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

Dave Singer singer at
Tue Sep 7 13:55:21 CEST 2004

At 11:02 AM +0100 9/7/04, Colin Perkins wrote:
>On 17 Aug 2004, at 14:42, Jose Rey wrote:
>>Dave and I have been discussing this offline and come to the following
>>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/".

It's fundamentally for presenting visual information, but that visual 
information is achieved by rendering text.  It all depends on what 
the meaning of "text codec" is...

>>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).

ah, OK.

for me, I don't mind which of text/ or video/ is chosen, provided it 
is only one of them!
David Singer
Apple Computer/QuickTime

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