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Diffstat (limited to 'libavcodec/libzvbi-teletextdec.c')
-rw-r--r--libavcodec/libzvbi-teletextdec.c570
1 files changed, 570 insertions, 0 deletions
diff --git a/libavcodec/libzvbi-teletextdec.c b/libavcodec/libzvbi-teletextdec.c
new file mode 100644
index 0000000000..e65e3fb55f
--- /dev/null
+++ b/libavcodec/libzvbi-teletextdec.c
@@ -0,0 +1,570 @@
+/*
+ * Teletext decoding for ffmpeg
+ * Copyright (c) 2005-2010, 2012 Wolfram Gloger
+ * Copyright (c) 2013 Marton Balint
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "libavcodec/ass.h"
+#include "libavutil/opt.h"
+#include "libavutil/bprint.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+
+#include <libzvbi.h>
+
+#define TEXT_MAXSZ (25 * (56 + 1) * 4 + 2)
+#define VBI_NB_COLORS 40
+#define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
+#define VBI_R(rgba) (((rgba) >> 0) & 0xFF)
+#define VBI_G(rgba) (((rgba) >> 8) & 0xFF)
+#define VBI_B(rgba) (((rgba) >> 16) & 0xFF)
+#define VBI_A(rgba) (((rgba) >> 24) & 0xFF)
+#define MAX_BUFFERED_PAGES 25
+#define BITMAP_CHAR_WIDTH 12
+#define BITMAP_CHAR_HEIGHT 10
+#define MAX_SLICES 64
+
+typedef struct TeletextPage
+{
+ AVSubtitleRect *sub_rect;
+ int pgno;
+ int subno;
+ int64_t pts;
+} TeletextPage;
+
+typedef struct TeletextContext
+{
+ AVClass *class;
+ char *pgno;
+ int x_offset;
+ int y_offset;
+ int format_id; /* 0 = bitmap, 1 = text/ass */
+ int chop_top;
+ int sub_duration; /* in msec */
+ int transparent_bg;
+ int chop_spaces;
+
+ int lines_processed;
+ TeletextPage *pages;
+ int nb_pages;
+ int64_t pts;
+ int handler_ret;
+
+ vbi_decoder * vbi;
+#ifdef DEBUG
+ vbi_export * ex;
+#endif
+ vbi_sliced sliced[MAX_SLICES];
+} TeletextContext;
+
+static int chop_spaces_utf8(const unsigned char* t, int len)
+{
+ t += len;
+ while (len > 0) {
+ if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
+ break;
+ --len;
+ }
+ return len;
+}
+
+static void subtitle_rect_free(AVSubtitleRect **sub_rect)
+{
+ av_freep(&(*sub_rect)->pict.data[0]);
+ av_freep(&(*sub_rect)->pict.data[1]);
+ av_freep(&(*sub_rect)->ass);
+ av_freep(sub_rect);
+}
+
+static int create_ass_text(TeletextContext *ctx, const char *text, char **ass)
+{
+ int ret;
+ AVBPrint buf, buf2;
+ const int ts_start = av_rescale_q(ctx->pts, AV_TIME_BASE_Q, (AVRational){1, 100});
+ const int ts_duration = av_rescale_q(ctx->sub_duration, (AVRational){1, 1000}, (AVRational){1, 100});
+
+ /* First we escape the plain text into buf. */
+ av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
+ ff_ass_bprint_text_event(&buf, text, strlen(text), "", 0);
+
+ if (!av_bprint_is_complete(&buf)) {
+ av_bprint_finalize(&buf, NULL);
+ return AVERROR(ENOMEM);
+ }
+
+ /* Then we create the ass dialog line in buf2 from the escaped text in buf. */
+ av_bprint_init(&buf2, 0, AV_BPRINT_SIZE_UNLIMITED);
+ ff_ass_bprint_dialog(&buf2, buf.str, ts_start, ts_duration, 0);
+ av_bprint_finalize(&buf, NULL);
+
+ if (!av_bprint_is_complete(&buf2)) {
