[mythtv-users] Issues with Set Top Box and Digital Channels

Mike Perkins mikep at randomtraveller.org.uk
Thu May 20 11:10:19 UTC 2010

Nick Couchman wrote:
> I'm trying to use MythTV to control a set-top converter box for digital TV.
> The STB feeds via a composite input into the card, and I have an IR blaster
> that controls the STB.  I have a script, /usr/bin/ch_chan.pl, and I can
> successfully, from the command line, issue a command line
> "/usr/bin/ch_chan.pl 31.1" and have the IR blaster send the commands to the
> STB and see the channel change.
> I'm having trouble on the MythTV side...a couple of issues that I believe are
> related.  First, if I try to use the "Fetch Channels from Lineup" option to
> pull the data from my SchedulesDirect.org account, it doesn't pull any
> channels *unless* I happen to have one of the remaining non-DTV channels
> present, then it pulls only that (those) channel(s).  For some reason, it
> appears to be choking on any channels that are in the digital TV format.  I'm
> not sure if this is because the numbers have a "." in them (e.g. 31.1), or
> because the call signs are longer than the traditional 4 letter call signs
> (e.g. KDVRDT instead of KDVR).  So, I get around this issue by manually
> entering the channels - name, channel number, and call sign.  This appears to
> work fine, until MythTV tries to go change the channel, and then nothing
> happens.  If I put some debugging lines in the script (ch_chan.pl), I can see
> that it does actually get called, but it appears to get called without any
> argument(s) - no channel number.  This further strengthens my suspicion that
> MythTV is, for some reason, choking on channels with a "." in them.
> I've done some web searching and mailing list search for similar, related, or
> identical issues, to no avail, so I apologize in advance if this is something
> that's already been asked, covered, discussed, etc., but I'd appreciate some
> help debugging this problem.  I'm running MythTV 0.21 (tried 0.23, too) from
> the Packman repository on OpenSuSE 11.2
As I understand it, when using an external channel change script it is passed 
the contents of the *frequency* field, not the channel number.

If you have filled in the channel number, you can probably do a bulk update on 
your database to populate the frequency field with the same value.


Mike Perkins

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