Libav
nutdec.c
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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 Libav.
7  *
8  * Libav 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  * Libav 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 Libav; 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/bswap.h"
25 #include "libavutil/dict.h"
26 #include "libavutil/mathematics.h"
27 #include "libavutil/tree.h"
28 #include "avio_internal.h"
29 #include "nut.h"
30 #include "riff.h"
31 
32 #undef NDEBUG
33 #include <assert.h>
34 
35 #define NUT_MAX_STREAMS 256 /* arbitrary sanity check value */
36 
37 static int get_str(AVIOContext *bc, char *string, unsigned int maxlen)
38 {
39  unsigned int len = ffio_read_varlen(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 {
59  int64_t v = ffio_read_varlen(bc) + 1;
60 
61  if (v & 1)
62  return -(v >> 1);
63  else
64  return (v >> 1);
65 }
66 
67 static uint64_t get_fourcc(AVIOContext *bc)
68 {
69  unsigned int len = ffio_read_varlen(bc);
70 
71  if (len == 2)
72  return avio_rl16(bc);
73  else if (len == 4)
74  return avio_rl32(bc);
75  else
76  return -1;
77 }
78 
79 #ifdef TRACE
80 static inline uint64_t get_v_trace(AVIOContext *bc, const char *file,
81  const char *func, int line)
82 {
83  uint64_t v = ffio_read_varlen(bc);
84 
85  av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n",
86  v, v, file, func, line);
87  return v;
88 }
89 
90 static inline int64_t get_s_trace(AVIOContext *bc, const char *file,
91  const char *func, int line)
92 {
93  int64_t v = get_s(bc);
94 
95  av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n",
96  v, v, file, func, line);
97  return v;
98 }
99 
100 #define ffio_read_varlen(bc) get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
101 #define get_s(bc) get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
102 #endif
103 
105  int calculate_checksum, uint64_t startcode)
106 {
107  int64_t size;
108 // start = avio_tell(bc) - 8;
109 
110  startcode = av_be2ne64(startcode);
111  startcode = ff_crc04C11DB7_update(0, (uint8_t*) &startcode, 8);
112 
114  size = ffio_read_varlen(bc);
115  if (size > 4096)
116  avio_rb32(bc);
117  if (ffio_get_checksum(bc) && size > 4096)
118  return -1;
119 
120  ffio_init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
121 
122  return size;
123 }
124 
125 static uint64_t find_any_startcode(AVIOContext *bc, int64_t pos)
126 {
127  uint64_t state = 0;
128 
129  if (pos >= 0)
130  /* Note, this may fail if the stream is not seekable, but that should
131  * not matter, as in this case we simply start where we currently are */
132  avio_seek(bc, pos, SEEK_SET);
133  while (!bc->eof_reached) {
134  state = (state << 8) | avio_r8(bc);
135  if ((state >> 56) != 'N')
136  continue;
137  switch (state) {
138  case MAIN_STARTCODE:
139  case STREAM_STARTCODE:
140  case SYNCPOINT_STARTCODE:
141  case INFO_STARTCODE:
142  case INDEX_STARTCODE:
143  return state;
144  }
145  }
146 
147  return 0;
148 }
149 
156 static int64_t find_startcode(AVIOContext *bc, uint64_t code, int64_t pos)
157 {
158  for (;;) {
159  uint64_t startcode = find_any_startcode(bc, pos);
160  if (startcode == code)
161  return avio_tell(bc) - 8;
162  else if (startcode == 0)
163  return -1;
164  pos = -1;
165  }
166 }
167 
