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 "libavutil/opt.h"
23 #include "libavutil/bprint.h"
24 #include "libavutil/intreadwrite.h"
28 #define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
29 #define VBI_NB_COLORS 40
30 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
31 #define VBI_R(rgba) (((rgba) >> 0) & 0xFF)
32 #define VBI_G(rgba) (((rgba) >> 8) & 0xFF)
33 #define VBI_B(rgba) (((rgba) >> 16) & 0xFF)
34 #define VBI_A(rgba) (((rgba) >> 24) & 0xFF)
35 #define MAX_BUFFERED_PAGES 25
37 typedef struct TeletextPage
39 AVSubtitleRect *sub_rect;
45 /* main data structure */
46 typedef struct TeletextContext
52 int format_id; /* 0 = bitmap, 1 = text */
54 int sub_duration; /* in msec */
68 /* Don't even _think_ about making sliced stack-local! */
69 vbi_sliced sliced[64];
72 /************************************************************************/
75 chop_spaces_utf8(const unsigned char* t, int len)
79 if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
87 subtitle_rect_free(AVSubtitleRect **sub_rect)
89 av_freep(&(*sub_rect)->pict.data[0]);
90 av_freep(&(*sub_rect)->pict.data[1]);
91 av_freep(&(*sub_rect)->text);
95 // draw a page as text
97 gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
101 char *vbi_text = av_malloc(TEXT_MAXSZ);
105 return AVERROR(ENOMEM);
107 sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
108 /*table mode*/ TRUE, FALSE,
110 page->columns, page->rows-chop_top);
112 av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
114 return AVERROR_EXTERNAL;
118 av_bprint_init(&buf, 0, TEXT_MAXSZ);
120 if (ctx->chop_spaces) {
124 // skip leading spaces and newlines
125 in += strspn(in, " \n");
126 // compute end of row
127 for (nl = 0; in[nl]; ++nl)
128 if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
132 // skip trailing spaces
133 sz = chop_spaces_utf8(in, nl);
134 av_bprint_append_data(&buf, in, sz);
135 av_bprintf(&buf, "\n");
139 av_bprintf(&buf, "%s\n", vbi_text);
143 if (!av_bprint_is_complete(&buf)) {
144 av_bprint_finalize(&buf, NULL);
145 return AVERROR(ENOMEM);
150 sub_rect->type = SUBTITLE_TEXT;
151 if ((ret = av_bprint_finalize(&buf, &sub_rect->text)) < 0)
153 av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->text);
155 sub_rect->type = SUBTITLE_NONE;
156 av_bprint_finalize(&buf, NULL);
162 fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top, uint8_t transparent_color, int resx, int resy)
166 // Hack for transparency, inspired by VLC code...
167 for (iy = 0; iy < resy; iy++) {
168 uint8_t *pixel = sub_rect->pict.data[0] + iy * sub_rect->pict.linesize[0];
169 vbi_char *vc = page->text + (iy / 10 + chop_top) * page->columns;
170 vbi_char *vcnext = vc + page->columns;
171 for (; vc < vcnext; vc++) {
172 uint8_t *pixelnext = pixel + 12;
173 switch (vc->opacity) {
174 case VBI_TRANSPARENT_SPACE:
175 memset(pixel, transparent_color, 12);
178 case VBI_SEMI_TRANSPARENT:
179 if (!ctx->transparent_bg)
181 case VBI_TRANSPARENT_FULL:
182 for(; pixel < pixelnext; pixel++)
183 if (*pixel == vc->background)
184 *pixel = transparent_color;
192 // draw a page as bitmap
194 gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
196 int resx = page->columns * 12;
197 int resy = (page->rows - chop_top) * 10;
198 uint8_t ci, cmax = 0;
200 vbi_char *vc = page->text + (chop_top * page->columns);
201 vbi_char *vcend = page->text + (page->rows * page->columns);
203 for (; vc < vcend; vc++) {
204 if (vc->opacity != VBI_TRANSPARENT_SPACE) {
205 cmax = VBI_NB_COLORS;
211 av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
212 sub_rect->type = SUBTITLE_NONE;
216 if ((ret = avpicture_alloc(&sub_rect->pict, AV_PIX_FMT_PAL8, resx, resy)) < 0)
218 // Yes, we want to allocate the palette on our own because AVSubtitle works this way
219 sub_rect->pict.data[1] = NULL;
221 vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
222 sub_rect->pict.data[0], sub_rect->pict.linesize[0],
