[mythtv] Managing channel lists for multiple cards

Bruce Markey bjm at lvcm.com
Tue Sep 13 19:10:53 UTC 2005

Geoffrey, we haven't heard from you in a while and I assumed
you'd moved on to better things. 

Do see the examples in the posts that Mike pointed to but I'd
like to touch on some key points here.

Geoffrey Hausheer wrote:
> I have a setup with 2 PVR250s (well, one is a M179, but whatever), one 
> of which tunes directly from Cable, and the other tunes through an STB.
> The direct-tuning gets channels 1-100, whereas the STB can get channels 
> 1-999 (or there-abouts)

This is a very common situation. Most people that have digital
cable also have analog channels and set two sources. I have this
myself and this config was certainly accounted for in testing
the new scheduler and beyond.

> Today, I need 2 DD subscriptions, with overlapping channels, which also 
> means that my low channels (1-100) show up twice in the EPG.

Minor point but you should be able to have one zap2it account and
set two 'lineups". They allow up to 4 per account.

If the channel number and the "callsign" match, the EPG should only
show one line. I suspect that this and what follows are the result
of mis-matched callsigns.
> In addition, I can't use 'Record on ths channel' and have the scheduler 
> be efficient.

Channels with the same callsign are considered to be the same
"station" so if the same show appears in both listings, it could
choose to record from any of the matching channels.

> My question is, would anyone object to moving channels over to using 
> dtv_multiplex (or something similar)?  It looks like dtv_multiplex is 
> designed to seperate the channel number from the card.  In this way, I 
> could have a single subscription (all my channels), and then set the 
> secnd card to only pick up a subset of the channels.

Careful here. There are obvious distinctions between "channels" and
"stations" that can easily be forgotten and assume they are the same
thing. The are not.

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.

Obviously, channel 3 in one city carries a different station than
channel 3 in another. In Las Vegas, KVBC (NBC) is on channel 3 but
KVBC is also carried on digital channel 123.

Channel 3 and 123 have mostly the same listings, however, 123 carries
some local politics show instead of Ebert & Roper on the weekends and
during the first half of Leno on weekdays. Both "channels" primarily
carry the same "station" but the listings, when done correctly, are
different. Many people have reported that that have a station 24hrs
from one source and only during part of the day from another source
with a different station the rest of the time (CNN Headline news
over night for example).

Listings are given per channel not per station. I could complacently
assume that all KVBC listings are the same and could be copied to
other KVBCs. If they were identical, it wouldn't matter either way
but when they are different, this would be a problem.

> Is there a better way to do this?  The downside is that it could 
> complicate channel setup (though the default would remain as they are 
> today...when a card is assigned a provider, it gets all channels from 
> that provider)
> Just a thought.  If this is a reasonable proposal, I'll try to work up a 
> patch.

Even though this may work for you for now, there really needs to be
a unique chanid for each provider/channel and listings in the program
table for the shows that will be carried over the channel for that

That said, it sounds like you are proposing that you should have
one video source but a different set or subset of channels from
that source associated with an input. That may work but that actually
loses some functionality. Say you have one source with ch 1-999. Your
digital input has chanid 1001-1945 and for your analog inputs, chanids
1003-1073. There is no distinction between 1003 from the analog input
and 1003 on the digital input. Currently, by having two different
sources I can use channel priority to choose if I'd prefer 1003 over
2003 or visa versa.

--  bjm

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