ffmpeg/libavcodec/libzvbi-teletextdec.c

   1 /*
   2  * Teletext decoding for ffmpeg
   3  * Copyright (c) 2005-2010, 2012 Wolfram Gloger
   4  * Copyright (c) 2013 Marton Balint
   5  *
   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.
  10  *
  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.
  15  *
  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
  19  */
  20
  21 #include "avcodec.h"
  22 #include "libavcodec/ass.h"
  23 #include "libavutil/opt.h"
  24 #include "libavutil/bprint.h"
  25 #include "libavutil/intreadwrite.h"
  26 #include "libavutil/log.h"
  27
  28 #include <libzvbi.h>
  29
  30 #define TEXT_MAXSZ    (25 * (56 + 1) * 4 + 2)
  31 #define VBI_NB_COLORS 40
  32 #define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
  33 #define VBI_R(rgba)   (((rgba) >> 0) & 0xFF)
  34 #define VBI_G(rgba)   (((rgba) >> 8) & 0xFF)
  35 #define VBI_B(rgba)   (((rgba) >> 16) & 0xFF)
  36 #define VBI_A(rgba)   (((rgba) >> 24) & 0xFF)
  37 #define MAX_BUFFERED_PAGES 25
  38 #define BITMAP_CHAR_WIDTH  12
  39 #define BITMAP_CHAR_HEIGHT 10
  40 #define MAX_SLICES 64
  41
  42 typedef struct TeletextPage
  43 {
  44     AVSubtitleRect *sub_rect;
  45     int pgno;
  46     int subno;
  47     int64_t pts;
  48 } TeletextPage;
  49
  50 typedef struct TeletextContext
  51 {
  52     AVClass        *class;
  53     char           *pgno;
  54     int             x_offset;
  55     int             y_offset;
  56     int             format_id; /* 0 = bitmap, 1 = text/ass */
  57     int             chop_top;
  58     int             sub_duration; /* in msec */
  59     int             transparent_bg;
  60     int             chop_spaces;
  61
  62     int             lines_processed;
  63     TeletextPage    *pages;
  64     int             nb_pages;
  65     int64_t         pts;
  66     int             handler_ret;
  67
  68     vbi_decoder *   vbi;
  69 #ifdef DEBUG
  70     vbi_export *    ex;
  71 #endif
  72     vbi_sliced      sliced[MAX_SLICES];
  73 } TeletextContext;
  74
  75 static int chop_spaces_utf8(const unsigned char* t, int len)
  76 {
  77     t += len;
  78     while (len > 0) {
  79         if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))
  80             break;
  81         --len;
  82     }
  83     return len;
  84 }
  85
  86 static void subtitle_rect_free(AVSubtitleRect **sub_rect)
  87 {
  88     av_freep(&(*sub_rect)->pict.data[0]);
  89     av_freep(&(*sub_rect)->pict.data[1]);
  90     av_freep(&(*sub_rect)->ass);
  91     av_freep(sub_rect);
  92 }
  93
  94 static int create_ass_text(TeletextContext *ctx, const char *text, char **ass)
  95 {
  96     int ret;
  97     AVBPrint buf, buf2;
  98     const int ts_start    = av_rescale_q(ctx->pts,          AV_TIME_BASE_Q,        (AVRational){1, 100});
  99     const int ts_duration = av_rescale_q(ctx->sub_duration, (AVRational){1, 1000}, (AVRational){1, 100});
 100
 101     /* First we escape the plain text into buf. */
 102     av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
 103     ff_ass_bprint_text_event(&buf, text, strlen(text), "", 0);
 104     av_bprintf(&buf, "\r\n");
 105
 106     if (!av_bprint_is_complete(&buf)) {
