1 /*
2 * Teletext decoding for ffmpeg
3 * Copyright (c) 2005-2010, 2012 Wolfram Gloger
4 * Copyright (c) 2013 Marton Balint
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "avcodec.h"
22 #include "libavcodec/ass.h"
23 #include "codec_internal.h"
24 #include "libavcodec/dvbtxt.h"
25 #include "libavutil/opt.h"
26 #include "libavutil/bprint.h"
27 #include "libavutil/internal.h"
28 #include "libavutil/intreadwrite.h"
29 #include "libavutil/log.h"
30 #include "libavutil/common.h"
31
32 #include <libzvbi.h>
33
34 #define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
35 #define VBI_NB_COLORS 40
36 #define VBI_TRANSPARENT_BLACK 8
37 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
38 #define VBI_R(rgba) (((rgba) >> 0) & 0xFF)
39 #define VBI_G(rgba) (((rgba) >> 8) & 0xFF)
40 #define VBI_B(rgba) (((rgba) >> 16) & 0xFF)
41 #define VBI_A(rgba) (((rgba) >> 24) & 0xFF)
42 #define MAX_BUFFERED_PAGES 25
43 #define BITMAP_CHAR_WIDTH 12
44 #define BITMAP_CHAR_HEIGHT 10
45 #define MAX_SLICES 64
46
47 typedef struct TeletextPage
48 {
49 AVSubtitleRect *sub_rect;
50 int pgno;
51 int subno;
52 int64_t pts;
53 } TeletextPage;
54
55 typedef struct TeletextContext
56 {
57 AVClass *class;
58 char *pgno;
59 int default_region;
60 int x_offset;
61 int y_offset;
62 int format_id; /* 0 = bitmap, 1 = text/ass, 2 = ass */
63 int chop_top;
64 int sub_duration; /* in msec */
65 int transparent_bg;
66 int opacity;
67 int chop_spaces;
68
69 int lines_processed;
70 TeletextPage *pages;
71 int nb_pages;
72 int64_t pts;
73 int handler_ret;
74
75 vbi_decoder * vbi;
76 vbi_sliced sliced[MAX_SLICES];
77
78 int readorder;
79 uint8_t subtitle_map[2048];
80 int last_pgno;
81 int last_p5;
82 int last_ass_alignment;
83 } TeletextContext;
84
my_ass_subtitle_header(AVCodecContext *avctx)85 static int my_ass_subtitle_header(AVCodecContext *avctx)
86 {
87 int ret = ff_ass_subtitle_header_default(avctx);
88 char *new_header;
89 uint8_t *event_pos;
90
91 if (ret < 0)
92 return ret;
93
94 event_pos = strstr(avctx->subtitle_header, "\r\n[Events]\r\n");
95 if (!event_pos)
96 return AVERROR_BUG;
97
98 new_header = av_asprintf("%.*s%s%s",
99 (int)(event_pos - avctx->subtitle_header), avctx->subtitle_header,
100 "Style: "
101 "Teletext," /* Name */
102 "Monospace,11," /* Font{name,size} */
103 "&Hffffff,&Hffffff,&H0,&H0," /* {Primary,Secondary,Outline,Back}Colour */
104 "0,0,0,0," /* Bold, Italic, Underline, StrikeOut */
105 "160,100," /* Scale{X,Y} */
106 "0,0," /* Spacing, Angle */
107 "3,0.1,0," /* BorderStyle, Outline, Shadow */
108 "5,1,1,1," /* Alignment, Margin[LRV] */
109 "0\r\n" /* Encoding */
110 "Style: "
111 "Subtitle," /* Name */
112 "Monospace,16," /* Font{name,size} */
113 "&Hffffff,&Hffffff,&H0,&H0," /* {Primary,Secondary,Outline,Back}Colour */
114 "0,0,0,0," /* Bold, Italic, Underline, StrikeOut */
115 "100,100," /* Scale{X,Y} */
116 "0,0," /* Spacing, Angle */
117 "1,1,1," /* BorderStyle, Outline, Shadow */
118 "8,48,48,20," /* Alignment, Margin[LRV] */
119 "0\r\n" /* Encoding */
120 , event_pos);
121
122 if (!new_header)
123 return AVERROR(ENOMEM);
124
