[FFmpeg-devel] [PATCH v3 4/4] {avcodec, avformat}: add TTML encoder and muxer
Jan Ekström
jeebjp at gmail.com
Fri Jan 22 12:37:34 EET 2021
From: Jan Ekström <jan.ekstrom at 24i.com>
Enables encoding of other subtitle formats into TTML and writing
them out as such documents.
Signed-off-by: Jan Ekström <jan.ekstrom at 24i.com>
---
Changelog | 1 +
doc/general_contents.texi | 1 +
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 1 +
libavcodec/ttmlenc.c | 179 +++++++++++++++++++++++++++++++++++++
libavcodec/version.h | 4 +-
libavformat/Makefile | 1 +
libavformat/allformats.c | 1 +
libavformat/ttmlenc.c | 166 ++++++++++++++++++++++++++++++++++
libavformat/version.h | 4 +-
tests/fate/subtitles.mak | 3 +
tests/ref/fate/sub-ttmlenc | 122 +++++++++++++++++++++++++
12 files changed, 480 insertions(+), 4 deletions(-)
create mode 100644 libavcodec/ttmlenc.c
create mode 100644 libavformat/ttmlenc.c
create mode 100644 tests/ref/fate/sub-ttmlenc
diff --git a/Changelog b/Changelog
index 0b27c15122..9a6aeb4128 100644
--- a/Changelog
+++ b/Changelog
@@ -56,6 +56,7 @@ version <next>:
- shufflepixels filter
- tmidequalizer filter
- estdif filter
+- TTML subtitle encoder and muxer
version 4.3:
diff --git a/doc/general_contents.texi b/doc/general_contents.texi
index 443e8ed8d1..d799382f84 100644
--- a/doc/general_contents.texi
+++ b/doc/general_contents.texi
@@ -1334,6 +1334,7 @@ performance on systems without hardware floating point support).
@item SubViewer v1 @tab @tab X @tab @tab X
@item SubViewer @tab @tab X @tab @tab X
@item TED Talks captions @tab @tab X @tab @tab X
+ at item TTML @tab X @tab @tab X @tab
@item VobSub (IDX+SUB) @tab @tab X @tab @tab X
@item VPlayer @tab @tab X @tab @tab X
@item WebVTT @tab X @tab X @tab X @tab X
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 5ce3ee0ec9..d26e0264de 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -669,6 +669,7 @@ OBJS-$(CONFIG_TSCC_DECODER) += tscc.o msrledec.o
OBJS-$(CONFIG_TSCC2_DECODER) += tscc2.o
OBJS-$(CONFIG_TTA_DECODER) += tta.o ttadata.o ttadsp.o
OBJS-$(CONFIG_TTA_ENCODER) += ttaenc.o ttaencdsp.o ttadata.o
+OBJS-$(CONFIG_TTML_ENCODER) += ttmlenc.o ass_split.o
OBJS-$(CONFIG_TWINVQ_DECODER) += twinvqdec.o twinvq.o metasound_data.o
OBJS-$(CONFIG_TXD_DECODER) += txd.o
OBJS-$(CONFIG_ULTI_DECODER) += ulti.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index f00d524747..81d20c44ec 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -686,6 +686,7 @@ extern AVCodec ff_subviewer_decoder;
extern AVCodec ff_subviewer1_decoder;
extern AVCodec ff_text_encoder;
extern AVCodec ff_text_decoder;
+extern AVCodec ff_ttml_encoder;
extern AVCodec ff_vplayer_decoder;
extern AVCodec ff_webvtt_encoder;
