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[rodh]

Hi,

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: http://wiki.cchtml.com/index.php/Aticonfighelp 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!

[chm · Accepted solution]

Hi,

1: Yes, you can connect up to 4 GPUs to a single S400 board.

2: You can genlock multiple displays that are connected to a single GPU as long as the connected monitors are identical.

3: The accepted input range for the house sync is between 15 and 120 Hz

Please note that the SyncDelay can only be used if an external sync signal is used. If one of the connected displays is used as TimingServer a SyncDelay cannot be specified.

[rodh]

Thank you for the answer, this is great.

However, I'm still unsure about question 1. Can I get 4 display cards and delay them all by a different amount with respect to a an external signal, with only one S400 card?

In other words: is the delay against external sync set on each display card or the S400 card?

Thanks a lot.

[chm]

You can define the delay agains the external sync per display card. This is part of the Timing Client configuration.