sscanf(str_value, "%d/%d", &st->r_frame_rate.num, &st->r_frame_rate.den);
595                 if (st->r_frame_rate.num >= 1000LL*st->r_frame_rate.den ||
596                     st->r_frame_rate.num < 0 || st->r_frame_rate.den < 0)
597                     st->r_frame_rate.num = st->r_frame_rate.den = 0;
598                 continue;
599             }
600 
601             if (metadata && av_strcasecmp(name, "Uses") &&
602                 av_strcasecmp(name, "Depends") && av_strcasecmp(name, "Replaces")) {
603                 if (event_flags)
604                     *event_flags |= metadata_flag;
605                 av_dict_set(metadata, name, str_value, 0);
606             }
607         }
608     }
609 
610     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
611         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
612         return AVERROR_INVALIDDATA;
613     }
614 fail:
615     return FFMIN(ret, 0);
616 }
617 
decode_syncpoint(NUTContext * nut,int64_t * ts,int64_t * back_ptr)618 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr)
619 {
620     AVFormatContext *s = nut->avf;
621     AVIOContext *bc    = s->pb;
622     int64_t end;
623     uint64_t tmp;
624     int ret;
625 
626     nut->last_syncpoint_pos = avio_tell(bc) - 8;
627 
628     end  = get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
629     end += avio_tell(bc);
630 
631     tmp       = ffio_read_varlen(bc);
632     *back_ptr = nut->last_syncpoint_pos - 16 * ffio_read_varlen(bc);
633     if (*back_ptr < 0)
634         return AVERROR_INVALIDDATA;
635 
636     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count],
637                     tmp / nut->time_base_count);
638 
639     if (nut->flags & NUT_BROADCAST) {
640         tmp = ffio_read_varlen(bc);
641         av_log(s, AV_LOG_VERBOSE, "Syncpoint wallclock %"PRId64"\n",
642                av_rescale_q(tmp / nut->time_base_count,
643                             nut->time_base[tmp % nut->time_base_count],
644                             AV_TIME_BASE_Q));
645     }
646 
647     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
648         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
649         return AVERROR_INVALIDDATA;
650     }
651 
652     *ts = tmp / nut->time_base_count *
653           av_q2d(nut->time_base[tmp % nut->time_base_count]) * AV_TIME_BASE;
654 
655     if ((ret = ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts)) < 0)
656         return ret;
657 
658     return 0;
659 }
660 
661 //FIXME calculate exactly, this is just a good approximation.
find_duration(NUTContext * nut,int64_t filesize)662 static int64_t find_duration(NUTContext *nut, int64_t filesize)
663 {
664     AVFormatContext *s = nut->avf;
665     int64_t duration = 0;
666 
667     ff_find_last_ts(s, -1, &duration, NULL, nut_read_timestamp);
668 
669     if(duration > 0)
670         s->duration_estimation_method = AVFMT_DURATION_FROM_PTS;
671     return duration;
672 }
673 
find_and_decode_index(NUTContext * nut)674 static int find_and_decode_index(NUTContext *nut)
675 {
676     AVFormatContext *s = nut->avf;
677     AVIOContext *bc    = s->pb;
678     uint64_t tmp, end;
679     int i, j, syncpoint_count;
680     int64_t filesize = avio_size(bc);
681     int64_t *syncpoints = NULL;
682     uint64_t max_pts;
683     int8_t *has_keyframe = NULL;
684     int ret = AVERROR_INVALIDDATA;
685 
686     if(filesize <= 0)
687         return -1;
688 
689     avio_seek(bc, filesize - 12, SEEK_SET);
690     avio_seek(bc, filesize - avio_rb64(bc), SEEK_SET);
691     if (avio_rb64(bc) != INDEX_STARTCODE) {
692         av_log(s, AV_LOG_WARNING, "no index at the end\n");
693 
694         if(s->duration<=0)
695             s->duration = find_duration(nut, filesize);
696         return ret;
697     }
698 
699     end  = get_packetheader(nut, bc, 1, INDEX_STARTCODE);
700     end += avio_tell(bc);
701 
702     max_pts = ffio_read_varlen(bc);
703     s->duration = av_rescale_q(max_pts / nut->time_base_count,
704                                nut->time_base[max_pts % nut->time_base_count],
705                                AV_TIME_BASE_Q);
706     s->duration_estimation_method = AVFMT_DURATION_FROM_PTS;
707 
708     GET_V(syncpoint_count, tmp < INT_MAX / 8 && tmp > 0);