125 av_free(avctx->subtitle_header);
126 avctx->subtitle_header = new_header;
127 avctx->subtitle_header_size = strlen(new_header);
128 return 0;
129 }
130
chop_spaces_utf8(const unsigned char* t, int len)131 static int chop_spaces_utf8(const unsigned char* t, int len)
132 {
133 t += len;
134 while (len > 0) {
135 if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
136 break;
137 --len;
138 }
139 return len;
140 }
141
subtitle_rect_free(AVSubtitleRect **sub_rect)142 static void subtitle_rect_free(AVSubtitleRect **sub_rect)
143 {
144 av_freep(&(*sub_rect)->data[0]);
145 av_freep(&(*sub_rect)->data[1]);
146 av_freep(&(*sub_rect)->ass);
147 av_freep(sub_rect);
148 }
149
create_ass_text(TeletextContext *ctx, const char *text)150 static char *create_ass_text(TeletextContext *ctx, const char *text)
151 {
152 char *dialog;
153 AVBPrint buf;
154
155 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
156 ff_ass_bprint_text_event(&buf, text, strlen(text), "", 0);
157 if (!av_bprint_is_complete(&buf)) {
158 av_bprint_finalize(&buf, NULL);
159 return NULL;
160 }
161 dialog = ff_ass_get_dialog(ctx->readorder++, 0, NULL, NULL, buf.str);
162 av_bprint_finalize(&buf, NULL);
163 return dialog;
164 }
165
166 /* Draw a page as text */
gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)167 static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
168 {
169 const char *in;
170 AVBPrint buf;
171 char *vbi_text = av_malloc(TEXT_MAXSZ);
172 int sz;
173
174 if (!vbi_text)
175 return AVERROR(ENOMEM);
176
177 sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
178 /*table mode*/ TRUE, FALSE,
179 0, chop_top,
180 page->columns, page->rows-chop_top);
181 if (sz <= 0) {
182 av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
183 av_free(vbi_text);
184 return AVERROR_EXTERNAL;
185 }
186 vbi_text[sz] = '\0';
187 in = vbi_text;
188 av_bprint_init(&buf, 0, TEXT_MAXSZ);
189
190 if (ctx->chop_spaces) {
191 for (;;) {
192 int nl, sz;
193
194 // skip leading spaces and newlines
195 in += strspn(in, " \n");
196 // compute end of row
197 for (nl = 0; in[nl]; ++nl)
198 if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
199 break;
200 if (!in[nl])
201 break;
202 // skip trailing spaces
203 sz = chop_spaces_utf8(in, nl);
204 av_bprint_append_data(&buf, in, sz);
205 av_bprintf(&buf, "\n");
206 in += nl;
207 }
208 } else {
209 av_bprintf(&buf, "%s\n", vbi_text);
210 }
211 av_free(vbi_text);
212
213 if (!av_bprint_is_complete(&buf)) {
214 av_bprint_finalize(&buf, NULL);
215 return AVERROR(ENOMEM);
216 }
217
218 if (buf.len) {
219 sub_rect->type = SUBTITLE_ASS;
220 sub_rect->ass = create_ass_text(ctx, buf.str);
221
222 if (!sub_rect->ass) {
223 av_bprint_finalize(&buf, NULL);
224 return AVERROR(ENOMEM);
225 }
226 av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
227 } else {
228 sub_rect->type = SUBTITLE_NONE;
229 }
230 av_bprint_finalize(&buf, NULL);
231 return 0;
232 }
233
bprint_color(const char *type, AVBPrint *buf, vbi_page *page, unsigned ci)234 static void bprint_color(const char *type, AVBPrint *buf, vbi_page *page, unsigned ci)
235 {
236 int r = VBI_R(page->color_map[ci]);