 107         av_bprint_finalize(&buf, NULL);
 108         return AVERROR(ENOMEM);
 109     }
 110
 111     /* Then we create the ass dialog line in buf2 from the escaped text in buf. */
 112     av_bprint_init(&buf2, 0, AV_BPRINT_SIZE_UNLIMITED);
 113     ff_ass_bprint_dialog(&buf2, buf.str, ts_start, ts_duration, 0);
 114     av_bprint_finalize(&buf, NULL);
 115
 116     if (!av_bprint_is_complete(&buf2)) {
 117         av_bprint_finalize(&buf2, NULL);
 118         return AVERROR(ENOMEM);
 119     }
 120
 121     if ((ret = av_bprint_finalize(&buf2, ass)) < 0)
 122         return ret;
 123
 124     return 0;
 125 }
 126
 127 /* Draw a page as text */
 128 static int gen_sub_text(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
 129 {
 130     const char *in;
 131     AVBPrint buf;
 132     char *vbi_text = av_malloc(TEXT_MAXSZ);
 133     int sz;
 134
 135     if (!vbi_text)
 136         return AVERROR(ENOMEM);
 137
 138     sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",
 139                                    /*table mode*/ TRUE, FALSE,
 140                                    0,             chop_top,
 141                                    page->columns, page->rows-chop_top);
 142     if (sz <= 0) {
 143         av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");
 144         av_free(vbi_text);
 145         return AVERROR_EXTERNAL;
 146     }
 147     vbi_text[sz] = '\0';
 148     in  = vbi_text;
 149     av_bprint_init(&buf, 0, TEXT_MAXSZ);
 150
 151     if (ctx->chop_spaces) {
 152         for (;;) {
 153             int nl, sz;
 154
 155             // skip leading spaces and newlines
 156             in += strspn(in, " \n");
 157             // compute end of row
 158             for (nl = 0; in[nl]; ++nl)
 159                 if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))
 160                     break;
 161             if (!in[nl])
 162                 break;
 163             // skip trailing spaces
 164             sz = chop_spaces_utf8(in, nl);
 165             av_bprint_append_data(&buf, in, sz);
 166             av_bprintf(&buf, "\n");
 167             in += nl;
 168         }
 169     } else {
 170         av_bprintf(&buf, "%s\n", vbi_text);
 171     }
 172     av_free(vbi_text);
 173
 174     if (!av_bprint_is_complete(&buf)) {
 175         av_bprint_finalize(&buf, NULL);
 176         return AVERROR(ENOMEM);
 177     }
 178
 179     if (buf.len) {
 180         int ret;
 181         sub_rect->type = SUBTITLE_ASS;
 182         if ((ret = create_ass_text(ctx, buf.str, &sub_rect->ass)) < 0) {
 183             av_bprint_finalize(&buf, NULL);
 184             return ret;
 185         }
 186         av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", sub_rect->ass);
 187     } else {
 188         sub_rect->type = SUBTITLE_NONE;
 189     }
 190     av_bprint_finalize(&buf, NULL);
 191     return 0;
 192 }
 193
 194 static void fix_transparency(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page,
 195                              int chop_top, uint8_t transparent_color, int resx, int resy)
 196 {
 197     int iy;
 198
 199     // Hack for transparency, inspired by VLC code...
