1 /*
2 * Closed Caption Decoding
3 * Copyright (c) 2015 Anshul Maheshwari
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 "codec_internal.h"
25 #include "libavutil/opt.h"
26
27 #define SCREEN_ROWS 15
28 #define SCREEN_COLUMNS 32
29
30 #define SET_FLAG(var, val) ( (var) |= ( 1 << (val)) )
31 #define UNSET_FLAG(var, val) ( (var) &= ~( 1 << (val)) )
32 #define CHECK_FLAG(var, val) ( (var) & ( 1 << (val)) )
33
34 static const AVRational ms_tb = {1, 1000};
35
36 enum cc_mode {
37 CCMODE_POPON,
38 CCMODE_PAINTON,
39 CCMODE_ROLLUP,
40 CCMODE_TEXT,
41 };
42
43 enum cc_color_code {
44 CCCOL_WHITE,
45 CCCOL_GREEN,
46 CCCOL_BLUE,
47 CCCOL_CYAN,
48 CCCOL_RED,
49 CCCOL_YELLOW,
50 CCCOL_MAGENTA,
51 CCCOL_USERDEFINED,
52 CCCOL_BLACK,
53 CCCOL_TRANSPARENT,
54 };
55
56 enum cc_font {
57 CCFONT_REGULAR,
58 CCFONT_ITALICS,
59 CCFONT_UNDERLINED,
60 CCFONT_UNDERLINED_ITALICS,
61 };
62
63 enum cc_charset {
64 CCSET_BASIC_AMERICAN,
65 CCSET_SPECIAL_AMERICAN,
66 CCSET_EXTENDED_SPANISH_FRENCH_MISC,
67 CCSET_EXTENDED_PORTUGUESE_GERMAN_DANISH,
68 };
69
70 static const char *charset_overrides[4][128] =
71 {
72 [CCSET_BASIC_AMERICAN] = {
73 [0x27] = "\u2019",
74 [0x2a] = "\u00e1",
75 [0x5c] = "\u00e9",
76 [0x5e] = "\u00ed",
77 [0x5f] = "\u00f3",
78 [0x60] = "\u00fa",
79 [0x7b] = "\u00e7",
80 [0x7c] = "\u00f7",
81 [0x7d] = "\u00d1",
82 [0x7e] = "\u00f1",
83 [0x7f] = "\u2588"
84 },
85 [CCSET_SPECIAL_AMERICAN] = {
86 [0x30] = "\u00ae",
87 [0x31] = "\u00b0",
88 [0x32] = "\u00bd",
89 [0x33] = "\u00bf",
90 [0x34] = "\u2122",
91 [0x35] = "\u00a2",
92 [0x36] = "\u00a3",
93 [0x37] = "\u266a",
94 [0x38] = "\u00e0",
95 [0x39] = "\u00A0",
96 [0x3a] = "\u00e8",
97 [0x3b] = "\u00e2",
98 [0x3c] = "\u00ea",
99 [0x3d] = "\u00ee",
100 [0x3e] = "\u00f4",
101 [0x3f] = "\u00fb",
102 },
103 [CCSET_EXTENDED_SPANISH_FRENCH_MISC] = {
104 [0x20] = "\u00c1",
105 [0x21] = "\u00c9",
106 [0x22] = "\u00d3",
107 [0x23] = "\u00da",
108 [0x24] = "\u00dc",
109 [0x25] = "\u00fc",
110 [0x26] = "\u00b4",
111 [0x27] = "\u00a1",
112 [0x28] = "*",
113 [0x29] = "\u2018",
114 [0x2a] = "-",
115 [0x2b] = "\u00a9",
116 [0x2c] = "\u2120",
117 [0x2d] = "\u00b7",
118 [0x2e] = "\u201c",
119 [0x2f] = "\u201d",
120 [0x30] = "\u00c0",
121 [0x31] = "\u00c2",
122 [0x32] = "\u00c7",
123 [0x33] = "\u00c8",
124 [0x34] = "\u00ca",
125 [0x35] = "\u00cb",
126 [0x36] = "\u00eb",
127 [0x37] = "\u00ce",
128 [0x38] = "\u00cf",
129 [0x39] = "\u00ef",
130 [0x3a] = "\u00d4",
131 [0x3b] = "\u00d9",
132 [0x3c] = "\u00f9",
133 [0x3d] = "\u00db",
134 [0x3e] = "\u00ab",
135 [0x3f] = "\u00bb",
136 },
137 [CCSET_EXTENDED_PORTUGUESE_GERMAN_DANISH] = {
138 [0x20] = "\u00c3",
139 [0x21] = "\u00e3",
140 [0x22] = "\u00cd",
141 [0x23] = "\u00cc",
142 [0x24] = "\u00ec",
143 [0x25] = "\u00d2",
144 [0x26] = "\u00f2",
145 [0x27] = "\u00d5",
146 [0x28] = "\u00f5",
147 [0x29] = "{",
148 [0x2a] = "}",
149 [0x2b] = "\\",
150 [0x2c] = "^",
151 [0x2d] = "_",
152 [0x2e] = "|",
153 [0x2f] = "~",
154 [0x30] = "\u00c4",
155 [0x31] = "\u00e4",
156 [0x32] = "\u00d6",