extern AVCodec ff_webvtt_decoder;
diff --git a/libavcodec/ttmlenc.c b/libavcodec/ttmlenc.c
new file mode 100644
index 0000000000..a9b1411467
--- /dev/null
+++ b/libavcodec/ttmlenc.c
@@ -0,0 +1,179 @@
+/*
+ * TTML subtitle encoder
+ * Copyright (c) 2020 24i
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * TTML subtitle encoder
+ * @see https://www.w3.org/TR/ttml1/
+ * @see https://www.w3.org/TR/ttml2/
+ * @see https://www.w3.org/TR/ttml-imsc/rec
+ */
+
+#include "avcodec.h"
+#include "libavutil/avstring.h"
+#include "libavutil/bprint.h"
+#include "ass_split.h"
+#include "ass.h"
+
+typedef struct {
+ AVCodecContext *avctx;
+ ASSSplitContext *ass_ctx;
+ AVBPrint buffer;
+} TTMLContext;
+
+static void ttml_text_cb(void *priv, const char *text, int len)
+{
+ TTMLContext *s = priv;
+ AVBPrint cur_line = { 0 };
+ AVBPrint *buffer = &s->buffer;
+
+ av_bprint_init(&cur_line, len, AV_BPRINT_SIZE_UNLIMITED);
+
+ av_bprint_append_data(&cur_line, text, len);
+ if (!av_bprint_is_complete(&cur_line)) {
+ av_log(s->avctx, AV_LOG_ERROR,
+ "Failed to move the current subtitle dialog to AVBPrint!\n");
+ av_bprint_finalize(&cur_line, NULL);
+ return;
+ }
+
+
+ av_bprint_escape(buffer, cur_line.str, NULL, AV_ESCAPE_MODE_XML_CHAR_DATA,
+ 0);
+
+ av_bprint_finalize(&cur_line, NULL);
+}
+
+static void ttml_new_line_cb(void *priv, int forced)
+{
+ TTMLContext *s = priv;
+
+ av_bprintf(&s->buffer, "<br/>");
+}
+
+static const ASSCodesCallbacks ttml_callbacks = {
+ .text = ttml_text_cb,
+ .new_line = ttml_new_line_cb,
+};
+
+static int ttml_encode_frame(AVCodecContext *avctx, uint8_t *buf,
+ int bufsize, const AVSubtitle *sub)
+{
+ TTMLContext *s = avctx->priv_data;
+ ASSDialog *dialog;
+ int i;
+
+ av_bprint_clear(&s->buffer);
+
+ for (i=0; i<sub->num_rects; i++) {
+ const char *ass = sub->rects[i]->ass;
+
+ if (sub->rects[i]->type != SUBTITLE_ASS) {
+ av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
+ return AVERROR(EINVAL);
+ }
+
+#if FF_API_ASS_TIMING
+ if (!strncmp(ass, "Dialogue: ", 10)) {
+ int num;
+ dialog = ff_ass_split_dialog(s->ass_ctx, ass, 0, &num);
+
+ for (; dialog && num--; dialog++) {
+ ff_ass_split_override_codes(&ttml_callbacks, s, dialog->text);
+ }
+ } else {
+#endif
+ dialog = ff_ass_split_dialog2(s->ass_ctx, ass);
+ if (!dialog)
+ return AVERROR(ENOMEM);
+
+ ff_ass_split_override_codes(&ttml_callbacks, s, dialog->text);
+ ff_ass_free_dialog(&dialog);
+#if FF_API_ASS_TIMING
+ }
+#endif
+ }
+
+ if (!av_bprint_is_complete(&s->buffer))
+ return AVERROR(ENOMEM);
+ if (!s->buffer.len)
+ return 0;
+
+ // force null-termination, so in case our destination buffer is
+ // too small, the return value is larger than bufsize minus null.
