[mythtv-users] digital cable channel scan incomplete

R. G. Newbury newbury at mandamus.org
Thu Dec 4 20:44:27 UTC 2008

matt lutz wrote:
> All,
> I've recently switched from DirecTV/OTA to digital cable.  I have a
> HDHomeRun that I wanted to tune the ATSC channels with.  I've successfully
> set up the new listings, the HDHR, and scanned for the channels.  I get the
> local networks in HD, and some other odd news channels, but I don't get a
> decent amount of the available content.  I've been able to map all of the
> channels it does find to the proper channel # and xmltv ID, but the big
> problem is the missing channels.
> If I use the HDHR windows app, I get all of them.  here is my listings page:
> http://www.silicondust.com/hdhomerun/lineupui?Cmd=LocationProgramsWeb&Country=US&Postcode=22302
> Mythtv doesn't find anything with a 'program' number of over 100 for some
> reason.  I've searched all over the place on how to add new channels to the
> database, and I've done what I think should be correct, but myth can't get a
> good channel lock on the new channel I add to the db.
> Like I said, I know the HDHR can tune the channel, because I can get it on
> my windows laptop using the HDHR software.  Does anyone have any ideas on
> what could be wrong in my myth setup?

It's not clear what you are actually adding to the db. What you need to 
add are: a) the frequency to dtv_multiplex and b) the channel info to 
the channel table.
The *number* which 'everyone' uses for a channel now means basically 
nothing. And there actually are NO channel frequencies with a number 
over 100: those are just for convenience.

There is page here: 

which discusses this in some detail,

If your hdhr can see it, then it can produce output which you can use to 
  set up your database. You really want to install the dvb-apps package 
to  start with. It's in Fedora 'Everything' but available elsewhere of 
course. Among other things it provides files listing frequencies and 
channel numbers:

Since these are ATSC OTA channels, you would use the first page and the 
azap program to scan for channels. Or you could just create entries in 
dtv_multiplex with numbers and frequencies.
THEN you have to find the digital streams, and set up the PID and other 
info in the channels table. The wiki page describes this, and how to 
test using azap and mplayer.

I suspect that you are trying to push into the database, the number 
which you would use in casual talk to describe a station, when its 
actual channel and PID are quite different due to the digital shift. The 
3 networks in Buffalo used to be '2,4 and 7' and they still call 
themselves that, but those are NOT the tuning frequency channels they use.

Finally, if you can tune some unknown channel in mythtv, and recognize 
it by its content against the guide you can use the on-screen editor to 
set the Name (WABC-DT) and XMLTVID, to match you Schedules Direct 
lineup. (But note: the xlmtvid is the definitive identifier at the 
SchedulesDirect end, but a tv station (or cable provider) and (and they 
do) change the frequency and/or PID of the digital stream whenever they 
damn well please!


More information about the mythtv-users mailing list