1 /*
2  * 3GPP TS 26.245 Timed Text encoder
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 <stdarg.h>
23 #include "avcodec.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/avstring.h"
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/mem.h"
28 #include "libavutil/common.h"
29 #include "ass_split.h"
30 #include "ass.h"
31 #include "bytestream.h"
32 #include "codec_internal.h"
33 
34 #define STYLE_FLAG_BOLD         (1<<0)
35 #define STYLE_FLAG_ITALIC       (1<<1)
36 #define STYLE_FLAG_UNDERLINE    (1<<2)
37 #define STYLE_RECORD_SIZE       12
38 #define SIZE_ADD                10
39 
40 #define STYL_BOX   (1<<0)
41 #define HLIT_BOX   (1<<1)
42 #define HCLR_BOX   (1<<2)
43 
44 #define DEFAULT_STYLE_FONT_ID  0x01
45 #define DEFAULT_STYLE_FONTSIZE 0x12
46 #define DEFAULT_STYLE_COLOR    0xffffffff
47 #define DEFAULT_STYLE_FLAG     0x00
48 
49 #define BGR_TO_RGB(c) (((c) & 0xff) << 16 | ((c) & 0xff00) | (((uint32_t)(c) >> 16) & 0xff))
50 #define FONTSIZE_SCALE(s,fs) ((fs) * (s)->font_scale_factor + 0.5)
51 #define av_bprint_append_any(buf, data, size)   av_bprint_append_data(buf, ((const char*)data), size)
52 
53 typedef struct {
54     uint16_t style_start;
55     uint16_t style_end;
56     uint8_t style_flag;
57     uint16_t style_fontID;
58     uint8_t style_fontsize;
59     uint32_t style_color;
60 } StyleBox;
61 
62 typedef struct {
63     uint16_t start;
64     uint16_t end;
65 } HighlightBox;
66 
67 typedef struct {
68    uint32_t color;
69 } HilightcolorBox;
70 
71 typedef struct {
72     AVClass *class;
73     AVCodecContext *avctx;
74 
75     ASSSplitContext *ass_ctx;
76     ASSStyle *ass_dialog_style;
77     StyleBox *style_attributes;
78     unsigned  count;
79     unsigned  style_attributes_bytes_allocated;
80     StyleBox  style_attributes_temp;
81     AVBPrint buffer;
82     HighlightBox hlit;
83     HilightcolorBox hclr;
84     uint8_t box_flags;
85     StyleBox d;
86     uint16_t text_pos;
87     char **fonts;
88     int font_count;
89     double font_scale_factor;
90     int frame_height;
91 } MovTextContext;
92 
93 typedef struct {
94     void (*encode)(MovTextContext *s);
95 } Box;
96 
mov_text_cleanup(MovTextContext *s)97 static void mov_text_cleanup(MovTextContext *s)
98 {
99     s->count = 0;
100     s->style_attributes_temp = s->d;
101 }
102 
encode_styl(MovTextContext *s)103 static void encode_styl(MovTextContext *s)
104 {
105     if ((s->box_flags & STYL_BOX) && s->count) {
106         uint8_t buf[12], *p = buf;
107 
108         bytestream_put_be32(&p, s->count * STYLE_RECORD_SIZE + SIZE_ADD);
109         bytestream_put_be32(&p, MKBETAG('s','t','y','l'));
110         bytestream_put_be16(&p, s->count);
111         /*The above three attributes are hard coded for now
112         but will come from ASS style in the future*/
113         av_bprint_append_any(&s->buffer, buf, 10);
114         for (unsigned j = 0; j < s->count; j++) {
115             const StyleBox *style = &s->style_attributes[j];
116 
117             p = buf;
118             bytestream_put_be16(&p, style->style_start);
119             bytestream_put_be16(&p, style->style_end);
120             bytestream_put_be16(&p, style->style_fontID);
121             bytestream_put_byte(&p, style->style_flag);
122             bytestream_put_byte(&p, style->style_fontsize);
123             bytestream_put_be32(&p, style->style_color);
124 
125             av_bprint_append_any(&s->buffer, buf, 12);
126         }
127     }
128     mov_text_cleanup(s);
129 }
130 
encode_hlit(MovTextContext *s)131 static void encode_hlit(MovTextContext *s)
132 {
133     if (s->box_flags & HLIT_BOX) {
134         uint8_t buf[12], *p = buf;
135 
136         bytestream_put_be32(&p, 12);
