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samidec.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  * SAMI subtitle demuxer
24  * @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
25  */
26 
27 #include "avformat.h"
28 #include "internal.h"
29 #include "subtitles.h"
30 #include "libavcodec/internal.h"
31 #include "libavutil/avstring.h"
32 #include "libavutil/bprint.h"
33 #include "libavutil/intreadwrite.h"
34 
35 typedef struct {
37 } SAMIContext;
38 
39 static int sami_probe(AVProbeData *p)
40 {
41  char buf[6];
42  FFTextReader tr;
43  ff_text_init_buf(&tr, p->buf, p->buf_size);
44  ff_text_read(&tr, buf, sizeof(buf));
45 
46  return !strncmp(buf, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
47 }
48 
50 {
51  SAMIContext *sami = s->priv_data;
53  AVBPrint buf, hdr_buf;
54  char c = 0;
55  int res = 0, got_first_sync_point = 0;
56  FFTextReader tr;
57  ff_text_init_avio(s, &tr, s->pb);
58 
59  if (!st)
60  return AVERROR(ENOMEM);
61  avpriv_set_pts_info(st, 64, 1, 1000);
64 
67 
68  while (!ff_text_eof(&tr)) {
69  AVPacket *sub;
70  const int64_t pos = ff_text_pos(&tr) - (c != 0);
71  int is_sync, n = ff_smil_extract_next_text_chunk(&tr, &buf, &c);
72 
73  if (n == 0)
74  break;
75 
76  is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
77  if (is_sync)
78  got_first_sync_point = 1;
79 
80  if (!got_first_sync_point) {
81  av_bprintf(&hdr_buf, "%s", buf.str);
82  } else {
83  sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
84  if (!sub) {
85  res = AVERROR(ENOMEM);
86  goto end;
87  }
88  if (is_sync) {
89  const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
90  sub->pos = pos;
91  sub->pts = p ? strtol(p, NULL, 10) : 0;
92  sub->duration = -1;
93  }
94  }
95  av_bprint_clear(&buf);
96  }
97 
98  res = avpriv_bprint_to_extradata(st->codec, &hdr_buf);
99  if (res < 0)
100  goto end;
101 
103 
104 end:
105  av_bprint_finalize(&buf, NULL);
106  return res;
107 }
108 
110 {
111  SAMIContext *sami = s->priv_data;
112  return ff_subtitles_queue_read_packet(&sami->q, pkt);
113 }
114 
115 static int sami_read_seek(AVFormatContext *s, int stream_index,
116  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
117 {
118  SAMIContext *sami = s->priv_data;
119  return ff_subtitles_queue_seek(&sami->q, s, stream_index,
120  min_ts, ts, max_ts, flags);
121 }
122 
124 {
125  SAMIContext *sami = s->priv_data;
126  ff_subtitles_queue_clean(&sami->q);
127  return 0;
128 }
129 
131  .name = "sami",
132  .long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
133  .priv_data_size = sizeof(SAMIContext),
137  .read_seek2 = sami_read_seek,
139  .extensions = "smi,sami",
140 };