+ av_bprint_finalize(&buf2, NULL);
+ return AVERROR(ENOMEM);
+ }
+
+ if ((ret = av_bprint_finalize(&buf2, ass)) < 0)
+ return ret;
+
+ return 0;
+}
+
+/* Draw a page as text */
+static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
+{
+ const char *in;
+ AVBPrint buf;
+ char *vbi_text = av_malloc(TEXT_MAXSZ);
+ int sz;
+
+ if (!vbi_text)
+ return AVERROR(ENOMEM);
+
+ sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
+ /*table mode*/ TRUE, FALSE,
+ 0, chop_top,
+ page->columns, page->rows-chop_top);
+ if (sz <= 0) {
+ av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
+ av_free(vbi_text);
+ return AVERROR_EXTERNAL;
+ }
+ vbi_text[sz] = '\0';
+ in = vbi_text;
+ av_bprint_init(&buf, 0, TEXT_MAXSZ);
+
+ if (ctx->chop_spaces) {
+ for (;;) {
+ int nl, sz;
+
+ // skip leading spaces and newlines
+ in += strspn(in, " \n");
+ // compute end of row
+ for (nl = 0; in[nl]; ++nl)
+ if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
+ break;
+ if (!in[nl])
+ break;
+ // skip trailing spaces
+ sz = chop_spaces_utf8(in, nl);
+ av_bprint_append_data(&buf, in, sz);
+ av_bprintf(&buf, "\n");
+ in += nl;
+ }
+ } else {
+ av_bprintf(&buf, "%s\n", vbi_text);
+ }
+ av_free(vbi_text);
+
+ if (!av_bprint_is_complete(&buf)) {
+ av_bprint_finalize(&buf, NULL);
+ return AVERROR(ENOMEM);
+ }
+
+ if (buf.len) {
+ int ret;
+ sub_rect->type = SUBTITLE_ASS;
+ if ((ret = create_ass_text(ctx, buf.str, &sub_rect->ass)) < 0) {
+ av_bprint_finalize(&buf, NULL);
+ return ret;
+ }
+ av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
+ } else {
+ sub_rect->type = SUBTITLE_NONE;
+ }
+ av_bprint_finalize(&buf, NULL);
+ return 0;
+}
+
+static void fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page,
+ int chop_top, uint8_t transparent_color, int resx, int resy)
+{
+ int iy;
+
+ // Hack for transparency, inspired by VLC code...
+ for (iy = 0; iy < resy; iy++) {
+ uint8_t *pixel = sub_rect->pict.data[0] + iy * sub_rect->pict.linesize[0];
+ vbi_char *vc = page->text + (iy / BITMAP_CHAR_HEIGHT + chop_top) * page->columns;
+ vbi_char *vcnext = vc + page->columns;
+ for (; vc < vcnext; vc++) {
+ uint8_t *pixelnext = pixel + BITMAP_CHAR_WIDTH;
+ switch (vc->opacity) {
+ case VBI_TRANSPARENT_SPACE:
+ memset(pixel, transparent_color, BITMAP_CHAR_WIDTH);
+ break;
+ case VBI_OPAQUE:
+ case VBI_SEMI_TRANSPARENT:
+ if (!ctx->transparent_bg)
+ break;
+ case VBI_TRANSPARENT_FULL:
+ for(; pixel < pixelnext; pixel++)
+ if (*pixel == vc->background)
+ *pixel = transparent_color;
+ break;
+ }
+ pixel = pixelnext;
+ }
+ }
+}
+
+/* Draw a page as bitmap */
+static int gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
+{
+ int resx = page->columns * BITMAP_CHAR_WIDTH;
+ int resy = (page->rows - chop_top) * BITMAP_CHAR_HEIGHT;
+ uint8_t ci, cmax = 0;
+ int ret;
+ vbi_char *vc = page->text + (chop_top * page->columns);
+ vbi_char *vcend = page->text + (page->rows * page->columns);
+
+ for (; vc < vcend; vc++) {
+ if (vc->opacity != VBI_TRANSPARENT_SPACE) {
+ cmax = VBI_NB_COLORS;
+ break;
+ }