137         bytestream_put_be32(&p, MKBETAG('h','l','i','t'));
138         bytestream_put_be16(&p, s->hlit.start);
139         bytestream_put_be16(&p, s->hlit.end);
140 
141         av_bprint_append_any(&s->buffer, buf, 12);
142     }
143 }
144 
encode_hclr(MovTextContext *s)145 static void encode_hclr(MovTextContext *s)
146 {
147     if (s->box_flags & HCLR_BOX) {
148         uint8_t buf[12], *p = buf;
149 
150         bytestream_put_be32(&p, 12);
151         bytestream_put_be32(&p, MKBETAG('h','c','l','r'));
152         bytestream_put_be32(&p, s->hclr.color);
153 
154         av_bprint_append_any(&s->buffer, buf, 12);
155     }
156 }
157 
158 static const Box box_types[] = {
159     { encode_styl },
160     { encode_hlit },
161     { encode_hclr },
162 };
163 
164 const static size_t box_count = FF_ARRAY_ELEMS(box_types);
165 
mov_text_encode_close(AVCodecContext *avctx)166 static int mov_text_encode_close(AVCodecContext *avctx)
167 {
168     MovTextContext *s = avctx->priv_data;
169 
170     ff_ass_split_free(s->ass_ctx);
171     av_freep(&s->style_attributes);
172     av_freep(&s->fonts);
173     av_bprint_finalize(&s->buffer, NULL);
174     return 0;
175 }
176 
encode_sample_description(AVCodecContext *avctx)177 static int encode_sample_description(AVCodecContext *avctx)
178 {
179     ASS *ass;
180     ASSStyle *style;
181     int i, j;
182     uint32_t back_color = 0;
183     int font_names_total_len = 0;
184     MovTextContext *s = avctx->priv_data;
185     uint8_t buf[30], *p = buf;
186 
187     //  0x00, 0x00, 0x00, 0x00, // uint32_t displayFlags
188     //  0x01,                   // int8_t horizontal-justification
189     //  0xFF,                   // int8_t vertical-justification
190     //  0x00, 0x00, 0x00, 0x00, // uint8_t background-color-rgba[4]
191     //     BoxRecord {
192     //  0x00, 0x00,             // int16_t top
193     //  0x00, 0x00,             // int16_t left
194     //  0x00, 0x00,             // int16_t bottom
195     //  0x00, 0x00,             // int16_t right
196     //     };
197     //     StyleRecord {
198     //  0x00, 0x00,             // uint16_t startChar
199     //  0x00, 0x00,             // uint16_t endChar
200     //  0x00, 0x01,             // uint16_t font-ID
201     //  0x00,                   // uint8_t face-style-flags
202     //  0x12,                   // uint8_t font-size
203     //  0xFF, 0xFF, 0xFF, 0xFF, // uint8_t text-color-rgba[4]
204     //     };
205     //     FontTableBox {
206     //  0x00, 0x00, 0x00, 0x12, // uint32_t size
207     //  'f', 't', 'a', 'b',     // uint8_t name[4]
208     //  0x00, 0x01,             // uint16_t entry-count
209     //     FontRecord {
210     //  0x00, 0x01,             // uint16_t font-ID
211     //  0x05,                   // uint8_t font-name-length
212     //  'S', 'e', 'r', 'i', 'f',// uint8_t font[font-name-length]
213     //     };
214     //     };
215 
216     // Populate sample description from ASS header
217     ass = (ASS*)s->ass_ctx;
218     // Compute font scaling factor based on (optionally) provided
219     // output video height and ASS script play_res_y
220     if (s->frame_height && ass->script_info.play_res_y)
221         s->font_scale_factor = (double)s->frame_height / ass->script_info.play_res_y;
222     else
223         s->font_scale_factor = 1;
224 
225     style = ff_ass_style_get(s->ass_ctx, "Default");
226     if (!style && ass->styles_count) {
227         style = &ass->styles[0];
228     }
229     s->d.style_fontID   = DEFAULT_STYLE_FONT_ID;
230     s->d.style_fontsize = DEFAULT_STYLE_FONTSIZE;
231     s->d.style_color    = DEFAULT_STYLE_COLOR;
232     s->d.style_flag     = DEFAULT_STYLE_FLAG;
233     if (style) {
234         s->d.style_fontsize = FONTSIZE_SCALE(s, style->font_size);
