[advocacy] Re: Subtitles and Code Pages (Text Encoding)

[Paul Bryson]

"Arc Riley" wrote...
> First of all, there is *NO* Xiph codec available at this time which
> provides subtitles.  This is the first indication that there's some
> serious FUD comming from the Matroski PR spin doctors.  If you
> investigate some of the other claims they've made about Ogg you'll find
> they've been running this long-term campain to spread misinformation
> about Ogg's capabilities and expandability.

Yeah, he popped into #matroska and asked about it.  I let him know that OGM and
Ogg are not the same thing.  A lot of people confuse the two.  Unfortunately the
Matroska PR Spin Doctor is enroute from China to Germany, so he was unable to
spread more FUD at the moment.  If you like, I could point him towards this
discussion?

> There are two Xiph subtitle formats being worked on, Writ and MNG (Ming).
> Neither have been seen outside a few examples, neither is a "standard"
> as neither are in a finished state.

None of us have heard of an MNG format for Ogg.  Do you have any links to
discussion or papers about it?  There is already a PNG video codec and I wonder
if it uses any of the same principles.

> Writ, as documented at http://wiki.xiph.org/OggWrit , uses Unicode
> exclusivly.  It doesn't use seperate codepages, much less the "current
> codepage of the software", as we instead chose a design which allows
> every language to be properly represented.

Thats good.  Generally speaking, code pages are just retarded.  UTF-8 was a good
choice.

> MNG, as you are probobally aware, is just a lossless animation format.
> It will allow all sorts of weird animated/colorised subtitles to be
> supported.  Since subtitles in this codec are done in graphics only,
> well, 'codepages' doesn't apply here.

Again, I would be interested if you could point me to any links here for MNG in
Ogg.

> There are a few third party subtitle formats being implemented in the
> wild for Ogg, none are anywhere near a standard, and none are
> representitive of the capabilities of Ogg.  Ogg is a container format.
> What some third party (ie, non-Xiph) subtitle format supports or does
> not support is not an issue with Ogg, but rather, an issue with that
> codec alone.

I don't know of any supported subtitle codecs in Ogg at the moment.  The closest
thing would be OGM, but that is definately not the same thing.

> Where the Matroska guys got it all wrong is trying to combine the
> subtitle format and scripting language with the container... this, IMHO,
> is *WRONG* *WRONG* *WRONG* (beating lame matroska script kiddies over
> the head with a rolled up newspaper).  These are seperate functions that
> should be handled in their own layers; a container to hold everything
> together and codecs to provide media of various types and formats.

*WRONG* *WRONG* *WRONG* Actually, I don't know.  In fact, noone really knows
what in the world you are refering to.  There is no scripting language in
Matroska, though it has be theorized on a bit in the past.

> Anyone can implement any subtitle format with Ogg because the subtitle
> format is treated as an independent codec, as it should be.  This allows
> for the flexibility to add new subtitle codecs in the future when new
> features are needed, etc.

This is only partially true.  The problem is that Xiph still hasn't defined how
to handle third party codecs.  Until that time, nothing is valid.

> I'll note, too, that Writ was designed specifically to allow future
> expansion without breaking compatability with older software/etc.  You
> should really take a look at it if you're interested in the nuts and
> bolts of subtitle formats.

You may also consider SSA and its bigger brother ASS.  Both are fairly mature
subtitle systems that allow for extremely complex effects and have a reasonable
following.  I'm not sure what you mean by compatibility as there isn't any
current OggWrit system out there to be compatible with.  Though, I am pretty
sure that even mplayer will display plain text when it detects an SSA/ASS
stream.

<p>Pamel

<p><p>--- >8 ----
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