 200     for (iy = 0; iy < resy; iy++) {
 201         uint8_t *pixel = sub_rect->pict.data[0] + iy * sub_rect->pict.linesize[0];
 202         vbi_char *vc = page->text + (iy / BITMAP_CHAR_HEIGHT + chop_top) * page->columns;
 203         vbi_char *vcnext = vc + page->columns;
 204         for (; vc < vcnext; vc++) {
 205             uint8_t *pixelnext = pixel + BITMAP_CHAR_WIDTH;
 206             switch (vc->opacity) {
 207                 case VBI_TRANSPARENT_SPACE:
 208                     memset(pixel, transparent_color, BITMAP_CHAR_WIDTH);
 209                     break;
 210                 case VBI_OPAQUE:
 211                 case VBI_SEMI_TRANSPARENT:
 212                     if (!ctx->transparent_bg)
 213                         break;
 214                 case VBI_TRANSPARENT_FULL:
 215                     for(; pixel < pixelnext; pixel++)
 216                         if (*pixel == vc->background)
 217                             *pixel = transparent_color;
 218                     break;
 219             }
 220             pixel = pixelnext;
 221         }
 222     }
 223 }
 224
 225 /* Draw a page as bitmap */
 226 static int gen_sub_bitmap(TeletextContext *ctx, AVSubtitleRect *sub_rect, vbi_page *page, int chop_top)
 227 {
 228     int resx = page->columns * BITMAP_CHAR_WIDTH;
 229     int resy = (page->rows - chop_top) * BITMAP_CHAR_HEIGHT;
 230     uint8_t ci, cmax = 0;
 231     int ret;
 232     vbi_char *vc = page->text + (chop_top * page->columns);
 233     vbi_char *vcend = page->text + (page->rows * page->columns);
 234
 235     for (; vc < vcend; vc++) {
 236         if (vc->opacity != VBI_TRANSPARENT_SPACE) {
 237             cmax = VBI_NB_COLORS;
 238             break;
 239         }
 240     }
 241
 242     if (cmax == 0) {
 243         av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);
 244         sub_rect->type = SUBTITLE_NONE;
 245         return 0;
 246     }
 247
 248     if ((ret = avpicture_alloc(&sub_rect->pict, AV_PIX_FMT_PAL8, resx, resy)) < 0)
 249         return ret;
 250     // Yes, we want to allocate the palette on our own because AVSubtitle works this way
 251     sub_rect->pict.data[1] = NULL;
 252
 253     vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,
 254                             sub_rect->pict.data[0], sub_rect->pict.linesize[0],
 255                             0, chop_top, page->columns, page->rows - chop_top,
 256                             /*reveal*/ 1, /*flash*/ 1);
 257
 258     fix_transparency(ctx, sub_rect, page, chop_top, cmax, resx, resy);
 259     sub_rect->x = ctx->x_offset;
 260     sub_rect->y = ctx->y_offset + chop_top * BITMAP_CHAR_HEIGHT;
 261     sub_rect->w = resx;
 262     sub_rect->h = resy;
 263     sub_rect->nb_colors = (int)cmax + 1;
 264     sub_rect->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
 265     if (!sub_rect->pict.data[1]) {
 266         av_freep(&sub_rect->pict.data[0]);
 267         return AVERROR(ENOMEM);
 268     }
 269     for (ci = 0; ci < cmax; ci++) {
 270         int r, g, b, a;
 271
 272         r = VBI_R(page->color_map[ci]);
 273         g = VBI_G(page->color_map[ci]);
 274         b = VBI_B(page->color_map[ci]);
 275         a = VBI_A(page->color_map[ci]);
 276         ((uint32_t *)sub_rect->pict.data[1])[ci] = RGBA(r, g, b, a);
 277         av_dlog(ctx, "palette %0x\n", ((uint32_t *)sub_rect->pict.data[1])[ci]);
 278     }
 279     ((uint32_t *)sub_rect->pict.data[1])[cmax] = RGBA(0, 0, 0, 0);
 280     sub_rect->type = SUBTITLE_BITMAP;
 281     return 0;
 282 }
 283
 284 static void handler(vbi_event *ev, void *user_data)
 285 {
 286     TeletextContext *ctx = user_data;
 287     TeletextPage *new_pages;
 288     vbi_page page;
 289     int res;
 290     char pgno_str[12];
 291     vbi_subno subno;
 292     vbi_page_type vpt;
 293     int chop_top;
 294     char *lang;
 295
 296     snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);
 297     av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",
 298            pgno_str, ev->ev.ttx_page.subno & 0xFF);
 299
 300     if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))
 301         return;
 302     if (ctx->handler_ret < 0)
 303         return;
 304
 305     res = vbi_fetch_vt_page(ctx->vbi, &page,
 306                             ev->ev.ttx_page.pgno,
 307                             ev->ev.ttx_page.subno,
 308                             VBI_WST_LEVEL_3p5, 25, TRUE);
 309
 310     if (!res)
 311         return;
 312
 313 #ifdef DEBUG
 314     fprintf(stderr, "\nSaving res=%d dy0=%d dy1=%d...\n",
 315             res, page.dirty.y0, page.dirty.y1);
 316     fflush(stderr);
 317
 318     if (!vbi_export_stdio(ctx->ex, stderr, &page))
 319         fprintf(stderr, "failed: %s\n", vbi_export_errstr(ctx->ex));
 320 #endif
 321
 322     vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);
 323     chop_top = ctx->chop_top ||
 324         ((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));
 325
 326     av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",
 327            page.columns, page.rows, chop_top);
 328
 329     if (ctx->nb_pages < MAX_BUFFERED_PAGES) {
 330         if ((new_pages = av_realloc_array(ctx->pages, ctx->nb_pages + 1, sizeof(TeletextPage)))) {
 331             TeletextPage *cur_page = new_pages + ctx->nb_pages;
 332             ctx->pages = new_pages;
 333             cur_page->sub_rect = av_mallocz(sizeof(*cur_page->sub_rect));
 334             cur_page->pts = ctx->pts;
 335             cur_page->pgno = ev->ev.ttx_page.pgno;
 336             cur_page->subno = ev->ev.ttx_page.subno;
 337             if (cur_page->sub_rect) {
 338                 res = (ctx->format_id == 0) ?