235         s->d.style_color = BGR_TO_RGB(style->primary_color & 0xffffff) << 8 |
236                            255 - ((uint32_t)style->primary_color >> 24);
237         s->d.style_flag = (!!style->bold      * STYLE_FLAG_BOLD)   |
238                           (!!style->italic    * STYLE_FLAG_ITALIC) |
239                           (!!style->underline * STYLE_FLAG_UNDERLINE);
240         back_color = (BGR_TO_RGB(style->back_color & 0xffffff) << 8) |
241                      (255 - ((uint32_t)style->back_color >> 24));
242     }
243 
244     bytestream_put_be32(&p, 0); // displayFlags
245     bytestream_put_be16(&p, 0x01FF); // horizontal/vertical justification (2x int8_t)
246     bytestream_put_be32(&p, back_color);
247     bytestream_put_be64(&p, 0); // BoxRecord - 4xint16_t: top, left, bottom, right
248     //     StyleRecord {
249     bytestream_put_be16(&p, s->d.style_start);
250     bytestream_put_be16(&p, s->d.style_end);
251     bytestream_put_be16(&p, s->d.style_fontID);
252     bytestream_put_byte(&p, s->d.style_flag);
253     bytestream_put_byte(&p, s->d.style_fontsize);
254     bytestream_put_be32(&p, s->d.style_color);
255     //     };
256     av_bprint_append_any(&s->buffer, buf, 30);
257 
258     // Build font table
259     // We can't build a complete font table since that would require
260     // scanning all dialogs first.  But we can at least fill in what
261     // is avaiable in the ASS header
262     if (style && ass->styles_count) {
263         // Find unique font names
264         if (style->font_name) {
265             av_dynarray_add(&s->fonts, &s->font_count, style->font_name);
266             font_names_total_len += strlen(style->font_name);
267         }
268         for (i = 0; i < ass->styles_count; i++) {
269             int found = 0;
270             if (!ass->styles[i].font_name)
271                 continue;
272             for (j = 0; j < s->font_count; j++) {
273                 if (!strcmp(s->fonts[j], ass->styles[i].font_name)) {
274                     found = 1;
275                     break;
276                 }
277             }
278             if (!found) {
279                 av_dynarray_add(&s->fonts, &s->font_count,
280                                            ass->styles[i].font_name);
281                 font_names_total_len += strlen(ass->styles[i].font_name);
282             }
283         }
284     } else
285         av_dynarray_add(&s->fonts, &s->font_count, (char*)"Serif");
286 
287     //     FontTableBox {
288     p = buf;
289     bytestream_put_be32(&p, SIZE_ADD + 3 * s->font_count + font_names_total_len); // Size
290     bytestream_put_be32(&p, MKBETAG('f','t','a','b'));
291     bytestream_put_be16(&p, s->font_count);
292 
293     av_bprint_append_any(&s->buffer, buf, 10);
294     //     FontRecord {
295     for (i = 0; i < s->font_count; i++) {
296         size_t len = strlen(s->fonts[i]);
297 
298         p = buf;
299         bytestream_put_be16(&p, i + 1); //fontID
300         bytestream_put_byte(&p, len);
301 
302         av_bprint_append_any(&s->buffer, buf, 3);
303         av_bprint_append_any(&s->buffer, s->fonts[i], len);
304     }
305     //     };
306     //     };
307 
308     if (!av_bprint_is_complete(&s->buffer)) {
309         return AVERROR(ENOMEM);
310     }
311 
312     avctx->extradata_size = s->buffer.len;
313     avctx->extradata = av_mallocz(avctx->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
314     if (!avctx->extradata) {
315         return AVERROR(ENOMEM);
316     }
317 
318     memcpy(avctx->extradata, s->buffer.str, avctx->extradata_size);
319     av_bprint_clear(&s->buffer);
320 
321     return 0;
322 }
323 
