Re: about tv:

From: Warner ten Kate (tenkate@natlab.research.philips.com)
Date: Thu, Feb 11 1999


Message-Id: <36C29A39.F6A4FEB2@natlab.research.philips.com>
Date: Thu, 11 Feb 1999 09:52:09 +0100
From: Warner ten Kate <tenkate@natlab.research.philips.com>
To: "Michael A. Dolan" <miked@tbt.com>
Cc: www-tv@w3.org
Subject: Re: about tv:

Mike,

I am afraid I disagree.

Michael A. Dolan wrote:
> 
> 1. Noone will argue that tv: is a great URL.  

That's to say, here I agree ;-)


> However it is a good URN.

It isn't in my association of "good":
a URN is supposed to be a persistent resource identifier. 
"current TV channel" is rather context dependent, so not persistent.


> 2. There isn't a scheme proposed yet (that I have seen) that addresses the
> multiple tuner issue.

At least the dvb: scheme addresses that issue, namely by abstracting
from that. The scheme identifies a resource, that's independent
of the number of tuners your device contains.


> 
> 3. Given the constraints of OBJECT and IMG and other places one wishes to
> apply the semantics of placing video/audio into a web page, I see little
> other mechanism than a URI to do it.  

Agree.


> 4. If a URI is appropriate for (3), then how does one put "currently tuned
> channel" onto a web page, if not with something like "tv:"?


So, that's the requirement.
I'll check our requirements doc on that and update accordingly.

You assume there is other information available containing 
the "currently tuned to" (that information has probably 
caused the tuning). 

I don't have the proper solution, but I think we should 
look whether relative URLs are of use here. Something 
along the lines that the base-URL sets the context: the 
currently tuned TV-channel and its associated HTML pages
(I mean the pages which are transmitted along with the video). 

The TV-channel is at the root defined by that base URL, so 
a reference like src="tv" could do, without colon suffix.
The colon will conflict with the relative URL parsing rules. 
"tv" is the 'file' name of the video stream located at the 
root - probably names like src="video" and src="lang-en" 
are more useful. I am not sure whether we can specify 
default names here (with default semantics).

Having just src="tv:" in a HTML page provides the author
any guarantee the tv stream is displayed he had in mind.
It is a scheme which works fine within a constrained
environment like a single analog TV channel with 
VBI data transmission. There are not much alternatives there.


Warner.