 339                     gen_sub_bitmap(ctx, cur_page->sub_rect, &page, chop_top) :
 340                     gen_sub_text  (ctx, cur_page->sub_rect, &page, chop_top);
 341                 if (res < 0) {
 342                     av_freep(&cur_page->sub_rect);
 343                     ctx->handler_ret = res;
 344                 } else {
 345                     ctx->pages[ctx->nb_pages++] = *cur_page;
 346                 }
 347             } else {
 348                 ctx->handler_ret = AVERROR(ENOMEM);
 349             }
 350         } else {
 351             ctx->handler_ret = AVERROR(ENOMEM);
 352         }
 353     } else {
 354         //TODO: If multiple packets contain more than one page, pages may got queued up, and this may happen...
 355         av_log(ctx, AV_LOG_ERROR, "Buffered too many pages, dropping page %s.\n", pgno_str);
 356         ctx->handler_ret = AVERROR(ENOSYS);
 357     }
 358
 359     vbi_unref_page(&page);
 360 }
 361
 362 static inline int data_identifier_is_teletext(int data_identifier) {
 363     /* See EN 301 775 section 4.4.2. */
 364     return (data_identifier >= 0x10 && data_identifier <= 0x1F ||
 365             data_identifier >= 0x99 && data_identifier <= 0x9B);
 366 }
 367
 368 static int slice_to_vbi_lines(TeletextContext *ctx, uint8_t* buf, int size)
 369 {
 370     int lines = 0;
 371     while (size >= 2 && lines < MAX_SLICES) {
 372         int data_unit_id     = buf[0];
 373         int data_unit_length = buf[1];
 374         if (data_unit_length + 2 > size)
 375             return AVERROR_INVALIDDATA;
 376         if (data_unit_id == 0x02 || data_unit_id == 0x03) {
 377             if (data_unit_length != 0x2c)
 378                 return AVERROR_INVALIDDATA;
 379             else {
 380                 int line_offset  = buf[2] & 0x1f;
 381                 int field_parity = buf[2] & 0x20;
 382                 int i;
 383                 ctx->sliced[lines].id = VBI_SLICED_TELETEXT_B;
 384                 ctx->sliced[lines].line = (line_offset > 0 ? (line_offset + (field_parity ? 0 : 313)) : 0);
 385                 for (i = 0; i < 42; i++)
 386                     ctx->sliced[lines].data[i] = vbi_rev8(buf[4 + i]);
 387                 lines++;
 388             }
 389         }
 390         size -= data_unit_length + 2;
 391         buf += data_unit_length + 2;
 392     }
 393     if (size)
 394         av_log(ctx, AV_LOG_WARNING, "%d bytes remained after slicing data\n", size);
 395     return lines;
 396 }
 397
 398 static int teletext_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *pkt)
 399 {
 400     TeletextContext *ctx = avctx->priv_data;
 401     AVSubtitle      *sub = data;
 402     int             ret = 0;
 403
 404     if (!ctx->vbi) {
 405         if (!(ctx->vbi = vbi_decoder_new()))
 406             return AVERROR(ENOMEM);
 407         if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {
 408             vbi_decoder_delete(ctx->vbi);
 409             ctx->vbi = NULL;
 410             return AVERROR(ENOMEM);
 411         }
 412     }
 413
 414     if (avctx->pkt_timebase.den && pkt->pts != AV_NOPTS_VALUE)
 415         ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, AV_TIME_BASE_Q);
 416
 417     if (pkt->size) {
 418         int lines;
 419         const int full_pes_size = pkt->size + 45; /* PES header is 45 bytes */