237 int g = VBI_G(page->color_map[ci]);
238 int b = VBI_B(page->color_map[ci]);
239 av_bprintf(buf, "{\\%s&H%02X%02X%02X&}", type, b, g, r);
240 }
241
242 #define IS_TXT_SPACE(ch) ((ch).unicode < 0x0020 || (ch).unicode >= 0xe000 || (ch).unicode == 0x00a0 ||\
243 (ch).size > VBI_DOUBLE_SIZE || (ch).opacity == VBI_TRANSPARENT_SPACE)
244
get_trim_info(vbi_page *page, vbi_char *row, int *leading, int *trailing, int *olen)245 static void get_trim_info(vbi_page *page, vbi_char *row, int *leading, int *trailing, int *olen)
246 {
247 int i, len = 0;
248 int char_seen = 0;
249
250 *leading = 0;
251
252 for (i = 0; i < page->columns; i++) {
253 uint16_t out = IS_TXT_SPACE(row[i]) ? 32 : row[i].unicode;
254
255 if (out == 32 && !char_seen)
256 (*leading)++;
257 else if (out != 32)
258 char_seen = 1, len = i - (*leading) + 1;
259 }
260
261 *olen = len;
262 *trailing = len > 0 ? page->columns - *leading - len : page->columns;
263 }
264
decode_string(vbi_page *page, vbi_char *row, AVBPrint *buf, int start, int end, vbi_color *cur_color, vbi_color *cur_back_color)265 static void decode_string(vbi_page *page, vbi_char *row, AVBPrint *buf,
266 int start, int end, vbi_color *cur_color, vbi_color *cur_back_color)
267 {
268 int i;
269
270 for (i = start; i < end; i++) {
271 uint16_t out = IS_TXT_SPACE(row[i]) ? 32 : row[i].unicode;
272
273 if (*cur_color != row[i].foreground) {
274 bprint_color("c", buf, page, row[i].foreground);
275 *cur_color = row[i].foreground;
276 }
277 if (*cur_back_color != row[i].background) {
278 bprint_color("3c", buf, page, row[i].background);
279 *cur_back_color = row[i].background;
280 }
281
282 if (out == 32) {
283 av_bprintf(buf, "\\h");
284 } else if (out == '\\' || out == '{' || out == '}') {
285 av_bprintf(buf, "\\%c", (char)out);
286 } else {
287 char tmp;
288 /* convert to utf-8 */
289 PUT_UTF8(out, tmp, av_bprint_chars(buf, tmp, 1););
290 }
291 }
292 }
293
294 /* Draw a page as ass formatted text */
gen_sub_ass(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)295 static int gen_sub_ass(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
296 {
297 int i;
298 int leading, trailing, len;
299 int last_trailing = -1, last_leading = -1;
300 int min_trailing = page->columns, min_leading = page->columns;
301 int alignment = 2;
302 int vertical_align = -1;
303 int can_align_left = 1, can_align_right = 1, can_align_center = 1;
304 int is_subtitle_page = ctx->subtitle_map[page->pgno & 0x7ff];
305 int empty_lines = 0;
306 vbi_color cur_color = VBI_WHITE;
307 vbi_color cur_back_color = VBI_BLACK;
308 AVBPrint buf;
309
310 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
311
312 for (i = chop_top; i < page->rows; i++) {
313 vbi_char *row = page->text + i * page->columns;
314
315 get_trim_info(page, row, &leading, &trailing, &len);
316
317 if (len) {
318 if (last_leading != -1 && last_leading != leading || leading > 5)
319 can_align_left = 0;
320 if (last_trailing != -1 && last_trailing != trailing || trailing > 2)
321 can_align_right = 0;
322 if (last_trailing != -1 && (FFABS((trailing - leading) - (last_trailing - last_leading)) > 1) || trailing - leading > 4)