157 [0x33] = "\u00f6",
158 [0x34] = "\u00df",
159 [0x35] = "\u00a5",
160 [0x36] = "\u00a4",
161 [0x37] = "\u00a6",
162 [0x38] = "\u00c5",
163 [0x39] = "\u00e5",
164 [0x3a] = "\u00d8",
165 [0x3b] = "\u00f8",
166 [0x3c] = "\u250c",
167 [0x3d] = "\u2510",
168 [0x3e] = "\u2514",
169 [0x3f] = "\u2518",
170 },
171 };
172
173 static const unsigned char bg_attribs[8] = // Color
174 {
175 CCCOL_WHITE,
176 CCCOL_GREEN,
177 CCCOL_BLUE,
178 CCCOL_CYAN,
179 CCCOL_RED,
180 CCCOL_YELLOW,
181 CCCOL_MAGENTA,
182 CCCOL_BLACK,
183 };
184
185 static const unsigned char pac2_attribs[32][3] = // Color, font, ident
186 {
187 { CCCOL_WHITE, CCFONT_REGULAR, 0 }, // 0x40 || 0x60
188 { CCCOL_WHITE, CCFONT_UNDERLINED, 0 }, // 0x41 || 0x61
189 { CCCOL_GREEN, CCFONT_REGULAR, 0 }, // 0x42 || 0x62
190 { CCCOL_GREEN, CCFONT_UNDERLINED, 0 }, // 0x43 || 0x63
191 { CCCOL_BLUE, CCFONT_REGULAR, 0 }, // 0x44 || 0x64
192 { CCCOL_BLUE, CCFONT_UNDERLINED, 0 }, // 0x45 || 0x65
193 { CCCOL_CYAN, CCFONT_REGULAR, 0 }, // 0x46 || 0x66
194 { CCCOL_CYAN, CCFONT_UNDERLINED, 0 }, // 0x47 || 0x67
195 { CCCOL_RED, CCFONT_REGULAR, 0 }, // 0x48 || 0x68
196 { CCCOL_RED, CCFONT_UNDERLINED, 0 }, // 0x49 || 0x69
197 { CCCOL_YELLOW, CCFONT_REGULAR, 0 }, // 0x4a || 0x6a
198 { CCCOL_YELLOW, CCFONT_UNDERLINED, 0 }, // 0x4b || 0x6b
199 { CCCOL_MAGENTA, CCFONT_REGULAR, 0 }, // 0x4c || 0x6c
200 { CCCOL_MAGENTA, CCFONT_UNDERLINED, 0 }, // 0x4d || 0x6d
201 { CCCOL_WHITE, CCFONT_ITALICS, 0 }, // 0x4e || 0x6e
202 { CCCOL_WHITE, CCFONT_UNDERLINED_ITALICS, 0 }, // 0x4f || 0x6f
203 { CCCOL_WHITE, CCFONT_REGULAR, 0 }, // 0x50 || 0x70
204 { CCCOL_WHITE, CCFONT_UNDERLINED, 0 }, // 0x51 || 0x71
205 { CCCOL_WHITE, CCFONT_REGULAR, 4 }, // 0x52 || 0x72
206 { CCCOL_WHITE, CCFONT_UNDERLINED, 4 }, // 0x53 || 0x73
207 { CCCOL_WHITE, CCFONT_REGULAR, 8 }, // 0x54 || 0x74
208 { CCCOL_WHITE, CCFONT_UNDERLINED, 8 }, // 0x55 || 0x75
209 { CCCOL_WHITE, CCFONT_REGULAR, 12 }, // 0x56 || 0x76
210 { CCCOL_WHITE, CCFONT_UNDERLINED, 12 }, // 0x57 || 0x77
211 { CCCOL_WHITE, CCFONT_REGULAR, 16 }, // 0x58 || 0x78
212 { CCCOL_WHITE, CCFONT_UNDERLINED, 16 }, // 0x59 || 0x79
213 { CCCOL_WHITE, CCFONT_REGULAR, 20 }, // 0x5a || 0x7a
214 { CCCOL_WHITE, CCFONT_UNDERLINED, 20 }, // 0x5b || 0x7b
215 { CCCOL_WHITE, CCFONT_REGULAR, 24 }, // 0x5c || 0x7c
216 { CCCOL_WHITE, CCFONT_UNDERLINED, 24 }, // 0x5d || 0x7d
217 { CCCOL_WHITE, CCFONT_REGULAR, 28 }, // 0x5e || 0x7e
218 { CCCOL_WHITE, CCFONT_UNDERLINED, 28 } // 0x5f || 0x7f
219 /* total 32 entries */
220 };
221
222 struct Screen {
223 /* +1 is used to compensate null character of string */
224 uint8_t characters[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
225 uint8_t charsets[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
226 uint8_t colors[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
227 uint8_t bgs[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
228 uint8_t fonts[SCREEN_ROWS+1][SCREEN_COLUMNS+1];
229 /*
230 * Bitmask of used rows; if a bit is not set, the
231 * corresponding row is not used.
