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srtdec.c
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1 /*
2  * SubRip subtitle demuxer
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "subtitles.h"
25 #include "libavutil/bprint.h"
26 #include "libavutil/intreadwrite.h"
27 
28 typedef struct {
30 } SRTContext;
31 
32 static int srt_probe(AVProbeData *p)
33 {
34  const unsigned char *ptr = p->buf;
35  int i, v, num = 0;
36 
37  if (AV_RB24(ptr) == 0xEFBBBF)
38  ptr += 3; /* skip UTF-8 BOM */
39 
40  for (i=0; i<2; i++) {
41  if ((num == i || num + 1 == i)
42  && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
43  return AVPROBE_SCORE_MAX;
44  num = atoi(ptr);
45  ptr += strcspn(ptr, "\n") + 1;
46  }
47  return 0;
48 }
49 
50 static int64_t get_pts(const char **buf, int *duration,
51  int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
52 {
53  int i;
54 
55  for (i=0; i<2; i++) {
56  int hh1, mm1, ss1, ms1;
57  int hh2, mm2, ss2, ms2;
58  if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
59  "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
60  &hh1, &mm1, &ss1, &ms1,
61  &hh2, &mm2, &ss2, &ms2,
62  x1, x2, y1, y2) >= 8) {
63  int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
64  int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
65  *duration = end - start;
66  *buf += strcspn(*buf, "\n") + 1;
67  return start;
68  }
69  *buf += strcspn(*buf, "\n") + 1;
70  }
71  return AV_NOPTS_VALUE;
72 }
73 
75 {
76  SRTContext *srt = s->priv_data;
77  AVBPrint buf;
79  int res = 0;
80 
81  if (!st)
82  return AVERROR(ENOMEM);
83  avpriv_set_pts_info(st, 64, 1, 1000);
86 
88 
89  while (!url_feof(s->pb)) {
90  ff_subtitles_read_chunk(s->pb, &buf);
91 
92  if (buf.len) {
93  int64_t pos = avio_tell(s->pb);
94  int64_t pts;
95  int duration;
96  const char *ptr = buf.str;
97  int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;
98  AVPacket *sub;
99 
100  pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
101  if (pts != AV_NOPTS_VALUE) {
102  int len = buf.len - (ptr - buf.str);
103  if (len <= 0)
104  continue;
105  sub = ff_subtitles_queue_insert(&srt->q, ptr, len, 0);
106  if (!sub) {
107  res = AVERROR(ENOMEM);
108  goto end;
109  }
110  sub->pos = pos;
111  sub->pts = pts;
112  sub->duration = duration;
113  if (x1 != -1) {
115  if (p) {
116  AV_WL32(p, x1);
117  AV_WL32(p + 4, y1);
118  AV_WL32(p + 8, x2);
119  AV_WL32(p + 12, y2);
120  }
121  }
122  }
123  }
124  }
125 
127 
128 end:
129  av_bprint_finalize(&buf, NULL);
130  return res;
131 }
132 
134 {
135  SRTContext *srt = s->priv_data;
136  return ff_subtitles_queue_read_packet(&srt->q, pkt);
137 }
138 
139 static int srt_read_seek(AVFormatContext *s, int stream_index,
140  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
141 {
142  SRTContext *srt = s->priv_data;
143  return ff_subtitles_queue_seek(&srt->q, s, stream_index,
144  min_ts, ts, max_ts, flags);
145 }
146 
148 {
149  SRTContext *srt = s->priv_data;
151  return 0;
152 }
153 
155  .name = "srt",
156  .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
157  .priv_data_size = sizeof(SRTContext),
161  .read_seek2 = srt_read_seek,
163 };