323 can_align_center = 0;
324 last_leading = leading;
325 last_trailing = trailing;
326 min_leading = FFMIN(leading, min_leading);
327 min_trailing = FFMIN(trailing, min_trailing);
328 }
329 }
330
331 if (!can_align_right && can_align_left && !can_align_center) {
332 ctx->last_ass_alignment = alignment = 1;
333 } else if (!can_align_right && !can_align_left && can_align_center) {
334 ctx->last_ass_alignment = alignment = 2;
335 } else if (can_align_right && !can_align_left && !can_align_center) {
336 ctx->last_ass_alignment = alignment = 3;
337 } else {
338 if (ctx->last_ass_alignment == 1 && can_align_left ||
339 ctx->last_ass_alignment == 2 && can_align_center ||
340 ctx->last_ass_alignment == 3 && can_align_right)
341 alignment = ctx->last_ass_alignment;
342 }
343
344 for (i = chop_top; i < page->rows; i++) {
345 int j;
346 vbi_char *row = page->text + i * page->columns;
347 int is_transparent_line;
348
349 for (j = 0; j < page->columns; j++)
350 if (row[j].opacity != VBI_TRANSPARENT_SPACE)
351 break;
352 is_transparent_line = (j == page->columns);
353
354 len = is_transparent_line ? 0 : page->columns;
355 leading = trailing = is_transparent_line ? page->columns : 0;
356
357 if (is_subtitle_page) {
358 if (!is_transparent_line)
359 get_trim_info(page, row, &leading, &trailing, &len);
360
361 if (vertical_align == -1 && len) {
362 vertical_align = (2 - (av_clip(i + 1, 0, 23) / 8));
363 av_bprintf(&buf, "{\\an%d}", alignment + vertical_align * 3);
364 if (vertical_align != 2)
365 empty_lines = 0;
366 }
367
368 if (len && empty_lines > 1)
369 for (empty_lines /= 2; empty_lines > 0; empty_lines--)
370 av_bprintf(&buf, " \\N");
371
372 if (alignment == 1 || alignment == 2 && !can_align_center)
373 leading = min_leading;
374 if (alignment == 3 || alignment == 2 && !can_align_center)
375 trailing = min_trailing;
376 }
377
378 if (len || !is_subtitle_page) {
379 decode_string(page, row, &buf, leading, page->columns - trailing, &cur_color, &cur_back_color);
380 av_bprintf(&buf, " \\N");
381 empty_lines = 0;
382 } else {
383 empty_lines++;
384 }
385 }
386
387 if (vertical_align == 0)
388 for (empty_lines = (empty_lines - 1) / 2; empty_lines > 0; empty_lines--)
389 av_bprintf(&buf, " \\N");
390
391 if (!av_bprint_is_complete(&buf)) {
392 av_bprint_finalize(&buf, NULL);
393 return AVERROR(ENOMEM);
394 }
395
396 if (buf.len) {
397 sub_rect->type = SUBTITLE_ASS;
398 sub_rect->ass = ff_ass_get_dialog(ctx->readorder++, 0, is_subtitle_page ? "Subtitle" : "Teletext", NULL, buf.str);
399
400 if (!sub_rect->ass) {
401 av_bprint_finalize(&buf, NULL);
402 return AVERROR(ENOMEM);
403 }
404 av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
405 } else {
406 sub_rect->type = SUBTITLE_NONE;
407 }
408 av_bprint_finalize(&buf, NULL);
409 return 0;
410 }
411
fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top, int resx, int resy)412 static void fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page,
413 int chop_top, int resx, int resy)
414 {
415 int iy;
416
417 // Hack for transparency, inspired by VLC code...
