Black frames /weird loading time on featured slider issue

Hi there, 

I am having issues with a featured slider on my site and was wondering if anyone had any thoughts or ideas to help fix the issue. 

My goal is to have a featured slider with small looping video clips and text/buttons to a page. I used a css code to create the slider for blocks and then used squarespaces background video to make the content. But when you first go to the page the 1st slide appears black - then again when it cycles back to the 1st one it goes black again. 

I tried compressing the videos to a smaller size and limiting the amount of videos but nothing really seems to be working.

The website is http://www.untitled.tv

Any help would be be really really appereciated! 

It looks like you found the solution. What did you do? I have the same problem and did the same, as you describe.