232 * for setting row 1 use row | (1 << 0)
233 * for setting row 15 use row | (1 << 14)
234 */
235 int16_t row_used;
236 };
237
238 typedef struct CCaptionSubContext {
239 AVClass *class;
240 int real_time;
241 int real_time_latency_msec;
242 int data_field;
243 struct Screen screen[2];
244 int active_screen;
245 uint8_t cursor_row;
246 uint8_t cursor_column;
247 uint8_t cursor_color;
248 uint8_t bg_color;
249 uint8_t cursor_font;
250 uint8_t cursor_charset;
251 AVBPrint buffer[2];
252 int buffer_index;
253 int buffer_changed;
254 int rollup;
255 enum cc_mode mode;
256 int64_t buffer_time[2];
257 int screen_touched;
258 int64_t last_real_time;
259 uint8_t prev_cmd[2];
260 int readorder;
261 } CCaptionSubContext;
262
init_decoder(AVCodecContext * avctx)263 static av_cold int init_decoder(AVCodecContext *avctx)
264 {
265 int ret;
266 CCaptionSubContext *ctx = avctx->priv_data;
267
268 av_bprint_init(&ctx->buffer[0], 0, AV_BPRINT_SIZE_UNLIMITED);
269 av_bprint_init(&ctx->buffer[1], 0, AV_BPRINT_SIZE_UNLIMITED);
270 /* taking by default roll up to 2 */
271 ctx->mode = CCMODE_ROLLUP;
272 ctx->bg_color = CCCOL_BLACK;
273 ctx->rollup = 2;
274 ctx->cursor_row = 10;
275 ret = ff_ass_subtitle_header(avctx, "Monospace",
276 ASS_DEFAULT_FONT_SIZE,
277 ASS_DEFAULT_COLOR,
278 ASS_DEFAULT_BACK_COLOR,
279 ASS_DEFAULT_BOLD,
280 ASS_DEFAULT_ITALIC,
281 ASS_DEFAULT_UNDERLINE,
282 3,
283 ASS_DEFAULT_ALIGNMENT);
284 if (ret < 0) {
285 return ret;
286 }
287
288 return ret;
289 }
290
close_decoder(AVCodecContext * avctx)291 static av_cold int close_decoder(AVCodecContext *avctx)
292 {
293 CCaptionSubContext *ctx = avctx->priv_data;
294 av_bprint_finalize(&ctx->buffer[0], NULL);
295 av_bprint_finalize(&ctx->buffer[1], NULL);
296 return 0;
297 }
298
flush_decoder(AVCodecContext * avctx)299 static void flush_decoder(AVCodecContext *avctx)
300 {
301 CCaptionSubContext *ctx = avctx->priv_data;
302 ctx->screen[0].row_used = 0;
303 ctx->screen[1].row_used = 0;
304 ctx->prev_cmd[0] = 0;
305 ctx->prev_cmd[1] = 0;
306 ctx->mode = CCMODE_ROLLUP;
307 ctx->rollup = 2;
308 ctx->cursor_row = 10;
309 ctx->cursor_column = 0;
310 ctx->cursor_font = 0;
311 ctx->cursor_color = 0;
312 ctx->bg_color = CCCOL_BLACK;
313 ctx->cursor_charset = 0;
314 ctx->active_screen = 0;
315 ctx->last_real_time = 0;
316 ctx->screen_touched = 0;
317 ctx->buffer_changed = 0;
318 if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
319 ctx->readorder = 0;
320 av_bprint_clear(&ctx->buffer[0]);
321 av_bprint_clear(&ctx->buffer[1]);
322 }
323
324 /**
325 * @param ctx closed caption context just to print log
326 */
write_char(CCaptionSubContext * ctx,struct Screen * screen,char ch)327 static void write_char(CCaptionSubContext *ctx, struct Screen *screen, char ch)
328 {
329 uint8_t col = ctx->cursor_column;
330 char *row = screen->characters[ctx->cursor_row];
331 char *font = screen->fonts[ctx->cursor_row];
332 char *color = screen->colors[ctx->cursor_row];
333 char *bg = screen->bgs[ctx->cursor_row];
334 char *charset = screen->charsets[ctx->cursor_row];
335
336 if (col < SCREEN_COLUMNS) {
337 row[col] = ch;
338 font[col] = ctx->cursor_font;
339 color[col] = ctx->cursor_color;
340 bg[col] = ctx->bg_color;
341 charset[col] = ctx->cursor_charset;
342 ctx->cursor_charset = CCSET_BASIC_AMERICAN;
343 if (ch) ctx->cursor_column++;
344 return;
345 }
346 /* We have extra space at end only for null character */
347 else if (col == SCREEN_COLUMNS && ch == 0) {
348 row[col] = ch;
349 return;
350 }
351 else {
352 av_log(ctx, AV_LOG_WARNING, "Data Ignored since exceeding screen width\n");
353 return;
354 }
355 }
356
357 /**
358 * This function after validating parity bit, also remove it from data pair.
