Genlock, short for "generator lock," is a synchronisation technology that ensures multiple video devices output frames at precisely the same moment. It's the gold standard for video wall synchronisation in broadcast, AV, and professional experience applications.
**How Genlock Works**
Every video device (camera, graphics card, display, media player) generates video output based on its internal timing circuits. Without synchronisation, these devices run independently—even devices set to the same frame rate will gradually drift apart.
Genlock solves this by:
1. **Reference Signal**: A master timing generator produces a sync signal (typically "blackburst" or "tri-level sync" in professional systems).
2. **Signal Distribution**: This reference is distributed to all devices via coaxial cable or specialized sync distribution amplifiers.
3. **Phase Lock**: Each device receives the reference and locks its internal video timing to match, becoming "genlocked" to the master.
4. **Synchronised Output**: All genlocked devices now output frames at exactly the same instant, synchronised to within nanoseconds.
**Why Genlock Matters**
**Video Walls**: Content spanning multiple environments requires frame-level sync. Genlock ensures seamless transitions where no tearing or jumping occurs.
**Broadcast Production**: Switching between cameras requires all sources be genlocked to the master sync, enabling clean cuts.
**Multi-Projector Installations**: Edge-blended projection requires all projectors to refresh simultaneously.
**LED Processing**: LED wall controllers use genlock to synchronise output across multiple receiving cards.
**Genlock vs Software Sync**
Hardware genlock provides the most precise synchronisation possible—timing accuracy measured in nanoseconds. However, it requires: - Specialized hardware (sync generators, distribution) - Physical cable connections - All devices in same location - Additional cost for specialized hardware
Software-based synchronisation (as used in SPARC) achieves near-genlock performance using network time protocols and intelligent buffering. This approach works across distributed installations without expensive hardware, making professional synchronisation accessible for more deployments.