709     syncpoints   = av_malloc_array(syncpoint_count, sizeof(int64_t));
710     has_keyframe = av_malloc_array(syncpoint_count + 1, sizeof(int8_t));
711     if (!syncpoints || !has_keyframe) {
712         ret = AVERROR(ENOMEM);
713         goto fail;
714     }
715     for (i = 0; i < syncpoint_count; i++) {
716         syncpoints[i] = ffio_read_varlen(bc);
717         if (syncpoints[i] <= 0)
718             goto fail;
719         if (i)
720             syncpoints[i] += syncpoints[i - 1];
721     }
722 
723     for (i = 0; i < s->nb_streams; i++) {
724         int64_t last_pts = -1;
725         for (j = 0; j < syncpoint_count;) {
726             uint64_t x = ffio_read_varlen(bc);
727             int type   = x & 1;
728             int n      = j;
729             x >>= 1;
730             if (type) {
731                 int flag = x & 1;
732                 x >>= 1;
733                 if (n + x >= syncpoint_count + 1) {
734                     av_log(s, AV_LOG_ERROR, "index overflow A %d + %"PRIu64" >= %d\n", n, x, syncpoint_count + 1);
735                     goto fail;
736                 }
737                 while (x--)
738                     has_keyframe[n++] = flag;
739                 has_keyframe[n++] = !flag;
740             } else {
741                 if (x <= 1) {
742                     av_log(s, AV_LOG_ERROR, "index: x %"PRIu64" is invalid\n", x);
743                     goto fail;
744                 }
745                 while (x != 1) {
746                     if (n >= syncpoint_count + 1) {
747                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
748                         goto fail;
749                     }
750                     has_keyframe[n++] = x & 1;
751                     x >>= 1;
752                 }
753             }
754             if (has_keyframe[0]) {
755                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
756                 goto fail;
757             }
758             av_assert0(n <= syncpoint_count + 1);
759             for (; j < n && j < syncpoint_count; j++) {
760                 if (has_keyframe[j]) {
761                     uint64_t B, A = ffio_read_varlen(bc);
762                     if (!A) {
763                         A = ffio_read_varlen(bc);
764                         B = ffio_read_varlen(bc);
765                         // eor_pts[j][i] = last_pts + A + B
766                     } else
767                         B = 0;
768                     av_add_index_entry(s->streams[i], 16 * syncpoints[j - 1],
769                                        last_pts + A, 0, 0, AVINDEX_KEYFRAME);
770                     last_pts += A + B;
771                 }
772             }
773         }
774     }
775 
776     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
777         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
778         goto fail;
779     }
780     ret = 0;
781 
782 fail:
783     av_free(syncpoints);
784     av_free(has_keyframe);
785     return ret;
786 }
787 
nut_read_close(AVFormatContext * s)788 static int nut_read_close(AVFormatContext *s)
789 {
790     NUTContext *nut = s->priv_data;
791     int i;
792 
793     av_freep(&nut->time_base);
794     av_freep(&nut->stream);
795     ff_nut_free_sp(nut);
796     for (i = 1; i < nut->header_count; i++)
797         av_freep(&nut->header[i]);
798 
799     return 0;
800 }
801 
nut_read_header(AVFormatContext * s)802 static int nut_read_header(AVFormatContext *s)
803 {
804     NUTContext *nut = s->priv_data;
805     AVIOContext *bc = s->pb;
806     int64_t pos;
807     int initialized_stream_count, ret;
808 
809     nut->avf = s;
810 
811     /* main header */
812     pos = 0;
813     ret = 0;
814     do {
815         if (ret == AVERROR(ENOMEM))
816             return ret;
817 
818         pos = find_startcode(bc, MAIN_STARTCODE, pos) + 1;
819         if (pos < 0 + 1) {
820             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
821             goto fail;
822         }
823     } while ((ret = decode_main_header(nut)) < 0);
824 
825     /* stream headers */
826     pos = 0;
827     for (initialized_stream_count = 0; initialized_stream_count < s->nb_streams;) {
828         pos = find_startcode(bc, STREAM_STARTCODE, pos) + 1;
