Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP andMedia Types)

[Jose Rey]

Dave, Magnus

--cut--
> >
> >As I said in my previous email, registering under 'text' top level type
> >would mean that the modifiers cannot be used.
>
> why is that true?  does text/* only admit of plain text?  so, for
> example, text/html would not be permitted either??
>

This is what I understand from the slides from Colin presented during the
meeting (see in http://www.dcs.gla.ac.uk/~csp/IETF60-AVT-Tue.zip,
"09-RTP-Media-Types.pdf"). Specially slide three where it says:

". In particular, it is expected that text media types are "to some
extent readable even without the software that interprets them"
- RFC 2046
- This rule is derived from email client behaviour; want to pass the message
to a dumb pager if there's no better display option"

Colin or Magnus may please correct me if I got it wrong...

Jose

> >Hence, we can differentiate
> >between applications that could make use of text w/o or w/
> modifiers to help
> >in the decision:
> >
> >also useful w/o modifiers (would be OK to use text/3gpp-tt)
> >====================
> >- captions (in most cases)
> >- instant messaging (?)
> >- timed text conversation (? )
> >
> >only useful w/ modifiers (only makes sense with video/3gpp-tt)
> >========================
> >- commercial banners (decorated)
> >- news tickers (decorated)
> >- karaoke
> >- clickable text strings
> >- some captions (e.g. scrolling end actors' list)
> >
> >Leaving aside that most captions could be useful w/o modifiers,
> the usage of
> >timed text for the 'text' type applications like instant
> messaging or text
> >conversation seems not very probable.  There are already simpler
> codecs and
> >payload formats to do this.   The whole set of features of timed text are
> >only available if the video/3gpp-tt is used... So maybe it is more
> >appropriate to register just under 'video'?
> >
> >What about interop? Would it still be a problem if we register both?
> >
> >Thanks,
> >
> >Jose
> >
> >-cut-
>
>
> --
> David Singer
> Apple Computer/QuickTime
>