1 /*
2 * 3GPP TS 26.245 Timed Text decoder
3 * Copyright (c) 2012 Philip Langdale <philipl@overt.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 "avcodec.h"
23 #include "ass.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/avstring.h"
26 #include "libavutil/common.h"
27 #include "libavutil/bprint.h"
28 #include "libavutil/intreadwrite.h"
29 #include "libavutil/mem.h"
30
31 #define STYLE_FLAG_BOLD (1<<0)
32 #define STYLE_FLAG_ITALIC (1<<1)
33 #define STYLE_FLAG_UNDERLINE (1<<2)
34
35 #define BOX_SIZE_INITIAL 40
36
37 #define STYL_BOX (1<<0)
38 #define HLIT_BOX (1<<1)
39 #define HCLR_BOX (1<<2)
40 #define TWRP_BOX (1<<3)
41
42 #define BOTTOM_LEFT 1
43 #define BOTTOM_CENTER 2
44 #define BOTTOM_RIGHT 3
45 #define MIDDLE_LEFT 4
46 #define MIDDLE_CENTER 5
47 #define MIDDLE_RIGHT 6
48 #define TOP_LEFT 7
49 #define TOP_CENTER 8
50 #define TOP_RIGHT 9
51
52 #define RGB_TO_BGR(c) (((c) & 0xff) << 16 | ((c) & 0xff00) | (((c) >> 16) & 0xff))
53
54 typedef struct {
55 uint16_t fontID;
56 const char *font;
57 uint8_t fontsize;
58 int color;
59 uint8_t alpha;
60 int back_color;
61 uint8_t back_alpha;
62 uint8_t bold;
63 uint8_t italic;
64 uint8_t underline;
65 int alignment;
66 } MovTextDefault;
67
68 typedef struct {
69 uint16_t fontID;
70 char *font;
71 } FontRecord;
72
73 typedef struct {
74 uint16_t style_start;
75 uint16_t style_end;
76 uint8_t style_flag;
77 uint8_t bold;
78 uint8_t italic;
79 uint8_t underline;
80 int color;
81 uint8_t alpha;
82 uint8_t fontsize;
83 uint16_t style_fontID;
84 } StyleBox;
85
86 typedef struct {
87 uint16_t hlit_start;
88 uint16_t hlit_end;
89 } HighlightBox;
90
91 typedef struct {
92 uint8_t hlit_color[4];
93 } HilightcolorBox;
94
95 typedef struct {
96 uint8_t wrap_flag;
97 } TextWrapBox;
98
99 typedef struct {
100 AVClass *class;
101 StyleBox **s;
102 StyleBox *s_temp;
103 HighlightBox h;
104 HilightcolorBox c;
105 FontRecord **ftab;
106 FontRecord *ftab_temp;
107 TextWrapBox w;
108 MovTextDefault d;
109 uint8_t box_flags;
110 uint16_t style_entries, ftab_entries;
111 uint64_t tracksize;
112 int size_var;
113 int count_s, count_f;
114 int readorder;
115 int frame_width;
116 int frame_height;
117 } MovTextContext;
118
119 typedef struct {
120 uint32_t type;
121 size_t base_size;
122 int (*decode)(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt);
123 } Box;
124
mov_text_cleanup(MovTextContext * m)125 static void mov_text_cleanup(MovTextContext *m)
126 {
127 int i;
128 if (m->box_flags & STYL_BOX) {
129 for(i = 0; i < m->count_s; i++) {
130 av_freep(&m->s[i]);
131 }
132 av_freep(&m->s);
133 m->count_s = 0;
134 m->style_entries = 0;
135 }
136 }
137
mov_text_cleanup_ftab(MovTextContext * m)138 static void mov_text_cleanup_ftab(MovTextContext *m)
139 {
140 int i;
141 if (m->ftab_temp)
142 av_freep(&m->ftab_temp->font);
143 av_freep(&m->ftab_temp);
144 if (m->ftab) {
145 for(i = 0; i < m->count_f; i++) {
146 av_freep(&m->ftab[i]->font);
147 av_freep(&m->ftab[i]);
148 }
149 }
150 av_freep(&m->ftab);
151 }
152