168 static int nut_probe(AVProbeData *p)
169 {
170  int i;
171  uint64_t code = 0;
172 
173  for (i = 0; i < p->buf_size; i++) {
174  code = (code << 8) | p->buf[i];
175  if (code == MAIN_STARTCODE)
176  return AVPROBE_SCORE_MAX;
177  }
178  return 0;
179 }
180 
181 #define GET_V(dst, check) \
182  do { \
183  tmp = ffio_read_varlen(bc); \
184  if (!(check)) { \
185  av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp); \
186  return AVERROR_INVALIDDATA; \
187  } \
188  dst = tmp; \
189  } while (0)
190 
191 static int skip_reserved(AVIOContext *bc, int64_t pos)
192 {
193  pos -= avio_tell(bc);
194  if (pos < 0) {
195  avio_seek(bc, pos, SEEK_CUR);
196  return AVERROR_INVALIDDATA;
197  } else {
198  while (pos--)
199  avio_r8(bc);
200  return 0;
201  }
202 }
203 
205 {
206  AVFormatContext *s = nut->avf;
207  AVIOContext *bc = s->pb;
208  uint64_t tmp, end;
209  unsigned int stream_count;
210  int i, j, count;
211  int tmp_stream, tmp_mul, tmp_pts, tmp_size, tmp_res, tmp_head_idx;
212 
213  end = get_packetheader(nut, bc, 1, MAIN_STARTCODE);
214  end += avio_tell(bc);
215 
216  tmp = ffio_read_varlen(bc);
217  if (tmp < 2 && tmp > NUT_VERSION) {
218  av_log(s, AV_LOG_ERROR, "Version %"PRId64" not supported.\n",
219  tmp);
220  return AVERROR(ENOSYS);
221  }
222 
223  GET_V(stream_count, tmp > 0 && tmp <= NUT_MAX_STREAMS);
224 
225  nut->max_distance = ffio_read_varlen(bc);
226  if (nut->max_distance > 65536) {
227  av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
228  nut->max_distance = 65536;
229  }
230 
231  GET_V(nut->time_base_count, tmp > 0 && tmp < INT_MAX / sizeof(AVRational));
232  nut->time_base = av_malloc(nut->time_base_count * sizeof(AVRational));
233 
234  for (i = 0; i < nut->time_base_count; i++) {
235  GET_V(nut->time_base[i].num, tmp > 0 && tmp < (1ULL << 31));
236  GET_V(nut->time_base[i].den, tmp > 0 && tmp < (1ULL << 31));
237  if (av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1) {
238  av_log(s, AV_LOG_ERROR, "time base invalid\n");
239  return AVERROR_INVALIDDATA;
240  }
241  }
242  tmp_pts = 0;
243  tmp_mul = 1;
244  tmp_stream = 0;
245  tmp_head_idx = 0;
246  for (i = 0; i < 256;) {
247  int tmp_flags = ffio_read_varlen(bc);
248  int tmp_fields = ffio_read_varlen(bc);
249 
250  if (tmp_fields > 0)
251  tmp_pts = get_s(bc);
252  if (tmp_fields > 1)
253  tmp_mul = ffio_read_varlen(bc);
254  if (tmp_fields > 2)
255  tmp_stream = ffio_read_varlen(bc);
256  if (tmp_fields > 3)
257  tmp_size = ffio_read_varlen(bc);
258  else
259  tmp_size = 0;
260  if (tmp_fields > 4)
261  tmp_res = ffio_read_varlen(bc);
262  else
263  tmp_res = 0;
264  if (tmp_fields > 5)
265  count = ffio_read_varlen(bc);
266  else
267  count = tmp_mul - tmp_size;
268  if (tmp_fields > 6)
269  get_s(bc);
270  if (tmp_fields > 7)
271  tmp_head_idx = ffio_read_varlen(bc);
272 
273  while (tmp_fields-- > 8)
274  ffio_read_varlen(bc);
275 
276  if (count == 0 || i + count > 256) {
277  av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
278  return AVERROR_INVALIDDATA;
279  }
280  if (tmp_stream >= stream_count) {
281  av_log(s, AV_LOG_ERROR, "illegal stream number\n");
282  return AVERROR_INVALIDDATA;
283  }
284 
285  for (j = 0; j < count; j++, i++) {
286  if (i == 'N') {
287  nut->frame_code[i].flags = FLAG_INVALID;
288  j--;
