[mythtv-users] Detecting / Recovering from HD channel broadcast changes?

R. G. Newbury newbury at mandamus.org
Fri Apr 6 02:40:12 UTC 2007


Todd Ignasiak wrote:
> Has anyone else run into this?  It happens infrequently enough that I
> usually just fix it and forget it..
> 
> Occasionally, my cable company changes the channel settings for my HD
> (QAM256) stations.   Actually, I'm not sure if it's the cable company,
> or the broadcast from the station .  But, some way or another, the
> channel info (PIDs?) are changing, and MythTV cannot view/record them.
>    After I notice a few missed recordings, I can go into mythtv-setup
> and rescan the channel and it works again.  MythTV doesn't seem to be
> as forgiving as some other devices to these changes.
> 
> Has anyone else run into this, or found a good way to detect and/or
> recover from it?

I doubt that there is anything that can be done. The usual problem is 
that the cableco moves the program to a different frequency(channel) 
although the virtual channel may not change. It's especially bothersome 
when they are transmitting stripped QAM (where the stream identity info 
is NOT included). It may just be Rogers Cable, but I find that the PID's 
don't change when the frequency changes.

> Maybe a polling script that compares the current info to the MythTV
> settings & alerts you to changes could at least find the issue before
> it causes failures.

Would be nice, but I think you would need another box to check your box! 
I get over 450 digital streams. The check scan would have to parse the 
frequency, virtual channel and PID and compare that with the present 
database.

Possible to do, but no such animal exists. And if you are working from 
stripped QAM, you still cannot tell *where* the channel has been moved 
to. You can guess, based on the PID, but that is *IT*. I have to watch 
the channels long enough to determine what they are...which is a real 
bitch when there are 6 or so CBC feeds all showing the same thing! And 8 
CTV feeds, and 6 Global feeds.

> Or, is there already some way to get MythTV to alert me when a
> recording fails?  As it is now, it just happily tries to record the
> whole program, and the status says it is recording, but there is no
> file output.     A more aggressive alerting/recovery mechanism would
> be nice.

Agreed, but I will dampen the fire by pointing out that I do most of my 
recording when I have gone to bed...I will *not* be there to see an 
alert. At best, I will see it the next day: too late to catch that 
error, but soon enough to fix it.

(And Rogers announces its channel changes...)

Geoff




More information about the mythtv-users mailing list