mov_text_tx3g(AVCodecContext * avctx,MovTextContext * m)153 static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
154 {
155 uint8_t *tx3g_ptr = avctx->extradata;
156 int i, box_size, font_length;
157 int8_t v_align, h_align;
158 StyleBox s_default;
159
160 m->count_f = 0;
161 m->ftab_entries = 0;
162 box_size = BOX_SIZE_INITIAL; /* Size till ftab_entries */
163 if (avctx->extradata_size < box_size)
164 return -1;
165
166 // Display Flags
167 tx3g_ptr += 4;
168 // Alignment
169 h_align = *tx3g_ptr++;
170 v_align = *tx3g_ptr++;
171 if (h_align == 0) {
172 if (v_align == 0)
173 m->d.alignment = TOP_LEFT;
174 if (v_align == 1)
175 m->d.alignment = MIDDLE_LEFT;
176 if (v_align == -1)
177 m->d.alignment = BOTTOM_LEFT;
178 }
179 if (h_align == 1) {
180 if (v_align == 0)
181 m->d.alignment = TOP_CENTER;
182 if (v_align == 1)
183 m->d.alignment = MIDDLE_CENTER;
184 if (v_align == -1)
185 m->d.alignment = BOTTOM_CENTER;
186 }
187 if (h_align == -1) {
188 if (v_align == 0)
189 m->d.alignment = TOP_RIGHT;
190 if (v_align == 1)
191 m->d.alignment = MIDDLE_RIGHT;
192 if (v_align == -1)
193 m->d.alignment = BOTTOM_RIGHT;
194 }
195 // Background Color
196 m->d.back_color = AV_RB24(tx3g_ptr);
197 tx3g_ptr += 3;
198 m->d.back_alpha = AV_RB8(tx3g_ptr);
199 tx3g_ptr += 1;
200 // BoxRecord
201 tx3g_ptr += 8;
202 // StyleRecord
203 tx3g_ptr += 4;
204 // fontID
205 m->d.fontID = AV_RB16(tx3g_ptr);
206 tx3g_ptr += 2;
207 // face-style-flags
208 s_default.style_flag = *tx3g_ptr++;
209 m->d.bold = !!(s_default.style_flag & STYLE_FLAG_BOLD);
210 m->d.italic = !!(s_default.style_flag & STYLE_FLAG_ITALIC);
211 m->d.underline = !!(s_default.style_flag & STYLE_FLAG_UNDERLINE);
212 // fontsize
213 m->d.fontsize = *tx3g_ptr++;
214 // Primary color
215 m->d.color = AV_RB24(tx3g_ptr);
216 tx3g_ptr += 3;
217 m->d.alpha = AV_RB8(tx3g_ptr);
218 tx3g_ptr += 1;
219 // FontRecord
220 // FontRecord Size
221 tx3g_ptr += 4;
222 // ftab
223 tx3g_ptr += 4;
224
225 m->ftab_entries = AV_RB16(tx3g_ptr);
226 tx3g_ptr += 2;
227
228 for (i = 0; i < m->ftab_entries; i++) {
229
230 box_size += 3;
231 if (avctx->extradata_size < box_size) {
232 mov_text_cleanup_ftab(m);
233 m->ftab_entries = 0;
234 return -1;
235 }
236 m->ftab_temp = av_mallocz(sizeof(*m->ftab_temp));
237 if (!m->ftab_temp) {
238 mov_text_cleanup_ftab(m);
239 return AVERROR(ENOMEM);
240 }
241 m->ftab_temp->fontID = AV_RB16(tx3g_ptr);
242 tx3g_ptr += 2;
243 font_length = *tx3g_ptr++;
244
245 box_size = box_size + font_length;
246 if (avctx->extradata_size < box_size) {
247 mov_text_cleanup_ftab(m);
248 m->ftab_entries = 0;
249 return -1;
250 }
251 m->ftab_temp->font = av_malloc(font_length + 1);
252 if (!m->ftab_temp->font) {
253 mov_text_cleanup_ftab(m);
254 return AVERROR(ENOMEM);
255 }
256 memcpy(m->ftab_temp->font, tx3g_ptr, font_length);
257 m->ftab_temp->font[font_length] = '\0';
258 av_dynarray_add(&m->ftab, &m->count_f, m->ftab_temp);
259 if (!m->ftab) {
260 mov_text_cleanup_ftab(m);
261 return AVERROR(ENOMEM);
262 }
263 m->ftab_temp = NULL;
264 tx3g_ptr = tx3g_ptr + font_length;
265 }
