Parallax Bg image jitter on some browsers

[Hova10]

Hey,
So i'm attending a web developer course, so i'm not that experienced with web development yet....
I just finished my 1st project of the course and i used Stellar.Js to add some parallax on my Bg img's. However, there's a crazy jitter on the img's if i view the website on anything other than firefox... I already tried that position:fixed thing, but nothing happened... The images still bounce around everytime i scroll....
Is there anything i can do to atleast reduce this jitter on chrome,safari and IE?

This is the website btw:

http://www.opinatus-solutions.com/

Tyvm in advance

[JayV30]

Looks pretty good to me on Chrome 35.0.1916.153 m running on Windows 8. Did you do something to solve this? I'm here poking around for a solution to the same problem on a site I'm developing.

[Hova10]

Haven't done anything. And to me the images still sort of bounce on any browser except firefox...