2 * Teletext decoding for ffmpeg
3 * Copyright (c) 2005-2010, 2012 Wolfram Gloger
4 * Copyright (c) 2013 Marton Balint
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.
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.
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
22 #include "libavcodec/ass.h"
23 #include "libavcodec/dvbtxt.h"
24 #include "libavutil/opt.h"
25 #include "libavutil/bprint.h"
26 #include "libavutil/internal.h"
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/log.h"
32 #define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
33 #define VBI_NB_COLORS 40
34 #define VBI_TRANSPARENT_BLACK 8
35 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
36 #define VBI_R(rgba) (((rgba) >> 0) & 0xFF)
37 #define VBI_G(rgba) (((rgba) >> 8) & 0xFF)
38 #define VBI_B(rgba) (((rgba) >> 16) & 0xFF)
39 #define VBI_A(rgba) (((rgba) >> 24) & 0xFF)
40 #define MAX_BUFFERED_PAGES 25
41 #define BITMAP_CHAR_WIDTH 12
42 #define BITMAP_CHAR_HEIGHT 10
45 typedef struct TeletextPage
47 AVSubtitleRect *sub_rect;
53 typedef struct TeletextContext
59 int format_id; /* 0 = bitmap, 1 = text/ass */
61 int sub_duration; /* in msec */
76 vbi_sliced sliced[MAX_SLICES];
79 static int chop_spaces_utf8(const unsigned char* t, int len)
83 if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
90 static void subtitle_rect_free(AVSubtitleRect **sub_rect)
92 av_freep(&(*sub_rect)->data[0]);
93 av_freep(&(*sub_rect)->data[1]);
94 av_freep(&(*sub_rect)->ass);
98 static int create_ass_text(TeletextContext *ctx, const char *text, char **ass)
102 const int ts_start = av_rescale_q(ctx->pts, AV_TIME_BASE_Q, (AVRational){1, 100});
103 const int ts_duration = av_rescale_q(ctx->sub_duration, (AVRational){1, 1000}, (AVRational){1, 100});
105 /* First we escape the plain text into buf. */
106 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
107 ff_ass_bprint_text_event(&buf, text, strlen(text), "", 0);
108 av_bprintf(&buf, "\r\n");
110 if (!av_bprint_is_complete(&buf)) {
111 av_bprint_finalize(&buf, NULL);
112 return AVERROR(ENOMEM);
115 /* Then we create the ass dialog line in buf2 from the escaped text in buf. */
116 av_bprint_init(&buf2, 0, AV_BPRINT_SIZE_UNLIMITED);
117 ff_ass_bprint_dialog(&buf2, buf.str, ts_start, ts_duration, 0);
118 av_bprint_finalize(&buf, NULL);
120 if (!av_bprint_is_complete(&buf2)) {
121 av_bprint_finalize(&buf2, NULL);
122 return AVERROR(ENOMEM);
125 if ((ret = av_bprint_finalize(&buf2, ass)) < 0)
131 /* Draw a page as text */
132 static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
136 char *vbi_text = av_malloc(TEXT_MAXSZ);
140 return AVERROR(ENOMEM);
142 sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
143 /*table mode*/ TRUE, FALSE,
145 page->columns, page->rows-chop_top);
147 av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
149 return AVERROR_EXTERNAL;
153 av_bprint_init(&buf, 0, TEXT_MAXSZ);
155 if (ctx->chop_spaces) {
159 // skip leading spaces and newlines
160 in += strspn(in, " \n");
161 // compute end of row
162 for (nl = 0; in[nl]; ++nl)
163 if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
167 // skip trailing spaces
168 sz = chop_spaces_utf8(in, nl);
169 av_bprint_append_data(&buf, in, sz);
170 av_bprintf(&buf, "\n");
174 av_bprintf(&buf, "%s\n", vbi_text);
178 if (!av_bprint_is_complete(&buf)) {
179 av_bprint_finalize(&buf, NULL);
180 return AVERROR(ENOMEM);
185 sub_rect->type = SUBTITLE_ASS;
186 if ((ret = create_ass_text(ctx, buf.str, &sub_rect->ass)) < 0) {
187 av_bprint_finalize(&buf, NULL);
190 av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
192 sub_rect->type = SUBTITLE_NONE;
194 av_bprint_finalize(&buf, NULL);
198 static void fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page,
199 int chop_top, int resx, int resy)
203 // Hack for transparency, inspired by VLC code...
