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 "config_components.h"
23
24 #include <stdarg.h>
25 #include "avcodec.h"
26 #include "libavutil/avstring.h"
27 #include "libavutil/bprint.h"
28 #include "ass_split.h"
29 #include "ass.h"
30 #include "codec_internal.h"
31
32
33 #define SRT_STACK_SIZE 64
34
35 typedef struct {
36 AVCodecContext *avctx;
37 ASSSplitContext *ass_ctx;
38 AVBPrint buffer;
39 char stack[SRT_STACK_SIZE];
40 int stack_ptr;
41 int alignment_applied;
42 } SRTContext;
43
44
45 #ifdef __GNUC__
46 __attribute__ ((__format__ (__printf__, 2, 3)))
47 #endif
srt_print(SRTContext *s, const char *str, ...)48 static void srt_print(SRTContext *s, const char *str, ...)
49 {
50 va_list vargs;
51 va_start(vargs, str);
52 av_vbprintf(&s->buffer, str, vargs);
53 va_end(vargs);
54 }
55
srt_stack_push(SRTContext *s, const char c)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
srt_stack_pop(SRTContext *s)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
srt_stack_find(SRTContext *s, const char c)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
srt_close_tag(SRTContext *s, char tag)80 static void srt_close_tag(SRTContext *s, char tag)
81 {
82 srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
83 }
84
srt_stack_push_pop(SRTContext *s, const char c, int close)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)
92 srt_close_tag(s, srt_stack_pop(s));
93 } else if (srt_stack_push(s, c) < 0)
94 av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
95 }
96
srt_style_apply(SRTContext *s, const char *style)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) ||
103 st->font_size != ASS_DEFAULT_FONT_SIZE ||
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
srt_encode_init(AVCodecContext *avctx)136 static av_cold int srt_encode_init(AVCodecContext *avctx)
137 {
138 SRTContext *s = avctx->priv_data;
139 s->avctx = avctx;
140 s->ass_ctx = ff_ass_split(avctx->subtitle_header);
141 av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
142 return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
143 }
144
srt_text_cb(void *priv, const char *text, int len)145 static void srt_text_cb(void *priv, const char *text, int len)
146 {
147 SRTContext *s = priv;
148 av_bprint_append_data(&s->buffer, text, len);
149 }
150
srt_new_line_cb(void *priv, int forced)151 static void srt_new_line_cb(void *priv, int forced)
152 {
153 srt_print(priv, "\r\n");
154 }
155
srt_style_cb(void *priv, char style, int close)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
srt_color_cb(void *priv, unsigned int color, unsigned int color_id)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
srt_font_name_cb(void *priv, const char *name)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
srt_font_size_cb(void *priv, int size)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
srt_alignment_cb(void *priv, int alignment)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
srt_cancel_overrides_cb(void *priv, const char *style)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
srt_move_cb(void *priv, int x1, int y1, int x2, int y2, int t1, int t2)202 static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
203 int t1, int t2)
204 {
205 // TODO: add a AV_PKT_DATA_SUBTITLE_POSITION side data when a new subtitles
206 // encoding API passing the AVPacket is available.