+ }
+
+ if (cmax == 0) {
+ av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
+ sub_rect->type = SUBTITLE_NONE;
+ return 0;
+ }
+
+ if ((ret = avpicture_alloc(&sub_rect->pict, AV_PIX_FMT_PAL8, resx, resy)) < 0)
+ return ret;
+ // Yes, we want to allocate the palette on our own because AVSubtitle works this way
+ sub_rect->pict.data[1] = NULL;
+
+ vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
+ sub_rect->pict.data[0], sub_rect->pict.linesize[0],
+ 0, chop_top, page->columns, page->rows - chop_top,
+ /*reveal*/ 1, /*flash*/ 1);
+
+ fix_transparency(ctx, sub_rect, page, chop_top, cmax, resx, resy);
+ sub_rect->x = ctx->x_offset;
+ sub_rect->y = ctx->y_offset + chop_top * BITMAP_CHAR_HEIGHT;
+ sub_rect->w = resx;
+ sub_rect->h = resy;
+ sub_rect->nb_colors = (int)cmax + 1;
+ sub_rect->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
+ if (!sub_rect->pict.data[1]) {
+ av_freep(&sub_rect->pict.data[0]);
+ return AVERROR(ENOMEM);
+ }
+ for (ci = 0; ci < cmax; ci++) {
+ int r, g, b, a;
+
+ r = VBI_R(page->color_map[ci]);
+ g = VBI_G(page->color_map[ci]);
+ b = VBI_B(page->color_map[ci]);
+ a = VBI_A(page->color_map[ci]);
+ ((uint32_t *)sub_rect->pict.data[1])[ci] = RGBA(r, g, b, a);
+ av_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->pict.data[1])[ci]);
+ }
+ ((uint32_t *)sub_rect->pict.data[1])[cmax] = RGBA(0, 0, 0, 0);
+ sub_rect->type = SUBTITLE_BITMAP;
+ return 0;
+}
+
+static void handler(vbi_event *ev, void *user_data)
+{
+ TeletextContext *ctx = user_data;
+ TeletextPage *new_pages;
+ vbi_page page;
+ int res;
+ char pgno_str[12];
+ vbi_subno subno;
+ vbi_page_type vpt;
+ int chop_top;
+ char *lang;
+
+ snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
+ av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
+ pgno_str, ev->ev.ttx_page.subno & 0xFF);
+
+ if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))
+ return;
+ if (ctx->handler_ret < 0)
+ return;
+
+ res = vbi_fetch_vt_page(ctx->vbi, &page,
+ ev->ev.ttx_page.pgno,
+ ev->ev.ttx_page.subno,
+ VBI_WST_LEVEL_3p5, 25, TRUE);
+
+ if (!res)
+ return;
+
+#ifdef DEBUG
+ fprintf(stderr, "\nSaving res=%d dy0=%d dy1=%d...\n",
+ res, page.dirty.y0, page.dirty.y1);
+ fflush(stderr);
+
+ if (!vbi_export_stdio(ctx->ex, stderr, &page))
+ fprintf(stderr, "failed: %s\n", vbi_export_errstr(ctx->ex));
+#endif
+
+ vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);
+ chop_top = ctx->chop_top ||
+ ((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));
+
+ av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
+ page.columns, page.rows, chop_top);
+
+ if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
+ if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
+ TeletextPage *cur_page = new_pages + ctx->nb_pages;
+ ctx->pages = new_pages;
+ cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
+ cur_page->pts = ctx->pts;
+ cur_page->pgno = ev->ev.ttx_page.pgno;
+ cur_page->subno = ev->ev.ttx_page.subno;
+ if (cur_page->sub_rect) {
+ res = (ctx->format_id == 0) ?
+ gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top) :
+ gen_sub_text (ctx, cur_page->sub_rect, &page, chop_top);
+ if (res < 0) {
+ av_freep(&cur_page->sub_rect);
+ ctx->handler_ret = res;
+ } else {
+ ctx->pages[ctx->nb_pages++] = *cur_page;
+ }
+ } else {
+ ctx->handler_ret = AVERROR(ENOMEM);
+ }
+ } else {
+ ctx->handler_ret = AVERROR(ENOMEM);
+ }
+ } else {
+ //TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
+ av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
+ ctx->handler_ret = AVERROR(ENOSYS);
+ }
+
+ vbi_unref_page(&page);
+}
+
+static inline int data_identifier_is_teletext(int data_identifier) {
+ /* See EN 301 775 section 4.4.2. */
+ return (data_identifier >= 0x10 && data_identifier <= 0x1F ||
+ data_identifier >= 0x99 && data_identifier <= 0x9B);
+}
+
+static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size)
+{
+ int lines = 0;
+ while (size >= 2 && lines < MAX_SLICES) {
+ int data_unit_id = buf[0];
+ int data_unit_length = buf[1];
+ if (data_unit_length + 2 > size)
+ return AVERROR_INVALIDDATA;
+ if (data_unit_id == 0x02 || data_unit_id == 0x03) {
+ if (data_unit_length != 0x2c)
+ return AVERROR_INVALIDDATA;
+ else {
+ int line_offset = buf[2] & 0x1f;
+ int field_parity = buf[2] & 0x20;
+ int i;
+ ctx->sliced[lines].id = VBI_SLICED_TELETEXT_B;
+ ctx->sliced[lines].line = (line_offset > 0 ? (line_offset + (field_parity ? 0 : 313)) : 0);
+ for (i = 0; i < 42; i++)
+ ctx->sliced[lines].data[i] = vbi_rev8(buf[4 + i]);
+ lines++;
+ }
+ }
+ size -= data_unit_length + 2;
+ buf += data_unit_length + 2;
+ }
+ if (size)
+ av_log(ctx, AV_LOG_WARNING, "%d bytes remained after slicing data\n", size);
+ return lines;
+}
+
+static int teletext_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *pkt)
+{
+ TeletextContext *ctx = avctx->priv_data;
+ AVSubtitle *sub = data;
+ int ret = 0;
+
+ if (!ctx->vbi) {
+ if (!(ctx->vbi = vbi_decoder_new()))
+ return AVERROR(ENOMEM);
+ if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
+ vbi_decoder_delete(ctx->vbi);
+ ctx->vbi = NULL;
+ return AVERROR(ENOMEM);
+ }
+ }
+
+ if (avctx->pkt_timebase.den && pkt->pts != AV_NOPTS_VALUE)
+ ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
+
+ if (pkt->size) {
+ int lines;
+ const int full_pes_size = pkt->size + 45; /* PES header is 45 bytes */
+
+ // We allow unreasonably big packets, even if the standard only allows a max size of 1472
+ if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size % 184 != 0)
+ return AVERROR_INVALIDDATA;
+
+ ctx->handler_ret = pkt->size;
+
+ if (data_identifier_is_teletext(*pkt->data)) {
+ if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
+ return lines;
+ av_dlog(avctx, "ctx=%p buf_size=%d lines=%u pkt_pts=%7.3f\n",
+ ctx, pkt->size, lines, (double)pkt->pts/90000.0);
+ if (lines > 0) {
+#ifdef DEBUG
+ int i;
+ av_log(avctx, AV_LOG_DEBUG, "line numbers:");
+ for(i = 0; i < lines; i++)
+ av_log(avctx, AV_LOG_DEBUG, " %d", ctx->sliced[i].line);
+ av_log(avctx, AV_LOG_DEBUG, "\n");
+#endif
+ vbi_decode(ctx->vbi, ctx->sliced, lines, 0.0);
+ ctx->lines_processed += lines;
+ }
+ }
+ ctx->pts = AV_NOPTS_VALUE;
+ ret = ctx->handler_ret;
+ }
+
+ if (ret < 0)
+ return ret;
+
+ // is there a subtitle to pass?