204 for (iy = 0; iy < resy; iy++) {
205 uint8_t *pixel = sub_rect->data[0] + iy * sub_rect->linesize[0];
206 vbi_char *vc = page->text + (iy / BITMAP_CHAR_HEIGHT + chop_top) * page->columns;
207 vbi_char *vcnext = vc + page->columns;
208 for (; vc < vcnext; vc++) {
209 uint8_t *pixelnext = pixel + BITMAP_CHAR_WIDTH;
210 switch (vc->opacity) {
211 case VBI_TRANSPARENT_SPACE:
212 memset(pixel, VBI_TRANSPARENT_BLACK, BITMAP_CHAR_WIDTH);
215 if (!ctx->transparent_bg)
217 case VBI_SEMI_TRANSPARENT:
218 if (ctx->opacity > 0) {
219 if (ctx->opacity < 255)
220 for(; pixel < pixelnext; pixel++)
221 if (*pixel == vc->background)
222 *pixel += VBI_NB_COLORS;
225 case VBI_TRANSPARENT_FULL:
226 for(; pixel < pixelnext; pixel++)
227 if (*pixel == vc->background)
228 *pixel = VBI_TRANSPARENT_BLACK;
236 /* Draw a page as bitmap */
237 static int gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
239 int resx = page->columns * BITMAP_CHAR_WIDTH;
240 int resy = (page->rows - chop_top) * BITMAP_CHAR_HEIGHT;
242 vbi_char *vc = page->text + (chop_top * page->columns);
243 vbi_char *vcend = page->text + (page->rows * page->columns);
245 for (; vc < vcend; vc++) {
246 if (vc->opacity != VBI_TRANSPARENT_SPACE)
251 av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
252 sub_rect->type = SUBTITLE_NONE;
256 sub_rect->data[0] = av_mallocz(resx * resy);
257 sub_rect->linesize[0] = resx;
258 if (!sub_rect->data[0])
259 return AVERROR(ENOMEM);
261 vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
262 sub_rect->data[0], sub_rect->linesize[0],
263 0, chop_top, page->columns, page->rows - chop_top,
264 /*reveal*/ 1, /*flash*/ 1);
266 fix_transparency(ctx, sub_rect, page, chop_top, resx, resy);
267 sub_rect->x = ctx->x_offset;
268 sub_rect->y = ctx->y_offset + chop_top * BITMAP_CHAR_HEIGHT;
271 sub_rect->nb_colors = ctx->opacity > 0 && ctx->opacity < 255 ? 2 * VBI_NB_COLORS : VBI_NB_COLORS;
272 sub_rect->data[1] = av_mallocz(AVPALETTE_SIZE);
273 if (!sub_rect->data[1]) {
274 av_freep(&sub_rect->data[0]);
275 return AVERROR(ENOMEM);
277 for (ci = 0; ci < VBI_NB_COLORS; ci++) {
280 r = VBI_R(page->color_map[ci]);
281 g = VBI_G(page->color_map[ci]);
282 b = VBI_B(page->color_map[ci]);
283 a = VBI_A(page->color_map[ci]);
284 ((uint32_t *)sub_rect->data[1])[ci] = RGBA(r, g, b, a);
285 ((uint32_t *)sub_rect->data[1])[ci + VBI_NB_COLORS] = RGBA(r, g, b, ctx->opacity);
286 ff_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->data[1])[ci]);
288 ((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK] = RGBA(0, 0, 0, 0);
289 ((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK + VBI_NB_COLORS] = RGBA(0, 0, 0, 0);
290 sub_rect->type = SUBTITLE_BITMAP;
294 static void handler(vbi_event *ev, void *user_data)
296 TeletextContext *ctx = user_data;
297 TeletextPage *new_pages;
306 snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
307 av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
308 pgno_str, ev->ev.ttx_page.subno & 0xFF);
310 if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))
312 if (ctx->handler_ret < 0)
315 res = vbi_fetch_vt_page(ctx->vbi, &page,
316 ev->ev.ttx_page.pgno,
317 ev->ev.ttx_page.subno,
318 VBI_WST_LEVEL_3p5, 25, TRUE);
324 fprintf(stderr, "\nSaving res=%d dy0=%d dy1=%d...\n",
325 res, page.dirty.y0, page.dirty.y1);
328 if (!vbi_export_stdio(ctx->ex, stderr, &page))
329 fprintf(stderr, "failed: %s\n", vbi_export_errstr(ctx->ex));
