Green noise on grabber after changing os

Hi,

I've been using hyperion for a long time with windows without any problem.

But after I changed my OS from windows to ubuntu 18.04, weird green noise started to appear on grabber screenshots.

I could not find any reason, do you have any idea?

Here some screenshots from grabber

I solved that issue 2 days ago. Thanks to my colleague, ubuntu or linux dist. uses color depth more than 8 bits. And my analog converter can not maps more than 8bit color depth.