[mythtv] The 125 Channel Problem Explained

tarek Lubani mythtv-dev@snowman.net
Thu, 24 Oct 2002 17:07:49 -0400

Hey guys!

After playing around much with the code (the equivalent of a little kid 
trying to figure out a boeing), and with the help of a very knowledgeable 
man (and author of TV Time, a linux dscaler; 
http://www.sf.net/projects/tvtime/), I think the 125 channel problem has 
been figured out:

1) Why it happens:

It seems that mythtv calls up all of its "usable" channels from 
"frequencies.c" in the libs/libmyth directory (of the source).. This is 
well and good except for the fact that none of these standards do (or can, 
for that matter) represent satellite!! So, it's a no-go if you want the OSD 
or whatever to show up for a >125 channel (>100 in some markets, etc)..

2) What can be done to "fix" it?

Seems like there are 2 main avenues to go:

a) Trick myth by putting in a "broadcast" standard for satellite.. this 
would have to go in the frequencies.c..

b) remove the dependence on this channel list altogether!

3) The solution I used:

Well, that one was easy. My knowledge is so limited that I could not pursue 
option (b), and instead went for option (a).. I opened up the frequencies.c 
and just put in a bunch of random frequencies.. I started at 100 and went 
all the way to 999 for the channels, which is pretty much all directv 
supports.. As for 0 - 100 for those with 5th gen receivers, by not deleting 
any of the entries, those are still supported.. so no prob..

The additions that I made to frequencies.c didn't break it (I think).. Just 
supplemented it.. so the frequency designations for 1 - 125 haven't changed 
(in theory)..

you can find the frequencies.c file that I used at:


A sample line (for archival / etc sakes):

     { "999",     61250 },

this can be repeated for all the channels that are needed..

Hope that all helps : )

tarek : )