289  continue;
290  }
291  nut->frame_code[i].flags = tmp_flags;
292  nut->frame_code[i].pts_delta = tmp_pts;
293  nut->frame_code[i].stream_id = tmp_stream;
294  nut->frame_code[i].size_mul = tmp_mul;
295  nut->frame_code[i].size_lsb = tmp_size + j;
296  nut->frame_code[i].reserved_count = tmp_res;
297  nut->frame_code[i].header_idx = tmp_head_idx;
298  }
299  }
300  assert(nut->frame_code['N'].flags == FLAG_INVALID);
301 
302  if (end > avio_tell(bc) + 4) {
303  int rem = 1024;
304  GET_V(nut->header_count, tmp < 128U);
305  nut->header_count++;
306  for (i = 1; i < nut->header_count; i++) {
307  uint8_t *hdr;
308  GET_V(nut->header_len[i], tmp > 0 && tmp < 256);
309  rem -= nut->header_len[i];
310  if (rem < 0) {
311  av_log(s, AV_LOG_ERROR, "invalid elision header\n");
312  return AVERROR_INVALIDDATA;
313  }
314  hdr = av_malloc(nut->header_len[i]);
315  if (!hdr)
316  return AVERROR(ENOMEM);
317  avio_read(bc, hdr, nut->header_len[i]);
318  nut->header[i] = hdr;
319  }
320  assert(nut->header_len[0] == 0);
321  }
322 
323  if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
324  av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
325  return AVERROR_INVALIDDATA;
326  }
327 
328  nut->stream = av_mallocz(sizeof(StreamContext) * stream_count);
329  for (i = 0; i < stream_count; i++)
331 
332  return 0;
333 }
334 
336 {
337  AVFormatContext *s = nut->avf;
338  AVIOContext *bc = s->pb;
339  StreamContext *stc;
340  int class, stream_id;
341  uint64_t tmp, end;
342  AVStream *st;
343 
344  end = get_packetheader(nut, bc, 1, STREAM_STARTCODE);
345  end += avio_tell(bc);
346 
347  GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
348  stc = &nut->stream[stream_id];
349  st = s->streams[stream_id];
350  if (!st)
351  return AVERROR(ENOMEM);
352 
353  class = ffio_read_varlen(bc);
354  tmp = get_fourcc(bc);
355  st->codec->codec_tag = tmp;
356  switch (class) {
357  case 0:
359  st->codec->codec_id = av_codec_get_id((const AVCodecTag * const []) {
362  0
363  },
364  tmp);
365  break;
366  case 1:
368  st->codec->codec_id = av_codec_get_id((const AVCodecTag * const []) {
371  0
372  },
373  tmp);
374  break;
375  case 2:
378  break;
379  case 3:
382  break;
383  default:
384  av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
385  return AVERROR(ENOSYS);
386  }
387  if (class < 3 && st->codec->codec_id == AV_CODEC_ID_NONE)
388  av_log(s, AV_LOG_ERROR,
389  "Unknown codec tag '0x%04x' for stream number %d\n",
390  (unsigned int) tmp, stream_id);
391 
392  GET_V(stc->time_base_id, tmp < nut->time_base_count);
393  GET_V(stc->msb_pts_shift, tmp < 16);
395  GET_V(stc->decode_delay, tmp < 1000); // sanity limit, raise this if Moore's law is true
396  st->codec->has_b_frames = stc->decode_delay;
397  ffio_read_varlen(bc); // stream flags
398 
399  GET_V(st->codec->extradata_size, tmp < (1 << 30));
400  if (st->codec->extradata_size) {
403  avio_read(bc, st->codec->extradata, st->codec->extradata_size);
404  }
405 
406  if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
407  GET_V(st->codec->width, tmp > 0);
408  GET_V(st->codec->height, tmp > 0);
411  if ((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)) {
412  av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n",
414  return AVERROR_INVALIDDATA;
415  }
