Genlock or generator locking is a broadcasting technique used by some video devices or systems to keep synchronized. This enables precisely frequency-locked video signals where every device knows when a frame starts and ends.

What is Gen lock used for?

Genlock synchronises the cameras. It uses the pulse that generates the frames within the camera as the synchronisation point. This pulse sends a signal telling each device to capture frames at exactly the same time, creating an incredibly accurate way to align multiple sources of video content.

Is genlock still needed?

In the HD world genlock is still with us, but using a composite signal as a reference has largely been supplanted by tri-level, which emits pulses that clock both the frame rate and the line rate. Because it synchronizes frames, genlock can be used to keep multiple devices from drifting apart.