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 "libavutil/bprint.h"
26 #include "ass_split.h"
27 #include "ass.h"
28
29
30 #define SRT_STACK_SIZE 64
31
32 typedef struct {
33 AVCodecContext *avctx;
34 ASSSplitContext *ass_ctx;
35 AVBPrint buffer;
36 char stack[SRT_STACK_SIZE];
37 int stack_ptr;
38 int alignment_applied;
39 } SRTContext;
40
41
42 #ifdef __GNUC__
43 __attribute__ ((__format__ (__printf__, 2, 3)))
44 #endif
srt_print(SRTContext * s,const char * str,...)45 static void srt_print(SRTContext *s, const char *str, ...)
46 {
47 va_list vargs;
48 va_start(vargs, str);
49 av_vbprintf(&s->buffer, str, vargs);
50 va_end(vargs);
51 }
52
srt_stack_push(SRTContext * s,const char c)53 static int srt_stack_push(SRTContext *s, const char c)
54 {
55 if (s->stack_ptr >= SRT_STACK_SIZE)
56 return -1;
57 s->stack[s->stack_ptr++] = c;
58 return 0;
59 }
60
srt_stack_pop(SRTContext * s)61 static char srt_stack_pop(SRTContext *s)
62 {
63 if (s->stack_ptr <= 0)
64 return 0;
65 return s->stack[--s->stack_ptr];
66 }
67
srt_stack_find(SRTContext * s,const char c)68 static int srt_stack_find(SRTContext *s, const char c)
69 {
70 int i;
71 for (i = s->stack_ptr-1; i >= 0; i--)
72 if (s->stack[i] == c)
73 break;
74 return i;
75 }
76
srt_close_tag(SRTContext * s,char tag)77 static void srt_close_tag(SRTContext *s, char tag)
78 {
79 srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
80 }
81
srt_stack_push_pop(SRTContext * s,const char c,int close)82 static void srt_stack_push_pop(SRTContext *s, const char c, int close)
83 {
84 if (close) {
85 int i = c ? srt_stack_find(s, c) : 0;
86 if (i < 0)
87 return;
88 while (s->stack_ptr != i)
89 srt_close_tag(s, srt_stack_pop(s));
90 } else if (srt_stack_push(s, c) < 0)
91 av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
92 }
93
srt_style_apply(SRTContext * s,const char * style)94 static void srt_style_apply(SRTContext *s, const char *style)
95 {
96 ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);
97 if (st) {
98 int c = st->primary_color & 0xFFFFFF;
99 if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||
100 st->font_size != ASS_DEFAULT_FONT_SIZE ||
101 c != ASS_DEFAULT_COLOR) {
102 srt_print(s, "<font");
103 if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))
104 srt_print(s, " face=\"%s\"", st->font_name);
105 if (st->font_size != ASS_DEFAULT_FONT_SIZE)
106 srt_print(s, " size=\"%d\"", st->font_size);
107 if (c != ASS_DEFAULT_COLOR)
108 srt_print(s, " color=\"#%06x\"",
109 (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);
110 srt_print(s, ">");
111 srt_stack_push(s, 'f');
112 }
113 if (st->bold != ASS_DEFAULT_BOLD) {
114 srt_print(s, "<b>");
115 srt_stack_push(s, 'b');
116 }
117 if (st->italic != ASS_DEFAULT_ITALIC) {
118 srt_print(s, "<i>");
119 srt_stack_push(s, 'i');
120 }
121 if (st->underline != ASS_DEFAULT_UNDERLINE) {
122 srt_print(s, "<u>");
123 srt_stack_push(s, 'u');
124 }
125 if (st->alignment != ASS_DEFAULT_ALIGNMENT) {
126 srt_print(s, "{\\an%d}", st->alignment);
127 s->alignment_applied = 1;
128 }
129 }
130 }
131
132
srt_encode_init(AVCodecContext * avctx)133 static av_cold int srt_encode_init(AVCodecContext *avctx)
134 {
135 SRTContext *s = avctx->priv_data;
136 s->avctx = avctx;
137 s->ass_ctx = ff_ass_split(avctx->subtitle_header);