418 for (iy = 0; iy < resy; iy++) {
419 uint8_t *pixel = sub_rect->data[0] + iy * sub_rect->linesize[0];
420 vbi_char *vc = page->text + (iy / BITMAP_CHAR_HEIGHT + chop_top) * page->columns;
421 vbi_char *vcnext = vc + page->columns;
422 for (; vc < vcnext; vc++) {
423 uint8_t *pixelnext = pixel + BITMAP_CHAR_WIDTH;
424 switch (vc->opacity) {
425 case VBI_TRANSPARENT_SPACE:
426 memset(pixel, VBI_TRANSPARENT_BLACK, BITMAP_CHAR_WIDTH);
427 break;
428 case VBI_OPAQUE:
429 if (!ctx->transparent_bg)
430 break;
431 case VBI_SEMI_TRANSPARENT:
432 if (ctx->opacity > 0) {
433 if (ctx->opacity < 255)
434 for(; pixel < pixelnext; pixel++)
435 if (*pixel == vc->background)
436 *pixel += VBI_NB_COLORS;
437 break;
438 }
439 case VBI_TRANSPARENT_FULL:
440 for(; pixel < pixelnext; pixel++)
441 if (*pixel == vc->background)
442 *pixel = VBI_TRANSPARENT_BLACK;
443 break;
444 }
445 pixel = pixelnext;
446 }
447 }
448 }
449
450 /* Draw a page as bitmap */
gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)451 static int gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
452 {
453 int resx = page->columns * BITMAP_CHAR_WIDTH;
454 int resy = (page->rows - chop_top) * BITMAP_CHAR_HEIGHT;
455 uint8_t ci;
456 vbi_char *vc = page->text + (chop_top * page->columns);
457 vbi_char *vcend = page->text + (page->rows * page->columns);
458
459 for (; vc < vcend; vc++) {
460 if (vc->opacity != VBI_TRANSPARENT_SPACE)
461 break;
462 }
463
464 if (vc >= vcend) {
465 av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
466 sub_rect->type = SUBTITLE_NONE;
467 return 0;
468 }
469
470 sub_rect->data[0] = av_mallocz(resx * resy);
471 sub_rect->linesize[0] = resx;
472 if (!sub_rect->data[0])
473 return AVERROR(ENOMEM);
474
475 vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
476 sub_rect->data[0], sub_rect->linesize[0],
477 0, chop_top, page->columns, page->rows - chop_top,
478 /*reveal*/ 1, /*flash*/ 1);
479
480 fix_transparency(ctx, sub_rect, page, chop_top, resx, resy);
481 sub_rect->x = ctx->x_offset;
482 sub_rect->y = ctx->y_offset + chop_top * BITMAP_CHAR_HEIGHT;
483 sub_rect->w = resx;
484 sub_rect->h = resy;
485 sub_rect->nb_colors = ctx->opacity > 0 && ctx->opacity < 255 ? 2 * VBI_NB_COLORS : VBI_NB_COLORS;
486 sub_rect->data[1] = av_mallocz(AVPALETTE_SIZE);
487 if (!sub_rect->data[1]) {
488 av_freep(&sub_rect->data[0]);
489 return AVERROR(ENOMEM);
490 }
491 for (ci = 0; ci < VBI_NB_COLORS; ci++) {
492 int r, g, b, a;
493
494 r = VBI_R(page->color_map[ci]);
495 g = VBI_G(page->color_map[ci]);
496 b = VBI_B(page->color_map[ci]);
497 a = VBI_A(page->color_map[ci]);
498 ((uint32_t *)sub_rect->data[1])[ci] = RGBA(r, g, b, a);
499 ((uint32_t *)sub_rect->data[1])[ci + VBI_NB_COLORS] = RGBA(r, g, b, ctx->opacity);
500 ff_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->data[1])[ci]);
501 }
502 ((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK] = RGBA(0, 0, 0, 0);
503 ((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK + VBI_NB_COLORS] = RGBA(0, 0, 0, 0);
504 sub_rect->type = SUBTITLE_BITMAP;
505 return 0;
506 }
507