829         if (pos < 0 + 1) {
830             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
831             goto fail;
832         }
833         if (decode_stream_header(nut) >= 0)
834             initialized_stream_count++;
835     }
836 
837     /* info headers */
838     pos = 0;
839     for (;;) {
840         uint64_t startcode = find_any_startcode(bc, pos);
841         pos = avio_tell(bc);
842 
843         if (startcode == 0) {
844             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
845             goto fail;
846         } else if (startcode == SYNCPOINT_STARTCODE) {
847             nut->next_startcode = startcode;
848             break;
849         } else if (startcode != INFO_STARTCODE) {
850             continue;
851         }
852 
853         decode_info_header(nut);
854     }
855 
856     s->internal->data_offset = pos - 8;
857 
858     if (bc->seekable & AVIO_SEEKABLE_NORMAL) {
859         int64_t orig_pos = avio_tell(bc);
860         find_and_decode_index(nut);
861         avio_seek(bc, orig_pos, SEEK_SET);
862     }
863     av_assert0(nut->next_startcode == SYNCPOINT_STARTCODE);
864 
865     ff_metadata_conv_ctx(s, NULL, ff_nut_metadata_conv);
866 
867     return 0;
868 
869 fail:
870     nut_read_close(s);
871 
872     return AVERROR_INVALIDDATA;
873 }
874 
read_sm_data(AVFormatContext * s,AVIOContext * bc,AVPacket * pkt,int is_meta,int64_t maxpos)875 static int read_sm_data(AVFormatContext *s, AVIOContext *bc, AVPacket *pkt, int is_meta, int64_t maxpos)
876 {
877     int count = ffio_read_varlen(bc);
878     int skip_start = 0;
879     int skip_end = 0;
880     int channels = 0;
881     int64_t channel_layout = 0;
882     int sample_rate = 0;
883     int width = 0;
884     int height = 0;
885     int i, ret;
886 
887     for (i=0; i<count; i++) {
888         uint8_t name[256], str_value[256], type_str[256];
889         int value;
890         if (avio_tell(bc) >= maxpos)
891             return AVERROR_INVALIDDATA;
892         ret = get_str(bc, name, sizeof(name));
893         if (ret < 0) {
894             av_log(s, AV_LOG_ERROR, "get_str failed while reading sm data\n");
895             return ret;
896         }
897         value = get_s(bc);
898 
899         if (value == -1) {
900             ret = get_str(bc, str_value, sizeof(str_value));
901             if (ret < 0) {
902                 av_log(s, AV_LOG_ERROR, "get_str failed while reading sm data\n");
903                 return ret;
904             }
905             av_log(s, AV_LOG_WARNING, "Unknown string %s / %s\n", name, str_value);
906         } else if (value == -2) {
907             uint8_t *dst = NULL;
908             int64_t v64, value_len;
909 
910             ret = get_str(bc, type_str, sizeof(type_str));
911             if (ret < 0) {
912                 av_log(s, AV_LOG_ERROR, "get_str failed while reading sm data\n");
913                 return ret;
914             }
915             value_len = ffio_read_varlen(bc);
916             if (value_len < 0 || value_len >= maxpos - avio_tell(bc))
917                 return AVERROR_INVALIDDATA;
918             if (!strcmp(name, "Palette")) {
919                 dst = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, value_len);
920             } else if (!strcmp(name, "Extradata")) {
921                 dst = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, value_len);
922             } else if (sscanf(name, "CodecSpecificSide%"SCNd64"", &v64) == 1) {
923                 dst = av_packet_new_side_data(pkt, AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL, value_len + 8);
924                 if(!dst)
925                     return AVERROR(ENOMEM);
926                 AV_WB64(dst, v64);
927                 dst += 8;
928             } else if (!strcmp(name, "ChannelLayout") && value_len == 8) {
929                 channel_layout = avio_rl64(bc);
930                 continue;
931             } else {
932                 av_log(s, AV_LOG_WARNING, "Unknown data %s / %s\n", name, type_str);
933                 avio_skip(bc, value_len);
934                 continue;
935             }
936             if(!dst)
937                 return AVERROR(ENOMEM);
938             avio_read(bc, dst, value_len);
