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 */
73 vbi_sliced sliced[MAX_SLICES];
78 static int chop_spaces_utf8(const unsigned char* t, int len)
82 if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
89 static void subtitle_rect_free(AVSubtitleRect **sub_rect)
91 av_freep(&(*sub_rect)->data[0]);
92 av_freep(&(*sub_rect)->data[1]);
93 av_freep(&(*sub_rect)->ass);
97 static char *create_ass_text(TeletextContext *ctx, const char *text)
102 av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
103 ff_ass_bprint_text_event(&buf, text, strlen(text), "", 0);
104 if (!av_bprint_is_complete(&buf)) {
105 av_bprint_finalize(&buf, NULL);
108 dialog = ff_ass_get_dialog(ctx->readorder++, 0, NULL, NULL, buf.str);
109 av_bprint_finalize(&buf, NULL);
113 /* Draw a page as text */
114 static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
118 char *vbi_text = av_malloc(TEXT_MAXSZ);
122 return AVERROR(ENOMEM);
124 sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
125 /*table mode*/ TRUE, FALSE,
127 page->columns, page->rows-chop_top);
129 av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
131 return AVERROR_EXTERNAL;
135 av_bprint_init(&buf, 0, TEXT_MAXSZ);
137 if (ctx->chop_spaces) {
141 // skip leading spaces and newlines
142 in += strspn(in, " \n");
143 // compute end of row
144 for (nl = 0; in[nl]; ++nl)
145 if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
149 // skip trailing spaces
150 sz = chop_spaces_utf8(in, nl);
151 av_bprint_append_data(&buf, in, sz);
152 av_bprintf(&buf, "\n");
156 av_bprintf(&buf, "%s\n", vbi_text);
160 if (!av_bprint_is_complete(&buf)) {
161 av_bprint_finalize(&buf, NULL);
162 return AVERROR(ENOMEM);
166 sub_rect->type = SUBTITLE_ASS;
167 sub_rect->ass = create_ass_text(ctx, buf.str);
169 if (!sub_rect->ass) {
170 av_bprint_finalize(&buf, NULL);
171 return AVERROR(ENOMEM);
173 av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
175 sub_rect->type = SUBTITLE_NONE;
177 av_bprint_finalize(&buf, NULL);
181 static void fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page,
182 int chop_top, int resx, int resy)
186 // Hack for transparency, inspired by VLC code...
187 for (iy = 0; iy < resy; iy++) {
188 uint8_t *pixel = sub_rect->data[0] + iy * sub_rect->linesize[0];
189 vbi_char *vc = page->text + (iy / BITMAP_CHAR_HEIGHT + chop_top) * page->columns;
190 vbi_char *vcnext = vc + page->columns;
191 for (; vc < vcnext; vc++) {
192 uint8_t *pixelnext = pixel + BITMAP_CHAR_WIDTH;
193 switch (vc->opacity) {
194 case VBI_TRANSPARENT_SPACE:
195 memset(pixel, VBI_TRANSPARENT_BLACK, BITMAP_CHAR_WIDTH);
198 if (!ctx->transparent_bg)
200 case VBI_SEMI_TRANSPARENT:
201 if (ctx->opacity > 0) {
202 if (ctx->opacity < 255)
203 for(; pixel < pixelnext; pixel++)
204 if (*pixel == vc->background)
205 *pixel += VBI_NB_COLORS;
208 case VBI_TRANSPARENT_FULL:
209 for(; pixel < pixelnext; pixel++)
210 if (*pixel == vc->background)
211 *pixel = VBI_TRANSPARENT_BLACK;
219 /* Draw a page as bitmap */
220 static int gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
222 int resx = page->columns * BITMAP_CHAR_WIDTH;
223 int resy = (page->rows - chop_top) * BITMAP_CHAR_HEIGHT;
225 vbi_char *vc = page->text + (chop_top * page->columns);
226 vbi_char *vcend = page->text + (page->rows * page->columns);
228 for (; vc < vcend; vc++) {
229 if (vc->opacity != VBI_TRANSPARENT_SPACE)
234 av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
235 sub_rect->type = SUBTITLE_NONE;
239 sub_rect->data[0] = av_mallocz(resx * resy);
240 sub_rect->linesize[0] = resx;
241 if (!sub_rect->data[0])
242 return AVERROR(ENOMEM);
244 vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
245 sub_rect->data[0], sub_rect->linesize[0],
246 0, chop_top, page->columns, page->rows - chop_top,
247 /*reveal*/ 1, /*flash*/ 1);
249 fix_transparency(ctx, sub_rect, page, chop_top, resx, resy);
250 sub_rect->x = ctx->x_offset;
251 sub_rect->y = ctx->y_offset + chop_top * BITMAP_CHAR_HEIGHT;
254 sub_rect->nb_colors = ctx->opacity > 0 && ctx->opacity < 255 ? 2 * VBI_NB_COLORS : VBI_NB_COLORS;
255 sub_rect->data[1] = av_mallocz(AVPALETTE_SIZE);
256 if (!sub_rect->data[1]) {
257 av_freep(&sub_rect->data[0]);
258 return AVERROR(ENOMEM);
260 for (ci = 0; ci < VBI_NB_COLORS; ci++) {
263 r = VBI_R(page->color_map[ci]);
