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

Colin Perkins csp at
Tue Sep 7 12:02:33 CEST 2004


On 17 Aug 2004, at 14:42, Jose Rey wrote:
> Dave and I have been discussing this offline and come to the following
> conclusions:
> 1.- it is not envisioned that the 3GPP Timed Text payload format will 
> be
> used for applications such as instant messaging or text conversation, 
> which do not precise of text decoration for working properly, since 
> there are other more appropriate media types covering these usages, 
> like text/t140. Hence,  video/ is enough.

I agree that this is not likely to be used for instant messaging or 
text conversation, although I don't understand why that would be 
relevant? Is this fundamentally text or a video codec? If it's a video 
codec, it should be under "video/", otherwise under "text/".

> 2.- we are not clear on what exactly means to "relax rules for media
> registration under text/".  I.e. is text/t140 an example of these 
> "relaxed" rules or does it comply with the traditional rules as per 
> rfc 2046?  Does the relaxed rules just mean that besides text also 
> payload headers of that media type are udnerstood?

My understanding is that the new rules are intended to allow formats 
such as 3GPP timed text to be registered under the text top-level media 
type, if appropriate, provided their domain of applicability is clearly 
specified (e.g. the domain of applicability might be that the type is 
defined for transfer via RTP only).


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