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Framelock question. Can I do this with the S400?

Question asked by rodh on Feb 1, 2012
Latest reply on Feb 9, 2012 by chm



I'm trying to solve a very specific problem. For this, I need to run 4 displays at 120Hz, and have the vsync for each trigger a quarter of a frame after the previous:

  1. Display 0, start frames at 0s, 4/480s, 8/480s, ...
  2. Display 1, start frames at 1/480s, 5/480s, 9/480s, ...
  3. Display 2, start frames at 2/480s, 6/480s, 10/480s, ...
  4. Display 3, start frames at 3/480s, 7/480s, 11/480s, ...


Now the question is, can I do this with one S400 and one or more graphic cards? I don't have access to the official documentation, but looking here: and scrolling down to the genlock section, it would appear here that a delay in ms can be set on a per-display level. Using: --glsync-setconfig=delay,fr_cntl,sig_src,smpl_rate,fld,edge,coef.


Based on this information, here are the questions I am trying to answer. Any help would be greatly appreciated:

  1. Can I have 4 display cards and only one S400, and delay the sync for each display, or would I need four seperate S400s to do this?
  2. Can I also get away with using less physical display cards. Could I potentially delay displays independently on the same card (assuming I'm using cards with multiple GPUs)
  3. Can I use a 120Hz input genlock signal or does the S400 only support broadcast standard genlock rates? If not, can I use a scan rate to genlock coefficient?


Many thanks for any help anyone might have on these questions. Or if you know a link to a PDF for the S400s manual (the datasheet was not hugely helpful), that would also be great!