Show dictionary · Video & LED
Genlock
Also: house sync · reference
Genlock (generator lock) synchronizes video equipment to a common reference signal so every device starts each frame at the same instant. A genlocked system switches cleanly between sources without frame-sync buffers, drift, or tearing.
In practice
The reference (black burst for SD-era gear, tri-level sync for HD) fans out from one generator to cameras, switchers, and playback. Sources that arrive locked can be cut directly; wild (unlocked) sources force the switcher to re-time them through a frame synchronizer, which costs up to a frame of delay per source.
On modern shows genlock earns its keep in latency and in LED-heavy rigs: locking cameras and processors reduces glass-to-glass delay and tames camera-versus-wall artifacts. IP video (ST 2110) replaces the black cable with PTP network timing, same concept, new plumbing.
How you’ll hear it
"Camera three is wild; get reference to it or we eat a frame of sync on every cut."
Related resources
Part of the eventools.io Show Dictionary, a free glossary of live event production terminology.