+ if (av_strlcpy(buf, s->buffer.str, bufsize) > bufsize - 1) {
+ av_log(avctx, AV_LOG_ERROR, "Buffer too small for TTML event.\n");
+ return AVERROR_BUFFER_TOO_SMALL;
+ }
+
+ return s->buffer.len;
+}
+
+static av_cold int ttml_encode_close(AVCodecContext *avctx)
+{
+ TTMLContext *s = avctx->priv_data;
+
+ ff_ass_split_free(s->ass_ctx);
+
+ av_bprint_finalize(&s->buffer, NULL);
+
+ return 0;
+}
+
+static av_cold int ttml_encode_init(AVCodecContext *avctx)
+{
+ int ret = AVERROR_BUG;
+ TTMLContext *s = avctx->priv_data;
+
+ s->avctx = avctx;
+
+ if (!(s->ass_ctx = ff_ass_split(avctx->subtitle_header))) {
+ ret = AVERROR_INVALIDDATA;
+ goto failure;
+ }
+
+ if (!(avctx->extradata = av_malloc(4 + AV_INPUT_BUFFER_PADDING_SIZE))) {
+ ret = AVERROR(ENOMEM);
+ goto failure;
+ }
+ avctx->extradata_size = 4;
+
+ av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
+
+ return 0;
+
+failure:
+ ff_ass_split_free(s->ass_ctx);
+ av_bprint_finalize(&s->buffer, NULL);
+
+ return ret;
+}
+
+AVCodec ff_ttml_encoder = {
+ .name = "ttml",
+ .long_name = NULL_IF_CONFIG_SMALL("TTML subtitle"),
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ .id = AV_CODEC_ID_TTML,
+ .priv_data_size = sizeof(TTMLContext),
+ .init = ttml_encode_init,
+ .encode_sub = ttml_encode_frame,
+ .close = ttml_encode_close,
+};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 9f80caa9e0..807062af7f 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -28,8 +28,8 @@
#include "libavutil/version.h"
#define LIBAVCODEC_VERSION_MAJOR 58
-#define LIBAVCODEC_VERSION_MINOR 117
-#define LIBAVCODEC_VERSION_MICRO 101
+#define LIBAVCODEC_VERSION_MINOR 118
+#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 3a8fbcbe5f..f39a613901 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -543,6 +543,7 @@ OBJS-$(CONFIG_TRUEHD_DEMUXER) += rawdec.o mlpdec.o
OBJS-$(CONFIG_TRUEHD_MUXER) += rawenc.o
OBJS-$(CONFIG_TTA_DEMUXER) += tta.o apetag.o img2.o
OBJS-$(CONFIG_TTA_MUXER) += ttaenc.o apetag.o img2.o
+OBJS-$(CONFIG_TTML_MUXER) += ttmlenc.o
OBJS-$(CONFIG_TTY_DEMUXER) += tty.o sauce.o
OBJS-$(CONFIG_TY_DEMUXER) += ty.o
OBJS-$(CONFIG_TXD_DEMUXER) += txd.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 6990af55f4..f4454e8362 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -442,6 +442,7 @@ extern AVInputFormat ff_truehd_demuxer;
extern AVOutputFormat ff_truehd_muxer;
extern AVInputFormat ff_tta_demuxer;
extern AVOutputFormat ff_tta_muxer;
+extern AVOutputFormat ff_ttml_muxer;
extern AVInputFormat ff_txd_demuxer;
extern AVInputFormat ff_tty_demuxer;
extern AVInputFormat ff_ty_demuxer;
diff --git a/libavformat/ttmlenc.c b/libavformat/ttmlenc.c
new file mode 100644
index 0000000000..826f110f86
--- /dev/null
+++ b/libavformat/ttmlenc.c
@@ -0,0 +1,166 @@
+/*
+ * TTML subtitle muxer
+ * Copyright (c) 2020 24i
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * TTML subtitle muxer
+ * @see https://www.w3.org/TR/ttml1/
+ * @see https://www.w3.org/TR/ttml2/
+ * @see https://www.w3.org/TR/ttml-imsc/rec
+ */
+
+#include "avformat.h"
+#include "internal.h"
+
+enum TTMLPacketType {
+ PACKET_TYPE_PARAGRAPH,
+ PACKET_TYPE_DOCUMENT,
+};
+
+typedef struct TTMLMuxContext {
+ enum TTMLPacketType input_type;
+ unsigned int document_written;
+} TTMLMuxContext;
+
+static const char ttml_header_text[] =
+"<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
+"<tt\n"
+" xmlns=\"http://www.w3.org/ns/ttml\"\n"
+" xmlns:ttm=\"http://www.w3.org/ns/ttml#metadata\"\n"
+" xmlns:tts=\"http://www.w3.org/ns/ttml#styling\"\n"
+" xml:lang=\"%s\">\n"
+" <body>\n"
+" <div>\n";
+
+static const char ttml_footer_text[] =
+" </div>\n"
+" </body>\n"
+"</tt>\n";
+
+static void ttml_write_time(AVIOContext *pb, const char tag[],
+ int64_t millisec)
+{
+ int64_t sec, min, hour;
+ sec = millisec / 1000;
+ millisec -= 1000 * sec;
+ min = sec / 60;
+ sec -= 60 * min;
+ hour = min / 60;
+ min -= 60 * hour;
+
+ avio_printf(pb, "%s=\"%02"PRId64":%02"PRId64":%02"PRId64".%03"PRId64"\"",
+ tag, hour, min, sec, millisec);
+}
+
+static int ttml_write_header(AVFormatContext *ctx)
+{
+ TTMLMuxContext *ttml_ctx = ctx->priv_data;
+ ttml_ctx->document_written = 0;
+
+ if (ctx->nb_streams != 1 ||
+ ctx->streams[0]->codecpar->codec_id != AV_CODEC_ID_TTML) {
+ av_log(ctx, AV_LOG_ERROR, "Exactly one TTML stream is required!\n");
+ return AVERROR(EINVAL);
+ }
+
+ {
+ AVStream *st = ctx->streams[0];
+ AVIOContext *pb = ctx->pb;
+
+ AVDictionaryEntry *lang = av_dict_get(st->metadata, "language", NULL,
+ 0);
+ const char *printed_lang = (lang && lang->value) ? lang->value : "";
+
+ // Not perfect, but decide whether the packet is a document or not
+ // by the existence of extradata.
