Sync out/in not working

Hi all.

I am having trouble with Sync out/in in CHOP.

We are using 4 PCs with NVIDIA Quadro A6000 and GSync2 built in.
TouchDesigner version is 2021.16960.

I am using for testing and am getting errors of up to 5 frames on each of the 4 PCs.


I have set Sync CHOP to default and enabled Window COMP framelock based on this article.

Please let me know if there is anything else I should be aware of.

I’d start with just two PCs. One Sync Out, and one Sync In.

An Info DAT attached to those will give you more information about what’s timing out.

Make sure your clients have their timeline realtime flag turned off, and their timeouts should be about 1 frame period (16 msec).

Hi rob,

Is it correct that the timeout for both Sync out/in should be 16ms?

The value of sync_incompletes for Chop in does not change. I believe this is correct.
However, the value of sync_totaldelay keeps increasing little by little.

The display may be off by about 2 frames.

We believe that if it works correctly, the frame misalignment will not occur.
Is this correct behavior?
Are there any other possible factors?

We are very stumped.

Yes, 16ms assumes 60 frames per second playback rate. That should be fine.
I would even lower to half that to make sure everything happens within the same frame boundary.
Default is 0.5 frame timeout. (or 8 msec in your case).

The sync_total delay incrementing slightly is not a problem, as there will be some delay each frame.
sync_incompletes is what you need to hold steady.

Also add an Info DAT, (not just Info CHOP) on the Sync Out for a per-client table of data.
You’ll be able to see which clients are failing to respond in time.

This should bring all clients to within one frame period.
Looks like you’re sometimes slightly longer?
Are there any delays from the clients to their displays?

Also, can you confirm your GSync is active?

I’ll see if I can dig up more info.

And you can confirm your clients sessions are set to Realtime Off , while your sync-out session has it left on?

Hi rob,

Thank you very much for your useful advice.

I will try them one by one.
I will report back later on the status.

Hey codelight,

Please use these two simple Server and Client toe files. Start the timer on the server side and it will loop indefinitely. Then run the SyncClient.toe on each of the client computers. Report back what the trail CHOP reports for the channel called sync_incompletes. Is it stable or increasing? (8.2 KB)

Hi, Jarrett

Sorry for the delay.
I tried the sample.
Sync In Chop sync_incompetes is increasing.
However, when I changed to 60FPS and set the timeout to 16ms, it stopped increasing.
However, there still seems to be a gap of about 1-2 frame.

I share a video of the test.
Sometimes the movies sync, sometimes they don’t.

Here is an improved server client example. Can you try these by running one for each view and run the test you show at the begining of this thread? (11.2 KB)

Hi Jarrett,

Thank you for the data.
There seems to be a problem with the equipment we are using for our test.
We will test in our production environment at a later date.
We will share the results with you.

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