FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/srtenc.c
Date: 2026-01-16 07:34:38
Exec Total Coverage
Lines: 99 139 71.2%
Functions: 18 22 81.8%
Branches: 44 74 59.5%
Line Branch Exec Source
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/bprint.h"
27 #include "ass_split.h"
28 #include "ass.h"
29 #include "codec_internal.h"
30
31
32 #define SRT_STACK_SIZE 64
33
34 typedef struct {
35 AVCodecContext *avctx;
36 ASSSplitContext *ass_ctx;
37 AVBPrint buffer;
38 char stack[SRT_STACK_SIZE];
39 int stack_ptr;
40 int alignment_applied;
41 } SRTContext;
42
43
44 246 static av_printf_format(2, 3) void srt_print(SRTContext *s, const char *str, ...)
45 {
46 va_list vargs;
47 246 va_start(vargs, str);
48 246 av_vbprintf(&s->buffer, str, vargs);
49 246 va_end(vargs);
50 246 }
51
52 46 static int srt_stack_push(SRTContext *s, const char c)
53 {
54
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 46 if (s->stack_ptr >= SRT_STACK_SIZE)
55 ✗ return -1;
56 46 s->stack[s->stack_ptr++] = c;
57 46 return 0;
58 }
59
60 46 static char srt_stack_pop(SRTContext *s)
61 {
62
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 46 if (s->stack_ptr <= 0)
63 ✗ return 0;
64 46 return s->stack[--s->stack_ptr];
65 }
66
67 14 static int srt_stack_find(SRTContext *s, const char c)
68 {
69 int i;
70
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 14 for (i = s->stack_ptr-1; i >= 0; i--)
71
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 14 if (s->stack[i] == c)
72 14 break;
73 14 return i;
74 }
75
76 46 static void srt_close_tag(SRTContext *s, char tag)
77 {
78
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 46 srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
79 46 }
80
81 189 static void srt_stack_push_pop(SRTContext *s, const char c, int close)
82 {
83
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 189 if (close) {
84
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 169 int i = c ? srt_stack_find(s, c) : 0;
85
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 169 if (i < 0)
86 ✗ return;
87
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 215 while (s->stack_ptr != i)
88 46 srt_close_tag(s, srt_stack_pop(s));
89
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 20 } else if (srt_stack_push(s, c) < 0)
90 ✗ av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
91 }
92
93 155 static void srt_style_apply(SRTContext *s, const char *style)
94 {
95 155 ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);
96
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 155 if (st) {
97 155 int c = st->primary_color & 0xFFFFFF;
98
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 155 if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||
99
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 129 st->font_size != ASS_DEFAULT_FONT_SIZE ||
100 c != ASS_DEFAULT_COLOR) {
101 26 srt_print(s, "<font");
102
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 26 if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))
103 26 srt_print(s, " face=\"%s\"", st->font_name);
104
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 26 if (st->font_size != ASS_DEFAULT_FONT_SIZE)
105 3 srt_print(s, " size=\"%d\"", st->font_size);
106
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 26 if (c != ASS_DEFAULT_COLOR)
107 ✗ srt_print(s, " color=\"#%06x\"",
108 ✗ (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);
109 26 srt_print(s, ">");
110 26 srt_stack_push(s, 'f');
111 }
112
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 155 if (st->bold != ASS_DEFAULT_BOLD) {
113 ✗ srt_print(s, "<b>");
114 ✗ srt_stack_push(s, 'b');
115 }
116
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 155 if (st->italic != ASS_DEFAULT_ITALIC) {
117 ✗ srt_print(s, "<i>");
118 ✗ srt_stack_push(s, 'i');
119 }
120
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 155 if (st->underline != ASS_DEFAULT_UNDERLINE) {
121 ✗ srt_print(s, "<u>");
122 ✗ srt_stack_push(s, 'u');
123 }
124
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 155 if (st->alignment != ASS_DEFAULT_ALIGNMENT) {
125 ✗ srt_print(s, "{\\an%d}", st->alignment);
126 ✗ s->alignment_applied = 1;
127 }
128 }
129 155 }
130
131
132 8 static av_cold int srt_encode_init(AVCodecContext *avctx)
133 {
134 8 SRTContext *s = avctx->priv_data;
135 8 s->avctx = avctx;
136 8 s->ass_ctx = ff_ass_split(avctx->subtitle_header);
137
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 8 return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
138 }
139
140 296 static void srt_text_cb(void *priv, const char *text, int len)
141 {
142 296 SRTContext *s = priv;
143 296 av_bprint_append_data(&s->buffer, text, len);
144 296 }
145
146 76 static void srt_new_line_cb(void *priv, int forced)
147 {
148 76 srt_print(priv, "\n");
149 76 }
150
151 34 static void srt_style_cb(void *priv, char style, int close)
152 {
153 34 srt_stack_push_pop(priv, style, close);
154
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 34 if (!close)
155 20 srt_print(priv, "<%c>", style);
156 34 }
157
158 ✗ static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)
159 {
160 ✗ if (color_id > 1)
161 ✗ return;
162 ✗ srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);
163 ✗ if (color != 0xFFFFFFFF)
164 ✗ srt_print(priv, "<font color=\"#%06x\">",
165 ✗ (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);
166 }
167
168 ✗ static void srt_font_name_cb(void *priv, const char *name)
169 {
170 ✗ srt_stack_push_pop(priv, 'f', !name);
171 ✗ if (name)
172 ✗ srt_print(priv, "<font face=\"%s\">", name);
173 ✗ }
174
175 ✗ static void srt_font_size_cb(void *priv, int size)
176 {
177 ✗ srt_stack_push_pop(priv, 'f', size < 0);
178 ✗ if (size >= 0)
179 ✗ srt_print(priv, "<font size=\"%d\">", size);
180 ✗ }
181
182 32 static void srt_alignment_cb(void *priv, int alignment)
183 {
184 32 SRTContext *s = priv;
185
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 32 if (!s->alignment_applied && alignment >= 0) {
186 23 srt_print(s, "{\\an%d}", alignment);
187 23 s->alignment_applied = 1;
188 }
189 32 }
190
191 ✗ static void srt_cancel_overrides_cb(void *priv, const char *style)
192 {
193 ✗ srt_stack_push_pop(priv, 0, 1);
194 ✗ srt_style_apply(priv, style);
195 ✗ }
196
197 32 static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
198 int t1, int t2)
199 {
200 // TODO: add a AV_PKT_DATA_SUBTITLE_POSITION side data when a new subtitles
201 // encoding API passing the AVPacket is available.