handler(vbi_event *ev, void *user_data)508 static void handler(vbi_event *ev, void *user_data)
509 {
510 TeletextContext *ctx = user_data;
511 TeletextPage *new_pages;
512 vbi_page page;
513 int res;
514 char pgno_str[12];
515 int chop_top;
516 int is_subtitle_page = ctx->subtitle_map[ev->ev.ttx_page.pgno & 0x7ff];
517
518 snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
519 av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
520 pgno_str, ev->ev.ttx_page.subno & 0xFF);
521
522 if (strcmp(ctx->pgno, "*") && (strcmp(ctx->pgno, "subtitle") || !is_subtitle_page) && !strstr(ctx->pgno, pgno_str))
523 return;
524 if (ctx->handler_ret < 0)
525 return;
526
527 res = vbi_fetch_vt_page(ctx->vbi, &page,
528 ev->ev.ttx_page.pgno,
529 ev->ev.ttx_page.subno,
530 VBI_WST_LEVEL_3p5, 25, TRUE);
531
532 if (!res)
533 return;
534
535 chop_top = ctx->chop_top || ((page.rows > 1) && is_subtitle_page);
536
537 av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
538 page.columns, page.rows, chop_top);
539
540 if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
541 if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
542 TeletextPage *cur_page = new_pages + ctx->nb_pages;
543 ctx->pages = new_pages;
544 cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
545 cur_page->pts = ctx->pts;
546 cur_page->pgno = ev->ev.ttx_page.pgno;
547 cur_page->subno = ev->ev.ttx_page.subno;
548 if (cur_page->sub_rect) {
549 switch (ctx->format_id) {
550 case 0:
551 res = gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top);
552 break;
553 case 1:
554 res = gen_sub_text(ctx, cur_page->sub_rect, &page, chop_top);
555 break;
556 case 2:
557 res = gen_sub_ass(ctx, cur_page->sub_rect, &page, chop_top);
558 break;
559 default:
560 res = AVERROR_BUG;
561 break;
562 }
563 if (res < 0) {
564 av_freep(&cur_page->sub_rect);
565 ctx->handler_ret = res;
566 } else {
567 ctx->pages[ctx->nb_pages++] = *cur_page;
568 }
569 } else {
570 ctx->handler_ret = AVERROR(ENOMEM);
571 }
572 } else {
573 ctx->handler_ret = AVERROR(ENOMEM);
574 }
575 } else {
576 //TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
577 av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
578 ctx->handler_ret = AVERROR(ENOSYS);
579 }
580
581 vbi_unref_page(&page);
582 }
583
slice_to_vbi_lines(TeletextContext *ctx, const uint8_t *buf, int size)584 static int slice_to_vbi_lines(TeletextContext *ctx, const uint8_t *buf, int size)
585 {
586 int lines = 0;
587 while (size >= 2 && lines < MAX_SLICES) {
588 int data_unit_id = buf[0];
589 int data_unit_length = buf[1];
590 if (data_unit_length + 2 > size)
591 return AVERROR_INVALIDDATA;
592 if (ff_data_unit_id_is_teletext(data_unit_id)) {
593 if (data_unit_length != 0x2c)
594 return AVERROR_INVALIDDATA;
595 else {
596 int line_offset = buf[2] & 0x1f;
597 int field_parity = buf[2] & 0x20;
598 uint8_t *p = ctx->sliced[lines].data;
599 int i, pmag;
600 ctx->sliced[lines].id = VBI_SLICED_TELETEXT_B;
601 ctx->sliced[lines].line = (line_offset > 0 ? (line_offset + (field_parity ? 0 : 313)) : 0);
602 for (i = 0; i < 42; i++)
