srtdec.c
Go to the documentation of this file.
1 /*
2  * SubRip subtitle demuxer
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4  *
5  * This file is part of Libav.
6  *
7  * Libav is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * Libav is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 #include "internal.h"
24 #include "libavutil/intreadwrite.h"
25 
26 static int srt_probe(AVProbeData *p)
27 {
28  unsigned char *ptr = p->buf;
29  int i, v, num = 0;
30 
31  if (AV_RB24(ptr) == 0xEFBBBF)
32  ptr += 3; /* skip UTF-8 BOM */
33 
34  for (i=0; i<2; i++) {
35  if (num == i && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
36  return AVPROBE_SCORE_MAX;
37  num = atoi(ptr);
38  ptr += strcspn(ptr, "\n") + 1;
39  }
40  return 0;
41 }
42 
44 {
46  if (!st)
47  return -1;
48  avpriv_set_pts_info(st, 64, 1, 1000);
51  return 0;
52 }
53 
54 static int64_t get_pts(const char *buf)
55 {
56  int i, v, hour, min, sec, hsec;
57 
58  for (i=0; i<2; i++) {
59  if (sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %*d:%*2d:%*2d%*1[,.]%3d",
60  &hour, &min, &sec, &hsec, &v) == 5) {
61  min += 60*hour;
62  sec += 60*min;
63  return sec*1000+hsec;
64  }
65  buf += strcspn(buf, "\n") + 1;
66  }
67  return AV_NOPTS_VALUE;
68 }
69 
70 static inline int is_eol(char c)
71 {
72  return c == '\r' || c == '\n';
73 }
74 
76 {
77  char buffer[2048], *ptr = buffer, *ptr2;
78  int64_t pos = avio_tell(s->pb);
79  int res = AVERROR_EOF;
80 
81  do {
82  ptr2 = ptr;
83  ptr += ff_get_line(s->pb, ptr, sizeof(buffer)+buffer-ptr);
84  } while (!is_eol(*ptr2) && !s->pb->eof_reached && ptr-buffer<sizeof(buffer)-1);
85 
86  if (buffer[0] && !(res = av_new_packet(pkt, ptr-buffer))) {
87  memcpy(pkt->data, buffer, pkt->size);
88  pkt->flags |= AV_PKT_FLAG_KEY;
89  pkt->pos = pos;
90  pkt->pts = pkt->dts = get_pts(pkt->data);
91  }
92  return res;
93 }
94 
96  .name = "srt",
97  .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle format"),
98  .read_probe = srt_probe,
99  .read_header = srt_read_header,
100  .read_packet = srt_read_packet,
101  .flags = AVFMT_GENERIC_INDEX,
102 };