[MPlayer-dev-eng] [PATCH] improvement of sami subtitles feature

[Jihyun Cho]

2013/2/16 Clément Bœsch <ubitux at gmail.com>

> On Fri, Feb 15, 2013 at 12:57:06PM +0900, Jihyun Cho wrote:
> > 2013/2/15 Clément Bœsch <ubitux at gmail.com>
> >
> > > On Thu, Feb 14, 2013 at 04:18:16PM +0900, Jihyun Cho wrote:
> > > [...]
> > > > I separated and trimmed the patch.
> > > > 'mplayer_sami_ass_converter.patch' depends on
> > > > 'mplayer_sami_html_character_entities.patch', because it uses
> > > sami_entities
> > > > table.
> > >
> > > AFAICT you are duplicating the SubRip-to-ASS code for the insane idea
> of
> > > supporting the SubRip markup into SAMI. Maybe because some weird
> converter
> > > copy/pasted the dialogues from a .srt to a .sami without taking into
> > > account the markup at all and so you got a broken file? Assuming this,
> we
> > > should support the SubRip markup in all the subtitles formats, which is
> > > wrong.
> > >
> > > I'm not really implicated in MPlayer development anymore so I won't
> object
> > > into its inclusion, but it is IMO not correct. Also, the patch is
> > > duplicating a lot of code which is a maintenance nightmare.
> > >
> > > On the other hand, the second patch (HTML codes mapping) is more
> > > interesting, and it might make sense to propose something similar into
> the
> > > SAMI decoder of FFmpeg.
> > >
> > > Now in an ideal world, MPlayer should replace the subreader.c with the
> > > subtitles support in FFmpeg (now that it supports every subtitles
> formats
> > > MPlayer has) and as a consequence remove the sub-ass-converting code I
> > > added a while ago as a "good enough temporary solution" (aka "clean
> hack")
> > > which won't be necessary anymore (the decoding process of FFmpeg
> subtitles
> > > is outputting ASS for every formats).
> > >
> > > Though, I see a few blocking things for this to happen in MPlayer:
> > >  - FFmpeg doesn't support character encoding convert yet, but I'm
> working
> > >    on it, and I expect this to be solved soon
> > >  - FFmpeg doesn't support UTF-16, this is a problem which could be
> somehow
> > >    work arounded in MPlayer given a few efforts, or better, fixed in
> > >    FFmpeg.
> > >  - The subtitles "dumping" code can't be replaced with FFmpeg API
> because
> > >    there is not enough subtitles encoders, so it will mean dropping
> > >    features
> > >  - It will require dropping a lot of code in MPlayer, and the
> development
> > >    of MPlayer being somehow slow lately, it might require some
> motivation
> > >    for the developer trying to that work.
> > >
> > > Anyway, the idea is that adding such code in MPlayer might be a
> pointless
> > > effort because one of the purpose of FFmpeg is actually to lighten up
> the
> > > burden of dealing with formats & codecs in MPlayer, including
> subtitles.
> > > This means whatever code you add in MPlayer for subtitles, it might
> > > disappear in a relatively short amount of time because of FFmpeg. So if
> > > you want your code to live on longer, I think it's wise to work on the
> > > subtitles support in FFmpeg instead. You might also get more insightful
> > > reviews about subtitles there since there is more activity.
> > >
> > > Now all I just said is relevant only if MPlayer moves to FFmpeg
> subtitles
> > > decoding at some point. While I believe it will happen in one or two
> > > MPlayer forks, I'm not so sure about the original project, so this is
> up
> > > to you to decide.
> > >
> > > Regards,
> > >
> >
> > As you said, Sami-to-ASS converter is temporary solution.
> > It has a lot of duplicated code with SubRip-to-ASS converter.
> > I think Sami-to-ASS converter can be merged to SubRip-to-ASS.
> > But Sami spec is not the same as SubRip spec. So I decided to separate
> two
> > converters.
>
> Yes. But the question was why are you trying to support SubRip markup into
> SAMI?
>

It's not SubRip markup. It's HTML markup.
SAMI is similar to HTML.
It supports not only Font & Style tags but also some HTML tags(eg. headline
tag, ruby tag, sub & superscript tags)
And SubRip supports Font & Style tags.
This part of two specs is similar.


> > As a result, a lot of code is duplicated.
> > I know it's not good solution. But it works.
> >
>
> > On the other hand, I tried converting Sami to ASS with FFmpeg.
> > But it is not enough to replace mplayer's subreader.c right now.
>
> If not (good?) enough? Or you meant something else?
>

As described above, SAMI supports many tags. But when I tested it, unparsed
tags were displayed on the video.
FFmpeg should add a parser to support SAMI subtitles.