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subviewerdec.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  * SubViewer subtitle demuxer
24  * @see https://en.wikipedia.org/wiki/SubViewer
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 {
38 
40 {
41  char c;
42  const unsigned char *ptr = p->buf;
43 
44  if (AV_RB24(ptr) == 0xEFBBBF)
45  ptr += 3; /* skip UTF-8 BOM */
46  if (sscanf(ptr, "%*u:%*u:%*u.%*u,%*u:%*u:%*u.%*u%c", &c) == 1)
48  if (!strncmp(ptr, "[INFORMATION]", 13))
49  return AVPROBE_SCORE_MAX/3;
50  return 0;
51 }
52 
53 static int read_ts(const char *s, int64_t *start, int *duration)
54 {
55  int64_t end;
56  int hh1, mm1, ss1, ms1;
57  int hh2, mm2, ss2, ms2;
58 
59  if (sscanf(s, "%u:%u:%u.%u,%u:%u:%u.%u",
60  &hh1, &mm1, &ss1, &ms1, &hh2, &mm2, &ss2, &ms2) == 8) {
61  end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
62  *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
63  *duration = end - *start;
64  return 0;
65  }
66  return -1;
67 }
68 
70 {
71  SubViewerContext *subviewer = s->priv_data;
72  AVStream *st = avformat_new_stream(s, NULL);
73  AVBPrint header;
74  int res = 0, new_event = 1;
75  int64_t pts_start = AV_NOPTS_VALUE;
76  int duration = -1;
77  AVPacket *sub = NULL;
78 
79  if (!st)
80  return AVERROR(ENOMEM);
81  avpriv_set_pts_info(st, 64, 1, 100);
84 
86 
87  while (!avio_feof(s->pb)) {
88  char line[2048];
89  int64_t pos = 0;
90  int len = ff_get_line(s->pb, line, sizeof(line));
91 
92  if (!len)
93  break;
94 
95  line[strcspn(line, "\r\n")] = 0;
96 
97  if (line[0] == '[' && strncmp(line, "[br]", 4)) {
98 
99  /* ignore event style, XXX: add to side_data? */
100  if (strstr(line, "[COLF]") || strstr(line, "[SIZE]") ||
101  strstr(line, "[FONT]") || strstr(line, "[STYLE]"))
102  continue;
103 
104  if (!st->codec->extradata) { // header not finalized yet
105  av_bprintf(&header, "%s\n", line);
106  if (!strncmp(line, "[END INFORMATION]", 17) || !strncmp(line, "[SUBTITLE]", 10)) {
107  /* end of header */
108  res = avpriv_bprint_to_extradata(st->codec, &header);
109  if (res < 0)
110  goto end;
111  } else if (strncmp(line, "[INFORMATION]", 13)) {
112  /* assume file metadata at this point */
113  int i, j = 0;
114  char key[32], value[128];
115 
116  for (i = 1; i < sizeof(key) - 1 && line[i] && line[i] != ']'; i++)
117  key[i - 1] = av_tolower(line[i]);
118  key[i - 1] = 0;
119 
120  if (line[i] == ']')
121  i++;
122  while (line[i] == ' ')
123  i++;
124  while (j < sizeof(value) - 1 && line[i] && line[i] != ']')
125  value[j++] = line[i++];
126  value[j] = 0;
127 
128  av_dict_set(&s->metadata, key, value, 0);
129  }
130  }
131  } else if (read_ts(line, &pts_start, &duration) >= 0) {
132  new_event = 1;
133  pos = avio_tell(s->pb);
134  } else if (*line) {
135  if (!new_event) {
136  sub = ff_subtitles_queue_insert(&subviewer->q, "\n", 1, 1);
137  if (!sub) {
138  res = AVERROR(ENOMEM);
139  goto end;
140  }
141  }
142  sub = ff_subtitles_queue_insert(&subviewer->q, line, strlen(line), !new_event);
143  if (!sub) {
144  res = AVERROR(ENOMEM);
145  goto end;
146  }
147  if (new_event) {
148  sub->pos = pos;
149  sub->pts = pts_start;
150  sub->duration = duration;
151  }
152  new_event = 0;
153  }
154  }
155 
156  ff_subtitles_queue_finalize(&subviewer->q);
157 
158 end:
159  av_bprint_finalize(&header, NULL);
160  return res;
161 }
162 
164 {
165  SubViewerContext *subviewer = s->priv_data;
166  return ff_subtitles_queue_read_packet(&subviewer->q, pkt);
167 }
168 
169 static int subviewer_read_seek(AVFormatContext *s, int stream_index,
170  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
171 {
172  SubViewerContext *subviewer = s->priv_data;
173  return ff_subtitles_queue_seek(&subviewer->q, s, stream_index,
174  min_ts, ts, max_ts, flags);
175 }
176 
178 {
179  SubViewerContext *subviewer = s->priv_data;
180  ff_subtitles_queue_clean(&subviewer->q);
181  return 0;
182 }
183 
185  .name = "subviewer",
186  .long_name = NULL_IF_CONFIG_SMALL("SubViewer subtitle format"),
187  .priv_data_size = sizeof(SubViewerContext),
191  .read_seek2 = subviewer_read_seek,
193  .extensions = "sub",
194 };