603 p[i] = vbi_rev8(buf[4 + i]);
604 /* Unfortunately libzvbi does not expose page flags, and
605 * vbi_classify_page only checks MIP, so we have to manually
606 * decode the page flags and store the results. */
607 pmag = vbi_unham16p(p);
608 if (pmag >= 0 && pmag >> 3 == 0) { // We found a row 0 header
609 int page = vbi_unham16p(p + 2);
610 int flags1 = vbi_unham16p(p + 6);
611 int flags2 = vbi_unham16p(p + 8);
612 if (page >= 0 && flags1 >= 0 && flags2 >= 0) {
613 int pgno = ((pmag & 7) << 8) + page;
614 // Check for disabled NEWSFLASH flag and enabled SUBTITLE and SUPRESS_HEADER flags
615 ctx->subtitle_map[pgno] = (!(flags1 & 0x40) && flags1 & 0x80 && flags2 & 0x01);
616 // Propagate ERASE_PAGE flag for repeated page headers to work around a libzvbi bug
617 if (ctx->subtitle_map[pgno] && pgno == ctx->last_pgno) {
618 int last_byte9 = vbi_unham8(ctx->last_p5);
619 if (last_byte9 >= 0 && last_byte9 & 0x8) {
620 int byte9 = vbi_unham8(p[5]);
621 if (byte9 >= 0)
622 p[5] = vbi_ham8(byte9 | 0x8);
623 }
624 }
625 ctx->last_pgno = pgno;
626 ctx->last_p5 = p[5];
627 }
628 }
629 lines++;
630 }
631 }
632 size -= data_unit_length + 2;
633 buf += data_unit_length + 2;
634 }
635 if (size)
636 av_log(ctx, AV_LOG_WARNING, "%d bytes remained after slicing data\n", size);
637 return lines;
638 }
639
teletext_decode_frame(AVCodecContext *avctx, AVSubtitle *sub, int *got_sub_ptr, const AVPacket *pkt)640 static int teletext_decode_frame(AVCodecContext *avctx, AVSubtitle *sub,
641 int *got_sub_ptr, const AVPacket *pkt)
642 {
643 TeletextContext *ctx = avctx->priv_data;
644 int ret = 0;
645
646 if (!ctx->vbi) {
647 if (!(ctx->vbi = vbi_decoder_new()))
648 return AVERROR(ENOMEM);
649 if (ctx->default_region != -1) {
650 av_log(avctx, AV_LOG_INFO, "Setting default zvbi region to %i\n", ctx->default_region);
651 vbi_teletext_set_default_region(ctx->vbi, ctx->default_region);
652 }
653 if (!vbi_event_handler_register(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
654 vbi_decoder_delete(ctx->vbi);
655 ctx->vbi = NULL;
656 return AVERROR(ENOMEM);
657 }
658 }
659
660 if (avctx->pkt_timebase.num && pkt->pts != AV_NOPTS_VALUE)
661 ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
662
663 if (pkt->size) {
664 int lines;
665 const int full_pes_size = pkt->size + 45; /* PES header is 45 bytes */
666
667 // We allow unreasonably big packets, even if the standard only allows a max size of 1472
668 if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size % 184 != 0)
669 return AVERROR_INVALIDDATA;
670
671 ctx->handler_ret = pkt->size;
672
673 if (ff_data_identifier_is_teletext(*pkt->data)) {
674 if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
675 return lines;
676 ff_dlog(avctx, "ctx=%p buf_size=%d lines=%u pkt_pts=%7.3f\n",
677 ctx, pkt->size, lines, (double)pkt->pts/90000.0);
678 if (lines > 0) {
679 vbi_decode(ctx->vbi, ctx->sliced, lines, 0.0);
680 ctx->lines_processed += lines;
681 }
682 }
683 ctx->pts = AV_NOPTS_VALUE;
684 ret = ctx->handler_ret;
685 }
686
687 if (ret < 0)
688 return ret;
689
690 // is there a subtitle to pass?