416  ffio_read_varlen(bc); /* csp type */
417  } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
418  GET_V(st->codec->sample_rate, tmp > 0);
419  ffio_read_varlen(bc); // samplerate_den
420  GET_V(st->codec->channels, tmp > 0);
421  }
422  if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
423  av_log(s, AV_LOG_ERROR,
424  "stream header %d checksum mismatch\n", stream_id);
425  return AVERROR_INVALIDDATA;
426  }
427  stc->time_base = &nut->time_base[stc->time_base_id];
428  avpriv_set_pts_info(s->streams[stream_id], 63, stc->time_base->num,
429  stc->time_base->den);
430  return 0;
431 }
432 
433 static void set_disposition_bits(AVFormatContext *avf, char *value,
434  int stream_id)
435 {
436  int flag = 0, i;
437 
438  for (i = 0; ff_nut_dispositions[i].flag; ++i)
439  if (!strcmp(ff_nut_dispositions[i].str, value))
440  flag = ff_nut_dispositions[i].flag;
441  if (!flag)
442  av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
443  for (i = 0; i < avf->nb_streams; ++i)
444  if (stream_id == i || stream_id == -1)
445  avf->streams[i]->disposition |= flag;
446 }
447 
449 {
450  AVFormatContext *s = nut->avf;
451  AVIOContext *bc = s->pb;
452  uint64_t tmp, chapter_start, chapter_len;
453  unsigned int stream_id_plus1, count;
454  int chapter_id, i;
455  int64_t value, end;
456  char name[256], str_value[1024], type_str[256];
457  const char *type;
458  AVChapter *chapter = NULL;
459  AVStream *st = NULL;
460  AVDictionary **metadata = NULL;
461 
462  end = get_packetheader(nut, bc, 1, INFO_STARTCODE);
463  end += avio_tell(bc);
464 
465  GET_V(stream_id_plus1, tmp <= s->nb_streams);
466  chapter_id = get_s(bc);
467  chapter_start = ffio_read_varlen(bc);
468  chapter_len = ffio_read_varlen(bc);
469  count = ffio_read_varlen(bc);
470 
471  if (chapter_id && !stream_id_plus1) {
472  int64_t start = chapter_start / nut->time_base_count;
473  chapter = avpriv_new_chapter(s, chapter_id,
474  nut->time_base[chapter_start %
475  nut->time_base_count],
476  start, start + chapter_len, NULL);
477  metadata = &chapter->metadata;
478  } else if (stream_id_plus1) {
479  st = s->streams[stream_id_plus1 - 1];
480  metadata = &st->metadata;
481  } else
482  metadata = &s->metadata;
483 
484  for (i = 0; i < count; i++) {
485  get_str(bc, name, sizeof(name));
486  value = get_s(bc);
487  if (value == -1) {
488  type = "UTF-8";
489  get_str(bc, str_value, sizeof(str_value));
490  } else if (value == -2) {
491  get_str(bc, type_str, sizeof(type_str));
492  type = type_str;
493  get_str(bc, str_value, sizeof(str_value));
494  } else if (value == -3) {
495  type = "s";
496  value = get_s(bc);
497  } else if (value == -4) {
498  type = "t";
499  value = ffio_read_varlen(bc);
500  } else if (value < -4) {
501  type = "r";
502  get_s(bc);
503  } else {
504  type = "v";
505  }
506 
507  if (stream_id_plus1 > s->nb_streams) {
508  av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
509  continue;
510  }
511 
512  if (!strcmp(type, "UTF-8")) {
513  if (chapter_id == 0 && !strcmp(name, "Disposition")) {
514  set_disposition_bits(s, str_value, stream_id_plus1 - 1);
515  continue;
516  }
517  if (metadata && av_strcasecmp(name, "Uses") &&
518  av_strcasecmp(name, "Depends") && av_strcasecmp(name, "Replaces"))
519  av_dict_set(metadata, name, str_value, 0);
