[mythtv] Input switching question

[Jerry Rubinow]

If I wanted to prevent myth from switching to an input that was
connected to the same external tuner that was in use by another input,
would the MainServer::Handle...() functions related to free recorders
be a workable place to put code for this?  Does all the tuner
switching code go through there?

For example, if I had a firewire input for HD channels, and an PVR
input for svideo from the same cable box for non-HD channels, I'd want
both inputs to look like they were busy if either one was being
recorded from, since both depend on the same cable box tuner.

I realize that I also need to put in checks, probably in schedule.cpp,
to prevent a show being scheduled on both connected inputs as well. 
But as a first step, I'm thinking the first change should prevent
channel changes in live tv from ruining in-progress recordings on the
other input.

Anything else I need to take into account?

Thanks,
-Jerry