Which term is the timing reference for HD video devices?

• A. Main Clock
• B. Wordclock
• C. Tail Pop
• D. Tri-Level Sync

Answer: (D)

In HD video systems, all devices must lock to the same timing so frames and lines line up across gear. The standard timing reference used for this is tri-level sync. It provides a precise, robust timing signal that carries the necessary sync information at the high data rates of HD video, allowing cameras, switchers, recorders, and monitors to genlock to a common clock and maintain consistent frame and line synchronization.

Wordclock, by contrast, is about timing for digital audio sample rates, not video timing. Tail pop isn’t a recognized timing reference in this context. Main clock is a general term for a clock but doesn’t specify the established HD video genlock reference. So tri-level sync is the best fit as the official timing reference for HD video devices.