mov_text_encode_init(AVCodecContext *avctx)324 static av_cold int mov_text_encode_init(AVCodecContext *avctx)
325 {
326     int ret;
327     MovTextContext *s = avctx->priv_data;
328     s->avctx = avctx;
329 
330     av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
331 
332     s->ass_ctx = ff_ass_split(avctx->subtitle_header);
333     if (!s->ass_ctx)
334         return AVERROR_INVALIDDATA;
335     ret = encode_sample_description(avctx);
336     if (ret < 0)
337         return ret;
338 
339     return 0;
340 }
341 
342 // Start a new style box if needed
mov_text_style_start(MovTextContext *s)343 static int mov_text_style_start(MovTextContext *s)
344 {
345     // there's an existing style entry
346     if (s->style_attributes_temp.style_start == s->text_pos)
347         // Still at same text pos, use same entry
348         return 1;
349     if (s->style_attributes_temp.style_flag     != s->d.style_flag   ||
350         s->style_attributes_temp.style_color    != s->d.style_color  ||
351         s->style_attributes_temp.style_fontID   != s->d.style_fontID ||
352         s->style_attributes_temp.style_fontsize != s->d.style_fontsize) {
353         StyleBox *tmp;
354 
355         // last style != defaults, end the style entry and start a new one
356         if (s->count + 1 > FFMIN(SIZE_MAX / sizeof(*s->style_attributes), UINT16_MAX) ||
357             !(tmp = av_fast_realloc(s->style_attributes,
358                                     &s->style_attributes_bytes_allocated,
359                                     (s->count + 1) * sizeof(*s->style_attributes)))) {
360             mov_text_cleanup(s);
361             av_bprint_clear(&s->buffer);
362             s->box_flags &= ~STYL_BOX;
363             return 0;
364         }
365         s->style_attributes = tmp;
366         s->style_attributes_temp.style_end = s->text_pos;
367         s->style_attributes[s->count++] = s->style_attributes_temp;
368         s->box_flags |= STYL_BOX;
369         s->style_attributes_temp = s->d;
370         s->style_attributes_temp.style_start = s->text_pos;
371     } else { // style entry matches defaults, drop entry
372         s->style_attributes_temp = s->d;
373         s->style_attributes_temp.style_start = s->text_pos;
374     }
375     return 1;
376 }
377 
mov_text_style_to_flag(const char style)378 static uint8_t mov_text_style_to_flag(const char style)
379 {
380     uint8_t style_flag = 0;
381 
382     switch (style){
383     case 'b':
384         style_flag = STYLE_FLAG_BOLD;
385         break;
386     case 'i':
387         style_flag = STYLE_FLAG_ITALIC;
388         break;
389     case 'u':
390         style_flag = STYLE_FLAG_UNDERLINE;
391         break;
392     }
393     return style_flag;
394 }
395 
mov_text_style_set(MovTextContext *s, uint8_t style_flags)396 static void mov_text_style_set(MovTextContext *s, uint8_t style_flags)
397 {
398     if (!((s->style_attributes_temp.style_flag & style_flags) ^ style_flags)) {
399         // setting flags that that are already set
400         return;
401     }
402     if (mov_text_style_start(s))
403         s->style_attributes_temp.style_flag |= style_flags;
404 }
405 
mov_text_style_cb(void *priv, const char style, int close)406 static void mov_text_style_cb(void *priv, const char style, int close)
407 {
408     MovTextContext *s = priv;
409     uint8_t style_flag = mov_text_style_to_flag(style);
410 
411     if (!!(s->style_attributes_temp.style_flag & style_flag) != close) {
412         // setting flag that is already set
413         return;
414     }
415     if (mov_text_style_start(s)) {
416         if (!close)
417             s->style_attributes_temp.style_flag |= style_flag;
418         else
419             s->style_attributes_temp.style_flag &= ~style_flag;
