[FFmpeg-devel] [PATCH 3/3] TTML encoder and muxer

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Mon Dec 7 15:56:41 EET 2020


Jan Ekström:
> 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       | 154 +++++++++++++++++++++++++++++++++++++
>  libavcodec/version.h       |   2 +-
>  libavformat/Makefile       |   1 +
>  libavformat/allformats.c   |   1 +
>  libavformat/ttmlenc.c      | 123 +++++++++++++++++++++++++++++
>  libavformat/version.h      |   2 +-
>  tests/fate/subtitles.mak   |   3 +
>  tests/ref/fate/sub-ttmlenc | 122 +++++++++++++++++++++++++++++
>  12 files changed, 410 insertions(+), 2 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 ebb1727875..71476eb366 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -48,6 +48,7 @@ version <next>:
>  - speechnorm filter
>  - SpeedHQ encoder
>  - asupercut filter
> +- TTML subtitle encoder and muxer
>  
>  
>  version 4.3:
> diff --git a/doc/general_contents.texi b/doc/general_contents.texi
> index 1be6f9b683..dca183e9ca 100644
> --- a/doc/general_contents.texi
> +++ b/doc/general_contents.texi
> @@ -1332,6 +1332,7 @@ 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 a6435c9e85..9d2b62a263 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -665,6 +665,7 @@ 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
>  OBJS-$(CONFIG_TXD_DECODER)             += txd.o
>  OBJS-$(CONFIG_ULTI_DECODER)            += ulti.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index 774d5670bf..b12538905b 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -685,6 +685,7 @@ 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..7eb89e73f4
> --- /dev/null
> +++ b/libavcodec/ttmlenc.c
> @@ -0,0 +1,154 @@
> +/*
> + * 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, 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(ENOSYS);
> +        }
> +
> +#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;
> +
> +    if (s->buffer.len > bufsize) {
> +        av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
> +        return -1;

Not AVERROR_BUFFER_TOO_SMALL?

> +    }
> +    memcpy(buf, s->buffer.str, s->buffer.len);

You are not copying the terminating NUL; and you also don't account for
it in the above check. Is this intended?

> +
> +    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)
> +{
> +    TTMLContext *s = avctx->priv_data;
> +    s->avctx = avctx;
> +    s->ass_ctx = ff_ass_split(avctx->subtitle_header);
> +    av_bprint_init(&s->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
> +    return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
> +}
> +
> +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 e4b81da7cb..4ee221b7f2 100644
> --- a/libavcodec/version.h
> +++ b/libavcodec/version.h
> @@ -28,7 +28,7 @@
>  #include "libavutil/version.h"
>  
>  #define LIBAVCODEC_VERSION_MAJOR  58
> -#define LIBAVCODEC_VERSION_MINOR 114
> +#define LIBAVCODEC_VERSION_MINOR 115
>  #define LIBAVCODEC_VERSION_MICRO 100
>  
>  #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index be5a482b01..cbf9de0fc6 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -542,6 +542,7 @@ 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 53e5374255..ce0ff0e2d3 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -441,6 +441,7 @@ 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..6ba248ee30
> --- /dev/null
> +++ b/libavformat/ttmlenc.c
> @@ -0,0 +1,123 @@
> +/*
> + * 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"
> +
> +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)
> +{
> +    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     *s = ctx->streams[0];

The typical naming in libavformat uses s for AVFormatContext and st for
stream. (I already wanted to complain that the first argument of
avpriv_set_pts_info() is wrong.)

> +        AVIOContext *pb = ctx->pb;
> +
> +        AVDictionaryEntry *lang = av_dict_get(s->metadata, "language", NULL, 0);
> +        const char *printed_lang = (lang && lang->value) ? lang->value : "";
> +
> +        avpriv_set_pts_info(s, 64, 1, 1000);
> +
> +        avio_printf(pb, ttml_header_text, printed_lang);
> +

"xml:lang=" is mandatory even without a language?

> +        avio_flush(pb);
> +    }
> +
> +    return 0;
> +}
> +
> +static int ttml_write_packet(AVFormatContext *ctx, AVPacket *pkt)
> +{
> +    AVIOContext  *pb = ctx->pb;
> +
> +    avio_printf(pb,     "      <p\n");
> +    ttml_write_time(pb, "        begin", pkt->pts);
> +    avio_printf(pb, "\n");

How about avio_w88(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");
> +
> +    return 0;
> +}
> +
> +static int ttml_write_trailer(AVFormatContext *ctx)
> +{
> +    AVIOContext  *pb = ctx->pb;
> +
> +    avio_printf(pb, ttml_footer_text);
> +    avio_flush(pb);
> +
> +    return 0;
> +}
> +
> +AVOutputFormat ff_ttml_muxer = {
> +    .name              = "ttml",
> +    .long_name         = NULL_IF_CONFIG_SMALL("TTML subtitle"),
> +    .extensions        = "ttml",
> +    .mime_type         = "text/ttml",
> +    .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 ddcca9ae50..b43193bcb1 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -32,7 +32,7 @@
>  // 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  64
> +#define LIBAVFORMAT_VERSION_MINOR  65
>  #define LIBAVFORMAT_VERSION_MICRO 100
>  
>  #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
> 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>
> 



More information about the ffmpeg-devel mailing list