[mythtv] Switching inputs with TV class?

[John Hurliman]

I'm adding a dropdown list to ManualBox to select the input source
(slowly working on making Instant Recording remote friendly), and
noticed it uses the TV object to display a preview video. While TVRec
has all the functions needed to explicitly change or toggle through
input sources, I was not sure how to go about this with the TV object.
Can anyone help me out?

jph