359 * The first byte doesn't pass parity, we replace it with a solid blank
360 * and process the pair.
361 * If the second byte doesn't pass parity, it returns INVALIDDATA
362 * user can ignore the whole pair and pass the other pair.
363 */
validate_cc_data_pair(const uint8_t * cc_data_pair,uint8_t * hi)364 static int validate_cc_data_pair(const uint8_t *cc_data_pair, uint8_t *hi)
365 {
366 uint8_t cc_valid = (*cc_data_pair & 4) >>2;
367 uint8_t cc_type = *cc_data_pair & 3;
368
369 *hi = cc_data_pair[1];
370
371 if (!cc_valid)
372 return AVERROR_INVALIDDATA;
373
374 // if EIA-608 data then verify parity.
375 if (cc_type==0 || cc_type==1) {
376 if (!av_parity(cc_data_pair[2])) {
377 return AVERROR_INVALIDDATA;
378 }
379 if (!av_parity(cc_data_pair[1])) {
380 *hi = 0x7F;
381 }
382 }
383
384 //Skip non-data
385 if ((cc_data_pair[0] == 0xFA || cc_data_pair[0] == 0xFC || cc_data_pair[0] == 0xFD)
386 && (cc_data_pair[1] & 0x7F) == 0 && (cc_data_pair[2] & 0x7F) == 0)
387 return AVERROR_PATCHWELCOME;
388
389 //skip 708 data
390 if (cc_type == 3 || cc_type == 2)
391 return AVERROR_PATCHWELCOME;
392
393 return 0;
394 }
395
get_writing_screen(CCaptionSubContext * ctx)396 static struct Screen *get_writing_screen(CCaptionSubContext *ctx)
397 {
398 switch (ctx->mode) {
399 case CCMODE_POPON:
400 // use Inactive screen
401 return ctx->screen + !ctx->active_screen;
402 case CCMODE_PAINTON:
403 case CCMODE_ROLLUP:
404 case CCMODE_TEXT:
405 // use active screen
406 return ctx->screen + ctx->active_screen;
407 }
408 /* It was never an option */
409 return NULL;
410 }
411
roll_up(CCaptionSubContext * ctx)412 static void roll_up(CCaptionSubContext *ctx)
413 {
414 struct Screen *screen;
415 int i, keep_lines;
416
417 if (ctx->mode == CCMODE_TEXT)
418 return;
419
420 screen = get_writing_screen(ctx);
421
422 /* +1 signify cursor_row starts from 0
423 * Can't keep lines less then row cursor pos
424 */
425 keep_lines = FFMIN(ctx->cursor_row + 1, ctx->rollup);
426
427 for (i = 0; i < SCREEN_ROWS; i++) {
428 if (i > ctx->cursor_row - keep_lines && i <= ctx->cursor_row)
429 continue;
430 UNSET_FLAG(screen->row_used, i);
431 }
432
433 for (i = 0; i < keep_lines && screen->row_used; i++) {
434 const int i_row = ctx->cursor_row - keep_lines + i + 1;
435
436 memcpy(screen->characters[i_row], screen->characters[i_row+1], SCREEN_COLUMNS);
437 memcpy(screen->colors[i_row], screen->colors[i_row+1], SCREEN_COLUMNS);
438 memcpy(screen->bgs[i_row], screen->bgs[i_row+1], SCREEN_COLUMNS);
439 memcpy(screen->fonts[i_row], screen->fonts[i_row+1], SCREEN_COLUMNS);
440 memcpy(screen->charsets[i_row], screen->charsets[i_row+1], SCREEN_COLUMNS);
441 if (CHECK_FLAG(screen->row_used, i_row + 1))
442 SET_FLAG(screen->row_used, i_row);
443 }
444
445 UNSET_FLAG(screen->row_used, ctx->cursor_row);
446 }
447
capture_screen(CCaptionSubContext * ctx)448 static int capture_screen(CCaptionSubContext *ctx)
449 {
450 int i, j, tab = 0;
451 struct Screen *screen = ctx->screen + ctx->active_screen;
452 enum cc_font prev_font = CCFONT_REGULAR;
453 enum cc_color_code prev_color = CCCOL_WHITE;
454 enum cc_color_code prev_bg_color = CCCOL_BLACK;
455 const int bidx = ctx->buffer_index;
456
457 av_bprint_clear(&ctx->buffer[bidx]);
458
