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

[Dave Singer]

At 11:39 AM +0200 8/12/04, Jose Rey wrote:
>Dave, Magnus,
>
>inline...
>>  -----Original Message-----
>>  From: avt-bounces at ietf.org [mailto:avt-bounces at ietf.org]On Behalf Of
>>  Dave Singer
>>  Sent: Tuesday, August 10, 2004 7:11 PM
>>  To: Magnus Westerlund; 'ietf-types at iana.org'
>>  Cc: IETF AVT WG
>>  Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP
>>  andMedia Types)
>>
>>
>>  At 5:55 PM +0200 8/9/04, Magnus Westerlund wrote:
>>  >Hi,
>>  >
>>  >As the RTP payload format is developed in IETF, rather than 3GPP I
>>  >think the MIME type used to identify that RTP payload format belongs
>>  >in the IETF tree. Especially as the vendor tree implies that the
>>  >3GPP has control over the registration and any updates, which I
>>  >don't think is appropriate for this payload format.
>>  >
>>  >The question is if 3GPP timed text should be registered in video,
>>  >text, or both. My reasoning behind actually registering in both
>>  >media types, would if one had clear indications that both are
>>  >appropriate for different usages of the RTP payload format.
>>
>>  I think both is the worst choice;  it's asking for interop
>>  problems, isn't it?
>>
>
>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??

>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