223 0, chop_top, page->columns, page->rows - chop_top,
224 /*reveal*/ 1, /*flash*/ 1);
226 fix_transparency(ctx, sub_rect, page, chop_top, cmax, resx, resy);
227 sub_rect->x = ctx->x_offset;
228 sub_rect->y = ctx->y_offset;
231 sub_rect->nb_colors = (int)cmax + 1;
232 sub_rect->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
233 if (!sub_rect->pict.data[1]) {
234 av_freep(&sub_rect->pict.data[0]);
235 return AVERROR(ENOMEM);
237 for (ci = 0; ci < cmax; ci++) {
240 r = VBI_R(page->color_map[ci]);
241 g = VBI_G(page->color_map[ci]);
242 b = VBI_B(page->color_map[ci]);
243 a = VBI_A(page->color_map[ci]);
244 ((uint32_t *)sub_rect->pict.data[1])[ci] = RGBA(r, g, b, a);
246 av_log(ctx, AV_LOG_DEBUG, "palette %0x\n",
247 ((uint32_t *)sub_rect->pict.data[1])[ci]);
250 ((uint32_t *)sub_rect->pict.data[1])[cmax] = RGBA(0, 0, 0, 0);
251 sub_rect->type = SUBTITLE_BITMAP;
256 handler(vbi_event *ev, void *user_data)
258 TeletextContext *ctx = user_data;
259 TeletextPage *new_pages;
268 snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
269 av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
270 pgno_str, ev->ev.ttx_page.subno & 0xFF);
272 if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))
275 /* Fetch the page. */
276 res = vbi_fetch_vt_page(ctx->vbi, &page,
277 ev->ev.ttx_page.pgno,
278 ev->ev.ttx_page.subno,
279 VBI_WST_LEVEL_3p5, 25, TRUE);
285 fprintf(stderr, "\nSaving res=%d dy0=%d dy1=%d...\n",
286 res, page.dirty.y0, page.dirty.y1);
289 if (!vbi_export_stdio(ctx->ex, stderr, &page))
290 fprintf(stderr, "failed: %s\n", vbi_export_errstr(ctx->ex));
293 vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);
294 chop_top = ctx->chop_top ||
295 ((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));
297 av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
298 page.columns, page.rows, chop_top);
300 if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
301 if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
302 TeletextPage *cur_page = new_pages + ctx->nb_pages;
303 ctx->pages = new_pages;
304 cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
305 cur_page->pts = ctx->pts;
306 cur_page->pgno = ev->ev.ttx_page.pgno;
307 cur_page->subno = ev->ev.ttx_page.subno;
308 if (cur_page->sub_rect) {
309 res = (ctx->format_id == 0) ?
310 gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top) :
311 gen_sub_text (ctx, cur_page->sub_rect, &page, chop_top);
313 av_freep(&cur_page->sub_rect);
315 ctx->pages[ctx->nb_pages++] = *cur_page;
318 av_log(ctx, AV_LOG_ERROR, "Failed to allocate memory to to buffer pages\n");
321 //TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
322 av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
325 vbi_unref_page(&page);
329 teletext_decode_frame(AVCodecContext *avctx,
330 void *data, int *data_size,
333 TeletextContext *ctx = avctx->priv_data;
334 AVSubtitle *sub = data;
335 const uint8_t *buf = pkt->data;
336 int left = pkt->size;
337 uint8_t pesheader[45] = {0x00, 0x00, 0x01, 0xbd, 0x00, 0x00, 0x85, 0x80, 0x24, 0x21, 0x00, 0x01, 0x00, 0x01};
338 int pesheader_size = sizeof(pesheader);
339 const uint8_t *pesheader_buf = pesheader;
343 if (!(ctx->vbi = vbi_decoder_new()))
344 return AVERROR(ENOMEM);
345 if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
346 vbi_decoder_delete(ctx->vbi);
348 return AVERROR(ENOMEM);
351 if (!ctx->dx && (!(ctx->dx = vbi_dvb_pes_demux_new (/* callback */ NULL, NULL))))
352 return AVERROR(ENOMEM);
354 if (avctx->pkt_timebase.den && pkt->pts != AV_NOPTS_VALUE)
355 ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
358 // We allow unreasonably big packets, even if the standard only allows a max size of 1472
359 if ((pesheader_size + left) < 184 || (pesheader_size + left) > 65504 || (pesheader_size + left) % 184 != 0)
360 return AVERROR_INVALIDDATA;
362 memset(pesheader + 14, 0xff, pesheader_size - 14);
363 AV_WB16(pesheader + 4, left + pesheader_size - 6);