459 for (i = 0; screen->row_used && i < SCREEN_ROWS; i++)
460 {
461 if (CHECK_FLAG(screen->row_used, i)) {
462 const char *row = screen->characters[i];
463 const char *charset = screen->charsets[i];
464 j = 0;
465 while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN)
466 j++;
467 if (!tab || j < tab)
468 tab = j;
469 }
470 }
471
472 for (i = 0; screen->row_used && i < SCREEN_ROWS; i++)
473 {
474 if (CHECK_FLAG(screen->row_used, i)) {
475 const char *row = screen->characters[i];
476 const char *font = screen->fonts[i];
477 const char *bg = screen->bgs[i];
478 const char *color = screen->colors[i];
479 const char *charset = screen->charsets[i];
480 const char *override;
481 int x, y, seen_char = 0;
482 j = 0;
483
484 /* skip leading space */
485 while (row[j] == ' ' && charset[j] == CCSET_BASIC_AMERICAN && j < tab)
486 j++;
487
488 x = ASS_DEFAULT_PLAYRESX * (0.1 + 0.0250 * j);
489 y = ASS_DEFAULT_PLAYRESY * (0.1 + 0.0533 * i);
490 av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
491
492 for (; j < SCREEN_COLUMNS; j++) {
493 const char *e_tag = "", *s_tag = "", *c_tag = "", *b_tag = "";
494
495 if (row[j] == 0)
496 break;
497
498 if (prev_font != font[j]) {
499 switch (prev_font) {
500 case CCFONT_ITALICS:
501 e_tag = "{\\i0}";
502 break;
503 case CCFONT_UNDERLINED:
504 e_tag = "{\\u0}";
505 break;
506 case CCFONT_UNDERLINED_ITALICS:
507 e_tag = "{\\u0}{\\i0}";
508 break;
509 }
510 switch (font[j]) {
511 case CCFONT_ITALICS:
512 s_tag = "{\\i1}";
513 break;
514 case CCFONT_UNDERLINED:
515 s_tag = "{\\u1}";
516 break;
517 case CCFONT_UNDERLINED_ITALICS:
518 s_tag = "{\\u1}{\\i1}";
519 break;
520 }
521 }
522 if (prev_color != color[j]) {
523 switch (color[j]) {
524 case CCCOL_WHITE:
525 c_tag = "{\\c&HFFFFFF&}";
526 break;
527 case CCCOL_GREEN:
528 c_tag = "{\\c&H00FF00&}";
529 break;
530 case CCCOL_BLUE:
531 c_tag = "{\\c&HFF0000&}";
532 break;
533 case CCCOL_CYAN:
534 c_tag = "{\\c&HFFFF00&}";
535 break;
536 case CCCOL_RED:
537 c_tag = "{\\c&H0000FF&}";
538 break;
539 case CCCOL_YELLOW:
540 c_tag = "{\\c&H00FFFF&}";
541 break;
542 case CCCOL_MAGENTA:
543 c_tag = "{\\c&HFF00FF&}";
544 break;
545 }
546 }
547 if (prev_bg_color != bg[j]) {
548 switch (bg[j]) {
549 case CCCOL_WHITE:
550 b_tag = "{\\3c&HFFFFFF&}";
551 break;
552 case CCCOL_GREEN:
553 b_tag = "{\\3c&H00FF00&}";
554 break;
555 case CCCOL_BLUE:
556 b_tag = "{\\3c&HFF0000&}";
557 break;
558 case CCCOL_CYAN:
559 b_tag = "{\\3c&HFFFF00&}";
560 break;
561 case CCCOL_RED:
562 b_tag = "{\\3c&H0000FF&}";
563 break;
564 case CCCOL_YELLOW:
565 b_tag = "{\\3c&H00FFFF&}";
566 break;
567 case CCCOL_MAGENTA:
568 b_tag = "{\\3c&HFF00FF&}";
569 break;
570 case CCCOL_BLACK:
571 b_tag = "{\\3c&H000000&}";
572 break;
573 }
574 }
575
576 prev_font = font[j];
577 prev_color = color[j];
578 prev_bg_color = bg[j];
579 override = charset_overrides[(int)charset[j]][(int)row[j]];
580 if (override) {
581 av_bprintf(&ctx->buffer[bidx], "%s%s%s%s%s", e_tag, s_tag, c_tag, b_tag, override);
582 seen_char = 1;
583 } else if (row[j] == ' ' && !seen_char) {
584 av_bprintf(&ctx->buffer[bidx], "%s%s%s%s\\h", e_tag, s_tag, c_tag, b_tag);
585 } else {
586 av_bprintf(&ctx->buffer[bidx], "%s%s%s%s%c", e_tag, s_tag, c_tag, b_tag, row[j]);
