[mythtv] ivtv (pvr350) snow on upgrade to recent svn

Bruce Markey bjm at lvcm.com
Tue Sep 20 21:10:11 UTC 2005

Roger James wrote:
> This is the bit that has confused me in the past. I have been reading your
> previous posts, so before going on let met verify some terminology.
> Station - programming source of a media stream, which may be simultaneously
> made available (broadcast) via number of different channels. i.e. MTV or
> BBC1, the content.
> Channel - a broadcast instance of a stations media stream. i.e., a UHF
> analog signal, a stream of a digital multiplex, etc, the transport
> mechanism.

Right, but I like a little more shock value to see the forest
rather than the trees.

Channel - a frequency or identifier for a TV set (or receiving device)
to distinguish the broadcast signal.

Station - a building with employees and lots of wires often with a
tower on top or on a nearby hill.

CNN is where Arron Brown works. "20" is a sequence of two buttons
on my remote control. When I press these buttons at my house, the
tuner picks up the signal from Cox Communications in Las Vegas
which is showing a picture of Arron Brown.

> So my confusion is, does a video source define a set of channels or

Channels. The station CNN in Atlanta, GA has reported their listings
of planned broadcasts in UTC to TMS and others. CNN ignores these
listings and show "State of Emergency" hurricane coverage all day
(BTW www.redcross.org) but that's not the point =). Cox in Las Vegas
is in Pacific daylight savings time and broadcasts CNN over frequency
20. So, I get Arron Brown on channel 20 at 7PM PDT. Somewhere in Ohio
the same broadcast is simultaneously shown on channel 34 at 10PM EDT.

> stations. The way in mythtv that you associate a particular video source
> with a particular input, would seem to suggest that it should define
> channels, but the way in which you interface it to a listings provider
> suggests that it should define stations.

See the KVBC example in the attached. The same station is carried
over two channels (digital and analog) from the same provider but
the listings are different per channel. This is not uncommon.

> In my case a small number of the stations available via digital terrestrial
> channels are also available via analog terrestrial channels.

I'm not familiar with TV in the UK but if these have different
tuning information then I would think that they would require
separate rows in the channel table.

> My fixed setup now has two video sources both using an an xmltv grabber. I
> suspect this means I am now grabbing some listings twice. I now have some

Yes but no big deal. Even if you expect these listings to all be
the same, they don't have to be and they are not for other myth
users like myself.

> "duplicate" entries in my channel sql table, but I have given these the same
> channel number and callsign. This means that only one of them is shown in
> the EPG.

Good enough.

--  bjm
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Subject: Re: [mythtv] Managing channel lists for multiple cards
Date: Tue, 13 Sep 2005 12:10:53 -0700
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