939         } else if (value == -3) {
940             value = get_s(bc);
941         } else if (value == -4) {
942             value = ffio_read_varlen(bc);
943         } else if (value < -4) {
944             get_s(bc);
945         } else {
946             if (!strcmp(name, "SkipStart")) {
947                 skip_start = value;
948             } else if (!strcmp(name, "SkipEnd")) {
949                 skip_end = value;
950             } else if (!strcmp(name, "Channels")) {
951                 channels = value;
952             } else if (!strcmp(name, "SampleRate")) {
953                 sample_rate = value;
954             } else if (!strcmp(name, "Width")) {
955                 width = value;
956             } else if (!strcmp(name, "Height")) {
957                 height = value;
958             } else {
959                 av_log(s, AV_LOG_WARNING, "Unknown integer %s\n", name);
960             }
961         }
962     }
963 
964     if (channels || channel_layout || sample_rate || width || height) {
965         uint8_t *dst = av_packet_new_side_data(pkt, AV_PKT_DATA_PARAM_CHANGE, 28);
966         if (!dst)
967             return AVERROR(ENOMEM);
968         bytestream_put_le32(&dst,
969                             AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT*(!!channels) +
970                             AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT*(!!channel_layout) +
971                             AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE*(!!sample_rate) +
972                             AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS*(!!(width|height))
973                            );
974         if (channels)
975             bytestream_put_le32(&dst, channels);
976         if (channel_layout)
977             bytestream_put_le64(&dst, channel_layout);
978         if (sample_rate)
979             bytestream_put_le32(&dst, sample_rate);
980         if (width || height){
981             bytestream_put_le32(&dst, width);
982             bytestream_put_le32(&dst, height);
983         }
984     }
985 
986     if (skip_start || skip_end) {
987         uint8_t *dst = av_packet_new_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES, 10);
988         if (!dst)
989             return AVERROR(ENOMEM);
990         AV_WL32(dst, skip_start);
991         AV_WL32(dst+4, skip_end);
992     }
993 
994     if (avio_tell(bc) >= maxpos)
995         return AVERROR_INVALIDDATA;
996 
997     return 0;
998 }
999 
decode_frame_header(NUTContext * nut,int64_t * pts,int * stream_id,uint8_t * header_idx,int frame_code)1000 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id,
1001                                uint8_t *header_idx, int frame_code)
1002 {
1003     AVFormatContext *s = nut->avf;
1004     AVIOContext *bc    = s->pb;
1005     StreamContext *stc;
1006     int size, flags, size_mul, pts_delta, i, reserved_count, ret;
1007     uint64_t tmp;
1008 
1009     if (!(nut->flags & NUT_PIPE) &&
1010         avio_tell(bc) > nut->last_syncpoint_pos + nut->max_distance) {
1011         av_log(s, AV_LOG_ERROR,
1012                "Last frame must have been damaged %"PRId64" > %"PRId64" + %d\n",
1013                avio_tell(bc), nut->last_syncpoint_pos, nut->max_distance);
1014         return AVERROR_INVALIDDATA;
1015     }
1016 
1017     flags          = nut->frame_code[frame_code].flags;
1018     size_mul       = nut->frame_code[frame_code].size_mul;
1019     size           = nut->frame_code[frame_code].size_lsb;
1020     *stream_id     = nut->frame_code[frame_code].stream_id;
1021     pts_delta      = nut->frame_code[frame_code].pts_delta;
1022     reserved_count = nut->frame_code[frame_code].reserved_count;
1023     *header_idx    = nut->frame_code[frame_code].header_idx;
1024 
1025     if (flags & FLAG_INVALID)
1026         return AVERROR_INVALIDDATA;
1027     if (flags & FLAG_CODED)
1028         flags ^= ffio_read_varlen(bc);
1029     if (flags & FLAG_STREAM_ID) {
1030         GET_V(*stream_id, tmp < s->nb_streams);
1031     }
1032     stc = &nut->stream[*stream_id];
1033     if (flags & FLAG_CODED_PTS) {
1034         int64_t coded_pts = ffio_read_varlen(bc);
1035         // FIXME check last_pts validity?