587 seen_char = 1;
588 }
589
590 }
591 av_bprintf(&ctx->buffer[bidx], "\\N");
592 }
593 }
594 if (!av_bprint_is_complete(&ctx->buffer[bidx]))
595 return AVERROR(ENOMEM);
596 if (screen->row_used && ctx->buffer[bidx].len >= 2) {
597 ctx->buffer[bidx].len -= 2;
598 ctx->buffer[bidx].str[ctx->buffer[bidx].len] = 0;
599 }
600 ctx->buffer_changed = 1;
601 return 0;
602 }
603
update_time(CCaptionSubContext * ctx,int64_t pts)604 static void update_time(CCaptionSubContext *ctx, int64_t pts)
605 {
606 ctx->buffer_time[0] = ctx->buffer_time[1];
607 ctx->buffer_time[1] = pts;
608 }
609
handle_bgattr(CCaptionSubContext * ctx,uint8_t hi,uint8_t lo)610 static void handle_bgattr(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
611 {
612 const int i = (lo & 0xf) >> 1;
613
614 ctx->bg_color = bg_attribs[i];
615 }
616
handle_textattr(CCaptionSubContext * ctx,uint8_t hi,uint8_t lo)617 static void handle_textattr(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
618 {
619 int i = lo - 0x20;
620 struct Screen *screen = get_writing_screen(ctx);
621
622 if (i >= 32)
623 return;
624
625 ctx->cursor_color = pac2_attribs[i][0];
626 ctx->cursor_font = pac2_attribs[i][1];
627
628 SET_FLAG(screen->row_used, ctx->cursor_row);
629 write_char(ctx, screen, ' ');
630 }
631
handle_pac(CCaptionSubContext * ctx,uint8_t hi,uint8_t lo)632 static void handle_pac(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
633 {
634 static const int8_t row_map[] = {
635 11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10
636 };
637 const int index = ( (hi<<1) & 0x0e) | ( (lo>>5) & 0x01 );
638 struct Screen *screen = get_writing_screen(ctx);
639 int indent, i;
640
641 if (row_map[index] <= 0) {
642 av_log(ctx, AV_LOG_DEBUG, "Invalid pac index encountered\n");
643 return;
644 }
645
646 lo &= 0x1f;
647
648 ctx->cursor_row = row_map[index] - 1;
649 ctx->cursor_color = pac2_attribs[lo][0];
650 ctx->cursor_font = pac2_attribs[lo][1];
651 ctx->cursor_charset = CCSET_BASIC_AMERICAN;
652 ctx->cursor_column = 0;
653 indent = pac2_attribs[lo][2];
654 for (i = 0; i < indent; i++) {
655 write_char(ctx, screen, ' ');
656 }
657 }
658
handle_edm(CCaptionSubContext * ctx)659 static int handle_edm(CCaptionSubContext *ctx)
660 {
661 struct Screen *screen = ctx->screen + ctx->active_screen;
662 int ret;
663
664 // In buffered mode, keep writing to screen until it is wiped.
665 // Before wiping the display, capture contents to emit subtitle.
666 if (!ctx->real_time)
667 ret = capture_screen(ctx);
668
669 screen->row_used = 0;
670 ctx->bg_color = CCCOL_BLACK;
671
672 // In realtime mode, emit an empty caption so the last one doesn't
673 // stay on the screen.
674 if (ctx->real_time)
675 ret = capture_screen(ctx);
676
677 return ret;
678 }
679
handle_eoc(CCaptionSubContext * ctx)680 static int handle_eoc(CCaptionSubContext *ctx)
681 {
682 int ret;
683
684 ctx->active_screen = !ctx->active_screen;
685
686 // In buffered mode, we wait til the *next* EOC and
687 // capture what was already on the screen since the last EOC.
688 if (!ctx->real_time)
689 ret = handle_edm(ctx);
690
691 ctx->cursor_column = 0;
692
693 // In realtime mode, we display the buffered contents (after
694 // flipping the buffer to active above) as soon as EOC arrives.
