The video switcher is a plate that allows you to switch between two video signals. You plug the input from the cameras, the output for the video transmitter and one control channel into the board to select which of the images is sent to the video transmitter. You can plug in the control signal either directly from the RC receiver or from the flight controller. The Vifly switcher supports classic PWM as well as SBUS, iBUS or DSMX protocol.
The switcher comes in handy especially on drones with a drop mechanism or on FPV aircraft where you can place additional cameras towards the wings or tail of the aircraft.