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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  return (sscanf(ptr, "%*u:%*u:%*u.%*u %*u:%*u:%*u.%*u %c", &c) == 1 ||
47  sscanf(ptr, "@%*u @%*u %c", &c) == 1);
48 }
49 
50 static int jacosub_probe(AVProbeData *p)
51 {
52  const char *ptr = p->buf;
53  const char *ptr_end = p->buf + p->buf_size;
54 
55  if (AV_RB24(ptr) == 0xEFBBBF)
56  ptr += 3; /* skip UTF-8 BOM */
57 
58  while (ptr < ptr_end) {
59  while (jss_whitespace(*ptr))
60  ptr++;
61  if (*ptr != '#' && *ptr != '\n') {
62  if (timed_line(ptr))
63  return AVPROBE_SCORE_MAX/2 + 1;
64  return 0;
65  }
66  ptr += strcspn(ptr, "\n") + 1;
67  }
68  return 0;
69 }
70 
71 static const char * const cmds[] = {
72  "CLOCKPAUSE",
73  "DIRECTIVE",
74  "FONT",
75  "HRES",
76  "INCLUDE",
77  "PALETTE",
78  "QUANTIZE",
79  "RAMP",
80  "SHIFT",
81  "TIMERES",
82 };
83 
84 static int get_jss_cmd(char k)
85 {
86  int i;
87 
88  k = av_toupper(k);
89  for (i = 0; i < FF_ARRAY_ELEMS(cmds); i++)
90  if (k == cmds[i][0])
91  return i;
92  return -1;
93 }
94 
96 {
97  JACOsubContext *jacosub = s->priv_data;
98  ff_subtitles_queue_clean(&jacosub->q);
99  return 0;
100 }
101 
102 static const char *read_ts(JACOsubContext *jacosub, const char *buf,
103  int64_t *start, int *duration)
104 {
105  int len;
106  unsigned hs, ms, ss, fs; // hours, minutes, seconds, frame start
107  unsigned he, me, se, fe; // hours, minutes, seconds, frame end
108  int ts_start, ts_end;
109 
110  /* timed format */
111  if (sscanf(buf, "%u:%u:%u.%u %u:%u:%u.%u %n",
112  &hs, &ms, &ss, &fs,
113  &he, &me, &se, &fe, &len) == 8) {
114  ts_start = (hs*3600 + ms*60 + ss) * jacosub->timeres + fs;
115  ts_end = (he*3600 + me*60 + se) * jacosub->timeres + fe;
116  goto shift_and_ret;
117  }
118 
119  /* timestamps format */
120  if (sscanf(buf, "@%u @%u %n", &ts_start, &ts_end, &len) == 2)
121  goto shift_and_ret;
122 
123  return NULL;
124 
125 shift_and_ret:
126  ts_start = (ts_start + jacosub->shift) * 100 / jacosub->timeres;
127  ts_end = (ts_end + jacosub->shift) * 100 / jacosub->timeres;
128  *start = ts_start;
129  *duration = ts_start + ts_end;
130  return buf + len;
131 }
132 
133 static int get_shift(int timeres, const char *buf)
134 {
135  int sign = 1;
136  int a = 0, b = 0, c = 0, d = 0;
137 #define SSEP "%*1[.:]"
138  int n = sscanf(buf, "%d"SSEP"%d"SSEP"%d"SSEP"%d", &a, &b, &c, &d);
139 #undef SSEP
140 
141  if (*buf == '-' || a < 0) {
142  sign = -1;
143  a = FFABS(a);
144  }
145 
146  switch (n) {
147  case 4: return sign * ((a*3600 + b*60 + c) * timeres + d);
148  case 3: return sign * (( a*60 + b) * timeres + c);
149  case 2: return sign * (( a) * timeres + b);
150  }
151 
152  return 0;
153 }
154 
156 {
157  AVBPrint header;
158  AVIOContext *pb = s->pb;
159  char line[JSS_MAX_LINESIZE];
160  JACOsubContext *jacosub = s->priv_data;
161  int shift_set = 0; // only the first shift matters
162  int merge_line = 0;
163  int i, ret;
164 
166  if (!st)
167  return AVERROR(ENOMEM);
168  avpriv_set_pts_info(st, 64, 1, 100);
171 
172  jacosub->timeres = 30;
173 
174  av_bprint_init(&header, 1024+FF_INPUT_BUFFER_PADDING_SIZE, 4096);
175 
176  while (!url_feof(pb)) {
177  int cmd_len;
178  const char *p = line;
179  int64_t pos = avio_tell(pb);
180  int len = ff_get_line(pb, line, sizeof(line));
181 
182  p = jss_skip_whitespace(p);
183 
184  /* queue timed line */
185  if (merge_line || timed_line(p)) {
186  AVPacket *sub;
187 
188  sub = ff_subtitles_queue_insert(&jacosub->q, line, len, merge_line);
189  if (!sub)
190  return AVERROR(ENOMEM);
191  sub->pos = pos;
192  merge_line = len > 1 && !strcmp(&line[len - 2], "\\\n");
193  continue;
194  }
195 
196  /* skip all non-compiler commands and focus on the command */
197  if (*p != '#')
198  continue;
199  p++;
200  i = get_jss_cmd(p[0]);
201  if (i == -1)
202  continue;
203 
204  /* trim command + spaces */
205  cmd_len = strlen(cmds[i]);
206  if (av_strncasecmp(p, cmds[i], cmd_len) == 0)
207  p += cmd_len;
208  else
209  p++;
210  p = jss_skip_whitespace(p);
211 
212  /* handle commands which affect the whole script */
213  switch (cmds[i][0]) {
214  case 'S': // SHIFT command affect the whole script...
215  if (!shift_set) {
216  jacosub->shift = get_shift(jacosub->timeres, p);
217  shift_set = 1;
218  }
219  av_bprintf(&header, "#S %s", p);
220  break;
221  case 'T': // ...but must be placed after TIMERES
222  jacosub->timeres = strtol(p, NULL, 10);
223  if (!jacosub->timeres)
224  jacosub->timeres = 30;
225  else
226  av_bprintf(&header, "#T %s", p);
227  break;
228  }
229  }
230 
231  /* general/essential directives in the extradata */
232  ret = avpriv_bprint_to_extradata(st->codec, &header);
233  if (ret < 0)
234  return ret;
235 
236  /* SHIFT and TIMERES affect the whole script so packet timing can only be
237  * done in a second pass */
238  for (i = 0; i < jacosub->q.nb_subs; i++) {
239  AVPacket *sub = &jacosub->q.subs[i];
240  read_ts(jacosub, sub->data, &sub->pts, &sub->duration);
241  }
242  ff_subtitles_queue_finalize(&jacosub->q);
243 
244  return 0;
245 }
246 
248 {
249  JACOsubContext *jacosub = s->priv_data;
250  return ff_subtitles_queue_read_packet(&jacosub->q, pkt);
251 }
252 
253 static int jacosub_read_seek(AVFormatContext *s, int stream_index,
254  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
255 {
256  JACOsubContext *jacosub = s->priv_data;
257  return ff_subtitles_queue_seek(&jacosub->q, s, stream_index,
258  min_ts, ts, max_ts, flags);
259 }
260 
262  .name = "jacosub",
263  .long_name = NULL_IF_CONFIG_SMALL("JACOsub subtitle format"),
264  .priv_data_size = sizeof(JACOsubContext),
268  .read_seek2 = jacosub_read_seek,
270 };