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