Genlock

Overview

Genlock (short for Generator Locking) refers to a method for temporal synchronization of multiple image sources using a common reference signal. A central device, the so-called sync or reference generator, provides a clock signal to which all connected cameras and video devices lock their image construction timing (frame and line start). This ensures all sources run in the same tempo and phase.

Genlock is not a lighting or grip device, but a camera and video synchronization technique from the broadcast sector. In the lighting and grip context, the term primarily appears in multi-camera setups, live productions, and LED wall/virtual production stages, where camera shutter, LED panel refresh, and light sources need to be coordinated.

Why It's Needed

Without a common clock, multiple cameras expose their frames at slightly different times. When switching between such sources in a live production, visible picture jumps occur because the image sources are not in phase. Genlock prevents this effect by ensuring all devices capture their images simultaneously.

• Multi-camera and Live Production: clean, jump-free switching between cameras in the vision mixer.
• LED Wall / Virtual Production: coordination of LED panel refresh and camera shutter to avoid flicker, banding, and moiré.
• Device Network: common time base for cameras, vision mixers, and other video hardware.

Reference Signals

Typically, two analog sync signal types serve as the clock reference:

Use on Set

Professional cameras have a dedicated Genlock input. The reference signal from the sync generator is distributed via cable to the cameras and other devices. Genlock exclusively controls image synchronization and should be distinguished from timecode sync: timecode addresses the numbering/assignment of frames for post-production, while Genlock ensures phase-accurate temporal locking of image construction.