I'm at work so can't help further - but "transform: translateX()" should be used instead of positioning relatively to the left/right for movement. It will make it a lot more smooth. Unfortunately it moves your "strips" over the static background image and breaks the effect. Adding a repeat-x; to them didn't'fix that problem.

I'm sure it's fixable but I can't think of how offhand, and as mentioned... at work. But that should be a good starting point for you. :)

Always good to just ship it! I half-figured it was on a to-do list given the nature of the project.