520  }
521  }
522 
523  if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
524  av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
525  return AVERROR_INVALIDDATA;
526  }
527  return 0;
528 }
529 
530 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr)
531 {
532  AVFormatContext *s = nut->avf;
533  AVIOContext *bc = s->pb;
534  int64_t end, tmp;
535  int ret;
536 
537  nut->last_syncpoint_pos = avio_tell(bc) - 8;
538 
539  end = get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
540  end += avio_tell(bc);
541 
542  tmp = ffio_read_varlen(bc);
543  *back_ptr = nut->last_syncpoint_pos - 16 * ffio_read_varlen(bc);
544  if (*back_ptr < 0)
545  return -1;
546 
547  ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count],
548  tmp / nut->time_base_count);
549 
550  if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
551  av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
552  return AVERROR_INVALIDDATA;
553  }
554 
555  *ts = tmp / s->nb_streams *
556  av_q2d(nut->time_base[tmp % s->nb_streams]) * AV_TIME_BASE;
557 
558  if ((ret = ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts)) < 0)
559  return ret;
560 
561  return 0;
562 }
563 
565 {
566  AVFormatContext *s = nut->avf;
567  AVIOContext *bc = s->pb;
568  uint64_t tmp, end;
569  int i, j, syncpoint_count;
570  int64_t filesize = avio_size(bc);
571  int64_t *syncpoints;
572  int8_t *has_keyframe;
573  int ret = AVERROR_INVALIDDATA;
574 
575  avio_seek(bc, filesize - 12, SEEK_SET);
576  avio_seek(bc, filesize - avio_rb64(bc), SEEK_SET);
577  if (avio_rb64(bc) != INDEX_STARTCODE) {
578  av_log(s, AV_LOG_ERROR, "no index at the end\n");
579  return ret;
580  }
581 
582  end = get_packetheader(nut, bc, 1, INDEX_STARTCODE);
583  end += avio_tell(bc);
584 
585  ffio_read_varlen(bc); // max_pts
586  GET_V(syncpoint_count, tmp < INT_MAX / 8 && tmp > 0);
587  syncpoints = av_malloc(sizeof(int64_t) * syncpoint_count);
588  has_keyframe = av_malloc(sizeof(int8_t) * (syncpoint_count + 1));
589  for (i = 0; i < syncpoint_count; i++) {
590  syncpoints[i] = ffio_read_varlen(bc);
591  if (syncpoints[i] <= 0)
592  goto fail;
593  if (i)
594  syncpoints[i] += syncpoints[i - 1];
595  }
596 
597  for (i = 0; i < s->nb_streams; i++) {
598  int64_t last_pts = -1;
599  for (j = 0; j < syncpoint_count;) {
600  uint64_t x = ffio_read_varlen(bc);
601  int type = x & 1;
602  int n = j;
603  x >>= 1;
604  if (type) {
605  int flag = x & 1;
606  x >>= 1;
607  if (n + x >= syncpoint_count + 1) {
608  av_log(s, AV_LOG_ERROR, "index overflow A\n");
609  goto fail;
610  }
611  while (x--)
612  has_keyframe[n++] = flag;
613  has_keyframe[n++] = !flag;
614  } else {
615  while (x != 1) {
616  if (n >= syncpoint_count + 1) {
617  av_log(s, AV_LOG_ERROR, "index overflow B\n");
618  goto fail;
619  }
620  has_keyframe[n++] = x & 1;
621  x >>= 1;
622  }
623  }
624  if (has_keyframe[0]) {
625  av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
626  goto fail;
627  }
628  assert(n <= syncpoint_count + 1);
629  for (; j < n && j < syncpoint_count; j++) {
630  if (has_keyframe[j]) {
631  uint64_t B, A = ffio_read_varlen(bc);
632  if (!A) {
633  A = ffio_read_varlen(bc);
634  B = ffio_read_varlen(bc);
635  // eor_pts[j][i] = last_pts + A + B
636  } else
637  B = 0;