138 av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
139 return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
140 }
141
srt_text_cb(void * priv,const char * text,int len)142 static void srt_text_cb(void *priv, const char *text, int len)
143 {
144 SRTContext *s = priv;
145 av_bprint_append_data(&s->buffer, text, len);
146 }
147
srt_new_line_cb(void * priv,int forced)148 static void srt_new_line_cb(void *priv, int forced)
149 {
150 srt_print(priv, "\r\n");
151 }
152
srt_style_cb(void * priv,char style,int close)153 static void srt_style_cb(void *priv, char style, int close)
154 {
155 srt_stack_push_pop(priv, style, close);
156 if (!close)
157 srt_print(priv, "<%c>", style);
158 }
159
srt_color_cb(void * priv,unsigned int color,unsigned int color_id)160 static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)
161 {
162 if (color_id > 1)
163 return;
164 srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);
165 if (color != 0xFFFFFFFF)
166 srt_print(priv, "<font color=\"#%06x\">",
167 (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);
168 }
169
srt_font_name_cb(void * priv,const char * name)170 static void srt_font_name_cb(void *priv, const char *name)
171 {
172 srt_stack_push_pop(priv, 'f', !name);
173 if (name)
174 srt_print(priv, "<font face=\"%s\">", name);
175 }
176
srt_font_size_cb(void * priv,int size)177 static void srt_font_size_cb(void *priv, int size)
178 {
179 srt_stack_push_pop(priv, 'f', size < 0);
180 if (size >= 0)
181 srt_print(priv, "<font size=\"%d\">", size);
182 }
183
srt_alignment_cb(void * priv,int alignment)184 static void srt_alignment_cb(void *priv, int alignment)
185 {
186 SRTContext *s = priv;
187 if (!s->alignment_applied && alignment >= 0) {
188 srt_print(s, "{\\an%d}", alignment);
189 s->alignment_applied = 1;
190 }
191 }
192
srt_cancel_overrides_cb(void * priv,const char * style)193 static void srt_cancel_overrides_cb(void *priv, const char *style)
194 {
195 srt_stack_push_pop(priv, 0, 1);
196 srt_style_apply(priv, style);
197 }
198
srt_move_cb(void * priv,int x1,int y1,int x2,int y2,int t1,int t2)199 static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
200 int t1, int t2)
201 {
202 // TODO: add a AV_PKT_DATA_SUBTITLE_POSITION side data when a new subtitles
203 // encoding API passing the AVPacket is available.
204 }
205
srt_end_cb(void * priv)206 static void srt_end_cb(void *priv)
207 {
208 srt_stack_push_pop(priv, 0, 1);
209 }
210
211 static const ASSCodesCallbacks srt_callbacks = {
212 .text = srt_text_cb,
213 .new_line = srt_new_line_cb,
214 .style = srt_style_cb,
215 .color = srt_color_cb,
216 .font_name = srt_font_name_cb,
217 .font_size = srt_font_size_cb,
218 .alignment = srt_alignment_cb,
219 .cancel_overrides = srt_cancel_overrides_cb,
220 .move = srt_move_cb,
221 .end = srt_end_cb,
222 };
223
224 static const ASSCodesCallbacks text_callbacks = {
225 .text = srt_text_cb,
226 .new_line = srt_new_line_cb,
227 };
228
encode_frame(AVCodecContext * avctx,unsigned char * buf,int bufsize,const AVSubtitle * sub,const ASSCodesCallbacks * cb)229 static int encode_frame(AVCodecContext *avctx,
230 unsigned char *buf, int bufsize, const AVSubtitle *sub,
231 const ASSCodesCallbacks *cb)
232 {
233 SRTContext *s = avctx->priv_data;
234 ASSDialog *dialog;
235 int i;
236