695 if (ctx->real_time)
696 ret = capture_screen(ctx);
697
698 return ret;
699 }
700
handle_delete_end_of_row(CCaptionSubContext * ctx)701 static void handle_delete_end_of_row(CCaptionSubContext *ctx)
702 {
703 struct Screen *screen = get_writing_screen(ctx);
704 write_char(ctx, screen, 0);
705 }
706
handle_char(CCaptionSubContext * ctx,char hi,char lo)707 static void handle_char(CCaptionSubContext *ctx, char hi, char lo)
708 {
709 struct Screen *screen = get_writing_screen(ctx);
710
711 SET_FLAG(screen->row_used, ctx->cursor_row);
712
713 switch (hi) {
714 case 0x11:
715 ctx->cursor_charset = CCSET_SPECIAL_AMERICAN;
716 break;
717 case 0x12:
718 if (ctx->cursor_column > 0)
719 ctx->cursor_column -= 1;
720 ctx->cursor_charset = CCSET_EXTENDED_SPANISH_FRENCH_MISC;
721 break;
722 case 0x13:
723 if (ctx->cursor_column > 0)
724 ctx->cursor_column -= 1;
725 ctx->cursor_charset = CCSET_EXTENDED_PORTUGUESE_GERMAN_DANISH;
726 break;
727 default:
728 ctx->cursor_charset = CCSET_BASIC_AMERICAN;
729 write_char(ctx, screen, hi);
730 break;
731 }
732
733 if (lo) {
734 write_char(ctx, screen, lo);
735 }
736 write_char(ctx, screen, 0);
737
738 if (ctx->mode != CCMODE_POPON)
739 ctx->screen_touched = 1;
740
741 if (lo)
742 ff_dlog(ctx, "(%c,%c)\n", hi, lo);
743 else
744 ff_dlog(ctx, "(%c)\n", hi);
745 }
746
process_cc608(CCaptionSubContext * ctx,uint8_t hi,uint8_t lo)747 static int process_cc608(CCaptionSubContext *ctx, uint8_t hi, uint8_t lo)
748 {
749 int ret = 0;
750
751 if (hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) {
752 return 0;
753 }
754
755 /* set prev command */
756 ctx->prev_cmd[0] = hi;
757 ctx->prev_cmd[1] = lo;
758
759 if ( (hi == 0x10 && (lo >= 0x40 && lo <= 0x5f)) ||
760 ( (hi >= 0x11 && hi <= 0x17) && (lo >= 0x40 && lo <= 0x7f) ) ) {
761 handle_pac(ctx, hi, lo);
762 } else if ( ( hi == 0x11 && lo >= 0x20 && lo <= 0x2f ) ||
763 ( hi == 0x17 && lo >= 0x2e && lo <= 0x2f) ) {
764 handle_textattr(ctx, hi, lo);
765 } else if ((hi == 0x10 && lo >= 0x20 && lo <= 0x2f)) {
766 handle_bgattr(ctx, hi, lo);
767 } else if (hi == 0x14 || hi == 0x15 || hi == 0x1c) {
768 switch (lo) {
769 case 0x20:
770 /* resume caption loading */
771 ctx->mode = CCMODE_POPON;
772 break;
773 case 0x24:
774 handle_delete_end_of_row(ctx);
775 break;
776 case 0x25:
777 case 0x26:
778 case 0x27:
779 ctx->rollup = lo - 0x23;
780 ctx->mode = CCMODE_ROLLUP;
781 break;
782 case 0x29:
783 /* resume direct captioning */
784 ctx->mode = CCMODE_PAINTON;
785 break;
786 case 0x2b:
787 /* resume text display */
788 ctx->mode = CCMODE_TEXT;
789 break;
790 case 0x2c:
791 /* erase display memory */
792 handle_edm(ctx);
793 break;
794 case 0x2d:
795 /* carriage return */
796 ff_dlog(ctx, "carriage return\n");
797 if (!ctx->real_time)
798 ret = capture_screen(ctx);
799 roll_up(ctx);
800 ctx->cursor_column = 0;
801 break;
802 case 0x2e:
803 /* erase buffered (non displayed) memory */
804 // Only in realtime mode. In buffered mode, we re-use the inactive screen
805 // for our own buffering.
806 if (ctx->real_time) {
807 struct Screen *screen = ctx->screen + !ctx->active_screen;
808 screen->row_used = 0;
809 }
810 break;
811 case 0x2f:
812 /* end of caption */
813 ff_dlog(ctx, "handle_eoc\n");
814 ret = handle_eoc(ctx);
815 break;
816 default:
817 ff_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo);
818 break;
819 }
820 } else if (hi >= 0x11 && hi <= 0x13) {
821 /* Special characters */
822 handle_char(ctx, hi, lo);
823 } else if (hi >= 0x20) {
824 /* Standard characters (always in pairs) */
825 handle_char(ctx, hi, lo);
826 ctx->prev_cmd[0] = ctx->prev_cmd[1] = 0;
827 } else if (hi == 0x17 && lo >= 0x21 && lo <= 0x23) {
828 int i;
829 /* Tab offsets (spacing) */
830 for (i = 0; i < lo - 0x20; i++) {
831 handle_char(ctx, ' ', 0);
832 }
833 } else {
834 /* Ignoring all other non data code */
835 ff_dlog(ctx, "Unknown command 0x%hhx 0x%hhx\n", hi, lo);
836 }
837
838 return ret;
839 }
840
decode(AVCodecContext * avctx,AVSubtitle * sub,int * got_sub,const AVPacket * avpkt)841 static int decode(AVCodecContext *avctx, AVSubtitle *sub,
842 int *got_sub, const AVPacket *avpkt)
843 {
844 CCaptionSubContext *ctx = avctx->priv_data;