638  av_add_index_entry(s->streams[i], 16 * syncpoints[j - 1],
639  last_pts + A, 0, 0, AVINDEX_KEYFRAME);
640  last_pts += A + B;
641  }
642  }
643  }
644  }
645 
646  if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
647  av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
648  goto fail;
649  }
650  ret = 0;
651 
652 fail:
653  av_free(syncpoints);
654  av_free(has_keyframe);
655  return ret;
656 }
657 
659 {
660  NUTContext *nut = s->priv_data;
661  AVIOContext *bc = s->pb;
662  int64_t pos;
663  int initialized_stream_count;
664 
665  nut->avf = s;
666 
667  /* main header */
668  pos = 0;
669  do {
670  pos = find_startcode(bc, MAIN_STARTCODE, pos) + 1;
671  if (pos < 0 + 1) {
672  av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
673  return AVERROR_INVALIDDATA;
674  }
675  } while (decode_main_header(nut) < 0);
676 
677  /* stream headers */
678  pos = 0;
679  for (initialized_stream_count = 0; initialized_stream_count < s->nb_streams;) {
680  pos = find_startcode(bc, STREAM_STARTCODE, pos) + 1;
681  if (pos < 0 + 1) {
682  av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
683  return AVERROR_INVALIDDATA;
684  }
685  if (decode_stream_header(nut) >= 0)
686  initialized_stream_count++;
687  }
688 
689  /* info headers */
690  pos = 0;
691  for (;;) {
692  uint64_t startcode = find_any_startcode(bc, pos);
693  pos = avio_tell(bc);
694 
695  if (startcode == 0) {
696  av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
697  return AVERROR_INVALIDDATA;
698  } else if (startcode == SYNCPOINT_STARTCODE) {
699  nut->next_startcode = startcode;
700  break;
701  } else if (startcode != INFO_STARTCODE) {
702  continue;
703  }
704 
705  decode_info_header(nut);
706  }
707 
708  s->data_offset = pos - 8;
709 
710  if (bc->seekable) {
711  int64_t orig_pos = avio_tell(bc);
713  avio_seek(bc, orig_pos, SEEK_SET);
714  }
715  assert(nut->next_startcode == SYNCPOINT_STARTCODE);
716 
718 
719  return 0;
720 }
721 
722 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id,
723  uint8_t *header_idx, int frame_code)
724 {
725  AVFormatContext *s = nut->avf;
726  AVIOContext *bc = s->pb;
727  StreamContext *stc;
728  int size, flags, size_mul, pts_delta, i, reserved_count;
729  uint64_t tmp;
730 
731  if (avio_tell(bc) > nut->last_syncpoint_pos + nut->max_distance) {
732  av_log(s, AV_LOG_ERROR,
733  "Last frame must have been damaged %"PRId64" > %"PRId64" + %d\n",
734  avio_tell(bc), nut->last_syncpoint_pos, nut->max_distance);
735  return AVERROR_INVALIDDATA;
736  }
737 
738  flags = nut->frame_code[frame_code].flags;
739  size_mul = nut->frame_code[frame_code].size_mul;
740  size = nut->frame_code[frame_code].size_lsb;
741  *stream_id = nut->frame_code[frame_code].stream_id;
742  pts_delta = nut->frame_code[frame_code].pts_delta;
743  reserved_count = nut->frame_code[frame_code].reserved_count;
744  *header_idx = nut->frame_code[frame_code].header_idx;
745 
746  if (flags & FLAG_INVALID)
747  return AVERROR_INVALIDDATA;
748  if (flags & FLAG_CODED)
749  flags ^= ffio_read_varlen(bc);
750  if (flags & FLAG_STREAM_ID) {
751  GET_V(*stream_id, tmp < s->nb_streams);
752  }
753  stc = &nut->stream[*stream_id];
754  if (flags & FLAG_CODED_PTS) {
755  int coded_pts = ffio_read_varlen(bc);
756  // FIXME check last_pts validity?
