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

Message ID 20201204144643.73279-4-jeebjp@gmail.com
State New
Headers show
Series Initial implementation of TTML encoding/muxing
Related show

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andriy/PPC64_make success Make finished
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Commit Message

Jan Ekström Dec. 4, 2020, 2:46 p.m. UTC
From: Jan Ekström <jan.ekstrom@24i.com>

Enables encoding of other subtitle formats into TTML and writing
them out as such documents.

Signed-off-by: Jan Ekström <jan.ekstrom@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

Comments

Paul B Mahol Dec. 4, 2020, 2:57 p.m. UTC | #1
AWESOME!!!!!!!!!!

On Fri, Dec 4, 2020 at 3:55 PM Jan Ekström <jeebjp@gmail.com> wrote:

> From: Jan Ekström <jan.ekstrom@24i.com>
>
> Enables encoding of other subtitle formats into TTML and writing
> them out as such documents.
>
> Signed-off-by: Jan Ekström <jan.ekstrom@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
> +@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;
> +    }
> +    memcpy(buf, s->buffer.str, s->buffer.len);
> +
> +    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];
> +        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);
> +
> +        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");
> +    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&apos;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&apos;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">&gt;<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/>&lt;</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&lt;3,5&gt;1,4&lt;6<br/>This shouldn&apos;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&apos;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&apos;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&apos;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&apos;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
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Andreas Rheinhardt Dec. 7, 2020, 1:56 p.m. UTC | #2
Jan Ekström:
> From: Jan Ekström <jan.ekstrom@24i.com>
> 
> Enables encoding of other subtitle formats into TTML and writing
> them out as such documents.
> 
> Signed-off-by: Jan Ekström <jan.ekstrom@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
> +@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&apos;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&apos;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">&gt;<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/>&lt;</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&lt;3,5&gt;1,4&lt;6<br/>This shouldn&apos;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&apos;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&apos;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&apos;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&apos;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>
>
Andreas Rheinhardt Dec. 7, 2020, 2:03 p.m. UTC | #3
Andreas Rheinhardt:
> Jan Ekström:
>> From: Jan Ekström <jan.ekstrom@24i.com>
>>
>> Enables encoding of other subtitle formats into TTML and writing
>> them out as such documents.
>>
>> Signed-off-by: Jan Ekström <jan.ekstrom@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
>> +@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?
> 

The srt encoder does it like you, the ass encoder is careful only to
output a NUL terminated string (with the NUL not accounted for in the
size); no documentation exists for avcodec_encode_subtitle(). ffmpeg.c
uses the size of the allocated (not-zeroed) buffer as bufsize; it also
does not add any padding at all (but it's buffer is huge (1MiB)).

>> +
>> +    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&apos;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&apos;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">&gt;<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/>&lt;</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&lt;3,5&gt;1,4&lt;6<br/>This shouldn&apos;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&apos;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&apos;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&apos;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&apos;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>
>>
>
Jan Ekström Dec. 7, 2020, 11:30 p.m. UTC | #4
On Mon, Dec 7, 2020 at 3:56 PM Andreas Rheinhardt
<andreas.rheinhardt@gmail.com> wrote:
>
> Jan Ekström:
> > From: Jan Ekström <jan.ekstrom@24i.com>
> >
> > Enables encoding of other subtitle formats into TTML and writing
> > them out as such documents.
> >
> > Signed-off-by: Jan Ekström <jan.ekstrom@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
> > +@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?
>

Yup. I just had noticed that as well as I started adding what was
recommended on IRC. Also it says "ASS event" even though it's a TTML
paragraph at this point, so I will also fix that.

> > +    }
> > +    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?

I think I followed either webvttenc or srtenc in this. Technically I
/think/ under certain circuimstances AVBprint does lead to a trailing
nul to be there if av_bprint_is_complete returns true, but I cannot
vouch for it - would have to check the implementation and especially
av_bprint_append_data.

>
> > +
> > +    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.)
>

I agree. Apparently this came from the times when this code was based
on webvttenc, where "s" was utilized for the AVStream in
webvtt_write_header . And then when you're trying to go back and
attempt to bring things up to a level you often miss these things.

> > +        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?
>

Yup. Looking at how the ttt TTML validator yells at you if you leave
it out, and what is noted in
https://www.w3.org/TR/ttml1/#content-attribute-langnot

> The xml:lang attribute must be specified on the tt element and may be specified by an instance of any other element type in the core vocabulary catalog except parameter vocabulary.

I then checked the XML specification regarding this and apparently an
empty string value is OK, so that's what we end up with.

> > +        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')?
>

Seems like a good way to do it.

> > +    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&apos;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&apos;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">&gt;<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/>&lt;</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&lt;3,5&gt;1,4&lt;6<br/>This shouldn&apos;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&apos;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&apos;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&apos;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&apos;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>
> >
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Jan Ekström Dec. 7, 2020, 11:35 p.m. UTC | #5
On Mon, Dec 7, 2020 at 4:03 PM Andreas Rheinhardt
<andreas.rheinhardt@gmail.com> wrote:
> >
> > You are not copying the terminating NUL; and you also don't account for
> > it in the above check. Is this intended?
> >
>
> The srt encoder does it like you, the ass encoder is careful only to
> output a NUL terminated string (with the NUL not accounted for in the
> size); no documentation exists for avcodec_encode_subtitle(). ffmpeg.c
> uses the size of the allocated (not-zeroed) buffer as bufsize; it also
> does not add any padding at all (but it's buffer is huge (1MiB)).
>

Yes, this is probably the roots of this code being based on the webvtt
and srt encoders showing up. I do agree that especially for text
buffers zero-termination makes sense, as long as it doesn't cause
funky things to happen when the packet is being written by muxer(s).

As noted, I have vague memories of AVBPrint handling zero-termination
in some cases, but my memory definitely needs a re-check.

Jan
Andreas Rheinhardt Dec. 7, 2020, 11:51 p.m. UTC | #6
Jan Ekström:
> On Mon, Dec 7, 2020 at 4:03 PM Andreas Rheinhardt
> <andreas.rheinhardt@gmail.com> wrote:
>>>
>>> You are not copying the terminating NUL; and you also don't account for
>>> it in the above check. Is this intended?
>>>
>>
>> The srt encoder does it like you, the ass encoder is careful only to
>> output a NUL terminated string (with the NUL not accounted for in the
>> size); no documentation exists for avcodec_encode_subtitle(). ffmpeg.c
>> uses the size of the allocated (not-zeroed) buffer as bufsize; it also
>> does not add any padding at all (but it's buffer is huge (1MiB)).
>>
> 
> Yes, this is probably the roots of this code being based on the webvtt
> and srt encoders showing up. I do agree that especially for text
> buffers zero-termination makes sense, as long as it doesn't cause
> funky things to happen when the packet is being written by muxer(s).
> 
> As noted, I have vague memories of AVBPrint handling zero-termination
> in some cases, but my memory definitely needs a re-check.
> 
An AVBPrint's string is always zero-terminated and said zero is not
included in the length (like strlen); but the problem starts to exists
when you copy the string without the trailing zero. You should modify
your check to "if (s->buffer.len >= bufsize)" and copy the NUL (or
zero-terminate yourself, I don't care).

- Andreas
diff mbox series

Patch

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
+@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;
+    }
+    memcpy(buf, s->buffer.str, s->buffer.len);
+
+    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];
+        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);
+
+        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");
+    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&apos;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&apos;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">&gt;<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/>&lt;</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&lt;3,5&gt;1,4&lt;6<br/>This shouldn&apos;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&apos;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&apos;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&apos;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&apos;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>