TV Namespaces

From: Michael A. Dolan (miked@tbt.com)
Date: Tue, Aug 31 1999


Message-Id: <3.0.5.32.19990831080743.00986c60@cts.com>
Date: Tue, 31 Aug 1999 08:07:43 -0700
To: www-tv@w3.org (WWW TV List)
From: "Michael A. Dolan" <miked@tbt.com>
Subject: TV Namespaces

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There are several namespaces in TV.  Here's a shot at describing 
them.  Again, this may have an ATSC slant.  If so, then some DVB-
specialist will:

Namespace            Authority           US      Intern'l
- ----------------------------------------------------------
Callsigns            ITU                 Yes     Yes
Networks             ?                   Yes     No
Channel Names        Transport Company   No      No
Feeds                ?                   No      No
Channel #            ITU                 Yes     Yes


Callsigns are global names for Broadcasters.  The top level authority 
is the ITU, with it being managed in the US by the FCC.  Everything 
that emits TV (as well as other kinds) radio waves has a callsign.  
But non-broadcast feeds (HBO) are not part of this namespace since 
they do not transmit directly to receivers.

Network names are generally unique within a country but not across 
countries.  Broadcasters can be either independents, or local 
affiliates of a network.  So broadcasters generally have a network 
affiliation (but it may be null).  There is a relationship between 
the Channels (names and/or numbers) and Networks.

Channel names are those names that appear in EPG's.  These names may 
be callsigns, network names, feed names and/or channel numbers.  They 
are assigned by the transport company carrying the guide, and are 
unique only within that transport company.

Feeds are non-broadcast programs that have names (HBO, HBOW, etc.)  
However, the Channel that is called HBO in one Transport may well not 
be the same Content as the Channel that is called HBO in some other 
Transport.  HBO has multiple feeds that the Transport Companies may 
or may not choose to carry.

Channel #'s are not unique globally without more information.  
However, they are in a well-managed namespace.  A channel # is unique 
given its ITU Region (in the case of a Broadcaster), or its Transport 
(given cable and satellite).  For example, channel 7 in US/ITU Region 
5 is globally unique and equal to KABC (Los Angeles).  There is a one-
to-one relationship between Broadcasters and (in the case of ATSC, 
major) channels.  Note also that ATSC channels have 2 numbers and are 
of the form <major>.<minor>.  A Broadcaster owns the major number and 
then can broadcast multiple minor (digital) channels.

For the curious, the US Region map is here:

http://www.fcc.gov/wtb/publicsafety/images/ps55rgns.gif

Within these areas (and immediately adjacent areas), there is no 
duplication of channel numbers.  Since in NTSC analog, channel == 
frequency.

	Mike

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Michael A. Dolan, Representing DIRECTV,  (619)445-9070   
PO Box 1673 Alpine, CA 91903        FAX: (619)445-6122