FFmpeg: libavcodec/libzvbi-teletextdec.c Source File

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libzvbi-teletextdec.c

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1 /*

2 * Teletext decoding for ffmpeg

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 */

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"

28 #include <libzvbi.h>

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

42 typedef struct TeletextPage

43 {

44 AVSubtitleRect *sub_rect;

45 int pgno;

46 int subno;

47 int64_t pts;

48 } TeletextPage;

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;

62 int lines_processed;

63 TeletextPage *pages;

64 int nb_pages;

65 int64_t pts;

66 int handler_ret;

68 vbi_decoder * vbi;

69 #ifdef DEBUG

70 vbi_export * ex;

71 #endif

72 vbi_sliced sliced[MAX_SLICES];

73 } TeletextContext;

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 }

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 }

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円';

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 };

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