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jacosubdec.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  * JACOsub subtitle demuxer
24  * @see http://unicorn.us.com/jacosub/jscripts.html
25  * @todo Support P[ALETTE] directive.
26  */
27 
28 #include "avformat.h"
29 #include "internal.h"
30 #include "subtitles.h"
31 #include "libavcodec/internal.h"
32 #include "libavcodec/jacosub.h"
33 #include "libavutil/avstring.h"
34 #include "libavutil/bprint.h"
35 #include "libavutil/intreadwrite.h"
36 
37 typedef struct {
38  int shift;
39  unsigned timeres;
42 
43 static int timed_line(const char *ptr)
44 {
45  char c;
46  int fs, fe;
47  return (sscanf(ptr, "%*u:%*u:%*u.%*u %*u:%*u:%*u.%*u %c", &c) == 1 ||
48  (sscanf(ptr, "@%u @%u %c", &fs, &fe, &c) == 3 && fs < fe));
49 }
50 
51 static int jacosub_probe(AVProbeData *p)
52 {
53  const char *ptr = p->buf;
54  const char *ptr_end = p->buf + p->buf_size;
55 
56  if (AV_RB24(ptr) == 0xEFBBBF)
57  ptr += 3; /* skip UTF-8 BOM */
58 
59  while (ptr < ptr_end) {
60  while (jss_whitespace(*ptr))
61  ptr++;
62  if (*ptr != '#' && *ptr != '\n') {
63  if (timed_line(ptr))
64  return AVPROBE_SCORE_EXTENSION + 1;
65  return 0;
66  }
67  ptr += ff_subtitles_next_line(ptr);
68  }
69  return 0;
70 }
71 
72 static const char * const cmds[] = {
73  "CLOCKPAUSE",
74  "DIRECTIVE",
75  "FONT",
76  "HRES",
77  "INCLUDE",
78  "PALETTE",
79  "QUANTIZE",
80  "RAMP",
81  "SHIFT",
82  "TIMERES",
83 };
84 
85 static int get_jss_cmd(char k)
86 {
87  int i;
88 
89  k = av_toupper(k);
90  for (i = 0; i < FF_ARRAY_ELEMS(cmds); i++)
91  if (k == cmds[i][0])
92  return i;
93  return -1;
94 }
95 
97 {
98  JACOsubContext *jacosub = s->priv_data;
99  ff_subtitles_queue_clean(&jacosub->q);
100  return 0;
101 }
102 
103 static const char *read_ts(JACOsubContext *jacosub, const char *buf,
104  int64_t *start, int *duration)
105 {
106  int len;
107  unsigned hs, ms, ss, fs; // hours, minutes, seconds, frame start
108  unsigned he, me, se, fe; // hours, minutes, seconds, frame end
109  int ts_start, ts_end;
110 
111  /* timed format */
112  if (sscanf(buf, "%u:%u:%u.%u %u:%u:%u.%u %n",
113  &hs, &ms, &ss, &fs,
114  &he, &me, &se, &fe, &len) == 8) {
115  ts_start = (hs*3600 + ms*60 + ss) * jacosub->timeres + fs;
116  ts_end = (he*3600 + me*60 + se) * jacosub->timeres + fe;
117  goto shift_and_ret;
118  }
119 
120  /* timestamps format */
121  if (sscanf(buf, "@%u @%u %n", &ts_start, &ts_end, &len) == 2)
122  goto shift_and_ret;
123 
124  return NULL;
125 
126 shift_and_ret:
127  ts_start = (ts_start + jacosub->shift) * 100 / jacosub->timeres;
128  ts_end = (ts_end + jacosub->shift) * 100 / jacosub->timeres;
129  *start = ts_start;
130  *duration = ts_start + ts_end;
131  return buf + len;
132 }
133 
134 static int get_shift(int timeres, const char *buf)
135 {
136  int sign = 1;
137  int a = 0, b = 0, c = 0, d = 0;
138 #define SSEP "%*1[.:]"
139  int n = sscanf(buf, "%d"SSEP"%d"SSEP"%d"SSEP"%d", &a, &b, &c, &d);
140 #undef SSEP
141 
142  if (*buf == '-' || a < 0) {
143  sign = -1;
144  a = FFABS(a);
145  }
146 
147  switch (n) {
148  case 4: return sign * ((a*3600 + b*60 + c) * timeres + d);