365 /* PTS is deliberately left as 0 in the PES header, otherwise libzvbi uses
366 * it to detect dropped frames. Unforunatey the guessed packet PTS values
367 * (see mpegts demuxer) are not accurate enough to pass that test. */
368 vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, NULL, &pesheader_buf, &pesheader_size);
372 unsigned int lines = vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, &pts, &buf, &left);
374 av_log(avctx, AV_LOG_DEBUG,
375 "ctx=%p buf_size=%d left=%u lines=%u pts=%f pkt_pts=%f\n",
376 ctx, pkt->size, left, lines, (double)pts/90000.0, (double)pkt->pts/90000.0);
381 for(i=0; i<lines; ++i)
382 av_log(avctx, AV_LOG_DEBUG,
383 "lines=%d id=%x\n", i, ctx->sliced[i].id);
385 vbi_decode(ctx->vbi, ctx->sliced, lines, (double)pts/90000.0);
386 ctx->lines_processed += lines;
389 ctx->pts = AV_NOPTS_VALUE;
393 // is there a subtitle to pass?
396 sub->format = (ctx->pages->sub_rect->type == SUBTITLE_TEXT ? 1: 0);
397 sub->start_display_time = 0;
398 sub->end_display_time = ctx->sub_duration;
400 sub->pts = ctx->pages->pts;
402 if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
403 sub->rects = av_malloc(sizeof(*sub->rects) * 1);
406 sub->rects[0] = ctx->pages->sub_rect;
409 av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
412 if (!sub->rects) // no rect was passed
413 subtitle_rect_free(&ctx->pages->sub_rect);
415 for (i = 0; i < ctx->nb_pages - 1; i++)
416 ctx->pages[i] = ctx->pages[i + 1];
426 static int teletext_init_decoder(AVCodecContext *avctx)
428 TeletextContext *ctx = avctx->priv_data;
429 unsigned int maj, min, rev;
431 vbi_version(&maj, &min, &rev);
432 if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
433 av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
434 return AVERROR_EXTERNAL;
439 ctx->pts = AV_NOPTS_VALUE;
444 ctx->ex = vbi_export_new("text", &t);
447 av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
451 static int teletext_close_decoder(AVCodecContext *avctx)
453 TeletextContext *ctx = avctx->priv_data;
456 av_log(avctx, AV_LOG_DEBUG, "lines_total=%u\n", ctx->lines_processed);
458 while (ctx->nb_pages)
459 subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
460 av_freep(&ctx->pages);
462 vbi_dvb_demux_delete(ctx->dx);
463 vbi_decoder_delete(ctx->vbi);
466 ctx->pts = AV_NOPTS_VALUE;
470 static void teletext_flush(AVCodecContext *avctx)
472 teletext_close_decoder(avctx);
475 #define OFFSET(x) offsetof(TeletextContext, x)
476 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
477 static const AVOption options[] = {
478 {"txt_page", "list of teletext page numbers to decode, * is all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
479 {"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
480 {"txt_format", "format of the subtitles (bitmap or text)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD, "txt_format"},
481 {"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
482 {"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
483 {"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
484 {"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
485 {"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
486 {"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = 30000}, 0, 86400000, SD},
487 {"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
491 static const AVClass teletext_class = {
492 .class_name = "libzvbi_teletextdec",
493 .item_name = av_default_item_name,
495 .version = LIBAVUTIL_VERSION_INT,
498 AVCodec ff_libzvbi_teletext_decoder = {
499 .name = "libzvbi_teletextdec",
500 .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
501 .type = AVMEDIA_TYPE_SUBTITLE,
502 .id = AV_CODEC_ID_DVB_TELETEXT,
503 .priv_data_size = sizeof(TeletextContext),
504 .init = teletext_init_decoder,
505 .close = teletext_close_decoder,
506 .decode = teletext_decode_frame,
507 .capabilities = CODEC_CAP_DELAY,
508 .flush = teletext_flush,
509 .priv_class= &teletext_class,