1036         if (coded_pts < (1LL << stc->msb_pts_shift)) {
1037             *pts = ff_lsb2full(stc, coded_pts);
1038         } else
1039             *pts = coded_pts - (1LL << stc->msb_pts_shift);
1040     } else
1041         *pts = stc->last_pts + pts_delta;
1042     if (flags & FLAG_SIZE_MSB)
1043         size += size_mul * ffio_read_varlen(bc);
1044     if (flags & FLAG_MATCH_TIME)
1045         get_s(bc);
1046     if (flags & FLAG_HEADER_IDX)
1047         *header_idx = ffio_read_varlen(bc);
1048     if (flags & FLAG_RESERVED)
1049         reserved_count = ffio_read_varlen(bc);
1050     for (i = 0; i < reserved_count; i++) {
1051         if (bc->eof_reached) {
1052             av_log(s, AV_LOG_ERROR, "reached EOF while decoding frame header\n");
1053             return AVERROR_INVALIDDATA;
1054         }
1055         ffio_read_varlen(bc);
1056     }
1057 
1058     if (*header_idx >= (unsigned)nut->header_count) {
1059         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
1060         return AVERROR_INVALIDDATA;
1061     }
1062     if (size > 4096)
1063         *header_idx = 0;
1064     size -= nut->header_len[*header_idx];
1065 
1066     if (flags & FLAG_CHECKSUM) {
1067         avio_rb32(bc); // FIXME check this
1068     } else if (!(nut->flags & NUT_PIPE) &&
1069                size > 2 * nut->max_distance ||
1070                FFABS(stc->last_pts - *pts) > stc->max_pts_distance) {
1071         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
1072         return AVERROR_INVALIDDATA;
1073     }
1074 
1075     stc->last_pts   = *pts;
1076     stc->last_flags = flags;
1077 
1078     return size;
1079 fail:
1080     return ret;
1081 }
1082 
decode_frame(NUTContext * nut,AVPacket * pkt,int frame_code)1083 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code)
1084 {
1085     AVFormatContext *s = nut->avf;
1086     AVIOContext *bc    = s->pb;
1087     int size, stream_id, discard, ret;
1088     int64_t pts, last_IP_pts;
1089     StreamContext *stc;
1090     uint8_t header_idx;
1091 
1092     size = decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
1093     if (size < 0)
1094         return size;
1095 
1096     stc = &nut->stream[stream_id];
1097 
1098     if (stc->last_flags & FLAG_KEY)
1099         stc->skip_until_key_frame = 0;
1100 
1101     discard     = s->streams[stream_id]->discard;
1102     last_IP_pts = s->streams[stream_id]->last_IP_pts;
1103     if ((discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY)) ||
1104         (discard >= AVDISCARD_BIDIR  && last_IP_pts != AV_NOPTS_VALUE &&
1105          last_IP_pts > pts) ||
1106         discard >= AVDISCARD_ALL ||
1107         stc->skip_until_key_frame) {
1108         avio_skip(bc, size);
1109         return 1;
1110     }
1111 
1112     ret = av_new_packet(pkt, size + nut->header_len[header_idx]);
1113     if (ret < 0)
1114         return ret;
1115     if (nut->header[header_idx])
1116         memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
1117     pkt->pos = avio_tell(bc); // FIXME
1118     if (stc->last_flags & FLAG_SM_DATA) {
1119         int sm_size;
1120         if (read_sm_data(s, bc, pkt, 0, pkt->pos + size) < 0) {
1121             ret = AVERROR_INVALIDDATA;
1122             goto fail;
1123         }
1124         if (read_sm_data(s, bc, pkt, 1, pkt->pos + size) < 0) {
1125             ret = AVERROR_INVALIDDATA;
1126             goto fail;
1127         }
1128         sm_size = avio_tell(bc) - pkt->pos;
1129         size      -= sm_size;
1130         pkt->size -= sm_size;
1131     }
1132 
1133     ret = avio_read(bc, pkt->data + nut->header_len[header_idx], size);
1134     if (ret != size) {
1135         if (ret < 0)
