2 * 3GPP TS 26.245 Timed Text decoder
3 * Copyright (c) 2012 Philip Langdale <philipl@overt.org>
5 * This file is part of FFmpeg.
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.
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.
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
24 #include "libavutil/avstring.h"
25 #include "libavutil/common.h"
26 #include "libavutil/bprint.h"
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/mem.h"
30 #define STYLE_FLAG_BOLD (1<<0)
31 #define STYLE_FLAG_ITALIC (1<<1)
32 #define STYLE_FLAG_UNDERLINE (1<<2)
34 #define BOX_SIZE_INITIAL 40
36 #define STYL_BOX (1<<0)
37 #define HLIT_BOX (1<<1)
38 #define HCLR_BOX (1<<2)
39 #define TWRP_BOX (1<<3)
42 #define BOTTOM_CENTER 2
43 #define BOTTOM_RIGHT 3
45 #define MIDDLE_CENTER 5
46 #define MIDDLE_RIGHT 6
72 uint16_t style_fontID;
81 uint8_t hlit_color[4];
94 FontRecord *ftab_temp;
98 uint16_t style_entries, ftab_entries;
101 int count_s, count_f;
108 int (*decode)(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt);
111 static void mov_text_cleanup(MovTextContext *m)
114 if (m->box_flags & STYL_BOX) {
115 for(i = 0; i < m->count_s; i++) {
120 m->style_entries = 0;
124 static void mov_text_cleanup_ftab(MovTextContext *m)
128 av_freep(&m->ftab_temp->font);
129 av_freep(&m->ftab_temp);
131 for(i = 0; i < m->count_f; i++) {
132 av_freep(&m->ftab[i]->font);
133 av_freep(&m->ftab[i]);
139 static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
141 uint8_t *tx3g_ptr = avctx->extradata;
142 int i, box_size, font_length;
143 int8_t v_align, h_align;
149 box_size = BOX_SIZE_INITIAL; /* Size till ftab_entries */
150 if (avctx->extradata_size < box_size)
156 h_align = *tx3g_ptr++;
157 v_align = *tx3g_ptr++;
160 m->d.alignment = TOP_LEFT;
162 m->d.alignment = MIDDLE_LEFT;
164 m->d.alignment = BOTTOM_LEFT;
168 m->d.alignment = TOP_CENTER;
170 m->d.alignment = MIDDLE_CENTER;
172 m->d.alignment = BOTTOM_CENTER;
176 m->d.alignment = TOP_RIGHT;
178 m->d.alignment = MIDDLE_RIGHT;
180 m->d.alignment = BOTTOM_RIGHT;
183 m->d.back_color = AV_RB24(tx3g_ptr);
190 style_fontID = AV_RB16(tx3g_ptr);
193 s_default.style_flag = *tx3g_ptr++;
194 m->d.bold = s_default.style_flag & STYLE_FLAG_BOLD;
195 m->d.italic = s_default.style_flag & STYLE_FLAG_ITALIC;
196 m->d.underline = s_default.style_flag & STYLE_FLAG_UNDERLINE;
198 m->d.fontsize = *tx3g_ptr++;
200 m->d.color = AV_RB24(tx3g_ptr);
208 m->ftab_entries = AV_RB16(tx3g_ptr);
211 for (i = 0; i < m->ftab_entries; i++) {
214 if (avctx->extradata_size < box_size) {
215 mov_text_cleanup_ftab(m);
219 m->ftab_temp = av_mallocz(sizeof(*m->ftab_temp));
221 mov_text_cleanup_ftab(m);
222 return AVERROR(ENOMEM);
224 m->ftab_temp->fontID = AV_RB16(tx3g_ptr);
226 font_length = *tx3g_ptr++;
228 box_size = box_size + font_length;
229 if (avctx->extradata_size < box_size) {
230 mov_text_cleanup_ftab(m);
234 m->ftab_temp->font = av_malloc(font_length + 1);
235 if (!m->ftab_temp->font) {
236 mov_text_cleanup_ftab(m);
237 return AVERROR(ENOMEM);
239 memcpy(m->ftab_temp->font, tx3g_ptr, font_length);
240 m->ftab_temp->font[font_length] = '\0';
241 av_dynarray_add(&m->ftab, &m->count_f, m->ftab_temp);
243 mov_text_cleanup_ftab(m);
244 return AVERROR(ENOMEM);
247 tx3g_ptr = tx3g_ptr + font_length;
249 for (i = 0; i < m->ftab_entries; i++) {
250 if (style_fontID == m->ftab[i]->fontID)
251 m->d.font = m->ftab[i]->font;
256 static int decode_twrp(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
258 m->box_flags |= TWRP_BOX;
259 m->w.wrap_flag = *tsmb++;
263 static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
265 m->box_flags |= HLIT_BOX;
266 m->h.hlit_start = AV_RB16(tsmb);
268 m->h.hlit_end = AV_RB16(tsmb);
273 static int decode_hclr(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
275 m->box_flags |= HCLR_BOX;
276 memcpy(m->c.hlit_color, tsmb, 4);
281 static int decode_styl(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
284 int style_entries = AV_RB16(tsmb);
286 // A single style record is of length 12 bytes.
