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assdec.c
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1 /*
2  * SSA/ASS demuxer
3  * Copyright (c) 2008 Michael Niedermayer
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avformat.h"
23 #include "internal.h"
24 #include "subtitles.h"
25 #include "libavcodec/internal.h"
26 #include "libavutil/bprint.h"
27 
28 typedef struct ASSContext{
30 }ASSContext;
31 
32 static int ass_probe(AVProbeData *p)
33 {
34  const char *header= "[Script Info]";
35 
36  if( !memcmp(p->buf , header, strlen(header))
37  || !memcmp(p->buf+3, header, strlen(header)))
38  return AVPROBE_SCORE_MAX;
39 
40  return 0;
41 }
42 
44 {
45  ASSContext *ass = s->priv_data;
47  return 0;
48 }
49 
50 static int read_ts(const uint8_t *p, int64_t *start, int *duration)
51 {
52  int64_t end;
53  int hh1, mm1, ss1, ms1;
54  int hh2, mm2, ss2, ms2;
55 
56  if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",
57  &hh1, &mm1, &ss1, &ms1,
58  &hh2, &mm2, &ss2, &ms2) == 8) {
59  end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
60  *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
61  *duration = end - *start;
62  return 0;
63  }
64  return -1;
65 }
66 
67 static int64_t get_line(AVBPrint *buf, AVIOContext *pb)
68 {
69  int64_t pos = avio_tell(pb);
70 
71  av_bprint_clear(buf);
72  for (;;) {
73  char c = avio_r8(pb);
74  if (!c)
75  break;
76  av_bprint_chars(buf, c, 1);
77  if (c == '\n')
78  break;
79  }
80  return pos;
81 }
82 
84 {
85  ASSContext *ass = s->priv_data;
86  AVBPrint header, line;
87  int header_remaining, res = 0;
88  AVStream *st;
89 
90  st = avformat_new_stream(s, NULL);
91  if (!st)
92  return AVERROR(ENOMEM);
93  avpriv_set_pts_info(st, 64, 1, 100);
96 
97  header_remaining= INT_MAX;
98 
101 
102  for (;;) {
103  int64_t pos = get_line(&line, s->pb);
104 
105  if (!line.str[0]) // EOF
106  break;
107 
108  if (!memcmp(line.str, "[Events]", 8))
109  header_remaining= 2;
110  else if (line.str[0]=='[')
111  header_remaining= INT_MAX;
112 
113  if (header_remaining) {
114  av_bprintf(&header, "%s", line.str);
115  header_remaining--;
116  } else {
117  int64_t ts_start = AV_NOPTS_VALUE;
118  int duration = -1;
119  AVPacket *sub;
120 
121  if (read_ts(line.str, &ts_start, &duration) < 0)
122  continue;
123  sub = ff_subtitles_queue_insert(&ass->q, line.str, line.len, 0);
124  if (!sub) {
125  res = AVERROR(ENOMEM);
126  goto end;
127  }
128  sub->pos = pos;
129  sub->pts = ts_start;
130  sub->duration = duration;
131  }
132  }
133 
134  av_bprint_finalize(&line, NULL);
135 
136  res = avpriv_bprint_to_extradata(st->codec, &header);
137  if (res < 0)
138  goto end;
139 
141 
142 end:
143  return res;
144 }
145 
147 {
148  ASSContext *ass = s->priv_data;
149  return ff_subtitles_queue_read_packet(&ass->q, pkt);
150 }
151 
152 static int ass_read_seek(AVFormatContext *s, int stream_index,
153  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
154 {
155  ASSContext *ass = s->priv_data;
156  return ff_subtitles_queue_seek(&ass->q, s, stream_index,
157  min_ts, ts, max_ts, flags);
158 }
159 
161  .name = "ass",
162  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
163  .priv_data_size = sizeof(ASSContext),
168  .read_seek2 = ass_read_seek,
169 };