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srtenc.c
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1 /*
2  * SubRip subtitle encoder
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
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 <stdarg.h>
23 #include "avcodec.h"
24 #include "libavutil/avstring.h"
25 #include "ass_split.h"
26 #include "ass.h"
27 
28 
29 #define SRT_STACK_SIZE 64
30 
31 typedef struct {
34  char buffer[2048];
35  char *ptr;
36  char *end;
37  char *dialog_start;
38  int count;
39  char stack[SRT_STACK_SIZE];
40  int stack_ptr;
42 } SRTContext;
43 
44 
45 #ifdef __GNUC__
46 __attribute__ ((__format__ (__printf__, 2, 3)))
47 #endif
48 static void srt_print(SRTContext *s, const char *str, ...)
49 {
50  va_list vargs;
51  va_start(vargs, str);
52  s->ptr += vsnprintf(s->ptr, s->end - s->ptr, str, vargs);
53  va_end(vargs);
54 }
55 
56 static int srt_stack_push(SRTContext *s, const char c)
57 {
58  if (s->stack_ptr >= SRT_STACK_SIZE)
59  return -1;
60  s->stack[s->stack_ptr++] = c;
61  return 0;
62 }
63 
64 static char srt_stack_pop(SRTContext *s)
65 {
66  if (s->stack_ptr <= 0)
67  return 0;
68  return s->stack[--s->stack_ptr];
69 }
70 
71 static int srt_stack_find(SRTContext *s, const char c)
72 {
73  int i;
74  for (i = s->stack_ptr-1; i >= 0; i--)
75  if (s->stack[i] == c)
76  break;
77  return i;
78 }
79 
80 static void srt_close_tag(SRTContext *s, char tag)
81 {
82  srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
83 }
84 
85 static void srt_stack_push_pop(SRTContext *s, const char c, int close)
86 {
87  if (close) {
88  int i = c ? srt_stack_find(s, c) : 0;
89  if (i < 0)
90  return;
91  while (s->stack_ptr != i)
93  } else if (srt_stack_push(s, c) < 0)
94  av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
95 }
96 
97 static void srt_style_apply(SRTContext *s, const char *style)
98 {
99  ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);
100  if (st) {
101  int c = st->primary_color & 0xFFFFFF;
102  if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||
104  c != ASS_DEFAULT_COLOR) {
105  srt_print(s, "<font");
106  if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))
107  srt_print(s, " face=\"%s\"", st->font_name);
108  if (st->font_size != ASS_DEFAULT_FONT_SIZE)
109  srt_print(s, " size=\"%d\"", st->font_size);
110  if (c != ASS_DEFAULT_COLOR)
111  srt_print(s, " color=\"#%06x\"",
112  (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);
113  srt_print(s, ">");
114  srt_stack_push(s, 'f');
115  }
116  if (st->bold != ASS_DEFAULT_BOLD) {
117  srt_print(s, "<b>");
118  srt_stack_push(s, 'b');
119  }
120  if (st->italic != ASS_DEFAULT_ITALIC) {
121  srt_print(s, "<i>");
122  srt_stack_push(s, 'i');
123  }
124  if (st->underline != ASS_DEFAULT_UNDERLINE) {
125  srt_print(s, "<u>");
126  srt_stack_push(s, 'u');
127  }
128  if (st->alignment != ASS_DEFAULT_ALIGNMENT) {
129  srt_print(s, "{\\an%d}", st->alignment);
130  s->alignment_applied = 1;
131  }
132  }
133 }
134 
135 
137 {
138  SRTContext *s = avctx->priv_data;
139  s->avctx = avctx;
140  s->ass_ctx = ff_ass_split(avctx->subtitle_header);
141  return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
142 }
143 
144 static void srt_text_cb(void *priv, const char *text, int len)
145 {
146  SRTContext *s = priv;
147  av_strlcpy(s->ptr, text, FFMIN(s->end-s->ptr, len+1));
148  s->ptr += len;
149 }
150 
151 static void srt_new_line_cb(void *priv, int forced)
152 {
153  srt_print(priv, "\r\n");
154 }
155 
156 static void srt_style_cb(void *priv, char style, int close)
157 {
158  srt_stack_push_pop(priv, style, close);
159  if (!close)
160  srt_print(priv, "<%c>", style);
161 }
162 
163 static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)
164 {
165  if (color_id > 1)
166  return;
167  srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);
168  if (color != 0xFFFFFFFF)
169  srt_print(priv, "<font color=\"#%06x\">",
170  (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);
171 }
172 
