“Gen lock” – or “generator lock” – is a way of synchronizing different camcorders. This is essential in a live-feed multi-camera shoot to ensure that video images remain stable even when switching between different cameras.
A Gen lock signal, sent to all of the camcorders involved in a shoot from a central source, tells each of them when they should begin recording. The same command is sent for every frame, and every scan line within the frame. Gen lock ‘locks’ camcorders into the same scan sequence.
Without a Gen lock input it is virtually impossible to conduct a multi-camera shoot.