PTB sync trouble over 50ft fiber-optic HDMI

Dear PTB Team,

We are trying to set up a PTB experiment where we use a dual-monitor setup. The drawn up design of the setup calls for a stimulus computer running PTB to be in one room (with an experimenter-monitored display as the second monitor) but also connected to a primary monitor in another room (viewed by the participant) by 50ft of fiber-optic HDMI cable. However, PTB runs into a synchronization failure. Will this setup ever work? We are happy to consider priority support if you think that would help.

I should add that PTB works fine when connected to one monitor by conventional cables. This is a Windows 10 setup.

Thank you for your time.


As a user, you should buy priority support regardless of whether you
need support, its the main vehicle for funding the maintenance of PTB
so that Mario can keep working on it and making sure we can all do the
research with the best tool.

Does your setup work with dual screen and two normal cables? I think
its probably not the cables problem, but dual screen in general with
Windows 10. If possible, consider switching to Linux.

Also, provide some more details. Is PTB fully up to date? What graphics card?


Thank you for the suggestion, I will ask the PI if he is willing to support the cause monetarily. A bit beyond the scope of the post, but shouldn’t funding agencies be bending over backward to support PTB if a grant were to be submitted?

You were correct in that the dual monitor did not work with standard cables.

I can consider switching to Linux, but since the change would be permanent I’d have to discuss with the PI’s on the project and our consultant at the EEG lab company.

It is unfortunately a dual-graphics card PC with:
Intel UHD Graphics 750
NVIDIA Quadro P1000

PTB version is 3.0.18

Thanks again,

Hi Andrew,

I wish they were. As far as i know, project like PTB need very specific funding programs geared towards the software that make science work. Normal funding programs are interested in basic or applied research results, not support of a software package that enables those results. If anything, it would to be something new to be developed in service of those groundbreaking research results.

You can perhaps dual boot linux and Windows, unless everyone would benefit from the switch.