| 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 |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 77 | static void srt_close_tag(SRTContext *s, char tag) |
| 78 | { |
| 79 | srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : ""); |
| 80 | } |
| 81 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 148 | static void srt_new_line_cb(void *priv, int forced) |
| 149 | { |
| 150 | srt_print(priv, "\r\n"); |
| 151 | } |
| 152 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 int srt_encode_frame(AVCodecContext *avctx, |
| 225 | unsigned char *buf, int bufsize, const AVSubtitle *sub) |
| 226 | { |
| 227 | SRTContext *s = avctx->priv_data; |
| 228 | ASSDialog *dialog; |
| 229 | int i, num; |
| 230 | |
| 231 | av_bprint_clear(&s->buffer); |
| 232 | |
| 233 | for (i=0; i<sub->num_rects; i++) { |
| 234 | |
| 235 | if (sub->rects[i]->type != SUBTITLE_ASS) { |
| 236 | av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n"); |
| 237 | return AVERROR(ENOSYS); |
| 238 | } |
| 239 | |
| 240 | dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num); |
| 241 | for (; dialog && num--; dialog++) { |
| 242 | s->alignment_applied = 0; |
| 243 | srt_style_apply(s, dialog->style); |
| 244 | ff_ass_split_override_codes(&srt_callbacks, s, dialog->text); |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | if (!av_bprint_is_complete(&s->buffer)) |
| 249 | return AVERROR(ENOMEM); |
| 250 | if (!s->buffer.len) |
| 251 | return 0; |
| 252 | |
| 253 | if (s->buffer.len > bufsize) { |
| 254 | av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n"); |
| 255 | return -1; |
| 256 | } |
| 257 | memcpy(buf, s->buffer.str, s->buffer.len); |
| 258 | |
| 259 | return s->buffer.len; |
| 260 | } |
| 261 | |
| 262 | static int srt_encode_close(AVCodecContext *avctx) |
| 263 | { |
| 264 | SRTContext *s = avctx->priv_data; |
| 265 | ff_ass_split_free(s->ass_ctx); |
| 266 | av_bprint_finalize(&s->buffer, NULL); |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | #if CONFIG_SRT_ENCODER |
| 271 | /* deprecated encoder */ |
| 272 | AVCodec ff_srt_encoder = { |
| 273 | .name = "srt", |
| 274 | .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"), |
| 275 | .type = AVMEDIA_TYPE_SUBTITLE, |
| 276 | .id = AV_CODEC_ID_SUBRIP, |
| 277 | .priv_data_size = sizeof(SRTContext), |
| 278 | .init = srt_encode_init, |
| 279 | .encode_sub = srt_encode_frame, |
| 280 | .close = srt_encode_close, |
| 281 | }; |
| 282 | #endif |
| 283 | |
| 284 | #if CONFIG_SUBRIP_ENCODER |
| 285 | AVCodec ff_subrip_encoder = { |
| 286 | .name = "subrip", |
| 287 | .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"), |
| 288 | .type = AVMEDIA_TYPE_SUBTITLE, |
| 289 | .id = AV_CODEC_ID_SUBRIP, |
| 290 | .priv_data_size = sizeof(SRTContext), |
| 291 | .init = srt_encode_init, |
| 292 | .encode_sub = srt_encode_frame, |
| 293 | .close = srt_encode_close, |
| 294 | }; |
| 295 | #endif |