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

At 6:30 PM +0200 8/12/04, Jose Rey wrote: 
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 

OK, is the distinction between:

payloads that not only carry text, but are also expressed in (possibly marked-up) text, such as HTMl, XML, RTF, and so on

payloads that display or carry text, but are expressed partly or fully in binary, such as 3GPP timed text, word documents, and so on?


 >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



--
David Singer
Apple Computer/QuickTime

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