[mythtv-users] HDTV changing channels

Doug Larrick dougl at charter.net
Mon Sep 13 09:30:27 EDT 2004

Preston Crow wrote:

> First, if I want to watch channel 7.1, I don't seem to be able to
> enter 7.1 to switch to it, as it doesn't think a period can be part
> of a channel number. Do I have to use some alternate encoding for my
> HDTV channels, like 1xyz for xy.z?

Yes, you need to use an alternate encoding.  I personally don't have a 
non-HD card in my system, so I just remove the dot... 7.1 becomes 71, 
2.2 becomes 22.  If you have non-HD sources, you might want to prefix it 
in some way.

> Also, Myth doesn't seem to be telling the card to change channels. If
> I set the external channel change command to /bin/true, it works
> fine, provided I first run dtvsignal to set the channel. However, if
> I don't use an external channel change program, Myth still doesn't
> change the channel for me.

When you say it fails to change channels, how are you trying to do so? 
Are you using channel up/down, typing numbers in Live TV, or are your 
scheduled recordings failing to start?  I have seen some strangeness 
when changing channels in Live TV (generally fixed by exiting to the 
menu and returning), but my recordings work just fine.  Tuning to 
stations that don't exist or with poor reception is still not as 
reliable as it should be.

You shouldn't be using an external channel changing script at all for HDTV.

> I've verified the channel settings in the channel editor. For
> example, 2.1 (PBS in Boston) has the TV Format set to ATSC and the
> Frequency ID set to 19-2. Unless I've misunderstood the other
> postings here, I think that's all correct.

Yes, that should be right.


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