691 if (ctx->nb_pages) {
692 int i;
693 sub->format = !!ctx->format_id;
694 sub->start_display_time = 0;
695 sub->end_display_time = ctx->sub_duration;
696 sub->num_rects = 0;
697 sub->pts = ctx->pages->pts;
698
699 if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
700 sub->rects = av_malloc(sizeof(*sub->rects));
701 if (sub->rects) {
702 sub->num_rects = 1;
703 sub->rects[0] = ctx->pages->sub_rect;
704 } else {
705 ret = AVERROR(ENOMEM);
706 }
707 } else {
708 av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
709 sub->rects = NULL;
710 }
711 if (!sub->rects) // no rect was passed
712 subtitle_rect_free(&ctx->pages->sub_rect);
713
714 for (i = 0; i < ctx->nb_pages - 1; i++)
715 ctx->pages[i] = ctx->pages[i + 1];
716 ctx->nb_pages--;
717
718 if (ret >= 0)
719 *got_sub_ptr = 1;
720 } else
721 *got_sub_ptr = 0;
722
723 return ret;
724 }
725
teletext_init_decoder(AVCodecContext *avctx)726 static int teletext_init_decoder(AVCodecContext *avctx)
727 {
728 TeletextContext *ctx = avctx->priv_data;
729 unsigned int maj, min, rev;
730
731 vbi_version(&maj, &min, &rev);
732 if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
733 av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
734 return AVERROR_EXTERNAL;
735 }
736
737 if (ctx->format_id == 0) {
738 avctx->width = 41 * BITMAP_CHAR_WIDTH;
739 avctx->height = 25 * BITMAP_CHAR_HEIGHT;
740 }
741
742 ctx->vbi = NULL;
743 ctx->pts = AV_NOPTS_VALUE;
744 ctx->last_pgno = -1;
745 ctx->last_ass_alignment = 2;
746
747 if (ctx->opacity == -1)
748 ctx->opacity = ctx->transparent_bg ? 0 : 255;
749
750 av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
751
752 switch (ctx->format_id) {
753 case 0:
754 return 0;
755 case 1:
756 return ff_ass_subtitle_header_default(avctx);
757 case 2:
758 return my_ass_subtitle_header(avctx);
759 }
760 return AVERROR_BUG;
761 }
762
teletext_close_decoder(AVCodecContext *avctx)763 static int teletext_close_decoder(AVCodecContext *avctx)
764 {
765 TeletextContext *ctx = avctx->priv_data;
766
767 ff_dlog(avctx, "lines_total=%u\n", ctx->lines_processed);
768 while (ctx->nb_pages)
769 subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
770 av_freep(&ctx->pages);
771
772 vbi_decoder_delete(ctx->vbi);
773 ctx->vbi = NULL;
774 ctx->pts = AV_NOPTS_VALUE;
775 ctx->last_pgno = -1;
776 ctx->last_ass_alignment = 2;
777 memset(ctx->subtitle_map, 0, sizeof(ctx->subtitle_map));
778 if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
779 ctx->readorder = 0;
780 return 0;
781 }
782
teletext_flush(AVCodecContext *avctx)783 static void teletext_flush(AVCodecContext *avctx)
784 {
785 teletext_close_decoder(avctx);
786 }
787
788 #define OFFSET(x) offsetof(TeletextContext, x)
789 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
790 static const AVOption options[] = {
791 {"txt_page", "page numbers to decode, subtitle for subtitles, * for all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
792 {"txt_default_region", "default G0 character set used for decoding", OFFSET(default_region), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 87, SD},
793 {"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
794 {"txt_format", "format of the subtitles (bitmap or text or ass)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 2, SD, "txt_format"},
795 {"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
796 {"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
797 {"ass", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 2}, 0, 0, SD, "txt_format"},
798 {"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
799 {"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
800 {"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
801 {"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 86400000, SD},
802 {"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
803 {"txt_opacity", "set opacity of the transparent background", OFFSET(opacity), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, SD},
804 { NULL },
805 };
806
807 static const AVClass teletext_class = {
808 .class_name = "libzvbi_teletextdec",
809 .item_name = av_default_item_name,
810 .option = options,
811 .version = LIBAVUTIL_VERSION_INT,
812 };
813
814 const FFCodec ff_libzvbi_teletext_decoder = {
815 .p.name = "libzvbi_teletextdec",
816 .p.long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
817 .p.type = AVMEDIA_TYPE_SUBTITLE,
818 .p.id = AV_CODEC_ID_DVB_TELETEXT,
819 .p.capabilities = AV_CODEC_CAP_DELAY,
820 .p.priv_class = &teletext_class,
821 .p.wrapper_name = "libzvbi",
822 .priv_data_size = sizeof(TeletextContext),
823 .init = teletext_init_decoder,
824 .close = teletext_close_decoder,
825 FF_CODEC_DECODE_SUB_CB(teletext_decode_frame),
826 .flush = teletext_flush,
827 };
828