First, my apologies for being a newbie. I've searched for this and couldn't find anything that I could tell was related to this problem.

I've successfully, or apparently very nearly successfully, installed KnoppMyth on an Athlon XP box, with a WinTV PVR-250. It uses an RS232 IR Blaster from irblaster.info to control a Scientific Atlanta 1850 cable box using "channelchange.sh" to send the channel change codes. When I watch Live TV, all is well, and I can record shows and the whole bit.

But when I've scheduled recordings, leaving MythTV to tune the channels itself, it changes the channels wrong, leading it to record snow every time. I checked out what it was doing (via the text the backend spews in terminal while it's running), and apparently, it appends a "10" before each channel -- eg, 1027 rather than just 27. And this only happens with scheduled recordings -- I can change channels fine in live TV.

I perused mythtv-setup several times in hopes that I forgot something related to channels, but I'm clueless as to what. I get the feeling I'm missing something really simple. Any idea what's going on?

Thanks very much in advance!

Looks like it's being called with the channel id (unique DB id for the channel record) rather than the channel number. The strange thing is that the script I use gets passed the channel number, someone else I was just helping gets passed the frequency, and you ...

Take a look at the channel table in the DB (using webmin is probably the easiest way), and let us know what that whole row looks like. I'm away from my KM machine or I'd cook up a mysql command that would extract that row for us to peer at...

Thanks! I'll take a look at this in a bit... I'm also away from my Myth box at the moment.

Hope this is the right one:



Thanks for your help!

Oops, so I should have clicked on the "view data" button. And I think you're exactly right... It's using the channel id (I'm guessing the primary keys of the table) rather than channum or freqid, either of which are more appropriate (at least from looking at the data):

How did you specify the exteranl tuning script to run in mythtv-setup? Is it just the bare script name or are there any argument substitution specifiers?

Just the bare script name and path: /etc/irblaster/change_channel.sh

OK, that's just bizarre. Why do three different users, running the same version see three different behaviors? Especially since your channel entries look pretty much like mine...

Let me do some spelunking to see if I can figure out if there's a setting that controls this.

Actually another idea has occured to me... Scan through your channels table and make sure that there aren't multiple entries for any of the channels and that all the channum and freqid values match:

This should give you the empty set.

Sorry for the late response here...This is adding up to be a hectic weekend already.

That command gleans slim pickin's from the table:



I'm pretty sure none of those are actually channels in my listings.

Well even given the existance of those, I'd go back and purge the video sources, recreate them and redownload your lineups from zap2it. You didn't "scan for channels" on an SDTV source by any chance did you? That generally isn't a good idea if you've got a listing source like zap2it available.

BTW - Another suspect thing to look for is any freqid or channum > 150.

Almost forgot to mention that I had a look through the relevant MythTv code and the channel data comes directly from the freqid column. So if your external tuning script is getting a screwy value, it's because there are screwy values in that column.

OK, done, and done. I think I might have actually scanned for channels despite using a cable box... I think in desperation because I hadn't gotten my ir blaster working properly.

Now...I'll schedule a recording and let you know what happens!! *fingers-crossed*

Might as well browse the channel table again too, since that'll give you instant feedback. Remember you want to see sane values in channum, and matching ones in freqid.

That did it!! I knew it was a stupid mistake I did somewhere along the way... First of all, it successfully records shows that I scheduled now, changing the channel properly. And second, because I was curious and you suggested it, there are absolutely NO channels now that have a different channum field from the freqid field.

Is that why it was screwing up before? That it had a few channels that were off kilter?

Thanks so much for your help!!!