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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  const unsigned char *ptr = p->buf;
41 
42  if (AV_RB24(ptr) == 0xEFBBBF)
43  ptr += 3; /* skip UTF-8 BOM */
44  return !av_strncasecmp(ptr, "<window", 7) ? AVPROBE_SCORE_EXTENSION : 0;
45 }
46 
47 static int read_ts(const char *s)
48 {
49  int hh, mm, ss, ms;
50 
51  if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600 + mm*60 + ss) * 100 + ms;
52  if (sscanf(s, "%u:%u:%u" , &hh, &mm, &ss ) == 3) return (hh*3600 + mm*60 + ss) * 100;
53  if (sscanf(s, "%u:%u.%u", &mm, &ss, &ms) == 3) return ( mm*60 + ss) * 100 + ms;
54  if (sscanf(s, "%u:%u" , &mm, &ss ) == 2) return ( mm*60 + ss) * 100;
55  if (sscanf(s, "%u.%u", &ss, &ms) == 2) return ( ss) * 100 + ms;
56  return strtol(s, NULL, 10) * 100;
57 }
58 
60 {
61  RealTextContext *rt = s->priv_data;
62  AVStream *st = avformat_new_stream(s, NULL);
63  AVBPrint buf;
64  char c = 0;
65  int res = 0, duration = read_ts("60"); // default duration is 60 seconds
66 
67  if (!st)
68  return AVERROR(ENOMEM);
69  avpriv_set_pts_info(st, 64, 1, 100);
72 
74 
75  while (!avio_feof(s->pb)) {
76  AVPacket *sub;
77  const int64_t pos = avio_tell(s->pb) - (c != 0);
78  int n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
79 
80  if (n == 0)
81  break;
82 
83  if (!av_strncasecmp(buf.str, "<window", 7)) {
84  /* save header to extradata */
85  const char *p = ff_smil_get_attr_ptr(buf.str, "duration");
86 
87  if (p)
88  duration = read_ts(p);
89  st->codec->extradata = av_strdup(buf.str);
90  if (!st->codec->extradata) {
91  res = AVERROR(ENOMEM);
92  goto end;
93  }
94  st->codec->extradata_size = buf.len + 1;
95  } else {
96  /* if we just read a <time> tag, introduce a new event, otherwise merge
97  * with the previous one */
98  int merge = !av_strncasecmp(buf.str, "<time", 5) ? 0 : 1;
99  sub = ff_subtitles_queue_insert(&rt->q, buf.str, buf.len, merge);
100  if (!sub) {
101  res = AVERROR(ENOMEM);
102  goto end;
103  }
104  if (!merge) {
105  const char *begin = ff_smil_get_attr_ptr(buf.str, "begin");
106  const char *end = ff_smil_get_attr_ptr(buf.str, "end");
107 
108  sub->pos = pos;
109  sub->pts = begin ? read_ts(begin) : 0;
110  sub->duration = end ? (read_ts(end) - sub->pts) : duration;
111  }
112  }
113  av_bprint_clear(&buf);
114  }
116 
117 end:
118  av_bprint_finalize(&buf, NULL);
119  return res;
120 }
121 
123 {
124  RealTextContext *rt = s->priv_data;
125  return ff_subtitles_queue_read_packet(&rt->q, pkt);
126 }
127 
128 static int realtext_read_seek(AVFormatContext *s, int stream_index,
129  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
130 {
131  RealTextContext *rt = s->priv_data;
132  return ff_subtitles_queue_seek(&rt->q, s, stream_index,
133  min_ts, ts, max_ts, flags);
134 }
135 
137 {
138  RealTextContext *rt = s->priv_data;
140  return 0;
141 }
142 
144  .name = "realtext",
145  .long_name = NULL_IF_CONFIG_SMALL("RealText subtitle format"),
146  .priv_data_size = sizeof(RealTextContext),
150  .read_seek2 = realtext_read_seek,
152  .extensions = "rt",
153 };