757  if (coded_pts < (1 << stc->msb_pts_shift)) {
758  *pts = ff_lsb2full(stc, coded_pts);
759  } else
760  *pts = coded_pts - (1 << stc->msb_pts_shift);
761  } else
762  *pts = stc->last_pts + pts_delta;
763  if (flags & FLAG_SIZE_MSB)
764  size += size_mul * ffio_read_varlen(bc);
765  if (flags & FLAG_MATCH_TIME)
766  get_s(bc);
767  if (flags & FLAG_HEADER_IDX)
768  *header_idx = ffio_read_varlen(bc);
769  if (flags & FLAG_RESERVED)
770  reserved_count = ffio_read_varlen(bc);
771  for (i = 0; i < reserved_count; i++)
772  ffio_read_varlen(bc);
773 
774  if (*header_idx >= (unsigned)nut->header_count) {
775  av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
776  return AVERROR_INVALIDDATA;
777  }
778  if (size > 4096)
779  *header_idx = 0;
780  size -= nut->header_len[*header_idx];
781 
782  if (flags & FLAG_CHECKSUM) {
783  avio_rb32(bc); // FIXME check this
784  } else if (size > 2 * nut->max_distance || FFABS(stc->last_pts - *pts) >
785  stc->max_pts_distance) {
786  av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
787  return AVERROR_INVALIDDATA;
788  }
789 
790  stc->last_pts = *pts;
791  stc->last_flags = flags;
792 
793  return size;
794 }
795 
796 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code)
797 {
798  AVFormatContext *s = nut->avf;
799  AVIOContext *bc = s->pb;
800  int size, stream_id, discard;
801  int64_t pts, last_IP_pts;
802  StreamContext *stc;
803  uint8_t header_idx;
804 
805  size = decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
806  if (size < 0)
807  return size;
808 
809  stc = &nut->stream[stream_id];
810 
811  if (stc->last_flags & FLAG_KEY)
812  stc->skip_until_key_frame = 0;
813 
814  discard = s->streams[stream_id]->discard;
815  last_IP_pts = s->streams[stream_id]->last_IP_pts;
816  if ((discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY)) ||
817  (discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE &&
818  last_IP_pts > pts) ||
819  discard >= AVDISCARD_ALL ||
820  stc->skip_until_key_frame) {
821  avio_skip(bc, size);
822  return 1;
823  }
824 
825  av_new_packet(pkt, size + nut->header_len[header_idx]);
826  memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
827  pkt->pos = avio_tell(bc); // FIXME
828  avio_read(bc, pkt->data + nut->header_len[header_idx], size);
829 
830  pkt->stream_index = stream_id;
831  if (stc->last_flags & FLAG_KEY)
832  pkt->flags |= AV_PKT_FLAG_KEY;
833  pkt->pts = pts;
834 
835  return 0;
836 }
837 
839 {
840  NUTContext *nut = s->priv_data;
841  AVIOContext *bc = s->pb;
842  int i, frame_code = 0, ret, skip;
843  int64_t ts, back_ptr;
844 
845  for (;;) {
846  int64_t pos = avio_tell(bc);
847  uint64_t tmp = nut->next_startcode;
848  nut->next_startcode = 0;
849 
850  if (tmp) {
851  pos -= 8;
852  } else {
853  frame_code = avio_r8(bc);
854  if (bc->eof_reached)
855  return AVERROR_EOF;
856  if (frame_code == 'N') {
857  tmp = frame_code;
858  for (i = 1; i < 8; i++)
859  tmp = (tmp << 8) + avio_r8(bc);
860  }
861  }
862  switch (tmp) {
863  case MAIN_STARTCODE:
864  case STREAM_STARTCODE:
865  case INDEX_STARTCODE:
866  skip = get_packetheader(nut, bc, 0, tmp);
867  avio_skip(bc, skip);
868  break;
869  case INFO_STARTCODE:
870  if (decode_info_header(nut) < 0)
871  goto resync;
872  break;
873  case SYNCPOINT_STARTCODE:
874  if (decode_syncpoint(nut, &ts, &back_ptr) < 0)
875  goto resync;
876  frame_code = avio_r8(bc);
877  case 0:
878  ret = decode_frame(nut, pkt, frame_code);
879  if (ret == 0)
880  return 0;
881  else if (ret == 1) // OK but discard packet
882  break;
883  default:
884 resync:
885  av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
886  tmp = find_any_startcode(bc, nut->last_syncpoint_pos + 1);
887  if (tmp == 0)