264 g = VBI_G(page->color_map[ci]);
265 b = VBI_B(page->color_map[ci]);
266 a = VBI_A(page->color_map[ci]);
267 ((uint32_t *)sub_rect->data[1])[ci] = RGBA(r, g, b, a);
268 ((uint32_t *)sub_rect->data[1])[ci + VBI_NB_COLORS] = RGBA(r, g, b, ctx->opacity);
269 ff_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->data[1])[ci]);
271 ((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK] = RGBA(0, 0, 0, 0);
272 ((uint32_t *)sub_rect->data[1])[VBI_TRANSPARENT_BLACK + VBI_NB_COLORS] = RGBA(0, 0, 0, 0);
273 sub_rect->type = SUBTITLE_BITMAP;
277 static void handler(vbi_event *ev, void *user_data)
279 TeletextContext *ctx = user_data;
280 TeletextPage *new_pages;
289 snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
290 av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
291 pgno_str, ev->ev.ttx_page.subno & 0xFF);
293 if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))
295 if (ctx->handler_ret < 0)
298 res = vbi_fetch_vt_page(ctx->vbi, &page,
299 ev->ev.ttx_page.pgno,
300 ev->ev.ttx_page.subno,
301 VBI_WST_LEVEL_3p5, 25, TRUE);
306 vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);
307 chop_top = ctx->chop_top ||
308 ((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));
310 av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
311 page.columns, page.rows, chop_top);
313 if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
314 if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
315 TeletextPage *cur_page = new_pages + ctx->nb_pages;
316 ctx->pages = new_pages;
317 cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
318 cur_page->pts = ctx->pts;
319 cur_page->pgno = ev->ev.ttx_page.pgno;
320 cur_page->subno = ev->ev.ttx_page.subno;
321 if (cur_page->sub_rect) {
322 res = (ctx->format_id == 0) ?
323 gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top) :
324 gen_sub_text (ctx, cur_page->sub_rect, &page, chop_top);
326 av_freep(&cur_page->sub_rect);
327 ctx->handler_ret = res;
329 ctx->pages[ctx->nb_pages++] = *cur_page;
332 ctx->handler_ret = AVERROR(ENOMEM);
335 ctx->handler_ret = AVERROR(ENOMEM);
338 //TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
339 av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
340 ctx->handler_ret = AVERROR(ENOSYS);
343 vbi_unref_page(&page);
346 static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size)
349 while (size >= 2 && lines < MAX_SLICES) {
350 int data_unit_id = buf[0];
351 int data_unit_length = buf[1];
352 if (data_unit_length + 2 > size)
353 return AVERROR_INVALIDDATA;
354 if (ff_data_unit_id_is_teletext(data_unit_id)) {
355 if (data_unit_length != 0x2c)
356 return AVERROR_INVALIDDATA;
358 int line_offset = buf[2] & 0x1f;
359 int field_parity = buf[2] & 0x20;
361 ctx->sliced[lines].id = VBI_SLICED_TELETEXT_B;
362 ctx->sliced[lines].line = (line_offset > 0 ? (line_offset + (field_parity ? 0 : 313)) : 0);
363 for (i = 0; i < 42; i++)
364 ctx->sliced[lines].data[i] = vbi_rev8(buf[4 + i]);
368 size -= data_unit_length + 2;
369 buf += data_unit_length + 2;
372 av_log(ctx, AV_LOG_WARNING, "%d bytes remained after slicing data\n", size);
376 static int teletext_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *pkt)
378 TeletextContext *ctx = avctx->priv_data;
379 AVSubtitle *sub = data;
384 if (!(ctx->vbi = vbi_decoder_new()))
385 return AVERROR(ENOMEM);
386 if (!vbi_event_handler_register(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
387 vbi_decoder_delete(ctx->vbi);
389 return AVERROR(ENOMEM);
393 if (avctx->pkt_timebase.num && pkt->pts != AV_NOPTS_VALUE)
394 ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
398 const int full_pes_size = pkt->size + 45; /* PES header is 45 bytes */
400 // We allow unreasonably big packets, even if the standard only allows a max size of 1472
401 if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size % 184 != 0)
402 return AVERROR_INVALIDDATA;
404 ctx->handler_ret = pkt->size;
406 if (ff_data_identifier_is_teletext(*pkt->data)) {
407 if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
409 ff_dlog(avctx, "ctx=%p buf_size=%d lines=%u pkt_pts=%7.3f\n",
410 ctx, pkt->size, lines, (double)pkt->pts/90000.0);
412 vbi_decode(ctx->vbi, ctx->sliced, lines, 0.0);
413 ctx->lines_processed += lines;
416 ctx->pts = AV_NOPTS_VALUE;
417 ret = ctx->handler_ret;
423 // is there a subtitle to pass?