+ ttml_ctx->input_type = st->codecpar->extradata ?
+ PACKET_TYPE_PARAGRAPH :
+ PACKET_TYPE_DOCUMENT;
+
+ avpriv_set_pts_info(st, 64, 1, 1000);
+
+ if (ttml_ctx->input_type == PACKET_TYPE_PARAGRAPH)
+ avio_printf(pb, ttml_header_text, printed_lang);
+ }
+
+ return 0;
+}
+
+static int ttml_write_packet(AVFormatContext *ctx, AVPacket *pkt)
+{
+ TTMLMuxContext *ttml_ctx = ctx->priv_data;
+ AVIOContext *pb = ctx->pb;
+
+ switch (ttml_ctx->input_type) {
+ case PACKET_TYPE_PARAGRAPH:
+ // write out a paragraph element with the given contents.
+ avio_printf(pb, " <p\n");
+ ttml_write_time(pb, " begin", pkt->pts);
+ avio_w8(pb, '\n');
+ ttml_write_time(pb, " end", pkt->pts + pkt->duration);
+ avio_printf(pb, ">");
+ avio_write(pb, pkt->data, pkt->size);
+ avio_printf(pb, "</p>\n");
+ break;
+ case PACKET_TYPE_DOCUMENT:
+ // dump the given document out as-is.
+ if (ttml_ctx->document_written) {
+ av_log(ctx, AV_LOG_ERROR,
+ "Attempting to write multiple TTML documents into a "
+ "single document! The XML specification forbids this "
+ "as there has to be a single root tag.\n");
+ return AVERROR(EINVAL);
+ }
+ avio_write(pb, pkt->data, pkt->size);
+ ttml_ctx->document_written = 1;
+ break;
+ default:
+ av_log(ctx, AV_LOG_ERROR, "Invalid TTML input packet type!\n");
+ return AVERROR(EINVAL);
+ }
+
+ return 0;
+}
+
+static int ttml_write_trailer(AVFormatContext *ctx)
+{
+ TTMLMuxContext *ttml_ctx = ctx->priv_data;
+ AVIOContext *pb = ctx->pb;
+
+ if (ttml_ctx->input_type == PACKET_TYPE_PARAGRAPH)
+ avio_printf(pb, ttml_footer_text);
+
+ return 0;
+}
+
+AVOutputFormat ff_ttml_muxer = {
+ .name = "ttml",
+ .long_name = NULL_IF_CONFIG_SMALL("TTML subtitle"),
+ .extensions = "ttml",
+ .mime_type = "text/ttml",
+ .priv_data_size = sizeof(TTMLMuxContext),
+ .flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |
+ AVFMT_TS_NONSTRICT,
+ .subtitle_codec = AV_CODEC_ID_TTML,
+ .write_header = ttml_write_header,
+ .write_packet = ttml_write_packet,
+ .write_trailer = ttml_write_trailer,
+};
diff --git a/libavformat/version.h b/libavformat/version.h
index a2b5901e74..b12ce3a843 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -32,8 +32,8 @@
// Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
// Also please add any ticket numbers that you believe might be affected here
#define LIBAVFORMAT_VERSION_MAJOR 58
-#define LIBAVFORMAT_VERSION_MINOR 65
-#define LIBAVFORMAT_VERSION_MICRO 101
+#define LIBAVFORMAT_VERSION_MINOR 66
+#define LIBAVFORMAT_VERSION_MICRO 100
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
LIBAVFORMAT_VERSION_MINOR, \
diff --git a/tests/fate/subtitles.mak b/tests/fate/subtitles.mak
index 6323d0f93d..ee65afe35b 100644
--- a/tests/fate/subtitles.mak
+++ b/tests/fate/subtitles.mak
@@ -106,6 +106,9 @@ fate-sub-scc: CMD = fmtstdout ass -ss 57 -i $(TARGET_SAMPLES)/sub/witch.scc
FATE_SUBTITLES-$(call ALLYES, MPEGTS_DEMUXER DVBSUB_DECODER DVBSUB_ENCODER) += fate-sub-dvb
fate-sub-dvb: CMD = framecrc -i $(TARGET_SAMPLES)/sub/dvbsubtest_filter.ts -map s:0 -c dvbsub
+FATE_SUBTITLES-$(call ALLYES, FILE_PROTOCOL PIPE_PROTOCOL SRT_DEMUXER SUBRIP_DECODER TTML_ENCODER TTML_MUXER) += fate-sub-ttmlenc
