Re: TV Glossary

From: Jack Lang (
Date: Tue, Aug 31 1999

Message-ID: <01ba01bef405$7f313e20$>
From: "Jack Lang" <>
To: <>
Date: Wed, 1 Sep 1999 00:06:43 +0100
Subject: Re: TV Glossary

> >Program - a collection of related video, audio and/or data in a
> >single "file".  This is also generically called "content".
> So a Program has a definite, limited size. Right?

It's size may not be known beforehand - for example coverage of a cricket
match or formulae one race.
Programs may also be part of a series.
Do programs include commercials (I vote not - commercials etc should be
programs in their own right). Programs usually have a single content author

> >Program Stream - as defined in ISO 13818-1 for MPEG - a streaming
> >version of a Program.
> >
> >Transport (Stream) - as defined by ISO 13818-1 for MPEG - a
> >multiplexed collection of concatenated Program Streams without
> >beginning or end.
> Query:
> what does multiplexing mean in this case?
> Two possibilities - breaking up a Program Stream to insert other Program
> Streams (like commercials) - and multiple unrelated Program Streams being
> transmitted at the same time (for instance normal programming + teletex)

There is the concept of a single service transport stream, although there
are cases were different TV stations time-share a single service transport
> >Content Author - usually a studio (Disney, ABC Studios) that creates
> >video, audio, and "data" or some aggregation of these.

The components may be seperately authored and then aggregated by a studio

The program may be comissioned by another party, or by a network.
> >
> >Channel - a Program Stream.  This is also known in DVB as a
> >"service".
> Now I'm confused; I would have thought that a Channel would be a Transport
> Stream.
Channel usually means from one network.
> >Network - company that authors and aggregates content and distributes
> >it (ABC).
> >
> >Transport Company - a company that aggregates and emits (usually in
> >cable or satellite) a collection of channels (DIRECTV).  This is also
> >sometimes referred to as a "network", but usually confuses folks when
> >it is.
> I'll assume that network-owned transport companies can be described as a
> Transport Company plus a Network, rather than confusing the terms.
> >Broadcaster - company that emits radio waves (KABC).
> Is a Broadcaster always a special case of Transport Company?
No - ntl: is a Broadcaster (we own radio masts, among other things), but not
a Transport company
A Transport company does things like collect PPV subscriptions.
A cable company is a special sort of broadcaster - emitting signal along its
private wires, but may also collect subscriptions on behalf of Transport
Sattelite companies (like Astra) are also by this definition Broadcasters

> >Affiliate - broadcaster (KABC) that gets most of its content from a
> >network, and thus has an affiliation to that network (ABC).
> >
> >Feed - the serialized stream of content from a network.
> Is a Feed a special case of a Program Stream?

A simplified view might be

Author(s) ->Network->Transport company ->Broadcaster
             program     service                      transport

In the UK, for example


However sometimes the same corporation performs multiple functions. On the
other hand there may be other specialist stages (like editing, adding
captions, and different switching centres and play-outs) that complicate the