1136             goto fail;
1137     }
1138     av_shrink_packet(pkt, nut->header_len[header_idx] + ret);
1139 
1140     pkt->stream_index = stream_id;
1141     if (stc->last_flags & FLAG_KEY)
1142         pkt->flags |= AV_PKT_FLAG_KEY;
1143     pkt->pts = pts;
1144 
1145     return 0;
1146 fail:
1147     av_packet_unref(pkt);
1148     return ret;
1149 }
1150 
nut_read_packet(AVFormatContext * s,AVPacket * pkt)1151 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
1152 {
1153     NUTContext *nut = s->priv_data;
1154     AVIOContext *bc = s->pb;
1155     int i, frame_code = 0, ret, skip;
1156     int64_t ts, back_ptr;
1157 
1158     for (;;) {
1159         int64_t pos  = avio_tell(bc);
1160         uint64_t tmp = nut->next_startcode;
1161         nut->next_startcode = 0;
1162 
1163         if (tmp) {
1164             pos -= 8;
1165         } else {
1166             frame_code = avio_r8(bc);
1167             if (avio_feof(bc))
1168                 return AVERROR_EOF;
1169             if (frame_code == 'N') {
1170                 tmp = frame_code;
1171                 for (i = 1; i < 8; i++)
1172                     tmp = (tmp << 8) + avio_r8(bc);
1173             }
1174         }
1175         switch (tmp) {
1176         case MAIN_STARTCODE:
1177         case STREAM_STARTCODE:
1178         case INDEX_STARTCODE:
1179             skip = get_packetheader(nut, bc, 0, tmp);
1180             avio_skip(bc, skip);
1181             break;
1182         case INFO_STARTCODE:
1183             if (decode_info_header(nut) < 0)
1184                 goto resync;
1185             break;
1186         case SYNCPOINT_STARTCODE:
1187             if (decode_syncpoint(nut, &ts, &back_ptr) < 0)
1188                 goto resync;
1189             frame_code = avio_r8(bc);
1190         case 0:
1191             ret = decode_frame(nut, pkt, frame_code);
1192             if (ret == 0)
1193                 return 0;
1194             else if (ret == 1) // OK but discard packet
1195                 break;
1196         default:
1197 resync:
1198             av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
1199             tmp = find_any_startcode(bc, FFMAX(nut->last_syncpoint_pos, nut->last_resync_pos) + 1);
1200             nut->last_resync_pos = avio_tell(bc);
1201             if (tmp == 0)
1202                 return AVERROR_INVALIDDATA;
1203             av_log(s, AV_LOG_DEBUG, "sync\n");
1204             nut->next_startcode = tmp;
1205         }
1206     }
1207 }
1208 
nut_read_timestamp(AVFormatContext * s,int stream_index,int64_t * pos_arg,int64_t pos_limit)1209 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index,
1210                                   int64_t *pos_arg, int64_t pos_limit)
1211 {
1212     NUTContext *nut = s->priv_data;
1213     AVIOContext *bc = s->pb;
1214     int64_t pos, pts, back_ptr;
1215     av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n",
1216            stream_index, *pos_arg, pos_limit);
1217 
1218     pos = *pos_arg;
1219     do {
1220         pos = find_startcode(bc, SYNCPOINT_STARTCODE, pos) + 1;
1221         if (pos < 1) {
1222             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
1223             return AV_NOPTS_VALUE;
1224         }
1225     } while (decode_syncpoint(nut, &pts, &back_ptr) < 0);
1226     *pos_arg = pos - 1;
1227     av_assert0(nut->last_syncpoint_pos == *pos_arg);
1228 
1229     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts, back_ptr);
1230     if (stream_index == -2)
1231         return back_ptr;
1232     av_assert0(stream_index == -1);
1233     return pts;
1234 }
1235 
read_seek(AVFormatContext * s,int stream_index,int64_t pts,int flags)1236 static int read_seek(AVFormatContext *s, int stream_index,
