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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  const unsigned char *ptr = p->buf;
42 
43  if (AV_RB24(ptr) == 0xEFBBBF)
44  ptr += 3; /* skip UTF-8 BOM */
45  return !strncmp(ptr, "<SAMI>", 6) ? AVPROBE_SCORE_MAX : 0;
46 }
47 
49 {
50  SAMIContext *sami = s->priv_data;
51  AVStream *st = avformat_new_stream(s, NULL);
52  AVBPrint buf, hdr_buf;
53  char c = 0;
54  int res = 0, got_first_sync_point = 0;
55 
56  if (!st)
57  return AVERROR(ENOMEM);
58  avpriv_set_pts_info(st, 64, 1, 1000);
61 
64 
65  while (!avio_feof(s->pb)) {
66  AVPacket *sub;
67  const int64_t pos = avio_tell(s->pb) - (c != 0);
68  int is_sync, n = ff_smil_extract_next_chunk(s->pb, &buf, &c);
69 
70  if (n == 0)
71  break;
72 
73  is_sync = !av_strncasecmp(buf.str, "<SYNC", 5);
74  if (is_sync)
75  got_first_sync_point = 1;
76 
77  if (!got_first_sync_point) {
78  av_bprintf(&hdr_buf, "%s", buf.str);
79  } else {
80  sub = ff_subtitles_queue_insert(&sami->q, buf.str, buf.len, !is_sync);
81  if (!sub) {
82  res = AVERROR(ENOMEM);
83  goto end;
84  }
85  if (is_sync) {
86  const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
87  sub->pos = pos;
88  sub->pts = p ? strtol(p, NULL, 10) : 0;
89  sub->duration = -1;
90  }
91  }
92  av_bprint_clear(&buf);
93  }
94 
95  res = avpriv_bprint_to_extradata(st->codec, &hdr_buf);
96  if (res < 0)
97  goto end;
98 
100 
101 end:
102  av_bprint_finalize(&buf, NULL);
103  return res;
104 }
105 
107 {
108  SAMIContext *sami = s->priv_data;
109  return ff_subtitles_queue_read_packet(&sami->q, pkt);
110 }
111 
112 static int sami_read_seek(AVFormatContext *s, int stream_index,
113  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
114 {
115  SAMIContext *sami = s->priv_data;
116  return ff_subtitles_queue_seek(&sami->q, s, stream_index,
117  min_ts, ts, max_ts, flags);
118 }
119 
121 {
122  SAMIContext *sami = s->priv_data;
123  ff_subtitles_queue_clean(&sami->q);
124  return 0;
125 }
126 
128  .name = "sami",
129  .long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle format"),
130  .priv_data_size = sizeof(SAMIContext),
134  .read_seek2 = sami_read_seek,
136  .extensions = "smi,sami",
137 };