+ if (ctx->nb_pages) {
+ int i;
+ sub->format = ctx->format_id;
+ sub->start_display_time = 0;
+ sub->end_display_time = ctx->sub_duration;
+ sub->num_rects = 0;
+ sub->pts = ctx->pages->pts;
+
+ if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
+ sub->rects = av_malloc(sizeof(*sub->rects));
+ if (sub->rects) {
+ sub->num_rects = 1;
+ sub->rects[0] = ctx->pages->sub_rect;
+ } else {
+ ret = AVERROR(ENOMEM);
+ }
+ } else {
+ av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
+ sub->rects = NULL;
+ }
+ if (!sub->rects) // no rect was passed
+ subtitle_rect_free(&ctx->pages->sub_rect);
+
+ for (i = 0; i < ctx->nb_pages - 1; i++)
+ ctx->pages[i] = ctx->pages[i + 1];
+ ctx->nb_pages--;
+
+ if (ret >= 0)
+ *data_size = 1;
+ } else
+ *data_size = 0;
+
+ return ret;
+}
+
+static int teletext_init_decoder(AVCodecContext *avctx)
+{
+ TeletextContext *ctx = avctx->priv_data;
+ unsigned int maj, min, rev;
+
+ vbi_version(&maj, &min, &rev);
+ if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
+ av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
+ return AVERROR_EXTERNAL;
+ }
+
+ if (ctx->format_id == 0) {
+ avctx->width = 41 * BITMAP_CHAR_WIDTH;
+ avctx->height = 25 * BITMAP_CHAR_HEIGHT;
+ }
+
+ ctx->vbi = NULL;
+ ctx->pts = AV_NOPTS_VALUE;
+
+#ifdef DEBUG
+ {
+ char *t;
+ ctx->ex = vbi_export_new("text", &t);
+ }
+#endif
+ av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
+ return (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
+}
+
+static int teletext_close_decoder(AVCodecContext *avctx)
+{
+ TeletextContext *ctx = avctx->priv_data;
+
+ av_dlog(avctx, "lines_total=%u\n", ctx->lines_processed);
+ while (ctx->nb_pages)
+ subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
+ av_freep(&ctx->pages);
+
+ vbi_decoder_delete(ctx->vbi);
+ ctx->vbi = NULL;
+ ctx->pts = AV_NOPTS_VALUE;
+ return 0;
+}
+
+static void teletext_flush(AVCodecContext *avctx)
+{
+ teletext_close_decoder(avctx);
+}
+
+#define OFFSET(x) offsetof(TeletextContext, x)
+#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
+static const AVOption options[] = {
+ {"txt_page", "list of teletext page numbers to decode, * is all", OFFSET(pgno), AV_OPT_TYPE_STRING, {.str = "*"}, 0, 0, SD},
+ {"txt_chop_top", "discards the top teletext line", OFFSET(chop_top), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
+ {"txt_format", "format of the subtitles (bitmap or text)", OFFSET(format_id), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD, "txt_format"},
+ {"bitmap", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 0, SD, "txt_format"},
+ {"text", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 0, SD, "txt_format"},
+ {"txt_left", "x offset of generated bitmaps", OFFSET(x_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
+ {"txt_top", "y offset of generated bitmaps", OFFSET(y_offset), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 65535, SD},
+ {"txt_chop_spaces", "chops leading and trailing spaces from text", OFFSET(chop_spaces), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, SD},
+ {"txt_duration", "display duration of teletext pages in msecs", OFFSET(sub_duration), AV_OPT_TYPE_INT, {.i64 = 30000}, 0, 86400000, SD},
+ {"txt_transparent", "force transparent background of the teletext", OFFSET(transparent_bg), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
+ { NULL },
+};
+
+static const AVClass teletext_class = {
+ .class_name = "libzvbi_teletextdec",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_libzvbi_teletext_decoder = {
+ .name = "libzvbi_teletextdec",
+ .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ .id = AV_CODEC_ID_DVB_TELETEXT,
+ .priv_data_size = sizeof(TeletextContext),
+ .init = teletext_init_decoder,
+ .close = teletext_close_decoder,
+ .decode = teletext_decode_frame,
+ .capabilities = CODEC_CAP_DELAY,
+ .flush = teletext_flush,
+ .priv_class= &teletext_class,
+};