 420
 421         // We allow unreasonably big packets, even if the standard only allows a max size of 1472
 422         if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size % 184 != 0)
 423             return AVERROR_INVALIDDATA;
 424
 425         ctx->handler_ret = pkt->size;
 426
 427         if (data_identifier_is_teletext(*pkt->data)) {
 428             if ((lines = slice_to_vbi_lines(ctx, pkt->data + 1, pkt->size - 1)) < 0)
 429                 return lines;
 430             av_dlog(avctx, "ctx=%p buf_size=%d lines=%u pkt_pts=%7.3f\n",
 431                     ctx, pkt->size, lines, (double)pkt->pts/90000.0);
 432             if (lines > 0) {
 433 #ifdef DEBUG
 434                 int i;
 435                 av_log(avctx, AV_LOG_DEBUG, "line numbers:");
 436                 for(i = 0; i < lines; i++)
 437                     av_log(avctx, AV_LOG_DEBUG, " %d", ctx->sliced[i].line);
 438                 av_log(avctx, AV_LOG_DEBUG, "\n");
 439 #endif
 440                 vbi_decode(ctx->vbi, ctx->sliced, lines, 0.0);
 441                 ctx->lines_processed += lines;
 442             }
 443         }
 444         ctx->pts = AV_NOPTS_VALUE;
 445         ret = ctx->handler_ret;
 446     }
 447
 448     if (ret < 0)
 449         return ret;
 450
 451     // is there a subtitle to pass?
 452     if (ctx->nb_pages) {
 453         int i;
 454         sub->format = ctx->format_id;
 455         sub->start_display_time = 0;
 456         sub->end_display_time = ctx->sub_duration;
 457         sub->num_rects = 0;
 458         sub->pts = ctx->pages->pts;
 459
 460         if (ctx->pages->sub_rect->type != SUBTITLE_NONE) {
 461             sub->rects = av_malloc(sizeof(*sub->rects));
 462             if (sub->rects) {
 463                 sub->num_rects = 1;
 464                 sub->rects[0] = ctx->pages->sub_rect;
 465             } else {
 466                 ret = AVERROR(ENOMEM);
 467             }
 468         } else {
 469             av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");
 470             sub->rects = NULL;
 471         }
 472         if (!sub->rects) // no rect was passed
 473             subtitle_rect_free(&ctx->pages->sub_rect);
 474
 475         for (i = 0; i < ctx->nb_pages - 1; i++)
 476             ctx->pages[i] = ctx->pages[i + 1];
 477         ctx->nb_pages--;
 478
 479         if (ret >= 0)
 480             *data_size = 1;
 481     } else
 482         *data_size = 0;
 483
 484     return ret;
 485 }
 486
 487 static int teletext_init_decoder(AVCodecContext *avctx)
 488 {
 489     TeletextContext *ctx = avctx->priv_data;
 490     unsigned int maj, min, rev;
 491
 492     vbi_version(&maj, &min, &rev);
 493     if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {
 494         av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");
 495         return AVERROR_EXTERNAL;
 496     }
 497
 498     if (ctx->format_id == 0) {
 499         avctx->width  = 41 * BITMAP_CHAR_WIDTH;
 500         avctx->height = 25 * BITMAP_CHAR_HEIGHT;
 501     }
 502
 503     ctx->vbi = NULL;
 504     ctx->pts = AV_NOPTS_VALUE;
 505
 506 #ifdef DEBUG
 507     {
 508         char *t;
 509         ctx->ex = vbi_export_new("text", &t);
 510     }
 511 #endif
 512     av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);