266 // In case of broken header, init default font
267 m->d.font = ASS_DEFAULT_FONT;
268 for (i = 0; i < m->ftab_entries; i++) {
269 if (m->d.fontID == m->ftab[i]->fontID)
270 m->d.font = m->ftab[i]->font;
271 }
272 return 0;
273 }
274
decode_twrp(const uint8_t * tsmb,MovTextContext * m,AVPacket * avpkt)275 static int decode_twrp(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
276 {
277 m->box_flags |= TWRP_BOX;
278 m->w.wrap_flag = *tsmb++;
279 return 0;
280 }
281
decode_hlit(const uint8_t * tsmb,MovTextContext * m,AVPacket * avpkt)282 static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
283 {
284 m->box_flags |= HLIT_BOX;
285 m->h.hlit_start = AV_RB16(tsmb);
286 tsmb += 2;
287 m->h.hlit_end = AV_RB16(tsmb);
288 tsmb += 2;
289 return 0;
290 }
291
decode_hclr(const uint8_t * tsmb,MovTextContext * m,AVPacket * avpkt)292 static int decode_hclr(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
293 {
294 m->box_flags |= HCLR_BOX;
295 memcpy(m->c.hlit_color, tsmb, 4);
296 tsmb += 4;
297 return 0;
298 }
299
decode_styl(const uint8_t * tsmb,MovTextContext * m,AVPacket * avpkt)300 static int decode_styl(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt)
301 {
302 int i;
303 int style_entries = AV_RB16(tsmb);
304 tsmb += 2;
305 // A single style record is of length 12 bytes.
306 if (m->tracksize + m->size_var + 2 + style_entries * 12 > avpkt->size)
307 return -1;
308
309 m->style_entries = style_entries;
310
311 m->box_flags |= STYL_BOX;
312 for(i = 0; i < m->style_entries; i++) {
313 m->s_temp = av_malloc(sizeof(*m->s_temp));
314 if (!m->s_temp) {
315 mov_text_cleanup(m);
316 return AVERROR(ENOMEM);
317 }
318 m->s_temp->style_start = AV_RB16(tsmb);
319 tsmb += 2;
320 m->s_temp->style_end = AV_RB16(tsmb);
321
322 if ( m->s_temp->style_end < m->s_temp->style_start
323 || (m->count_s && m->s_temp->style_start < m->s[m->count_s - 1]->style_end)) {
324 av_freep(&m->s_temp);
325 mov_text_cleanup(m);
326 return AVERROR(ENOMEM);
327 }
328
329 tsmb += 2;
330 m->s_temp->style_fontID = AV_RB16(tsmb);
331 tsmb += 2;
332 m->s_temp->style_flag = AV_RB8(tsmb);
333 m->s_temp->bold = !!(m->s_temp->style_flag & STYLE_FLAG_BOLD);
334 m->s_temp->italic = !!(m->s_temp->style_flag & STYLE_FLAG_ITALIC);
335 m->s_temp->underline = !!(m->s_temp->style_flag & STYLE_FLAG_UNDERLINE);
336 tsmb++;
337 m->s_temp->fontsize = AV_RB8(tsmb);
338 tsmb++;
339 m->s_temp->color = AV_RB24(tsmb);
340 tsmb += 3;
341 m->s_temp->alpha = AV_RB8(tsmb);
342 tsmb++;
343 av_dynarray_add(&m->s, &m->count_s, m->s_temp);
344 if(!m->s) {
345 mov_text_cleanup(m);
346 return AVERROR(ENOMEM);
347 }
348 }
349 return 0;
350 }
351
352 static const Box box_types[] = {
353 { MKBETAG('s','t','y','l'), 2, decode_styl },
354 { MKBETAG('h','l','i','t'), 4, decode_hlit },
355 { MKBETAG('h','c','l','r'), 4, decode_hclr },
356 { MKBETAG('t','w','r','p'), 1, decode_twrp }
357 };
358
359 const static size_t box_count = FF_ARRAY_ELEMS(box_types);
360
361 // Return byte length of the UTF-8 sequence starting at text[0]. 0 on error.