237 av_bprint_clear(&s->buffer);
238
239 for (i=0; i<sub->num_rects; i++) {
240 const char *ass = sub->rects[i]->ass;
241
242 if (sub->rects[i]->type != SUBTITLE_ASS) {
243 av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
244 return AVERROR(EINVAL);
245 }
246
247 #if FF_API_ASS_TIMING
248 if (!strncmp(ass, "Dialogue: ", 10)) {
249 int num;
250 dialog = ff_ass_split_dialog(s->ass_ctx, ass, 0, &num);
251 for (; dialog && num--; dialog++) {
252 s->alignment_applied = 0;
253 if (avctx->codec_id == AV_CODEC_ID_SUBRIP)
254 srt_style_apply(s, dialog->style);
255 ff_ass_split_override_codes(cb, s, dialog->text);
256 }
257 } else {
258 #endif
259 dialog = ff_ass_split_dialog2(s->ass_ctx, ass);
260 if (!dialog)
261 return AVERROR(ENOMEM);
262 s->alignment_applied = 0;
263 if (avctx->codec_id == AV_CODEC_ID_SUBRIP)
264 srt_style_apply(s, dialog->style);
265 ff_ass_split_override_codes(cb, s, dialog->text);
266 ff_ass_free_dialog(&dialog);
267 #if FF_API_ASS_TIMING
268 }
269 #endif
270 }
271
272 if (!av_bprint_is_complete(&s->buffer))
273 return AVERROR(ENOMEM);
274 if (!s->buffer.len)
275 return 0;
276
277 if (s->buffer.len > bufsize) {
278 av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
279 return AVERROR_BUFFER_TOO_SMALL;
280 }
281 memcpy(buf, s->buffer.str, s->buffer.len);
282
283 return s->buffer.len;
284 }
285
srt_encode_frame(AVCodecContext * avctx,unsigned char * buf,int bufsize,const AVSubtitle * sub)286 static int srt_encode_frame(AVCodecContext *avctx,
287 unsigned char *buf, int bufsize, const AVSubtitle *sub)
288 {
289 return encode_frame(avctx, buf, bufsize, sub, &srt_callbacks);
290 }
291
text_encode_frame(AVCodecContext * avctx,unsigned char * buf,int bufsize,const AVSubtitle * sub)292 static int text_encode_frame(AVCodecContext *avctx,
293 unsigned char *buf, int bufsize, const AVSubtitle *sub)
294 {
295 return encode_frame(avctx, buf, bufsize, sub, &text_callbacks);
296 }
297
srt_encode_close(AVCodecContext * avctx)298 static int srt_encode_close(AVCodecContext *avctx)
299 {
300 SRTContext *s = avctx->priv_data;
301 ff_ass_split_free(s->ass_ctx);
302 av_bprint_finalize(&s->buffer, NULL);
303 return 0;
304 }
305
306 #if CONFIG_SRT_ENCODER
307 /* deprecated encoder */
308 AVCodec ff_srt_encoder = {
309 .name = "srt",
310 .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
311 .type = AVMEDIA_TYPE_SUBTITLE,
312 .id = AV_CODEC_ID_SUBRIP,
313 .priv_data_size = sizeof(SRTContext),
314 .init = srt_encode_init,
315 .encode_sub = srt_encode_frame,
316 .close = srt_encode_close,
317 };
318 #endif
319
320 #if CONFIG_SUBRIP_ENCODER
321 AVCodec ff_subrip_encoder = {
322 .name = "subrip",
323 .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
324 .type = AVMEDIA_TYPE_SUBTITLE,
325 .id = AV_CODEC_ID_SUBRIP,
326 .priv_data_size = sizeof(SRTContext),
327 .init = srt_encode_init,
328 .encode_sub = srt_encode_frame,
329 .close = srt_encode_close,
330 };
331 #endif
332
333 #if CONFIG_TEXT_ENCODER
334 AVCodec ff_text_encoder = {
335 .name = "text",
336 .long_name = NULL_IF_CONFIG_SMALL("Raw text subtitle"),
337 .type = AVMEDIA_TYPE_SUBTITLE,
338 .id = AV_CODEC_ID_TEXT,
339 .priv_data_size = sizeof(SRTContext),
340 .init = srt_encode_init,
341 .encode_sub = text_encode_frame,
342 .close = srt_encode_close,
343 };
344 #endif
345