 513     return (ctx->format_id == 1) ? ff_ass_subtitle_header_default(avctx) : 0;
 514 }
 515
 516 static int teletext_close_decoder(AVCodecContext *avctx)
 517 {
 518     TeletextContext *ctx = avctx->priv_data;
 519
 520     av_dlog(avctx, "lines_total=%u\n", ctx->lines_processed);
 521     while (ctx->nb_pages)
 522         subtitle_rect_free(&ctx->pages[--ctx->nb_pages].sub_rect);
 523     av_freep(&ctx->pages);
 524
 525     vbi_decoder_delete(ctx->vbi);
 526     ctx->vbi = NULL;
 527     ctx->pts = AV_NOPTS_VALUE;
 528     return 0;
 529 }
 530
 531 static void teletext_flush(AVCodecContext *avctx)
 532 {
 533     teletext_close_decoder(avctx);
 534 }
 535
 536 #define OFFSET(x) offsetof(TeletextContext, x)
 537 #define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
 538 static const AVOption options[] = {
 539     {"txt_page",        "list of teletext page numbers to decode, * is all", OFFSET(pgno),           AV_OPT_TYPE_STRING, {.str = "*"},      0, 0,        SD},
 540     {"txt_chop_top",    "discards the top teletext line",                    OFFSET(chop_top),       AV_OPT_TYPE_INT,    {.i64 = 1},        0, 1,        SD},
 541     {"txt_format",      "format of the subtitles (bitmap or text)",          OFFSET(format_id),      AV_OPT_TYPE_INT,    {.i64 = 0},        0, 1,        SD,  "txt_format"},
 542     {"bitmap",          NULL,                                                0,                      AV_OPT_TYPE_CONST,  {.i64 = 0},        0, 0,        SD,  "txt_format"},
 543     {"text",            NULL,                                                0,                      AV_OPT_TYPE_CONST,  {.i64 = 1},        0, 0,        SD,  "txt_format"},
 544     {"txt_left",        "x offset of generated bitmaps",                     OFFSET(x_offset),       AV_OPT_TYPE_INT,    {.i64 = 0},        0, 65535,    SD},
 545     {"txt_top",         "y offset of generated bitmaps",                     OFFSET(y_offset),       AV_OPT_TYPE_INT,    {.i64 = 0},        0, 65535,    SD},
 546     {"txt_chop_spaces", "chops leading and trailing spaces from text",       OFFSET(chop_spaces),    AV_OPT_TYPE_INT,    {.i64 = 1},        0, 1,        SD},
 547     {"txt_duration",    "display duration of teletext pages in msecs",       OFFSET(sub_duration),   AV_OPT_TYPE_INT,    {.i64 = 30000},    0, 86400000, SD},
 548     {"txt_transparent", "force transparent background of the teletext",      OFFSET(transparent_bg), AV_OPT_TYPE_INT,    {.i64 = 0},        0, 1,        SD},
 549     { NULL },
 550 };
 551
 552 static const AVClass teletext_class = {
 553     .class_name = "libzvbi_teletextdec",
 554     .item_name  = av_default_item_name,
 555     .option     = options,
 556     .version    = LIBAVUTIL_VERSION_INT,
 557 };
 558
 559 AVCodec ff_libzvbi_teletext_decoder = {
 560     .name      = "libzvbi_teletextdec",
 561     .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),
 562     .type      = AVMEDIA_TYPE_SUBTITLE,
 563     .id        = AV_CODEC_ID_DVB_TELETEXT,
 564     .priv_data_size = sizeof(TeletextContext),
 565     .init      = teletext_init_decoder,
 566     .close     = teletext_close_decoder,
 567     .decode    = teletext_decode_frame,
 568     .capabilities = CODEC_CAP_DELAY,
 569     .flush     = teletext_flush,
 570     .priv_class= &teletext_class,
 571 };