149  case 3: return sign * (( a*60 + b) * timeres + c);
150  case 2: return sign * (( a) * timeres + b);
151  }
152 
153  return 0;
154 }
155 
157 {
159  AVIOContext *pb = s->pb;
160  char line[JSS_MAX_LINESIZE];
161  JACOsubContext *jacosub = s->priv_data;
162  int shift_set = 0; // only the first shift matters
163  int merge_line = 0;
164  int i, ret;
165 
166  AVStream *st = avformat_new_stream(s, NULL);
167  if (!st)
168  return AVERROR(ENOMEM);
169  avpriv_set_pts_info(st, 64, 1, 100);
172 
173  jacosub->timeres = 30;
174 
175  av_bprint_init(&header, 1024+FF_INPUT_BUFFER_PADDING_SIZE, 4096);
176 
177  while (!avio_feof(pb)) {
178  int cmd_len;
179  const char *p = line;
180  int64_t pos = avio_tell(pb);
181  int len = ff_get_line(pb, line, sizeof(line));
182 
183  p = jss_skip_whitespace(p);
184 
185  /* queue timed line */
186  if (merge_line || timed_line(p)) {
187  AVPacket *sub;
188 
189  sub = ff_subtitles_queue_insert(&jacosub->q, line, len, merge_line);
190  if (!sub)
191  return AVERROR(ENOMEM);
192  sub->pos = pos;
193  merge_line = len > 1 && !strcmp(&line[len - 2], "\\\n");
194  continue;
195  }
196 
197  /* skip all non-compiler commands and focus on the command */
198  if (*p != '#')
199  continue;
200  p++;
201  i = get_jss_cmd(p[0]);
202  if (i == -1)
203  continue;
204 
205  /* trim command + spaces */
206  cmd_len = strlen(cmds[i]);
207  if (av_strncasecmp(p, cmds[i], cmd_len) == 0)
208  p += cmd_len;
209  else
210  p++;
211  p = jss_skip_whitespace(p);
212 
213  /* handle commands which affect the whole script */
214  switch (cmds[i][0]) {
215  case 'S': // SHIFT command affect the whole script...
216  if (!shift_set) {
217  jacosub->shift = get_shift(jacosub->timeres, p);
218  shift_set = 1;
219  }
220  av_bprintf(&header, "#S %s", p);
221  break;
222  case 'T': // ...but must be placed after TIMERES
223  jacosub->timeres = strtol(p, NULL, 10);
224  if (!jacosub->timeres)
225  jacosub->timeres = 30;
226  else
227  av_bprintf(&header, "#T %s", p);
228  break;
229  }
230  }
231 
232  /* general/essential directives in the extradata */
233  ret = avpriv_bprint_to_extradata(st->codec, &header);
234  if (ret < 0)
235  goto fail;
236 
237  /* SHIFT and TIMERES affect the whole script so packet timing can only be
238  * done in a second pass */
239  for (i = 0; i < jacosub->q.nb_subs; i++) {
240  AVPacket *sub = &jacosub->q.subs[i];
241  read_ts(jacosub, sub->data, &sub->pts, &sub->duration);
242  }
243  ff_subtitles_queue_finalize(&jacosub->q);
244 
245  return 0;
246 fail:
248  return ret;
249 }
250 
252 {
253  JACOsubContext *jacosub = s->priv_data;
254  return ff_subtitles_queue_read_packet(&jacosub->q, pkt);
255 }
256 
257 static int jacosub_read_seek(AVFormatContext *s, int stream_index,
258  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
259 {
260  JACOsubContext *jacosub = s->priv_data;
261  return ff_subtitles_queue_seek(&jacosub->q, s, stream_index,
262  min_ts, ts, max_ts, flags);
263 }
264 
266  .name = "jacosub",
267  .long_name = NULL_IF_CONFIG_SMALL("JACOsub subtitle format"),
268  .priv_data_size = sizeof(JACOsubContext),
272  .read_seek2 = jacosub_read_seek,
274 };