420     }
421 }
422 
mov_text_color_set(MovTextContext *s, uint32_t color)423 static void mov_text_color_set(MovTextContext *s, uint32_t color)
424 {
425     if ((s->style_attributes_temp.style_color & 0xffffff00) == color) {
426         // color hasn't changed
427         return;
428     }
429     if (mov_text_style_start(s))
430         s->style_attributes_temp.style_color = (color & 0xffffff00) |
431                             (s->style_attributes_temp.style_color & 0xff);
432 }
433 
mov_text_color_cb(void *priv, unsigned int color, unsigned int color_id)434 static void mov_text_color_cb(void *priv, unsigned int color, unsigned int color_id)
435 {
436     MovTextContext *s = priv;
437 
438     color = BGR_TO_RGB(color) << 8;
439     if (color_id == 1) {    //primary color changes
440         mov_text_color_set(s, color);
441     } else if (color_id == 2) {    //secondary color changes
442         if (!(s->box_flags & HCLR_BOX))
443             // Highlight alpha not set yet, use current primary alpha
444             s->hclr.color = s->style_attributes_temp.style_color;
445         if (!(s->box_flags & HLIT_BOX) || s->hlit.start == s->text_pos) {
446             s->box_flags |= HCLR_BOX;
447             s->box_flags |= HLIT_BOX;
448             s->hlit.start = s->text_pos;
449             s->hclr.color = color | (s->hclr.color & 0xFF);
450         }
451         else //close tag
452             s->hlit.end = s->text_pos;
453         /* If there are more than one secondary color changes in ASS,
454            take start of first section and end of last section. Movtext
455            allows only one highlight box per sample.
456          */
457     }
458     // Movtext does not support changes to other color_id (outline, background)
459 }
460 
mov_text_alpha_set(MovTextContext *s, uint8_t alpha)461 static void mov_text_alpha_set(MovTextContext *s, uint8_t alpha)
462 {
463     if ((s->style_attributes_temp.style_color & 0xff) == alpha) {
464         // color hasn't changed
465         return;
466     }
467     if (mov_text_style_start(s))
468         s->style_attributes_temp.style_color =
469                 (s->style_attributes_temp.style_color & 0xffffff00) | alpha;
470 }
471 
mov_text_alpha_cb(void *priv, int alpha, int alpha_id)472 static void mov_text_alpha_cb(void *priv, int alpha, int alpha_id)
473 {
474     MovTextContext *s = priv;
475 
476     alpha = 255 - alpha;
477     if (alpha_id == 1) // primary alpha changes
478         mov_text_alpha_set(s, alpha);
479     else if (alpha_id == 2) {    //secondary alpha changes
480         if (!(s->box_flags & HCLR_BOX))
481             // Highlight color not set yet, use current primary color
482             s->hclr.color = s->style_attributes_temp.style_color;
483         if (!(s->box_flags & HLIT_BOX) || s->hlit.start == s->text_pos) {
484             s->box_flags |= HCLR_BOX;
485             s->box_flags |= HLIT_BOX;
486             s->hlit.start = s->text_pos;
487             s->hclr.color = (s->hclr.color & 0xffffff00) | alpha;
488         }
489         else //close tag
490             s->hlit.end = s->text_pos;
491     }
492     // Movtext does not support changes to other alpha_id (outline, background)
493 }
494 
find_font_id(MovTextContext *s, const char *name)495 static uint16_t find_font_id(MovTextContext *s, const char *name)
496 {
497     if (!name)
498         return 1;
499 
500     for (int i = 0; i < s->font_count; i++) {
501         if (!strcmp(name, s->fonts[i]))
502             return i + 1;
503     }
504     return 1;
505 }
506 
mov_text_font_name_set(MovTextContext *s, const char *name)507 static void mov_text_font_name_set(MovTextContext *s, const char *name)
508 {
