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