Subject: [SIP] Re: "Static" Images

From: Lawrence Conroy <[email-masked]>
Date: Sat, 17 Jun 2000 12:25:08 +0100

I understand that the idea is a "low-data-rate" image transfer
scheme (so Static is possibly the wrong word :).

Agree it's a SDP issue rather than purely a SIP issue.

In those cases where there's only a single group of items, one could 
use the same
approach we used in PINT - having a fmtp line that indicates a URI
and/or an "in-line" item carried in another numbered sub-part.

This is kind of similar to the INFO/INVITE/... approach, and Colin's 
http suggestion,
but allows more than one item and could be a set of URIs rather than 
just in-line
(or a combination).

Remember that PINT has defined extensions that may WELL be useful in a
"normal" IP net conference.

If it's a *really* low refresh rate, then why not Re-Invite using the
same scheme? It doesn't have to be an INFO.

You *may* not even need this - what's wrong with a URI pointing to a
Progressive JPEG/Interlaced GIF/...? I had assumed that every ad-based
service would have some of these wasting the end-users bandwidth.

If, OTOH, it's a low but significant refresh rate, then it is a kind
of animated image//video stream, so RTP-over-whatever seems appropriate.

Final point - who said HTTP == HTTP/1.1?
HTTP 1.0 is a doddle, and this kind of request is not exactly complex.
-- 
All the best, Lawrence
-----------------------------------------------------------------------
| Lawrence Conroy,    | "These Opinions must be mine, 'cos if they    |
| Roke Manor Research |  were my Company's they'd pay me for them"    |
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