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

[Jose Rey]

> -----Original Message-----
> From: Colin Perkins [mailto:csp at csperkins.org]
> Sent: Tuesday, September 07, 2004 2:26 PM
> To: Jose Rey
> Cc: Magnus Westerlund; IETF-Types; IETF AVT WG; Dave Singer
> Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP
> andMediaTypes)
>
>
> Jose,
>
> On 7 Sep 2004, at 12:56, Jose Rey wrote:
> >> -----Original Message-----
> >> From: Colin Perkins [mailto:csp at csperkins.org]
> >> Sent: Tuesday, September 07, 2004 12:03 PM
> >> To: Jose Rey
> >> Cc: IETF AVT WG; Dave Singer; Magnus Westerlund; IETF-Types
> >> Subject: Re: Media Types in 3GPP Timed text draft (was: RE: [AVT] RTP
> >> andMediaTypes)
> >>
> >> 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?
> >
> > below..
> >
> >> Is this fundamentally text or a video codec? If it's a video
> >> codec, it should be under "video/", otherwise under "text/".
> >
> > I think it is a video codec, since without the video capabilities
> > (modifiers) it would just provide the same services as , e.g.,
> > conversational text=just plain timed text, for which it is not thought
> > to be used.
>
> There are other text formats that include formatting modifiers, for
> example "text/html". I don't understand why their presence would make
> this a video format.
>

Ok, I was guiding myself more by the what I understood as type of apps.
However, just for my clarity: if we wouldn't use the "relaxed rules" could I
still use text/? Is text/t140 conformat to the 'traditional rules'?


> >>> 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).
> >
> > The MIME subtype /3gpp-tt cannot be used for HTML download since for
> > that
> > purpose a 3gp file and therefore the video/3gp MIME type is used.  So I
> > think this is indeed restricted to RTP.  However,  what is the gain of
> > doing that?
>
> My point was that, since this is restricted to transport via RTP, it
> can be registered under the "text" top-level media type.
>

What I mean is what would be the use of having two, not one or the other.

I think that as Magnus says there may be more motivation to go for text/
because of the selectability. That and the above are good reasons for me.

Summarising, it seems that we agree to choose text/.  Great! I can change
the registration to text/ if this settles it and submit the new revision and
let the MIME people review it.

Cheers,

Jose

> > Given the answer to the first question I think registering under
> > text/ would not be of any use?
>
> Why not? It would seem to be the natural home for a timed text format.
>
> Colin
>
>