207 }
208
srt_end_cb(void *priv)209 static void srt_end_cb(void *priv)
210 {
211 srt_stack_push_pop(priv, 0, 1);
212 }
213
214 static const ASSCodesCallbacks srt_callbacks = {
215 .text = srt_text_cb,
216 .new_line = srt_new_line_cb,
217 .style = srt_style_cb,
218 .color = srt_color_cb,
219 .font_name = srt_font_name_cb,
220 .font_size = srt_font_size_cb,
221 .alignment = srt_alignment_cb,
222 .cancel_overrides = srt_cancel_overrides_cb,
223 .move = srt_move_cb,
224 .end = srt_end_cb,
225 };
226
227 static const ASSCodesCallbacks text_callbacks = {
228 .text = srt_text_cb,
229 .new_line = srt_new_line_cb,
230 };
231
encode_frame(AVCodecContext *avctx, unsigned char *buf, int bufsize, const AVSubtitle *sub, const ASSCodesCallbacks *cb)232 static int encode_frame(AVCodecContext *avctx,
233 unsigned char *buf, int bufsize, const AVSubtitle *sub,
234 const ASSCodesCallbacks *cb)
235 {
236 SRTContext *s = avctx->priv_data;
237 ASSDialog *dialog;
238 int i;
239
240 av_bprint_clear(&s->buffer);
241
242 for (i=0; i<sub->num_rects; i++) {
243 const char *ass = sub->rects[i]->ass;
244
245 if (sub->rects[i]->type != SUBTITLE_ASS) {
246 av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
247 return AVERROR(EINVAL);
248 }
249
250 dialog = ff_ass_split_dialog(s->ass_ctx, ass);
251 if (!dialog)
252 return AVERROR(ENOMEM);
253 s->alignment_applied = 0;
254 if (avctx->codec_id == AV_CODEC_ID_SUBRIP)
255 srt_style_apply(s, dialog->style);
256 ff_ass_split_override_codes(cb, s, dialog->text);
257 ff_ass_free_dialog(&dialog);
258 }
259
260 if (!av_bprint_is_complete(&s->buffer))
261 return AVERROR(ENOMEM);
262 if (!s->buffer.len)
263 return 0;
264
265 if (s->buffer.len > bufsize) {
266 av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
267 return AVERROR_BUFFER_TOO_SMALL;
268 }
269 memcpy(buf, s->buffer.str, s->buffer.len);
270
271 return s->buffer.len;
272 }
273
srt_encode_frame(AVCodecContext *avctx, unsigned char *buf, int bufsize, const AVSubtitle *sub)274 static int srt_encode_frame(AVCodecContext *avctx,
275 unsigned char *buf, int bufsize, const AVSubtitle *sub)
276 {
277 return encode_frame(avctx, buf, bufsize, sub, &srt_callbacks);
278 }
279
text_encode_frame(AVCodecContext *avctx, unsigned char *buf, int bufsize, const AVSubtitle *sub)280 static int text_encode_frame(AVCodecContext *avctx,
281 unsigned char *buf, int bufsize, const AVSubtitle *sub)
282 {
283 return encode_frame(avctx, buf, bufsize, sub, &text_callbacks);
284 }
285
srt_encode_close(AVCodecContext *avctx)286 static int srt_encode_close(AVCodecContext *avctx)
287 {
288 SRTContext *s = avctx->priv_data;
289 ff_ass_split_free(s->ass_ctx);
290 av_bprint_finalize(&s->buffer, NULL);
291 return 0;
292 }
293
294 #if CONFIG_SRT_ENCODER
295 /* deprecated encoder */
296 const FFCodec ff_srt_encoder = {
297 .p.name = "srt",
298 .p.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
299 .p.type = AVMEDIA_TYPE_SUBTITLE,
300 .p.id = AV_CODEC_ID_SUBRIP,
301 .priv_data_size = sizeof(SRTContext),
302 .init = srt_encode_init,
303 FF_CODEC_ENCODE_SUB_CB(srt_encode_frame),
304 .close = srt_encode_close,
305 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
306 };
307 #endif
308
309 #if CONFIG_SUBRIP_ENCODER
310 const FFCodec ff_subrip_encoder = {
311 .p.name = "subrip",
312 .p.long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
313 .p.type = AVMEDIA_TYPE_SUBTITLE,
314 .p.id = AV_CODEC_ID_SUBRIP,
315 .priv_data_size = sizeof(SRTContext),
316 .init = srt_encode_init,
317 FF_CODEC_ENCODE_SUB_CB(srt_encode_frame),
318 .close = srt_encode_close,
319 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
320 };
321 #endif
322
323 #if CONFIG_TEXT_ENCODER
324 const FFCodec ff_text_encoder = {
325 .p.name = "text",
326 .p.long_name = NULL_IF_CONFIG_SMALL("Raw text subtitle"),
327 .p.type = AVMEDIA_TYPE_SUBTITLE,
328 .p.id = AV_CODEC_ID_TEXT,
329 .priv_data_size = sizeof(SRTContext),
330 .init = srt_encode_init,
331 FF_CODEC_ENCODE_SUB_CB(text_encode_frame),
332 .close = srt_encode_close,
333 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
334 };
335 #endif
336