Terminology / Sync / Genlock
Genlock
A technique for locking the sync signals of multiple video devices to the same frequency and phase. In multi-camera live production or when multiple sources feed a switcher, all sources must be genlocked to prevent rolling or tearing at the point of transition.
There are several systems for Genlock
Black Burst (Bi‑Level Sync)
A reference video signal that contains no picture content but carries vertical sync, horizontal sync, and color burst. Used to establish a timing reference and align sync across multiple video devices. Most common for older SD systems.
- Format: 0.3 V bi‑level sync
Tri-Level
The modern, high‑precision genlock standard for HD, UHD, and high‑frame‑rate video. While Black Burst was the backbone of SD broadcast, Tri‑Level is the backbone of everything from 1080p to 4K/8K, live production, LED volumes, and professional cameras. Tri‑Level Sync matches the timing of the video format -Format: +/- 300mV pulse , timing at zero point crossing