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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  while (*ptr == '\r' || *ptr == '\n')
41  ptr++;
42  for (i=0; i<2; i++) {
43  if ((num == i || num + 1 == i)
44  && sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
45  return AVPROBE_SCORE_MAX;
46  num = atoi(ptr);
47  ptr += ff_subtitles_next_line(ptr);
48  }
49  return 0;
50 }
51 
52 static int64_t get_pts(const char **buf, int *duration,
53  int32_t *x1, int32_t *y1, int32_t *x2, int32_t *y2)
54 {
55  int i;
56 
57  for (i=0; i<2; i++) {
58  int hh1, mm1, ss1, ms1;
59  int hh2, mm2, ss2, ms2;
60  if (sscanf(*buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
61  "%*[ ]X1:%u X2:%u Y1:%u Y2:%u",
62  &hh1, &mm1, &ss1, &ms1,
63  &hh2, &mm2, &ss2, &ms2,
64  x1, x2, y1, y2) >= 8) {
65  int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
66  int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
67  *duration = end - start;
68  *buf += ff_subtitles_next_line(*buf);
69  return start;
70  }
71  *buf += ff_subtitles_next_line(*buf);
72  }
73  return AV_NOPTS_VALUE;
74 }
75 
77 {
78  SRTContext *srt = s->priv_data;
79  AVBPrint buf;
80  AVStream *st = avformat_new_stream(s, NULL);
81  int res = 0;
82 
83  if (!st)
84  return AVERROR(ENOMEM);
85  avpriv_set_pts_info(st, 64, 1, 1000);
88 
90 
91  while (!avio_feof(s->pb)) {
92  ff_subtitles_read_chunk(s->pb, &buf);
93 
94  if (buf.len) {
95  int64_t pos = avio_tell(s->pb);
96  int64_t pts;
97  int duration;
98  const char *ptr = buf.str;
99  int32_t x1 = -1, y1 = -1, x2 = -1, y2 = -1;
100  AVPacket *sub;
101 
102  pts = get_pts(&ptr, &duration, &x1, &y1, &x2, &y2);
103  if (pts != AV_NOPTS_VALUE) {
104  int len = buf.len - (ptr - buf.str);
105  if (len <= 0)
106  continue;
107  sub = ff_subtitles_queue_insert(&srt->q, ptr, len, 0);
108  if (!sub) {
109  res = AVERROR(ENOMEM);
110  goto end;
111  }
112  sub->pos = pos;
113  sub->pts = pts;
114  sub->duration = duration;
115  if (x1 != -1) {
117  if (p) {
118  AV_WL32(p, x1);
119  AV_WL32(p + 4, y1);
120  AV_WL32(p + 8, x2);
121  AV_WL32(p + 12, y2);
122  }
123  }
124  }
125  }
126  }
127 
129 
130 end:
131  av_bprint_finalize(&buf, NULL);
132  return res;
133 }
134 
136 {
137  SRTContext *srt = s->priv_data;
138  return ff_subtitles_queue_read_packet(&srt->q, pkt);
139 }
140 
141 static int srt_read_seek(AVFormatContext *s, int stream_index,
142  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
143 {
144  SRTContext *srt = s->priv_data;
145  return ff_subtitles_queue_seek(&srt->q, s, stream_index,
146  min_ts, ts, max_ts, flags);
147 }
148 
150 {
151  SRTContext *srt = s->priv_data;
153  return 0;
154 }
155 
157  .name = "srt",
158  .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
159  .priv_data_size = sizeof(SRTContext),
163  .read_seek2 = srt_read_seek,
165 };