287 if (m->tracksize + m->size_var + 2 + style_entries * 12 > avpkt->size)
290 m->style_entries = style_entries;
292 m->box_flags |= STYL_BOX;
293 for(i = 0; i < m->style_entries; i++) {
294 m->s_temp = av_malloc(sizeof(*m->s_temp));
297 return AVERROR(ENOMEM);
299 m->s_temp->style_start = AV_RB16(tsmb);
301 m->s_temp->style_end = AV_RB16(tsmb);
303 m->s_temp->style_fontID = AV_RB16(tsmb);
305 m->s_temp->style_flag = AV_RB8(tsmb);
307 m->s_temp->fontsize = AV_RB8(tsmb);
308 av_dynarray_add(&m->s, &m->count_s, m->s_temp);
311 return AVERROR(ENOMEM);
320 static const Box box_types[] = {
321 { MKBETAG('s','t','y','l'), 2, decode_styl },
322 { MKBETAG('h','l','i','t'), 4, decode_hlit },
323 { MKBETAG('h','c','l','r'), 4, decode_hclr },
324 { MKBETAG('t','w','r','p'), 1, decode_twrp }
327 const static size_t box_count = FF_ARRAY_ELEMS(box_types);
329 static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
336 if (text < text_end && m->box_flags & TWRP_BOX) {
337 if (m->w.wrap_flag == 1) {
338 av_bprintf(buf, "{\\q1}"); /* End of line wrap */
340 av_bprintf(buf, "{\\q2}"); /* No wrap */
344 while (text < text_end) {
345 if (m->box_flags & STYL_BOX) {
346 for (i = 0; i < m->style_entries; i++) {
347 if (m->s[i]->style_flag && text_pos == m->s[i]->style_end) {
348 av_bprintf(buf, "{\\r}");
351 for (i = 0; i < m->style_entries; i++) {
352 if (m->s[i]->style_flag && text_pos == m->s[i]->style_start) {
353 if (m->s[i]->style_flag & STYLE_FLAG_BOLD)
354 av_bprintf(buf, "{\\b1}");
355 if (m->s[i]->style_flag & STYLE_FLAG_ITALIC)
356 av_bprintf(buf, "{\\i1}");
357 if (m->s[i]->style_flag & STYLE_FLAG_UNDERLINE)
358 av_bprintf(buf, "{\\u1}");
359 av_bprintf(buf, "{\\fs%d}", m->s[i]->fontsize);
360 for (j = 0; j < m->ftab_entries; j++) {
361 if (m->s[i]->style_fontID == m->ftab[j]->fontID)
362 av_bprintf(buf, "{\\fn%s}", m->ftab[j]->font);
367 if (m->box_flags & HLIT_BOX) {
368 if (text_pos == m->h.hlit_start) {
369 /* If hclr box is present, set the secondary color to the color
370 * specified. Otherwise, set primary color to white and secondary
371 * color to black. These colors will come from TextSampleModifier
372 * boxes in future and inverse video technique for highlight will
375 if (m->box_flags & HCLR_BOX) {
376 av_bprintf(buf, "{\\2c&H%02x%02x%02x&}", m->c.hlit_color[2],
377 m->c.hlit_color[1], m->c.hlit_color[0]);
379 av_bprintf(buf, "{\\1c&H000000&}{\\2c&HFFFFFF&}");
382 if (text_pos == m->h.hlit_end) {
383 if (m->box_flags & HCLR_BOX) {
384 av_bprintf(buf, "{\\2c&H000000&}");
386 av_bprintf(buf, "{\\1c&HFFFFFF&}{\\2c&H000000&}");
395 av_bprintf(buf, "\\N");
398 av_bprint_chars(buf, *text, 1);
408 static int mov_text_init(AVCodecContext *avctx) {
410 * TODO: Handle the default text style.
