At 11:39 AM +0200 8/12/04, Jose Rey wrote:
Dave, Magnus,
inline...
-----Original Message----- From: avt-bounces@ietf.org [mailto:avt-bounces@ietf.org]On Behalf Of Dave Singer Sent: Tuesday, August 10, 2004 7:11 PM To: Magnus Westerlund; 'ietf-types@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