1237                      int64_t pts, int flags)
1238 {
1239     NUTContext *nut    = s->priv_data;
1240     AVStream *st       = s->streams[stream_index];
1241     Syncpoint dummy    = { .ts = pts * av_q2d(st->time_base) * AV_TIME_BASE };
1242     Syncpoint nopts_sp = { .ts = AV_NOPTS_VALUE, .back_ptr = AV_NOPTS_VALUE };
1243     Syncpoint *sp, *next_node[2] = { &nopts_sp, &nopts_sp };
1244     int64_t pos, pos2, ts;
1245     int i;
1246 
1247     if (nut->flags & NUT_PIPE) {
1248         return AVERROR(ENOSYS);
1249     }
1250 
1251     if (st->index_entries) {
1252         int index = av_index_search_timestamp(st, pts, flags);
1253         if (index < 0)
1254             index = av_index_search_timestamp(st, pts, flags ^ AVSEEK_FLAG_BACKWARD);
1255         if (index < 0)
1256             return -1;
1257 
1258         pos2 = st->index_entries[index].pos;
1259         ts   = st->index_entries[index].timestamp;
1260     } else {
1261         av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pts_cmp,
1262                      (void **) next_node);
1263         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n",
1264                next_node[0]->pos, next_node[1]->pos, next_node[0]->ts,
1265                next_node[1]->ts);
1266         pos = ff_gen_search(s, -1, dummy.ts, next_node[0]->pos,
1267                             next_node[1]->pos, next_node[1]->pos,
1268                             next_node[0]->ts, next_node[1]->ts,
1269                             AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
1270         if (pos < 0)
1271             return pos;
1272 
1273         if (!(flags & AVSEEK_FLAG_BACKWARD)) {
1274             dummy.pos    = pos + 16;
1275             next_node[1] = &nopts_sp;
1276             av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp,
1277                          (void **) next_node);
1278             pos2 = ff_gen_search(s, -2, dummy.pos, next_node[0]->pos,
1279                                  next_node[1]->pos, next_node[1]->pos,
1280                                  next_node[0]->back_ptr, next_node[1]->back_ptr,
1281                                  flags, &ts, nut_read_timestamp);
1282             if (pos2 >= 0)
1283                 pos = pos2;
1284             // FIXME dir but I think it does not matter
1285         }
1286         dummy.pos = pos;
1287         sp = av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp,
1288                           NULL);
1289 
1290         av_assert0(sp);
1291         pos2 = sp->back_ptr - 15;
1292     }
1293     av_log(s, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
1294     pos = find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
1295     avio_seek(s->pb, pos, SEEK_SET);
1296     nut->last_syncpoint_pos = pos;
1297     av_log(s, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
1298     if (pos2 > pos || pos2 + 15 < pos)
1299         av_log(s, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
1300     for (i = 0; i < s->nb_streams; i++)
1301         nut->stream[i].skip_until_key_frame = 1;
1302 
1303     nut->last_resync_pos = 0;
1304 
1305     return 0;
1306 }
1307 
1308 AVInputFormat ff_nut_demuxer = {
1309     .name           = "nut",
1310     .long_name      = NULL_IF_CONFIG_SMALL("NUT"),
1311     .flags          = AVFMT_SEEK_TO_PTS,
1312     .priv_data_size = sizeof(NUTContext),
1313     .read_probe     = nut_probe,
1314     .read_header    = nut_read_header,
1315     .read_packet    = nut_read_packet,
1316     .read_close     = nut_read_close,
1317     .read_seek      = read_seek,
1318     .extensions     = "nut",
1319     .codec_tag      = ff_nut_codec_tags,
1320 };
1321