As a subset of frame synchronization, genlock is commonly used in video post-production, nonlinear editing (NLE), and broadcast studios. Its use ensures that a workstation’s graphics output is locked (LOCK) to an externally generated (GEN) signal, guaranteeing that the studio’s devices (cameras, videotape recorders, character or title generators, and so on) work together effectively. The NVIDIA Quadro G-Sync option card ensures subscanline-level synchronization to the external sync source.

Through the BNC genlock connector on board the NVIDIA Quadro G-Sync, the graphics video timing can be synchronized to an external timing source. In turn, this source provides a periodic signal to the display system to lock the vertical refresh rate.

Genlock used in typical NLE video environment

Typically, a workstation user plugs a “house sync” signal into the graphics board—usually set at NTSC (U.S.) or PAL (Europe) rates—instructing the graphics board to trigger various edges of the external sync signal.