332 vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);
333 chop_top = ctx->chop_top ||
334 ((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));
336 av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
337 page.columns, page.rows, chop_top);
339 if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
340 if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
341 TeletextPage *cur_page = new_pages + ctx->nb_pages;
342 ctx->pages = new_pages;
343 cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
344 cur_page->pts = ctx->pts;
345 cur_page->pgno = ev->ev.ttx_page.pgno;
346 cur_page->subno = ev->ev.ttx_page.subno;
347 if (cur_page->sub_rect) {
348 res = (ctx->format_id == 0) ?
349 gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top) :
350 gen_sub_text (ctx, cur_page->sub_rect, &page, chop_top);
352 av_freep(&cur_page->sub_rect);
353 ctx->handler_ret = res;
355 ctx->pages[ctx->nb_pages++] = *cur_page;
358 ctx->handler_ret = AVERROR(ENOMEM);
361 ctx->handler_ret = AVERROR(ENOMEM);
364 //TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
365 av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
366 ctx->handler_ret = AVERROR(ENOSYS);
369 vbi_unref_page(&page);
372 static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size)
375 while (size >= 2 && lines < MAX_SLICES) {
376 int data_unit_id = buf[0];
377 int data_unit_length = buf[1];
378 if (data_unit_length + 2 > size)
379 return AVERROR_INVALIDDATA;
380 if (ff_data_unit_id_is_teletext(data_unit_id)) {
381 if (data_unit_length != 0x2c)
382 return AVERROR_INVALIDDATA;
384 int line_offset = buf[2] & 0x1f;
385 int field_parity = buf[2] & 0x20;
387 ctx->sliced[lines].id = VBI_SLICED_TELETEXT_B;
388 ctx->sliced[lines].line = (line_offset > 0 ? (line_offset + (field_parity ? 0 : 313)) : 0);
389 for (i = 0; i < 42; i++)
390 ctx->sliced[lines].data[i] = vbi_rev8(buf[4 + i]);
394 size -= data_unit_length + 2;
395 buf += data_unit_length + 2;
398 av_log(ctx, AV_LOG_WARNING, "%d bytes remained after slicing data\n", size);
402 static int teletext_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *pkt)
404 TeletextContext *ctx = avctx->priv_data;
405 AVSubtitle *sub = data;
410 if (!(ctx->vbi = vbi_decoder_new()))
411 return AVERROR(ENOMEM);
412 if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
413 vbi_decoder_delete(ctx->vbi);
415 return AVERROR(ENOMEM);
419 if (avctx->pkt_timebase.num && pkt->pts != AV_NOPTS_VALUE)
420 ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
424 const int full_pes_size = pkt->size + 45; /* PES header is 45 bytes */
426 // We allow unreasonably big packets, even if the standard only allows a max size of 1472
427 if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size % 184 != 0)
428 return AVERROR_INVALIDDATA;
430 ctx->handler_ret = pkt->size;
432 if (ff_data_identifier_is_teletext(*pkt->data)) {
433 if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
435 ff_dlog(avctx, "ctx=%p buf_size=%d lines=%u pkt_pts=%7.3f\n",
436 ctx, pkt->size, lines, (double)pkt->pts/90000.0);
440 av_log(avctx, AV_LOG_DEBUG, "line numbers:");
441 for(i = 0; i < lines; i++)
442 av_log(avctx, AV_LOG_DEBUG, " %d", ctx->sliced[i].line);
443 av_log(avctx, AV_LOG_DEBUG, "\n");
445 vbi_decode(ctx->vbi, ctx->sliced, lines, 0.0);
446 ctx->lines_processed += lines;
449 ctx->pts = AV_NOPTS_VALUE;
450 ret = ctx->handler_ret;
456 // is there a subtitle to pass?