get_utf8_length_at(const char * text,const char * text_end)362 static int get_utf8_length_at(const char *text, const char *text_end)
363 {
364 const char *start = text;
365 int err = 0;
366 uint32_t c;
367 GET_UTF8(c, text < text_end ? (uint8_t)*text++ : (err = 1, 0), goto error;);
368 if (err)
369 goto error;
370 return text - start;
371 error:
372 return 0;
373 }
374
text_to_ass(AVBPrint * buf,const char * text,const char * text_end,AVCodecContext * avctx)375 static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
376 AVCodecContext *avctx)
377 {
378 MovTextContext *m = avctx->priv_data;
379 int i = 0;
380 int text_pos = 0;
381 int style_active = 0;
382 int entry = 0;
383 int color = m->d.color;
384
385 if (text < text_end && m->box_flags & TWRP_BOX) {
386 if (m->w.wrap_flag == 1) {
387 av_bprintf(buf, "{\\q1}"); /* End of line wrap */
388 } else {
389 av_bprintf(buf, "{\\q2}"); /* No wrap */
390 }
391 }
392
393 while (text < text_end) {
394 int len;
395
396 if ((m->box_flags & STYL_BOX) && entry < m->style_entries) {
397 if (text_pos == m->s[entry]->style_start) {
398 style_active = 1;
399 if (m->s[entry]->bold ^ m->d.bold)
400 av_bprintf(buf, "{\\b%d}", m->s[entry]->bold);
401 if (m->s[entry]->italic ^ m->d.italic)
402 av_bprintf(buf, "{\\i%d}", m->s[entry]->italic);
403 if (m->s[entry]->underline ^ m->d.underline)
404 av_bprintf(buf, "{\\u%d}", m->s[entry]->underline);
405 if (m->s[entry]->fontsize != m->d.fontsize)
406 av_bprintf(buf, "{\\fs%d}", m->s[entry]->fontsize);
407 if (m->s[entry]->style_fontID != m->d.fontID)
408 for (i = 0; i < m->ftab_entries; i++) {
409 if (m->s[entry]->style_fontID == m->ftab[i]->fontID)
410 av_bprintf(buf, "{\\fn%s}", m->ftab[i]->font);
411 }
412 if (m->d.color != m->s[entry]->color) {
413 color = m->s[entry]->color;
414 av_bprintf(buf, "{\\1c&H%X&}", RGB_TO_BGR(color));
415 }
416 if (m->d.alpha != m->s[entry]->alpha)
417 av_bprintf(buf, "{\\1a&H%02X&}", 255 - m->s[entry]->alpha);
418 }
419 if (text_pos == m->s[entry]->style_end) {
420 if (style_active) {
421 av_bprintf(buf, "{\\r}");
422 style_active = 0;
423 color = m->d.color;
424 }
425 entry++;
426 }
427 }
428 if (m->box_flags & HLIT_BOX) {
429 if (text_pos == m->h.hlit_start) {
430 /* If hclr box is present, set the secondary color to the color
431 * specified. Otherwise, set primary color to white and secondary
432 * color to black. These colors will come from TextSampleModifier
433 * boxes in future and inverse video technique for highlight will
434 * be implemented.
