add button to change camview?

[Bishamon1987]

Is it possible to add a button to this system to change video in device?
I want to have 2 camera's, one for forward view (i have a car with bad visibility for boulders while parking due to a very low seat. But while parking i want to be able to switch forward and backward views. Or see them both at the same time.

I am very bad in scripting. I don't understand the scripts of cam_overlay for like 90% so that wont be doable for me.

[meekys]

Honestly, if only a single cam will show at a time, it might be easier to have an external script just start/top cam_overlay as appropriate
ie, kill cam_overlay process, then start cam_overlay again with the appropriate device

Seeing them both at the same time would currently not be possible, cam_overlay is very much designed for a single input/output.
That being said, with a bit of tweaking (to get different position/scaling of the output) it might be possible to get two instances running side-by-side.