173 static void srt_font_name_cb(void *priv, const char *name)
174 {
175  srt_stack_push_pop(priv, 'f', !name);
176  if (name)
177  srt_print(priv, "<font face=\"%s\">", name);
178 }
179 
180 static void srt_font_size_cb(void *priv, int size)
181 {
182  srt_stack_push_pop(priv, 'f', size < 0);
183  if (size >= 0)
184  srt_print(priv, "<font size=\"%d\">", size);
185 }
186 
187 static void srt_alignment_cb(void *priv, int alignment)
188 {
189  SRTContext *s = priv;
190  if (!s->alignment_applied && alignment >= 0) {
191  srt_print(s, "{\\an%d}", alignment);
192  s->alignment_applied = 1;
193  }
194 }
195 
196 static void srt_cancel_overrides_cb(void *priv, const char *style)
197 {
198  srt_stack_push_pop(priv, 0, 1);
199  srt_style_apply(priv, style);
200 }
201 
202 static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
203  int t1, int t2)
204 {
205  SRTContext *s = priv;
206 
207  if (s->avctx->codec->id == AV_CODEC_ID_SRT) {
208  char buffer[32];
209  int len = snprintf(buffer, sizeof(buffer),
210  " X1:%03u X2:%03u Y1:%03u Y2:%03u", x1, x2, y1, y2);
211  if (s->end - s->ptr > len) {
212  memmove(s->dialog_start+len, s->dialog_start, s->ptr-s->dialog_start+1);
213  memcpy(s->dialog_start, buffer, len);
214  s->ptr += len;
215  }
216  }
217 }
218 
219 static void srt_end_cb(void *priv)
220 {
221  SRTContext *s = priv;
222 
223  srt_stack_push_pop(priv, 0, 1);
224  if (s->avctx->codec->id == AV_CODEC_ID_SRT)
225  srt_print(priv, "\r\n\r\n");
226 }
227 
229  .text = srt_text_cb,
230  .new_line = srt_new_line_cb,
231  .style = srt_style_cb,
232  .color = srt_color_cb,
233  .font_name = srt_font_name_cb,
234  .font_size = srt_font_size_cb,
235  .alignment = srt_alignment_cb,
236  .cancel_overrides = srt_cancel_overrides_cb,
237  .move = srt_move_cb,
238  .end = srt_end_cb,
239 };
240 
242  unsigned char *buf, int bufsize, const AVSubtitle *sub)
243 {
244  SRTContext *s = avctx->priv_data;
245  ASSDialog *dialog;
246  int i, len, num;
247 
248  s->ptr = s->buffer;
249  s->end = s->ptr + sizeof(s->buffer);
250 
251  for (i=0; i<sub->num_rects; i++) {
252 
253  if (sub->rects[i]->type != SUBTITLE_ASS) {
254  av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
255  return AVERROR(ENOSYS);
256  }
257 
258  dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num);
259  for (; dialog && num--; dialog++) {
260  if (avctx->codec->id == AV_CODEC_ID_SRT) {
261  int sh, sm, ss, sc = 10 * dialog->start;
262  int eh, em, es, ec = 10 * dialog->end;
263  sh = sc/3600000; sc -= 3600000*sh;
264  sm = sc/ 60000; sc -= 60000*sm;
265  ss = sc/ 1000; sc -= 1000*ss;
266  eh = ec/3600000; ec -= 3600000*eh;
267  em = ec/ 60000; ec -= 60000*em;
268  es = ec/ 1000; ec -= 1000*es;
269  srt_print(s,"%d\r\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d\r\n",
270  ++s->count, sh, sm, ss, sc, eh, em, es, ec);
271  s->dialog_start = s->ptr - 2;
272  }
273  s->alignment_applied = 0;
274  srt_style_apply(s, dialog->style);
275  ff_ass_split_override_codes(&srt_callbacks, s, dialog->text);
276  }
277  }
278 
279  if (s->ptr == s->buffer)
280  return 0;
281 
282  len = av_strlcpy(buf, s->buffer, bufsize);
283 
284  if (len > bufsize-1) {
285  av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
286  return -1;
287  }
288 
289  return len;
290 }
291 
293 {
294  SRTContext *s = avctx->priv_data;
296  return 0;
297 }
298 
299 #if CONFIG_SRT_ENCODER
300 /* deprecated encoder */
301 AVCodec ff_srt_encoder = {
302  .name = "srt",
303  .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle with embedded timing"),
304  .type = AVMEDIA_TYPE_SUBTITLE,
305  .id = AV_CODEC_ID_SRT,
306  .priv_data_size = sizeof(SRTContext),
308  .encode_sub = srt_encode_frame,
310 };
311 #endif
312 
313 #if CONFIG_SUBRIP_ENCODER
314 AVCodec ff_subrip_encoder = {
315  .name = "subrip",
316  .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
317  .type = AVMEDIA_TYPE_SUBTITLE,
318  .id = AV_CODEC_ID_SUBRIP,
319  .priv_data_size = sizeof(SRTContext),
321  .encode_sub = srt_encode_frame,
323 };
324 #endif