426 sub->format = ctx->format_id;
427 sub->start_display_time = 0;
428 sub->end_display_time = ctx->sub_duration;
430 sub->pts = ctx->pages->pts;
432 if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
433 sub->rects = av_malloc(sizeof(*sub->rects));
436 sub->rects[0] = ctx->pages->sub_rect;
438 FF_DISABLE_DEPRECATION_WARNINGS
439 for (j = 0; j < 4; j++) {
440 sub->rects[0]->pict.data[j] = sub->rects[0]->data[j];
441 sub->rects[0]->pict.linesize[j] = sub->rects[0]->linesize[j];
443 FF_ENABLE_DEPRECATION_WARNINGS
446 ret = AVERROR(ENOMEM);
449 av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
452 if (!sub->rects) // no rect was passed
453 subtitle_rect_free(&ctx->pages->sub_rect);
455 for (i = 0; i < ctx->nb_pages - 1; i++)
456 ctx->pages[i] = ctx->pages[i + 1];
467 static int teletext_init_decoder(AVCodecContext *avctx)
469 TeletextContext *ctx = avctx->priv_data;
470 unsigned int maj, min, rev;
472 vbi_version(&maj, &min, &rev);
473 if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
474 av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
475 return AVERROR_EXTERNAL;
478 if (ctx->format_id == 0) {
479 avctx->width = 41 * BITMAP_CHAR_WIDTH;
480 avctx->height = 25 * BITMAP_CHAR_HEIGHT;
484 ctx->pts = AV_NOPTS_VALUE;
486 if (ctx->opacity == -1)
487 ctx->opacity = ctx->transparent_bg ? 0 : 255;
489 av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
490 return (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
493 static int teletext_close_decoder(AVCodecContext *avctx)
495 TeletextContext *ctx = avctx->priv_data;
497 ff_dlog(avctx, "lines_total=%u\n", ctx->lines_processed);
498 while (ctx->nb_pages)
499 subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
500 av_freep(&ctx->pages);
502 vbi_decoder_delete(ctx->vbi);
504 ctx->pts = AV_NOPTS_VALUE;
505 if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
510 static void teletext_flush(AVCodecContext *avctx)
512 teletext_close_decoder(avctx);
515 #define OFFSET(x) offsetof(TeletextContext, x)
516 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
517 static const AVOption options[] = {
518 {"txt_page", "list of teletext page numbers to decode, * is all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
519 {"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
520 {"txt_format", "format of the subtitles (bitmap or text)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD, "txt_format"},
521 {"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
522 {"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
523 {"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
524 {"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
525 {"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
526 {"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 86400000, SD},
527 {"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
528 {"txt_opacity", "set opacity of the transparent background", OFFSET(opacity), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, SD},
532 static const AVClass teletext_class = {
533 .class_name = "libzvbi_teletextdec",
534 .item_name = av_default_item_name,
536 .version = LIBAVUTIL_VERSION_INT,
539 AVCodec ff_libzvbi_teletext_decoder = {
540 .name = "libzvbi_teletextdec",
541 .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
542 .type = AVMEDIA_TYPE_SUBTITLE,
543 .id = AV_CODEC_ID_DVB_TELETEXT,
544 .priv_data_size = sizeof(TeletextContext),
545 .init = teletext_init_decoder,
546 .close = teletext_close_decoder,
547 .decode = teletext_decode_frame,
548 .capabilities = AV_CODEC_CAP_DELAY,
549 .flush = teletext_flush,
550 .priv_class= &teletext_class,
551 .wrapper_name = "libzvbi",