+fate-sub-ttmlenc: CMD = fmtstdout ttml -i $(TARGET_SAMPLES)/sub/SubRip_capability_tester.srt
+
FATE_SUBTITLES-$(call ENCMUX, ASS, ASS) += $(FATE_SUBTITLES_ASS-yes)
FATE_SUBTITLES += $(FATE_SUBTITLES-yes)
diff --git a/tests/ref/fate/sub-ttmlenc b/tests/ref/fate/sub-ttmlenc
new file mode 100644
index 0000000000..624f37d092
--- /dev/null
+++ b/tests/ref/fate/sub-ttmlenc
@@ -0,0 +1,122 @@
+<?xml version="1.0" encoding="utf-8"?>
+<tt
+ xmlns="http://www.w3.org/ns/ttml"
+ xmlns:ttm="http://www.w3.org/ns/ttml#metadata"
+ xmlns:tts="http://www.w3.org/ns/ttml#styling"
+ xml:lang="">
+ <body>
+ <div>
+ <p
+ begin="00:00:00.000"
+ end="00:00:00.000">Don't show this text it may be used to insert hidden data</p>
+ <p
+ begin="00:00:01.500"
+ end="00:00:04.500">SubRip subtitles capability tester 1.3o by ale5000<br/>Use VLC 1.1 or higher as reference for most things and MPC Home Cinema for others<br/>This text should be blue<br/>This text should be red<br/>This text should be black<br/>If you see this with the normal font, the player don't (fully) support font face</p>
+ <p
+ begin="00:00:04.500"
+ end="00:00:04.500">Hidden</p>
+ <p
+ begin="00:00:04.501"
+ end="00:00:07.500">This text should be small<br/>This text should be normal<br/>This text should be big</p>
+ <p
+ begin="00:00:07.501"
+ end="00:00:11.500">This should be an E with an accent: È<br/>日本語<br/>This text should be bold, italics and underline<br/>This text should be small and green<br/>This text should be small and red<br/>This text should be big and brown</p>
+ <p
+ begin="00:00:11.501"
+ end="00:00:14.500">This line should be bold<br/>This line should be italics<br/>This line should be underline<br/>This line should be strikethrough<br/>Both lines<br/>should be underline</p>
+ <p
+ begin="00:00:14.501"
+ end="00:00:17.500">><br/>It would be a good thing to<br/>hide invalid html tags that are closed and show the text in them<br/>but show un-closed invalid html tags<br/>Show not opened tags<br/><</p>
+ <p
+ begin="00:00:17.501"
+ end="00:00:20.500">and also<br/>hide invalid html tags with parameters that are closed and show the text in them<br/>but show un-closed invalid html tags<br/>This text should be showed underlined without problems also: 2<3,5>1,4<6<br/>This shouldn't be underlined</p>
+ <p
+ begin="00:00:20.501"
+ end="00:00:21.500">This text should be in the normal position...</p>
+ <p
+ begin="00:00:21.501"
+ end="00:00:22.500">This text should NOT be in the normal position</p>
+ <p
+ begin="00:00:22.501"
+ end="00:00:24.500">Implementation is the same of the ASS tag<br/>This text should be at the<br/>top and horizontally centered</p>
+ <p
+ begin="00:00:22.501"
+ end="00:00:24.500">This text should be at the<br/>middle and horizontally centered</p>
+ <p
+ begin="00:00:22.501"
+ end="00:00:24.500">This text should be at the<br/>bottom and horizontally centered</p>
+ <p
+ begin="00:00:24.501"
+ end="00:00:26.500">This text should be at the<br/>top and horizontally at the left</p>
+ <p
+ begin="00:00:24.501"
+ end="00:00:26.500">This text should be at the<br/>middle and horizontally at the left<br/>(The second position must be ignored)</p>