435 */
436 if (m->box_flags & HCLR_BOX) {
437 av_bprintf(buf, "{\\2c&H%02x%02x%02x&}", m->c.hlit_color[2],
438 m->c.hlit_color[1], m->c.hlit_color[0]);
439 } else {
440 av_bprintf(buf, "{\\1c&H000000&}{\\2c&HFFFFFF&}");
441 }
442 }
443 if (text_pos == m->h.hlit_end) {
444 if (m->box_flags & HCLR_BOX) {
445 av_bprintf(buf, "{\\2c&H%X&}", RGB_TO_BGR(m->d.color));
446 } else {
447 av_bprintf(buf, "{\\1c&H%X&}{\\2c&H%X&}",
448 RGB_TO_BGR(color), RGB_TO_BGR(m->d.color));
449 }
450 }
451 }
452
453 len = get_utf8_length_at(text, text_end);
454 if (len < 1) {
455 av_log(avctx, AV_LOG_ERROR, "invalid UTF-8 byte in subtitle\n");
456 len = 1;
457 }
458 for (i = 0; i < len; i++) {
459 switch (*text) {
460 case '\r':
461 break;
462 case '\n':
463 av_bprintf(buf, "\\N");
464 break;
465 default:
466 av_bprint_chars(buf, *text, 1);
467 break;
468 }
469 text++;
470 }
471 text_pos++;
472 }
473
474 return 0;
475 }
476
mov_text_init(AVCodecContext * avctx)477 static int mov_text_init(AVCodecContext *avctx) {
478 /*
479 * TODO: Handle the default text style.
480 * NB: Most players ignore styles completely, with the result that
481 * it's very common to find files where the default style is broken
482 * and respecting it results in a worse experience than ignoring it.
483 */
484 int ret;
485 MovTextContext *m = avctx->priv_data;
486 ret = mov_text_tx3g(avctx, m);
487 if (ret == 0) {
488 if (!m->frame_width || !m->frame_height) {
489 m->frame_width = ASS_DEFAULT_PLAYRESX;
490 m->frame_height = ASS_DEFAULT_PLAYRESY;
491 }
492 return ff_ass_subtitle_header_full(avctx,
493 m->frame_width, m->frame_height,
494 m->d.font, m->d.fontsize,
495 (255U - m->d.alpha) << 24 | RGB_TO_BGR(m->d.color),
496 (255U - m->d.alpha) << 24 | RGB_TO_BGR(m->d.color),
497 (255U - m->d.back_alpha) << 24 | RGB_TO_BGR(m->d.back_color),
498 (255U - m->d.back_alpha) << 24 | RGB_TO_BGR(m->d.back_color),
499 m->d.bold, m->d.italic, m->d.underline,
500 ASS_DEFAULT_BORDERSTYLE, m->d.alignment);
501 } else
502 return ff_ass_subtitle_header_default(avctx);
503 }
504
mov_text_decode_frame(AVCodecContext * avctx,void * data,int * got_sub_ptr,AVPacket * avpkt)505 static int mov_text_decode_frame(AVCodecContext *avctx,
506 void *data, int *got_sub_ptr, AVPacket *avpkt)
507 {
508 AVSubtitle *sub = data;
509 MovTextContext *m = avctx->priv_data;
510 int ret;
511 AVBPrint buf;
512 char *ptr = avpkt->data;
513 char *end;
514 int text_length, tsmb_type, ret_tsmb;
515 uint64_t tsmb_size;
516 const uint8_t *tsmb;
517 size_t i;
518
519 if (!ptr || avpkt->size < 2)
520 return AVERROR_INVALIDDATA;
521
522 /*
523 * A packet of size two with value zero is an empty subtitle
524 * used to mark the end of the previous non-empty subtitle.
525 * We can just drop them here as we have duration information
526 * already. If the value is non-zero, then it's technically a
527 * bad packet.
528 */
529 if (avpkt->size == 2)
530 return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
531
532 /*
533 * The first two bytes of the packet are the length of the text string
534 * In complex cases, there are style descriptors appended to the string
535 * so we can't just assume the packet size is the string size.
