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realtextdec.c
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1 /*
2  * Copyright (c) 2012 Clément Bœsch
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * RealText subtitle demuxer
24  * @see http://service.real.com/help/library/guides/ProductionGuide/prodguide/htmfiles/realtext.htm
25  */
26 
27 #include "avformat.h"
28 #include "internal.h"
29 #include "subtitles.h"
30 #include "libavutil/avstring.h"
31 #include "libavutil/bprint.h"
32 #include "libavutil/intreadwrite.h"
33 
34 typedef struct {
37 
39 {
40  char buf[7];
41  FFTextReader tr;
42  ff_text_init_buf(&tr, p->buf, p->buf_size);
43  ff_text_read(&tr, buf, sizeof(buf));
44 
45  return !av_strncasecmp(buf, "<window", 7) ? AVPROBE_SCORE_EXTENSION : 0;
46 }
47 
48 static int read_ts(const char *s)
49 {
50  int hh, mm, ss, ms;
51 
52  if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600 + mm*60 + ss) * 100 + ms;
53  if (sscanf(s, "%u:%u:%u" , &hh, &mm, &ss ) == 3) return (hh*3600 + mm*60 + ss) * 100;
54  if (sscanf(s, "%u:%u.%u", &mm, &ss, &ms) == 3) return ( mm*60 + ss) * 100 + ms;
55  if (sscanf(s, "%u:%u" , &mm, &ss ) == 2) return ( mm*60 + ss) * 100;
56  if (sscanf(s, "%u.%u", &ss, &ms) == 2) return ( ss) * 100 + ms;
57  return strtol(s, NULL, 10) * 100;
58 }
59 
61 {
62  RealTextContext *rt = s->priv_data;
64  AVBPrint buf;
65  char c = 0;
66  int res = 0, duration = read_ts("60"); // default duration is 60 seconds
67  FFTextReader tr;
68  ff_text_init_avio(s, &tr, s->pb);
69 
70  if (!st)
71  return AVERROR(ENOMEM);
72  avpriv_set_pts_info(st, 64, 1, 100);
75 
77 
78  while (!ff_text_eof(&tr)) {
79  AVPacket *sub;
80  const int64_t pos = ff_text_pos(&tr) - (c != 0);
81  int n = ff_smil_extract_next_text_chunk(&tr, &buf, &c);
82 
83  if (n == 0)
84  break;
85 
86  if (!av_strncasecmp(buf.str, "<window", 7)) {
87  /* save header to extradata */
88  const char *p = ff_smil_get_attr_ptr(buf.str, "duration");
89 
90  if (p)
91  duration = read_ts(p);
92  st->codec->extradata = av_strdup(buf.str);
93  if (!st->codec->extradata) {
94  res = AVERROR(ENOMEM);
95  goto end;
96  }
97  st->codec->extradata_size = buf.len + 1;
98  } else {
99  /* if we just read a <time> tag, introduce a new event, otherwise merge
100  * with the previous one */
101  int merge = !av_strncasecmp(buf.str, "<time", 5) ? 0 : 1;
102  sub = ff_subtitles_queue_insert(&rt->q, buf.str, buf.len, merge);
103  if (!sub) {
104  res = AVERROR(ENOMEM);
105  goto end;
106  }
107  if (!merge) {
108  const char *begin = ff_smil_get_attr_ptr(buf.str, "begin");
109  const char *end = ff_smil_get_attr_ptr(buf.str, "end");
110 
111  sub->pos = pos;
112  sub->pts = begin ? read_ts(begin) : 0;
113  sub->duration = end ? (read_ts(end) - sub->pts) : duration;
114  }
115  }
116  av_bprint_clear(&buf);
117  }
119 
120 end:
121  av_bprint_finalize(&buf, NULL);
122  return res;
123 }
124 
126 {
127  RealTextContext *rt = s->priv_data;
128  return ff_subtitles_queue_read_packet(&rt->q, pkt);
129 }
130 
131 static int realtext_read_seek(AVFormatContext *s, int stream_index,
132  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
133 {
134  RealTextContext *rt = s->priv_data;
135  return ff_subtitles_queue_seek(&rt->q, s, stream_index,
136  min_ts, ts, max_ts, flags);
137 }
138 
140 {
141  RealTextContext *rt = s->priv_data;
143  return 0;
144 }
145 
147  .name = "realtext",
148  .long_name = NULL_IF_CONFIG_SMALL("RealText subtitle format"),
149  .priv_data_size = sizeof(RealTextContext),
153  .read_seek2 = realtext_read_seek,
155  .extensions = "rt",
156 };