Re: one more requirement

From: Gomer Thomas (gomer@lgerca.com)
Date: Wed, Jan 06 1999


Message-ID: <3693C5ED.6BB848A9@lgerca.com>
Date: Wed, 06 Jan 1999 15:22:05 -0500
From: Gomer Thomas <gomer@lgerca.com>
To: WWW TV List <www-tv@w3.org>
Subject: Re: one more requirement

Mike -

To add these to the application scenario list we need enough detail to
understand the application scenarios. How are these URIs used? Where do they
come from? How is the application supposed to treat them?

My understanding is that they typically appear in HTML pages. I think one
example given in the WebTV internet draft is <img src=tv:>. Presumably the HTML
engine rendering the HTML page is supposed to play the currently tuned channel
in the space defined by the other parameters of the img tag, or use some
default size if no size parameters are specified? Where would the HTML page
typically come from in this scenario? A web site? VBI line 21 of an NTSC
broadcast channel? I.e., what is the context within which a designation such as
"7" or "abc" should be interpreted?

I do not believe that we need to proserve legacy syntax, but I do believe that
we need to ensure that the application requirements met by that syntax is met
in some way within our framework.

For example, my own personal view is that the syntax <img src=tv:> is
unfortunate. It says to put in an image space something which is not an image
in the usual sense, and it uses the syntax of a URI for something which is not
identifying anything. If I had been part of the original design team, I would
have recommended syntax more like the following for your three examples:

   * <tv>
   * <tv chan=7> or possibly <tv src=ntsc://7>
   * <tv network=abc> or possibly <tv src=ntsc://abc>

and for the other example sometimes given in this context:

   * <tv station=wnyc> or possibly <tv src=ntsc:wnyc> (but how to distinguish
     network from station?)

This proposed "tv" tag could of course have other appropriate attributes for
specifying size, volume level, closed captioning, etc., or perhaps parameters
like volume level and closed captioning could be specified by queries at the
end of the URI.


Michael A. Dolan wrote:

> I think we should add to the application scenario list (or requirements,
> whichever is more appropriate) the existing commercial practice for "tv"
> URI's in existing (NTSC) broadcast systems.  This list may not be complete,
> but the ones I know about are:
>
>         tv:                    [reference to the currently tuned channel]
>         tv:<channel_number>    tv:7
>         tv:<network_name>      tv:abc
>
> This syntax obviously presumes a specific transport and is very limited in
> scope, but one could envision a more complex scheme where this syntax falls
> out as valid *relative* URI's.
>
> In any event, I think this syntax should be addressed and accommodated if
> possible as we move forward with our designs.
>
>         Mike
>
> ---------------------------------------------------------------------------
> Michael A. Dolan, Representing DIRECTV,  (619)445-9070   FAX: (619)445-6122
> PO Box 1673 Alpine, CA 91903, Overnight: 20239 Japatul Rd, Alpine, CA 91901

--
Gomer Thomas
LGERCA, Inc.
40 Washington Road
Princeton Junction, NJ 08550
phone: 609-716-3513
fax: 609-716-3503