509     int fontID = find_font_id(s, name);
510     if (s->style_attributes_temp.style_fontID == fontID) {
511         // color hasn't changed
512         return;
513     }
514     if (mov_text_style_start(s))
515         s->style_attributes_temp.style_fontID = fontID;
516 }
517 
mov_text_font_name_cb(void *priv, const char *name)518 static void mov_text_font_name_cb(void *priv, const char *name)
519 {
520     mov_text_font_name_set((MovTextContext*)priv, name);
521 }
522 
mov_text_font_size_set(MovTextContext *s, int size)523 static void mov_text_font_size_set(MovTextContext *s, int size)
524 {
525     size = FONTSIZE_SCALE(s, size);
526     if (s->style_attributes_temp.style_fontsize == size) {
527         // color hasn't changed
528         return;
529     }
530     if (mov_text_style_start(s))
531         s->style_attributes_temp.style_fontsize = size;
532 }
533 
mov_text_font_size_cb(void *priv, int size)534 static void mov_text_font_size_cb(void *priv, int size)
535 {
536     mov_text_font_size_set((MovTextContext*)priv, size);
537 }
538 
mov_text_end_cb(void *priv)539 static void mov_text_end_cb(void *priv)
540 {
541     // End of text, close any open style record
542     mov_text_style_start((MovTextContext*)priv);
543 }
544 
mov_text_ass_style_set(MovTextContext *s, ASSStyle *style)545 static void mov_text_ass_style_set(MovTextContext *s, ASSStyle *style)
546 {
547     uint8_t    style_flags, alpha;
548     uint32_t   color;
549 
550     if (style) {
551         style_flags = (!!style->bold      * STYLE_FLAG_BOLD)   |
552                       (!!style->italic    * STYLE_FLAG_ITALIC) |
553                       (!!style->underline * STYLE_FLAG_UNDERLINE);
554         mov_text_style_set(s, style_flags);
555         color = BGR_TO_RGB(style->primary_color & 0xffffff) << 8;
556         mov_text_color_set(s, color);
557         alpha = 255 - ((uint32_t)style->primary_color >> 24);
558         mov_text_alpha_set(s, alpha);
559         mov_text_font_size_set(s, style->font_size);
560         mov_text_font_name_set(s, style->font_name);
561     } else {
562         // End current style record, go back to defaults
563         mov_text_style_start(s);
564     }
565 }
566 
mov_text_dialog(MovTextContext *s, ASSDialog *dialog)567 static void mov_text_dialog(MovTextContext *s, ASSDialog *dialog)
568 {
569     ASSStyle *style = ff_ass_style_get(s->ass_ctx, dialog->style);
570 
571     s->ass_dialog_style = style;
572     mov_text_ass_style_set(s, style);
573 }
574 
mov_text_cancel_overrides_cb(void *priv, const char *style_name)575 static void mov_text_cancel_overrides_cb(void *priv, const char *style_name)
576 {
577     MovTextContext *s = priv;
578     ASSStyle *style;
579 
580     if (!style_name || !*style_name)
581         style = s->ass_dialog_style;
582     else
583         style= ff_ass_style_get(s->ass_ctx, style_name);
584 
585     mov_text_ass_style_set(s, style);
586 }
587 
utf8_strlen(const char *text, int len)588 static unsigned utf8_strlen(const char *text, int len)
589 {
590     unsigned i = 0, ret = 0;
591     while (i < len) {
592         char c = text[i];
593         if ((c & 0x80) == 0)
594             i += 1;
595         else if ((c & 0xE0) == 0xC0)
596             i += 2;
597         else if ((c & 0xF0) == 0xE0)
598             i += 3;
599         else if ((c & 0xF8) == 0xF0)
600             i += 4;
601         else
602             return 0;
603         ret++;
604     }
605     return ret;
606 }
607 
mov_text_text_cb(void *priv, const char *text, int len)608 static void mov_text_text_cb(void *priv, const char *text, int len)
609 {
610     unsigned utf8_len = utf8_strlen(text, len);
611     MovTextContext *s = priv;
612     av_bprint_append_data(&s->buffer, text, len);
