I would like to implement simple custom control with slider, that would use the value in a command that is sent to the system.
The command would be: v4l2-ctl -d /dev/video0 -c brightness=xxx
where xxx would be variable set by the slicer.
I've checked around, but I have not seen a solution that would mention the ability to use variables in system commands.
Is there a way how to do this?