411 * NB: Most players ignore styles completely, with the result that
412 * it's very common to find files where the default style is broken
413 * and respecting it results in a worse experience than ignoring it.
416 MovTextContext *m = avctx->priv_data;
417 ret = mov_text_tx3g(avctx, m);
419 return ff_ass_subtitle_header(avctx, m->d.font, m->d.fontsize, m->d.color,
420 m->d.back_color, m->d.bold, m->d.italic,
421 m->d.underline, ASS_DEFAULT_BORDERSTYLE,
424 return ff_ass_subtitle_header_default(avctx);
427 static int mov_text_decode_frame(AVCodecContext *avctx,
428 void *data, int *got_sub_ptr, AVPacket *avpkt)
430 AVSubtitle *sub = data;
431 MovTextContext *m = avctx->priv_data;
434 char *ptr = avpkt->data;
436 int text_length, tsmb_type, ret_tsmb;
440 if (!ptr || avpkt->size < 2)
441 return AVERROR_INVALIDDATA;
444 * A packet of size two with value zero is an empty subtitle
445 * used to mark the end of the previous non-empty subtitle.
446 * We can just drop them here as we have duration information
447 * already. If the value is non-zero, then it's technically a
450 if (avpkt->size == 2)
451 return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
454 * The first two bytes of the packet are the length of the text string
455 * In complex cases, there are style descriptors appended to the string
456 * so we can't just assume the packet size is the string size.
458 text_length = AV_RB16(ptr);
459 end = ptr + FFMIN(2 + text_length, avpkt->size);
465 m->tracksize = 2 + text_length;
466 m->style_entries = 0;
469 // Note that the spec recommends lines be no longer than 2048 characters.
470 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
471 if (text_length + 2 != avpkt->size) {
472 while (m->tracksize + 8 <= avpkt->size) {
473 // A box is a minimum of 8 bytes.
474 tsmb = ptr + m->tracksize - 2;
475 tsmb_size = AV_RB32(tsmb);
477 tsmb_type = AV_RB32(tsmb);
480 if (tsmb_size == 1) {
481 if (m->tracksize + 16 > avpkt->size)
483 tsmb_size = AV_RB64(tsmb);
488 //size_var is equal to 8 or 16 depending on the size of box
490 if (tsmb_size == 0) {
491 av_log(avctx, AV_LOG_ERROR, "tsmb_size is 0\n");
492 return AVERROR_INVALIDDATA;
495 if (tsmb_size > avpkt->size - m->tracksize)
498 for (size_t i = 0; i < box_count; i++) {
499 if (tsmb_type == box_types[i].type) {
500 if (m->tracksize + m->size_var + box_types[i].base_size > avpkt->size)
502 ret_tsmb = box_types[i].decode(tsmb, m, avpkt);
507 m->tracksize = m->tracksize + tsmb_size;
509 text_to_ass(&buf, ptr, end, m);
512 text_to_ass(&buf, ptr, end, m);
514 ret = ff_ass_add_rect(sub, buf.str, m->readorder++, 0, NULL, NULL);
515 av_bprint_finalize(&buf, NULL);
518 *got_sub_ptr = sub->num_rects > 0;
522 static int mov_text_decode_close(AVCodecContext *avctx)
524 MovTextContext *m = avctx->priv_data;
525 mov_text_cleanup_ftab(m);
530 static void mov_text_flush(AVCodecContext *avctx)
532 MovTextContext *m = avctx->priv_data;
533 if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
537 AVCodec ff_movtext_decoder = {
539 .long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
540 .type = AVMEDIA_TYPE_SUBTITLE,
541 .id = AV_CODEC_ID_MOV_TEXT,
542 .priv_data_size = sizeof(MovTextContext),
543 .init = mov_text_init,
544 .decode = mov_text_decode_frame,
545 .close = mov_text_decode_close,
546 .flush = mov_text_flush,