459 sub->format = ctx->format_id;
460 sub->start_display_time = 0;
461 sub->end_display_time = ctx->sub_duration;
463 sub->pts = ctx->pages->pts;
465 if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
466 sub->rects = av_malloc(sizeof(*sub->rects));
469 sub->rects[0] = ctx->pages->sub_rect;
471 FF_DISABLE_DEPRECATION_WARNINGS
472 for (j = 0; j < 4; j++) {
473 sub->rects[0]->pict.data[j] = sub->rects[0]->data[j];
474 sub->rects[0]->pict.linesize[j] = sub->rects[0]->linesize[j];
476 FF_ENABLE_DEPRECATION_WARNINGS
479 ret = AVERROR(ENOMEM);
482 av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
485 if (!sub->rects) // no rect was passed
486 subtitle_rect_free(&ctx->pages->sub_rect);
488 for (i = 0; i < ctx->nb_pages - 1; i++)
489 ctx->pages[i] = ctx->pages[i + 1];
500 static int teletext_init_decoder(AVCodecContext *avctx)
502 TeletextContext *ctx = avctx->priv_data;
503 unsigned int maj, min, rev;
505 vbi_version(&maj, &min, &rev);
506 if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
507 av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
508 return AVERROR_EXTERNAL;
511 if (ctx->format_id == 0) {
512 avctx->width = 41 * BITMAP_CHAR_WIDTH;
513 avctx->height = 25 * BITMAP_CHAR_HEIGHT;
517 ctx->pts = AV_NOPTS_VALUE;
519 if (ctx->opacity == -1)
520 ctx->opacity = ctx->transparent_bg ? 0 : 255;
525 ctx->ex = vbi_export_new("text", &t);
528 av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
529 return (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
532 static int teletext_close_decoder(AVCodecContext *avctx)
534 TeletextContext *ctx = avctx->priv_data;
536 ff_dlog(avctx, "lines_total=%u\n", ctx->lines_processed);
537 while (ctx->nb_pages)
538 subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
539 av_freep(&ctx->pages);
541 vbi_decoder_delete(ctx->vbi);
543 ctx->pts = AV_NOPTS_VALUE;
547 static void teletext_flush(AVCodecContext *avctx)
549 teletext_close_decoder(avctx);
552 #define OFFSET(x) offsetof(TeletextContext, x)
553 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
554 static const AVOption options[] = {
555 {"txt_page", "list of teletext page numbers to decode, * is all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
556 {"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
557 {"txt_format", "format of the subtitles (bitmap or text)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD, "txt_format"},
558 {"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
559 {"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
560 {"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
561 {"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
562 {"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
563 {"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = 30000}, 0, 86400000, SD},
564 {"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
565 {"txt_opacity", "set opacity of the transparent background", OFFSET(opacity), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, SD},
569 static const AVClass teletext_class = {
570 .class_name = "libzvbi_teletextdec",
571 .item_name = av_default_item_name,
573 .version = LIBAVUTIL_VERSION_INT,
576 AVCodec ff_libzvbi_teletext_decoder = {
577 .name = "libzvbi_teletextdec",
578 .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
579 .type = AVMEDIA_TYPE_SUBTITLE,
580 .id = AV_CODEC_ID_DVB_TELETEXT,
581 .priv_data_size = sizeof(TeletextContext),
582 .init = teletext_init_decoder,
583 .close = teletext_close_decoder,
584 .decode = teletext_decode_frame,
585 .capabilities = AV_CODEC_CAP_DELAY,
586 .flush = teletext_flush,
587 .priv_class= &teletext_class,