[advocacy] Subtitles and Code Pages (Text Encoding)

[Arc Riley]

On Sun, Apr 04, 2004 at 04:54:54AM +0000, N. E. Johnson wrote:
> Statements comparing ???????????????? (matroska (sic.)) to Ogg imply that 
> Ogg subtitles are interpreted according to the current codepage of the 
> software and that the Ogg does not contain information about what codepage 
> subtitles are encoded in. Is this true?

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.

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.

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.

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.

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.

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.

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.

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.


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