On 2/1/17, wm4 <nfx...@googlemail.com> wrote:
> On Wed, 01 Feb 2017 11:05:48 +0200
> Petri Hintukainen <phint...@gmail.com> wrote:
>
>> ti, 2017-01-31 kello 16:42 +0100, wm4 kirjoitti:
>> > On Tue, 31 Jan 2017 15:22:17 +0100
>> > Paul B Mahol <one...@gmail.com> wrote:
>> >
>> > > Signed-off-by: Paul B Mahol <one...@gmail.com>
>> > > ---
>> > > libavcodec/Makefile | 2 +
>> > > libavcodec/allcodecs.c | 2 +
>> > > libavcodec/textst_parser.c | 49 ++++++++++++++++++++
>> > > libavcodec/textstdec.c | 108
>> > > +++++++++++++++++++++++++++++++++++++++++++++
>> > > libavformat/utils.c | 1 +
>> > > 5 files changed, 162 insertions(+)
>> > > create mode 100644 libavcodec/textst_parser.c
>> > > create mode 100644 libavcodec/textstdec.c
>> > >
>> > > diff --git a/libavcodec/Makefile b/libavcodec/Makefile
>> > > index 43a6add..edadb0f 100644
>> > > --- a/libavcodec/Makefile
>> > > +++ b/libavcodec/Makefile
>> > > @@ -539,6 +539,7 @@ OBJS-$(CONFIG_SVQ1_ENCODER) +=
>> > > svq1enc.o svq1.o h263data.o \
>> > > OBJS-$(CONFIG_SVQ3_DECODER) += svq3.o svq13.o
>> > > mpegutils.o h264data.o
>> > > OBJS-$(CONFIG_TEXT_DECODER) += textdec.o ass.o
>> > > OBJS-$(CONFIG_TEXT_ENCODER) += srtenc.o ass_split.o
>> > > +OBJS-$(CONFIG_TEXTST_DECODER) += textstdec.o ass.o
>> > > OBJS-$(CONFIG_TAK_DECODER) += takdec.o tak.o takdsp.o
>> > > OBJS-$(CONFIG_TARGA_DECODER) += targa.o
>> > > OBJS-$(CONFIG_TARGA_ENCODER) += targaenc.o rle.o
>> > > @@ -945,6 +946,7 @@ OBJS-$(CONFIG_RV30_PARSER) +=
>> > > rv34_parser.o
>> > > OBJS-$(CONFIG_RV40_PARSER) += rv34_parser.o
>> > > OBJS-$(CONFIG_SIPR_PARSER) += sipr_parser.o
>> > > OBJS-$(CONFIG_TAK_PARSER) += tak_parser.o tak.o
>> > > +OBJS-$(CONFIG_TEXTST_PARSER) += textst_parser.o
>> > > OBJS-$(CONFIG_VC1_PARSER) += vc1_parser.o vc1.o
>> > > vc1data.o \
>> > > simple_idct.o wmv2data.o
>> > > OBJS-$(CONFIG_VP3_PARSER) += vp3_parser.o
>> > > diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
>> > > index f92b2b7..9a90533 100644
>> > > --- a/libavcodec/allcodecs.c
>> > > +++ b/libavcodec/allcodecs.c
>> > > @@ -581,6 +581,7 @@ void avcodec_register_all(void)
>> > > REGISTER_DECODER(SUBVIEWER, subviewer);
>> > > REGISTER_DECODER(SUBVIEWER1, subviewer1);
>> > > REGISTER_ENCDEC (TEXT, text);
>> > > + REGISTER_DECODER(TEXTST, textst);
>> > > REGISTER_DECODER(VPLAYER, vplayer);
>> > > REGISTER_ENCDEC (WEBVTT, webvtt);
>> > > REGISTER_ENCDEC (XSUB, xsub);
>> > > @@ -704,6 +705,7 @@ void avcodec_register_all(void)
>> > > REGISTER_PARSER(RV40, rv40);
>> > > REGISTER_PARSER(SIPR, sipr);
>> > > REGISTER_PARSER(TAK, tak);
>> > > + REGISTER_PARSER(TEXTST, textst);
>> > > REGISTER_PARSER(VC1, vc1);
>> > > REGISTER_PARSER(VORBIS, vorbis);
>> > > REGISTER_PARSER(VP3, vp3);
>> > > diff --git a/libavcodec/textst_parser.c
>> > > b/libavcodec/textst_parser.c
>> > > new file mode 100644
>> > > index 0000000..5079a96
>> > > --- /dev/null
>> > > +++ b/libavcodec/textst_parser.c
>> > > @@ -0,0 +1,49 @@
>> > > +/*
>> > > + * 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
>> > > + * HDMV TextST subtitle parser
>> > > + */
>> > > +
>> > > +#include "libavutil/intreadwrite.h"
>> > > +#include "parser.h"
>> > > +
>> > > +static int textst_parse(AVCodecParserContext *s1, AVCodecContext
>> > > *avctx,
>> > > + const uint8_t **poutbuf, int
>> > > *poutbuf_size,
>> > > + const uint8_t *buf, int buf_size)
>> > > +{
>> > > + if (buf_size > 13) {
>> > > + int64_t end;
>> > > +
>> > > + s1->pts = ((int64_t)(buf[3] & 1) << 32) |
>> > > AV_RB32(&buf[4]);
>> > > + end = ((int64_t)(buf[8] & 1) << 32) | AV_RB32(&buf[9]);
>> > > + s1->duration = (end - s1->pts);
>> > > + }
>> > > +
>> > > + /* always return the full packet. this parser isn't doing any
>> > > splitting or
>> > > + combining, only packet analysis */
>> > > + *poutbuf = buf;
>> > > + *poutbuf_size = buf_size;
>> > > + return buf_size;
>> > > +}
>> > > +
>> > > +AVCodecParser ff_textst_parser = {
>> > > + .codec_ids = { AV_CODEC_ID_HDMV_TEXT_SUBTITLE },
>> > > + .parser_parse = textst_parse,
>> > > +};
>> >
>> > Why does it need to be in a parser, instead of the demuxer? It seems
>> > like this codec exists only in .ts anyway, and the way PTS/duration
>> > is
>> > extracted seems very closely tied to the format.
>>
>> I think a parser could be good idea, it could be useful when remuxing ?
>>
>> In the original BluRay mpeg-ts files this codec uses PES private stream
>> 2, so there are no timestamps in packets coming from mpeg-ts demuxer.
>>
>> Parser could also store the first segment (style segment) in extradata.
>> I think matroska stores style segment in extradata (not 100% sure, I
>> don't have such files at hand). This kind of makes sense, it allows
>> starting playback from middle of the mkv file.
>>
>> Maybe parser should not overwrite the timestamps if those are already
>> present ? I don't know if timestamps in subtitle segments are modified
>> when muxing to matroska.
>
> This codec is supported in mpeg-ts only. There are no hints that it's
> supported in Matroska. If it were, the parser would break _very_ badly
> on it when demuxing from mkv too.
It _IS_ supported in matroska as S_HDMV/TEXTST
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