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 35typedef 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 48static 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 56static 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 64static 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 71static 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 80static void srt_close_tag(SRTContext *s, char tag) 81{ 82 srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : ""); 83} 84 85static 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 97static 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 136static 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 145static 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 151static void srt_new_line_cb(void *priv, int forced) 152{ 153 srt_print(priv, "\r\n"); 154} 155 156static 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 163static 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 173static 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 180static 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 187static 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 196static 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 202static 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 209static void srt_end_cb(void *priv) 210{ 211 srt_stack_push_pop(priv, 0, 1); 212} 213 214static 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 227static const ASSCodesCallbacks text_callbacks = { 228 .text = srt_text_cb, 229 .new_line = srt_new_line_cb, 230}; 231 232static 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 274static 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 280static 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 286static 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 */ 296const 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 310const 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 324const 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