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microdvddec.c
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1 /*
2  * MicroDVD subtitle demuxer
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4  * Copyright (c) 2012 Clément Bœsch <ubitux@gmail.com>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "avformat.h"
24 #include "internal.h"
25 #include "subtitles.h"
26 #include "libavutil/intreadwrite.h"
27 
28 #define MAX_LINESIZE 2048
29 
30 
31 typedef struct {
34 
35 
37 {
38  unsigned char c;
39  const uint8_t *ptr = p->buf;
40  int i;
41 
42  if (AV_RB24(ptr) == 0xEFBBBF)
43  ptr += 3; /* skip UTF-8 BOM */
44 
45  for (i=0; i<3; i++) {
46  if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
47  sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
48  sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
49  return 0;
50  ptr += strcspn(ptr, "\n") + 1;
51  }
52  return AVPROBE_SCORE_MAX;
53 }
54 
55 static int64_t get_pts(const char *buf)
56 {
57  int frame;
58  char c;
59 
60  if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
61  return frame;
62  return AV_NOPTS_VALUE;
63 }
64 
65 static int get_duration(const char *buf)
66 {
67  int frame_start, frame_end;
68 
69  if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
70  return frame_end - frame_start;
71  return -1;
72 }
73 
75 {
76  AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
77  MicroDVDContext *microdvd = s->priv_data;
78  AVStream *st = avformat_new_stream(s, NULL);
79  int i = 0;
80  char line[MAX_LINESIZE];
81 
82  if (!st)
83  return AVERROR(ENOMEM);
84 
85  while (!url_feof(s->pb)) {
86  char *p = line;
87  AVPacket *sub;
88  int64_t pos = avio_tell(s->pb);
89  int len = ff_get_line(s->pb, line, sizeof(line));
90 
91  if (!len)
92  break;
93  line[strcspn(line, "\r\n")] = 0;
94  if (i++ < 3) {
95  int frame;
96  double fps;
97  char c;
98 
99  if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
100  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
101  && frame <= 1 && fps > 3 && fps < 100)
102  pts_info = av_d2q(fps, 100000);
103  if (!st->codec->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
104  st->codec->extradata = av_strdup(line + 11);
105  if (!st->codec->extradata)
106  return AVERROR(ENOMEM);
107  st->codec->extradata_size = strlen(st->codec->extradata) + 1;
108  continue;
109  }
110  }
111 #define SKIP_FRAME_ID \
112  p = strchr(p, '}'); \
113  if (!p) { \
114  av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \
115  " at line %d\n", line, i); \
116  continue; \
117  } \
118  p++
121  if (!*p)
122  continue;
123  sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
124  if (!sub)
125  return AVERROR(ENOMEM);
126  sub->pos = pos;
127  sub->pts = get_pts(line);
128  sub->duration = get_duration(line);
129  }
130  ff_subtitles_queue_finalize(&microdvd->q);
131  avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
134  return 0;
135 }
136 
138 {
139  MicroDVDContext *microdvd = s->priv_data;
140  return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
141 }
142 
143 static int microdvd_read_seek(AVFormatContext *s, int stream_index,
144  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
145 {
146  MicroDVDContext *microdvd = s->priv_data;
147  return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
148  min_ts, ts, max_ts, flags);
149 }
150 
152 {
153  MicroDVDContext *microdvd = s->priv_data;
154  ff_subtitles_queue_clean(&microdvd->q);
155  return 0;
156 }
157 
159  .name = "microdvd",
160  .long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
161  .priv_data_size = sizeof(MicroDVDContext),
165  .read_seek2 = microdvd_read_seek,
167 };