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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include "libavcodec/ass.h"
23 #include "libavutil/opt.h"
24 #include "libavutil/bprint.h"
25 #include "libavutil/intreadwrite.h"
29 #define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
30 #define VBI_NB_COLORS 40
31 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
32 #define VBI_R(rgba) (((rgba) >> 0) & 0xFF)
33 #define VBI_G(rgba) (((rgba) >> 8) & 0xFF)
34 #define VBI_B(rgba) (((rgba) >> 16) & 0xFF)
35 #define VBI_A(rgba) (((rgba) >> 24) & 0xFF)
36 #define MAX_BUFFERED_PAGES 25
38 typedef struct TeletextPage
40 AVSubtitleRect *sub_rect;
46 /* main data structure */
47 typedef struct TeletextContext
53 int format_id; /* 0 = bitmap, 1 = text/ass */
55 int sub_duration; /* in msec */
70 /* Don't even _think_ about making sliced stack-local! */
71 vbi_sliced sliced[64];
74 /************************************************************************/
77 chop_spaces_utf8(const unsigned char* t, int len)
81 if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
89 subtitle_rect_free(AVSubtitleRect **sub_rect)
91 av_freep(&(*sub_rect)->pict.data[0]);
92 av_freep(&(*sub_rect)->pict.data[1]);
93 av_freep(&(*sub_rect)->ass);
98 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);
109 if (!av_bprint_is_complete(&buf)) {
110 av_bprint_finalize(&buf, NULL);
111 return AVERROR(ENOMEM);
114 /* Then we create the ass dialog line in buf2 from the escaped text in buf. */
115 av_bprint_init(&buf2, 0, AV_BPRINT_SIZE_UNLIMITED);
116 ff_ass_bprint_dialog(&buf2, buf.str, ts_start, ts_duration, 0);
117 av_bprint_finalize(&buf, NULL);
119 if (!av_bprint_is_complete(&buf2)) {
120 av_bprint_finalize(&buf2, NULL);
121 return AVERROR(ENOMEM);
124 if ((ret = av_bprint_finalize(&buf2, ass)) < 0)
130 // draw a page as text
132 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);
199 fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top, uint8_t transparent_color, 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->pict.data[0] + iy * sub_rect->pict.linesize[0];
206 vbi_char *vc = page->text + (iy / 10 + chop_top) * page->columns;
207 vbi_char *vcnext = vc + page->columns;
208 for (; vc < vcnext; vc++) {
209 uint8_t *pixelnext = pixel + 12;
210 switch (vc->opacity) {
211 case VBI_TRANSPARENT_SPACE:
212 memset(pixel, transparent_color, 12);
215 case VBI_SEMI_TRANSPARENT:
216 if (!ctx->transparent_bg)
218 case VBI_TRANSPARENT_FULL:
219 for(; pixel < pixelnext; pixel++)
220 if (*pixel == vc->background)
221 *pixel = transparent_color;
229 // draw a page as bitmap
231 gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
233 int resx = page->columns * 12;
234 int resy = (page->rows - chop_top) * 10;
235 uint8_t ci, cmax = 0;
237 vbi_char *vc = page->text + (chop_top * page->columns);
238 vbi_char *vcend = page->text + (page->rows * page->columns);
240 for (; vc < vcend; vc++) {
241 if (vc->opacity != VBI_TRANSPARENT_SPACE) {
242 cmax = VBI_NB_COLORS;
248 av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
249 sub_rect->type = SUBTITLE_NONE;
253 if ((ret = avpicture_alloc(&sub_rect->pict, AV_PIX_FMT_PAL8, resx, resy)) < 0)
255 // Yes, we want to allocate the palette on our own because AVSubtitle works this way
256 sub_rect->pict.data[1] = NULL;
258 vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
259 sub_rect->pict.data[0], sub_rect->pict.linesize[0],
260 0, chop_top, page->columns, page->rows - chop_top,
261 /*reveal*/ 1, /*flash*/ 1);
263 fix_transparency(ctx, sub_rect, page, chop_top, cmax, resx, resy);
264 sub_rect->x = ctx->x_offset;
265 sub_rect->y = ctx->y_offset;
268 sub_rect->nb_colors = (int)cmax + 1;
269 sub_rect->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
270 if (!sub_rect->pict.data[1]) {
271 av_freep(&sub_rect->pict.data[0]);
272 return AVERROR(ENOMEM);
274 for (ci = 0; ci < cmax; ci++) {
277 r = VBI_R(page->color_map[ci]);
278 g = VBI_G(page->color_map[ci]);
279 b = VBI_B(page->color_map[ci]);
280 a = VBI_A(page->color_map[ci]);
281 ((uint32_t *)sub_rect->pict.data[1])[ci] = RGBA(r, g, b, a);
283 av_log(ctx, AV_LOG_DEBUG, "palette %0x\n",
284 ((uint32_t *)sub_rect->pict.data[1])[ci]);
287 ((uint32_t *)sub_rect->pict.data[1])[cmax] = RGBA(0, 0, 0, 0);
288 sub_rect->type = SUBTITLE_BITMAP;
293 handler(vbi_event *ev, void *user_data)
295 TeletextContext *ctx = user_data;
296 TeletextPage *new_pages;
305 snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
306 av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
307 pgno_str, ev->ev.ttx_page.subno & 0xFF);
309 if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))
311 if (ctx->handler_ret < 0)
314 /* Fetch the page. */
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);
373 teletext_decode_frame(AVCodecContext *avctx,
374 void *data, int *data_size,
377 TeletextContext *ctx = avctx->priv_data;
378 AVSubtitle *sub = data;
379 const uint8_t *buf = pkt->data;
380 int left = pkt->size;
