Which of the three nDisplay sync topologies (framelock only, genlock only, genlock plus framelock) does Epic recommend for an LED volume, and why?

Problem. Cluster PCs drive LED processors and the camera must not capture different frames on different panels. Conditions. Multi-PC nDisplay cluster with NVIDIA Quadro GPUs and Sync II cards. Method. Epic describes three schemes. (1) Framelock only: daisy-chained sync cards, no external clock; Epic says it suits isolated displays but not a stage whose other devices share an external master clock. (2) Genlock only: each PC gets its own BNC feed from one generator; VSync is synced but NVIDIA barriers are unavailable, so Epic says presentation control at application level is imprecise. (3) Genlock plus framelock: the external clock enters the primary PC GPU and RJ45 daisy chain carries framelock to the render nodes, which allows NVIDIA barriers; Epic calls this the most desirable for virtual production. Failure modes. Genlock only gives unreliable frame presentation (Epic: not 100 percent reliable). Limitations. NVIDIA-specific; AMD FirePro S400 is mentioned only for Mosaic/Eyefinity aggregation. Version and date. Current Epic page, fetched 2026-10-23. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Correction folded 2026-10-24 from C3-B786-01 (curator-reviewed, C3R-0613/0616): Problem. C3-B771-01 states that AMD FirePro S400 is mentioned only for Mosaic/Eyefinity aggregation and that the framelock/genlock method is NVIDIA-specific. Conditions. Multi-PC nDisplay clusters. Method. Epic's page says that to synchronise displays driven by multiple PCs using daisy-chaining, one GPU acts as master clock and shares it using sync cards like the Nvidia Quadro Sync II or AMD Firepro S400; it also names Firepro S400 alongside Quadro Sync II for Mosaic and Eyefinity groups. The NVIDIA swap-group and barrier mechanism and the NVIDIA API are specific to NVIDIA. Failure modes. Reading the page as ruling out AMD sync cards for cross-PC daisy-chaining. Limitations. The page does not say whether the AMD route supports engine-level barriers. Version/date. Epic page as fetched 2026-10-24T00:48:23Z. Limitations: The page is partly written in historical terms ('previous experience'); hardware generations (Quadro Sync II) may be superseded and the page does not cover non-NVIDIA or SMPTE 2110 PTP locking. Corrected by C3-B786-01 (2026-10-24); where the correction disagrees, the correction governs. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://dev.epicgames.com/documentation/en-us/unreal-engine/synchronization-in-ndisplay-in-unreal-engine",
      "note": "Display Synchronisation Demystified; Display Synchronisation Demystified; Display Synchronisation Demystified"
    }
  ]
}