+ <p
+ begin="00:00:24.501"
+ end="00:00:26.500">This text should be at the<br/>bottom and horizontally at the left</p>
+ <p
+ begin="00:00:26.501"
+ end="00:00:28.500">This text should be at the<br/>top and horizontally at the right</p>
+ <p
+ begin="00:00:26.501"
+ end="00:00:28.500">This text should be at the<br/>middle and horizontally at the right</p>
+ <p
+ begin="00:00:26.501"
+ end="00:00:28.500">This text should be at the<br/>bottom and horizontally at the right</p>
+ <p
+ begin="00:00:28.501"
+ end="00:00:31.500">This could be the most difficult thing to implement</p>
+ <p
+ begin="00:00:31.501"
+ end="00:00:50.500">First text</p>
+ <p
+ begin="00:00:33.500"
+ end="00:00:35.500">Second, it shouldn't overlap first</p>
+ <p
+ begin="00:00:35.501"
+ end="00:00:37.500">Third, it should replace second</p>
+ <p
+ begin="00:00:36.501"
+ end="00:00:50.500">Fourth, it shouldn't overlap first and third</p>
+ <p
+ begin="00:00:40.501"
+ end="00:00:45.500">Fifth, it should replace third</p>
+ <p
+ begin="00:00:45.501"
+ end="00:00:50.500">Sixth, it shouldn't be<br/>showed overlapped</p>
+ <p
+ begin="00:00:50.501"
+ end="00:00:52.500">TEXT 1 (bottom)</p>
+ <p
+ begin="00:00:50.501"
+ end="00:00:52.500">text 2</p>
+ <p
+ begin="00:00:52.501"
+ end="00:00:54.500">Hide these tags:<br/>also hide these tags:<br/>but show this: {normal text}</p>
+ <p
+ begin="00:00:54.501"
+ end="00:01:00.500"><br/>\ N is a forced line break<br/>\ h is a hard space<br/>Normal spaces at the start and at the end of the line are trimmed while hard spaces are not trimmed.<br/>The\hline\hwill\hnever\hbreak\hautomatically\hright\hbefore\hor\hafter\ha\hhard\hspace.\h:-D</p>
+ <p
+ begin="00:00:54.501"
+ end="00:00:56.500"><br/>\h\h\h\h\hA (05 hard spaces followed by a letter)<br/>A (Normal spaces followed by a letter)<br/>A (No hard spaces followed by a letter)</p>
+ <p
+ begin="00:00:56.501"
+ end="00:00:58.500">\h\h\h\h\hA (05 hard spaces followed by a letter)<br/>A (Normal spaces followed by a letter)<br/>A (No hard spaces followed by a letter)<br/>Show this: \TEST and this: \-)</p>
+ <p
+ begin="00:00:58.501"
+ end="00:01:00.500"><br/>A letter followed by 05 hard spaces: A\h\h\h\h\h<br/>A letter followed by normal spaces: A<br/>A letter followed by no hard spaces: A<br/>05 hard spaces between letters: A\h\h\h\h\hA<br/>5 normal spaces between letters: A A<br/><br/>^--Forced line break</p>
+ <p
+ begin="00:01:00.501"
+ end="00:01:02.500">Both line should be strikethrough,<br/>yes.<br/>Correctly closed tags<br/>should be hidden.</p>
+ <p
+ begin="00:01:02.501"
+ end="00:01:04.500">It shouldn't be strikethrough,<br/>not opened tag showed as text.<br/>Not opened tag showed as text.</p>
+ <p
+ begin="00:01:04.501"
+ end="00:01:06.500">Three lines should be strikethrough,<br/>yes.<br/>Not closed tags showed as text</p>
+ <p
+ begin="00:01:06.501"
+ end="00:01:08.500">Both line should be strikethrough but<br/>the wrong closing tag should be showed</p>
+ </div>
+ </body>
+</tt>
--
2.29.2
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