381 uint8_t pesheader[45] = {0x00, 0x00, 0x01, 0xbd, 0x00, 0x00, 0x85, 0x80, 0x24, 0x21, 0x00, 0x01, 0x00, 0x01};
382 int pesheader_size = sizeof(pesheader);
383 const uint8_t *pesheader_buf = pesheader;
387 if (!(ctx->vbi = vbi_decoder_new()))
388 return AVERROR(ENOMEM);
389 if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
390 vbi_decoder_delete(ctx->vbi);
392 return AVERROR(ENOMEM);
395 if (!ctx->dx && (!(ctx->dx = vbi_dvb_pes_demux_new (/* callback */ NULL, NULL))))
396 return AVERROR(ENOMEM);
398 if (avctx->pkt_timebase.den && pkt->pts != AV_NOPTS_VALUE)
399 ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
402 // We allow unreasonably big packets, even if the standard only allows a max size of 1472
403 if ((pesheader_size + left) < 184 || (pesheader_size + left) > 65504 || (pesheader_size + left) % 184 != 0)
404 return AVERROR_INVALIDDATA;
406 memset(pesheader + 14, 0xff, pesheader_size - 14);
407 AV_WB16(pesheader + 4, left + pesheader_size - 6);
409 /* PTS is deliberately left as 0 in the PES header, otherwise libzvbi uses
410 * it to detect dropped frames. Unforunatey the guessed packet PTS values
411 * (see mpegts demuxer) are not accurate enough to pass that test. */
412 vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, NULL, &pesheader_buf, &pesheader_size);
414 ctx->handler_ret = pkt->size;
418 unsigned int lines = vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, &pts, &buf, &left);
420 av_log(avctx, AV_LOG_DEBUG,
421 "ctx=%p buf_size=%d left=%u lines=%u pts=%f pkt_pts=%f\n",
422 ctx, pkt->size, left, lines, (double)pts/90000.0, (double)pkt->pts/90000.0);
427 for(i=0; i<lines; ++i)
428 av_log(avctx, AV_LOG_DEBUG,
429 "lines=%d id=%x\n", i, ctx->sliced[i].id);
431 vbi_decode(ctx->vbi, ctx->sliced, lines, (double)pts/90000.0);
432 ctx->lines_processed += lines;
435 ctx->pts = AV_NOPTS_VALUE;
436 ret = ctx->handler_ret;
442 // is there a subtitle to pass?
445 sub->format = ctx->format_id;
446 sub->start_display_time = 0;
447 sub->end_display_time = ctx->sub_duration;
449 sub->pts = ctx->pages->pts;
451 if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
452 sub->rects = av_malloc(sizeof(*sub->rects) * 1);
455 sub->rects[0] = ctx->pages->sub_rect;
457 ret = AVERROR(ENOMEM);
460 av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
463 if (!sub->rects) // no rect was passed
464 subtitle_rect_free(&ctx->pages->sub_rect);
466 for (i = 0; i < ctx->nb_pages - 1; i++)
467 ctx->pages[i] = ctx->pages[i + 1];
478 static int teletext_init_decoder(AVCodecContext *avctx)
480 TeletextContext *ctx = avctx->priv_data;
481 unsigned int maj, min, rev;
483 vbi_version(&maj, &min, &rev);
484 if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
485 av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
486 return AVERROR_EXTERNAL;
491 ctx->pts = AV_NOPTS_VALUE;
496 ctx->ex = vbi_export_new("text", &t);
499 av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
500 return (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
503 static int teletext_close_decoder(AVCodecContext *avctx)
505 TeletextContext *ctx = avctx->priv_data;
508 av_log(avctx, AV_LOG_DEBUG, "lines_total=%u\n", ctx->lines_processed);
510 while (ctx->nb_pages)
511 subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
512 av_freep(&ctx->pages);
514 vbi_dvb_demux_delete(ctx->dx);
515 vbi_decoder_delete(ctx->vbi);
518 ctx->pts = AV_NOPTS_VALUE;
522 static void teletext_flush(AVCodecContext *avctx)
524 teletext_close_decoder(avctx);
527 #define OFFSET(x) offsetof(TeletextContext, x)
528 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
529 static const AVOption options[] = {
530 {"txt_page", "list of teletext page numbers to decode, * is all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
531 {"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
532 {"txt_format", "format of the subtitles (bitmap or text)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD, "txt_format"},
533 {"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
534 {"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
535 {"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
536 {"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
537 {"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
538 {"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = 30000}, 0, 86400000, SD},
539 {"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
543 static const AVClass teletext_class = {
544 .class_name = "libzvbi_teletextdec",
545 .item_name = av_default_item_name,
547 .version = LIBAVUTIL_VERSION_INT,
550 AVCodec ff_libzvbi_teletext_decoder = {
551 .name = "libzvbi_teletextdec",
552 .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
553 .type = AVMEDIA_TYPE_SUBTITLE,
554 .id = AV_CODEC_ID_DVB_TELETEXT,
555 .priv_data_size = sizeof(TeletextContext),
556 .init = teletext_init_decoder,
557 .close = teletext_close_decoder,
558 .decode = teletext_decode_frame,
559 .capabilities = CODEC_CAP_DELAY,
560 .flush = teletext_flush,
561 .priv_class= &teletext_class,