FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
assdec.c
Go to the documentation of this file.
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 <stdint.h>
23 
24 #include "avformat.h"
25 #include "internal.h"
26 #include "subtitles.h"
27 #include "libavcodec/internal.h"
28 #include "libavutil/bprint.h"
29 
30 typedef struct ASSContext {
32 } ASSContext;
33 
34 static int ass_probe(AVProbeData *p)
35 {
36  char buf[13];
37  FFTextReader tr;
38  ff_text_init_buf(&tr, p->buf, p->buf_size);
39 
40  ff_text_read(&tr, buf, sizeof(buf));
41 
42  if (!memcmp(buf, "[Script Info]", 13))
43  return AVPROBE_SCORE_MAX;
44 
45  return 0;
46 }
47 
49 {
50  ASSContext *ass = s->priv_data;
52  return 0;
53 }
54 
55 static int read_ts(const uint8_t *p, int64_t *start, int *duration)
56 {
57  int64_t end;
58  int hh1, mm1, ss1, ms1;
59  int hh2, mm2, ss2, ms2;
60 
61  if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",
62  &hh1, &mm1, &ss1, &ms1,
63  &hh2, &mm2, &ss2, &ms2) == 8) {
64  end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
65  *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
66  *duration = end - *start;
67  return 0;
68  }
69  return -1;
70 }
71 
72 static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
73 {
74  int64_t pos = ff_text_pos(tr);
75 
76  av_bprint_clear(buf);
77  for (;;) {
78  char c = ff_text_r8(tr);
79  if (!c)
80  break;
81  av_bprint_chars(buf, c, 1);
82  if (c == '\n')
83  break;
84  }
85  return pos;
86 }
87 
89 {
90  ASSContext *ass = s->priv_data;
92  int header_remaining, res = 0;
93  AVStream *st;
94  FFTextReader tr;
95  ff_text_init_avio(&tr, s->pb);
96 
97  st = avformat_new_stream(s, NULL);
98  if (!st)
99  return AVERROR(ENOMEM);
100  avpriv_set_pts_info(st, 64, 1, 100);
103 
104  header_remaining = INT_MAX;
105 
108 
109  for (;;) {
110  int64_t pos = get_line(&line, &tr);
111 
112  if (!line.str[0]) // EOF
113  break;
114 
115  if (!memcmp(line.str, "[Events]", 8))
116  header_remaining = 2;
117  else if (line.str[0] == '[')
118  header_remaining = INT_MAX;
119 
120  if (header_remaining) {
121  av_bprintf(&header, "%s", line.str);
122  header_remaining--;
123  } else {
124  int64_t ts_start = AV_NOPTS_VALUE;
125  int duration = -1;
126  AVPacket *sub;
127 
128  if (read_ts(line.str, &ts_start, &duration) < 0)
129  continue;
130  sub = ff_subtitles_queue_insert(&ass->q, line.str, line.len, 0);
131  if (!sub) {
132  res = AVERROR(ENOMEM);
133  goto end;
134  }
135  sub->pos = pos;
136  sub->pts = ts_start;
137  sub->duration = duration;
138  }
139  }
140 
141  av_bprint_finalize(&line, NULL);
142 
143  res = avpriv_bprint_to_extradata(st->codec, &header);
144  if (res < 0)
145  goto end;
146 
148 
149 end:
150  return res;
151 }
152 
154 {
155  ASSContext *ass = s->priv_data;
156  return ff_subtitles_queue_read_packet(&ass->q, pkt);
157 }
158 
159 static int ass_read_seek(AVFormatContext *s, int stream_index,
160  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
161 {
162  ASSContext *ass = s->priv_data;
163  return ff_subtitles_queue_seek(&ass->q, s, stream_index,
164  min_ts, ts, max_ts, flags);
165 }
166 
168  .name = "ass",
169  .long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
170  .priv_data_size = sizeof(ASSContext),
175  .read_seek2 = ass_read_seek,
176 };