888  return AVERROR_INVALIDDATA;
889  av_log(s, AV_LOG_DEBUG, "sync\n");
890  nut->next_startcode = tmp;
891  }
892  }
893 }
894 
895 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index,
896  int64_t *pos_arg, int64_t pos_limit)
897 {
898  NUTContext *nut = s->priv_data;
899  AVIOContext *bc = s->pb;
900  int64_t pos, pts, back_ptr;
901  av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n",
902  stream_index, *pos_arg, pos_limit);
903 
904  pos = *pos_arg;
905  do {
906  pos = find_startcode(bc, SYNCPOINT_STARTCODE, pos) + 1;
907  if (pos < 1) {
908  assert(nut->next_startcode == 0);
909  av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
910  return AV_NOPTS_VALUE;
911  }
912  } while (decode_syncpoint(nut, &pts, &back_ptr) < 0);
913  *pos_arg = pos - 1;
914  assert(nut->last_syncpoint_pos == *pos_arg);
915 
916  av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts, back_ptr);
917  if (stream_index == -1)
918  return pts;
919  else if (stream_index == -2)
920  return back_ptr;
921 
922  return AV_NOPTS_VALUE;
923 }
924 
925 static int read_seek(AVFormatContext *s, int stream_index,
926  int64_t pts, int flags)
927 {
928  NUTContext *nut = s->priv_data;
929  AVStream *st = s->streams[stream_index];
930  Syncpoint dummy = { .ts = pts * av_q2d(st->time_base) * AV_TIME_BASE };
931  Syncpoint nopts_sp = { .ts = AV_NOPTS_VALUE, .back_ptr = AV_NOPTS_VALUE };
932  Syncpoint *sp, *next_node[2] = { &nopts_sp, &nopts_sp };
933  int64_t pos, pos2, ts;
934  int i;
935 
936  if (st->index_entries) {
937  int index = av_index_search_timestamp(st, pts, flags);
938  if (index < 0)
939  return -1;
940 
941  pos2 = st->index_entries[index].pos;
942  ts = st->index_entries[index].timestamp;
943  } else {
944  av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pts_cmp,
945  (void **) next_node);
946  av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n",
947  next_node[0]->pos, next_node[1]->pos, next_node[0]->ts,
948  next_node[1]->ts);
949  pos = ff_gen_search(s, -1, dummy.ts, next_node[0]->pos,
950  next_node[1]->pos, next_node[1]->pos,
951  next_node[0]->ts, next_node[1]->ts,
953 
954  if (!(flags & AVSEEK_FLAG_BACKWARD)) {
955  dummy.pos = pos + 16;
956  next_node[1] = &nopts_sp;
957  av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
958  (void **) next_node);
959  pos2 = ff_gen_search(s, -2, dummy.pos, next_node[0]->pos,
960  next_node[1]->pos, next_node[1]->pos,
961  next_node[0]->back_ptr, next_node[1]->back_ptr,
962  flags, &ts, nut_read_timestamp);
963  if (pos2 >= 0)
964  pos = pos2;
965  // FIXME dir but I think it does not matter
966  }
967  dummy.pos = pos;
968  sp = av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
969  NULL);
970 
971  assert(sp);
972  pos2 = sp->back_ptr - 15;
973  }
974  av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
975  pos = find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
976  avio_seek(s->pb, pos, SEEK_SET);
977  av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
978  if (pos2 > pos || pos2 + 15 < pos)
979  av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
980  for (i = 0; i < s->nb_streams; i++)
981  nut->stream[i].skip_until_key_frame = 1;
982 
983  return 0;
984 }
985 
987 {
988  NUTContext *nut = s->priv_data;
989  int i;
990 
991  av_freep(&nut->time_base);
992  av_freep(&nut->stream);
993  ff_nut_free_sp(nut);
994  for (i = 1; i < nut->header_count; i++)
995  av_freep(&nut->header[i]);
996 
997  return 0;
998 }
999 
1001  .name = "nut",
1002  .long_name = NULL_IF_CONFIG_SMALL("NUT"),
1003  .priv_data_size = sizeof(NUTContext),
1004  .read_probe = nut_probe,
1008  .read_seek = read_seek,
1009  .extensions = "nut",
1010  .codec_tag = ff_nut_codec_tags,
1011 };