845 int64_t in_time = sub->pts;
846 int64_t start_time;
847 int64_t end_time;
848 int bidx = ctx->buffer_index;
849 const uint8_t *bptr = avpkt->data;
850 int len = avpkt->size;
851 int ret = 0;
852 int i;
853 unsigned nb_rect_allocated = 0;
854
855 for (i = 0; i < len; i += 3) {
856 uint8_t hi, cc_type = bptr[i] & 1;
857
858 if (ctx->data_field < 0)
859 ctx->data_field = cc_type;
860
861 if (validate_cc_data_pair(bptr + i, &hi))
862 continue;
863
864 if (cc_type != ctx->data_field)
865 continue;
866
867 ret = process_cc608(ctx, hi & 0x7f, bptr[i + 2] & 0x7f);
868 if (ret < 0)
869 return ret;
870
871 if (!ctx->buffer_changed)
872 continue;
873 ctx->buffer_changed = 0;
874
875 if (!ctx->real_time && ctx->mode == CCMODE_POPON)
876 ctx->buffer_index = bidx = !ctx->buffer_index;
877
878 update_time(ctx, in_time);
879
880 if (ctx->buffer[bidx].str[0] || ctx->real_time) {
881 ff_dlog(ctx, "cdp writing data (%s)\n", ctx->buffer[bidx].str);
882 start_time = ctx->buffer_time[0];
883 sub->pts = start_time;
884 end_time = ctx->buffer_time[1];
885 if (!ctx->real_time)
886 sub->end_display_time = av_rescale_q(end_time - start_time,
887 AV_TIME_BASE_Q, ms_tb);
888 else
889 sub->end_display_time = -1;
890 ret = ff_ass_add_rect2(sub, ctx->buffer[bidx].str, ctx->readorder++, 0, NULL, NULL, &nb_rect_allocated);
891 if (ret < 0)
892 return ret;
893 ctx->last_real_time = sub->pts;
894 ctx->screen_touched = 0;
895 }
896 }
897
898 if (!bptr && !ctx->real_time && ctx->buffer[!ctx->buffer_index].str[0]) {
899 bidx = !ctx->buffer_index;
900 ret = ff_ass_add_rect2(sub, ctx->buffer[bidx].str, ctx->readorder++, 0, NULL, NULL, &nb_rect_allocated);
901 if (ret < 0)
902 return ret;
903 sub->pts = ctx->buffer_time[1];
904 sub->end_display_time = av_rescale_q(ctx->buffer_time[1] - ctx->buffer_time[0],
905 AV_TIME_BASE_Q, ms_tb);
906 if (sub->end_display_time == 0)
907 sub->end_display_time = ctx->buffer[bidx].len * 20;
908 }
909
910 if (ctx->real_time && ctx->screen_touched &&
911 sub->pts >= ctx->last_real_time + av_rescale_q(ctx->real_time_latency_msec, ms_tb, AV_TIME_BASE_Q)) {
912 ctx->last_real_time = sub->pts;
913 ctx->screen_touched = 0;
914
915 capture_screen(ctx);
916 ctx->buffer_changed = 0;
917
918 ret = ff_ass_add_rect2(sub, ctx->buffer[bidx].str, ctx->readorder++, 0, NULL, NULL, &nb_rect_allocated);
919 if (ret < 0)
920 return ret;
921 sub->end_display_time = -1;
922 }
923
924 *got_sub = sub->num_rects > 0;
925 return ret;
926 }
927
928 #define OFFSET(x) offsetof(CCaptionSubContext, x)
929 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
930 static const AVOption options[] = {
931 { "real_time", "emit subtitle events as they are decoded for real-time display", OFFSET(real_time), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, SD },
932 { "real_time_latency_msec", "minimum elapsed time between emitting real-time subtitle events", OFFSET(real_time_latency_msec), AV_OPT_TYPE_INT, { .i64 = 200 }, 0, 500, SD },
933 { "data_field", "select data field", OFFSET(data_field), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, SD, "data_field" },
934 { "auto", "pick first one that appears", 0, AV_OPT_TYPE_CONST, { .i64 =-1 }, 0, 0, SD, "data_field" },
935 { "first", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, 0, 0, SD, "data_field" },
936 { "second", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, 0, 0, SD, "data_field" },
937 {NULL}
938 };
939
940 static const AVClass ccaption_dec_class = {
941 .class_name = "Closed caption Decoder",
942 .item_name = av_default_item_name,
943 .option = options,
944 .version = LIBAVUTIL_VERSION_INT,
945 };
946
947 const FFCodec ff_ccaption_decoder = {
948 .p.name = "cc_dec",
949 .p.long_name = NULL_IF_CONFIG_SMALL("Closed Caption (EIA-608 / CEA-708)"),
950 .p.type = AVMEDIA_TYPE_SUBTITLE,
951 .p.id = AV_CODEC_ID_EIA_608,
952 .p.priv_class = &ccaption_dec_class,
953 .p.capabilities = AV_CODEC_CAP_DELAY,
954 .priv_data_size = sizeof(CCaptionSubContext),
955 .init = init_decoder,
956 .close = close_decoder,
957 .flush = flush_decoder,
958 FF_CODEC_DECODE_SUB_CB(decode),
959 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
960 };
961