536 */
537 text_length = AV_RB16(ptr);
538 end = ptr + FFMIN(2 + text_length, avpkt->size);
539 ptr += 2;
540
541 mov_text_cleanup(m);
542
543 tsmb_size = 0;
544 m->tracksize = 2 + text_length;
545 m->style_entries = 0;
546 m->box_flags = 0;
547 m->count_s = 0;
548 // Note that the spec recommends lines be no longer than 2048 characters.
549 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
550 if (text_length + 2 != avpkt->size) {
551 while (m->tracksize + 8 <= avpkt->size) {
552 // A box is a minimum of 8 bytes.
553 tsmb = ptr + m->tracksize - 2;
554 tsmb_size = AV_RB32(tsmb);
555 tsmb += 4;
556 tsmb_type = AV_RB32(tsmb);
557 tsmb += 4;
558
559 if (tsmb_size == 1) {
560 if (m->tracksize + 16 > avpkt->size)
561 break;
562 tsmb_size = AV_RB64(tsmb);
563 tsmb += 8;
564 m->size_var = 16;
565 } else
566 m->size_var = 8;
567 //size_var is equal to 8 or 16 depending on the size of box
568
569 if (tsmb_size == 0) {
570 av_log(avctx, AV_LOG_ERROR, "tsmb_size is 0\n");
571 return AVERROR_INVALIDDATA;
572 }
573
574 if (tsmb_size > avpkt->size - m->tracksize)
575 break;
576
577 for (i = 0; i < box_count; i++) {
578 if (tsmb_type == box_types[i].type) {
579 if (m->tracksize + m->size_var + box_types[i].base_size > avpkt->size)
580 break;
581 ret_tsmb = box_types[i].decode(tsmb, m, avpkt);
582 if (ret_tsmb == -1)
583 break;
584 }
585 }
586 m->tracksize = m->tracksize + tsmb_size;
587 }
588 text_to_ass(&buf, ptr, end, avctx);
589 mov_text_cleanup(m);
590 } else
591 text_to_ass(&buf, ptr, end, avctx);
592
593 ret = ff_ass_add_rect(sub, buf.str, m->readorder++, 0, NULL, NULL);
594 av_bprint_finalize(&buf, NULL);
595 if (ret < 0)
596 return ret;
597 *got_sub_ptr = sub->num_rects > 0;
598 return avpkt->size;
599 }
600
mov_text_decode_close(AVCodecContext * avctx)601 static int mov_text_decode_close(AVCodecContext *avctx)
602 {
603 MovTextContext *m = avctx->priv_data;
604 mov_text_cleanup_ftab(m);
605 mov_text_cleanup(m);
606 return 0;
607 }
608
mov_text_flush(AVCodecContext * avctx)609 static void mov_text_flush(AVCodecContext *avctx)
610 {
611 MovTextContext *m = avctx->priv_data;
612 if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
613 m->readorder = 0;
614 }
615
616 #define OFFSET(x) offsetof(MovTextContext, x)
617 #define FLAGS AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM
618 static const AVOption options[] = {
619 { "width", "Frame width, usually video width", OFFSET(frame_width), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
620 { "height", "Frame height, usually video height", OFFSET(frame_height), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
621 { NULL },
622 };
623
624 static const AVClass mov_text_decoder_class = {
625 .class_name = "MOV text decoder",
626 .item_name = av_default_item_name,
627 .option = options,
628 .version = LIBAVUTIL_VERSION_INT,
629 };
630
631 AVCodec ff_movtext_decoder = {
632 .name = "mov_text",
633 .long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
634 .type = AVMEDIA_TYPE_SUBTITLE,
635 .id = AV_CODEC_ID_MOV_TEXT,
636 .priv_data_size = sizeof(MovTextContext),
637 .priv_class = &mov_text_decoder_class,
638 .init = mov_text_init,
639 .decode = mov_text_decode_frame,
640 .close = mov_text_decode_close,
641 .flush = mov_text_flush,
642 };
643