613     // If it's not utf-8, just use the byte length
614     s->text_pos += utf8_len ? utf8_len : len;
615 }
616 
mov_text_new_line_cb(void *priv, int forced)617 static void mov_text_new_line_cb(void *priv, int forced)
618 {
619     MovTextContext *s = priv;
620     s->text_pos += 1;
621     av_bprint_chars(&s->buffer, '\n', 1);
622 }
623 
624 static const ASSCodesCallbacks mov_text_callbacks = {
625     .text             = mov_text_text_cb,
626     .new_line         = mov_text_new_line_cb,
627     .style            = mov_text_style_cb,
628     .color            = mov_text_color_cb,
629     .alpha            = mov_text_alpha_cb,
630     .font_name        = mov_text_font_name_cb,
631     .font_size        = mov_text_font_size_cb,
632     .cancel_overrides = mov_text_cancel_overrides_cb,
633     .end              = mov_text_end_cb,
634 };
635 
mov_text_encode_frame(AVCodecContext *avctx, unsigned char *buf, int bufsize, const AVSubtitle *sub)636 static int mov_text_encode_frame(AVCodecContext *avctx, unsigned char *buf,
637                                  int bufsize, const AVSubtitle *sub)
638 {
639     MovTextContext *s = avctx->priv_data;
640     ASSDialog *dialog;
641     int i, length;
642 
643     s->text_pos = 0;
644     s->count = 0;
645     s->box_flags = 0;
646     av_bprint_clear(&s->buffer);
647     for (i = 0; i < sub->num_rects; i++) {
648         const char *ass = sub->rects[i]->ass;
649 
650         if (sub->rects[i]->type != SUBTITLE_ASS) {
651             av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
652             return AVERROR(EINVAL);
653         }
654 
655         dialog = ff_ass_split_dialog(s->ass_ctx, ass);
656         if (!dialog)
657             return AVERROR(ENOMEM);
658         mov_text_dialog(s, dialog);
659         ff_ass_split_override_codes(&mov_text_callbacks, s, dialog->text);
660         ff_ass_free_dialog(&dialog);
661     }
662 
663     if (s->buffer.len > UINT16_MAX)
664         return AVERROR(ERANGE);
665     AV_WB16(buf, s->buffer.len);
666     buf += 2;
667 
668     for (size_t j = 0; j < box_count; j++)
669         box_types[j].encode(s);
670 
671     if (!av_bprint_is_complete(&s->buffer))
672         return AVERROR(ENOMEM);
673 
674     if (!s->buffer.len)
675         return 0;
676 
677     if (s->buffer.len > bufsize - 3) {
678         av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
679         return AVERROR_BUFFER_TOO_SMALL;
680     }
681 
682     memcpy(buf, s->buffer.str, s->buffer.len);
683     length = s->buffer.len + 2;
684 
685     return length;
686 }
687 
688 #define OFFSET(x) offsetof(MovTextContext, x)
689 #define FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM
690 static const AVOption options[] = {
691     { "height", "Frame height, usually video height", OFFSET(frame_height), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
692     { NULL },
693 };
694 
695 static const AVClass mov_text_encoder_class = {
696     .class_name = "MOV text enoder",
697     .item_name  = av_default_item_name,
698     .option     = options,
699     .version    = LIBAVUTIL_VERSION_INT,
700 };
701 
702 const FFCodec ff_movtext_encoder = {
703     .p.name         = "mov_text",
704     .p.long_name    = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"),
705     .p.type         = AVMEDIA_TYPE_SUBTITLE,
706     .p.id           = AV_CODEC_ID_MOV_TEXT,
707     .priv_data_size = sizeof(MovTextContext),
708     .p.priv_class   = &mov_text_encoder_class,
709     .init           = mov_text_encode_init,
710     FF_CODEC_ENCODE_SUB_CB(mov_text_encode_frame),
711     .close          = mov_text_encode_close,
712     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
713 };
714