202 32 }
203
204 155 static void srt_end_cb(void *priv)
205 {
206 155 srt_stack_push_pop(priv, 0, 1);
207 155 }
208
209 static const ASSCodesCallbacks srt_callbacks = {
210 .text = srt_text_cb,
211 .new_line = srt_new_line_cb,
212 .style = srt_style_cb,
213 .color = srt_color_cb,
214 .font_name = srt_font_name_cb,
215 .font_size = srt_font_size_cb,
216 .alignment = srt_alignment_cb,
217 .cancel_overrides = srt_cancel_overrides_cb,
218 .move = srt_move_cb,
219 .end = srt_end_cb,
220 };
221
222 static const ASSCodesCallbacks text_callbacks = {
223 .text = srt_text_cb,
224 .new_line = srt_new_line_cb,
225 };
226
227 192 static int encode_frame(AVCodecContext *avctx,
228 unsigned char *buf, int bufsize, const AVSubtitle *sub,
229 const ASSCodesCallbacks *cb)
230 {
231 192 SRTContext *s = avctx->priv_data;
232 ASSDialog *dialog;
233 int i;
234
235 192 av_bprint_init_for_buffer(&s->buffer, buf, bufsize);
236
237
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 384 for (i=0; i<sub->num_rects; i++) {
238 192 const char *ass = sub->rects[i]->ass;
239
240
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 192 if (sub->rects[i]->type != SUBTITLE_ASS) {
241 ✗ av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
242 ✗ return AVERROR(EINVAL);
243 }
244
245 192 dialog = ff_ass_split_dialog(s->ass_ctx, ass);
246
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 192 if (!dialog)
247 ✗ return AVERROR(ENOMEM);
248 192 s->alignment_applied = 0;
249
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 192 if (avctx->codec_id == AV_CODEC_ID_SUBRIP)
250 155 srt_style_apply(s, dialog->style);
251 192 ff_ass_split_override_codes(cb, s, dialog->text);
252 192 ff_ass_free_dialog(&dialog);
253 }
254
255
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 192 if (!s->buffer.len)
256 6 return 0;
257
258
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 186 if (!av_bprint_is_complete(&s->buffer)) {
259 ✗ av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
260 ✗ return AVERROR_BUFFER_TOO_SMALL;
261 }
262
263 186 return s->buffer.len;
264 }
265
266 155 static int srt_encode_frame(AVCodecContext *avctx,
267 unsigned char *buf, int bufsize, const AVSubtitle *sub)
268 {
269 155 return encode_frame(avctx, buf, bufsize, sub, &srt_callbacks);
270 }
271
272 37 static int text_encode_frame(AVCodecContext *avctx,
273 unsigned char *buf, int bufsize, const AVSubtitle *sub)
274 {
275 37 return encode_frame(avctx, buf, bufsize, sub, &text_callbacks);
276 }
277
278 8 static av_cold int srt_encode_close(AVCodecContext *avctx)
279 {
280 8 SRTContext *s = avctx->priv_data;
281 8 ff_ass_split_free(s->ass_ctx);
282 8 return 0;
283 }
284
285 #if CONFIG_SRT_ENCODER
286 /* deprecated encoder */
287 const FFCodec ff_srt_encoder = {
288 .p.name = "srt",
289 CODEC_LONG_NAME("SubRip subtitle"),
290 .p.type = AVMEDIA_TYPE_SUBTITLE,
291 .p.id = AV_CODEC_ID_SUBRIP,
292 .priv_data_size = sizeof(SRTContext),
293 .init = srt_encode_init,
294 FF_CODEC_ENCODE_SUB_CB(srt_encode_frame),
295 .close = srt_encode_close,
296 };
297 #endif
298
299 #if CONFIG_SUBRIP_ENCODER
300 const FFCodec ff_subrip_encoder = {
301 .p.name = "subrip",
302 CODEC_LONG_NAME("SubRip subtitle"),
303 .p.type = AVMEDIA_TYPE_SUBTITLE,
304 .p.id = AV_CODEC_ID_SUBRIP,
305 .priv_data_size = sizeof(SRTContext),
306 .init = srt_encode_init,
307 FF_CODEC_ENCODE_SUB_CB(srt_encode_frame),
308 .close = srt_encode_close,
309 };
310 #endif
311
312 #if CONFIG_TEXT_ENCODER
313 const FFCodec ff_text_encoder = {
314 .p.name = "text",
315 CODEC_LONG_NAME("Raw text subtitle"),
316 .p.type = AVMEDIA_TYPE_SUBTITLE,
317 .p.id = AV_CODEC_ID_TEXT,
318 .priv_data_size = sizeof(SRTContext),
319 .init = srt_encode_init,
320 FF_CODEC_ENCODE_SUB_CB(text_encode_frame),
321 .close = srt_encode_close,
322 };
323 #endif
324