What is up with my YouTube video?

So I made this video a couple of months ago and posted it to YouTube. I was just watching it today and I noticed that at the top and bottom of the frame are two awkward black bars that keep moving in the frame during the video.
Here is the video for reference:
Does anyone have a clue what this could be? I used Windows Movie Maker and shot of my Nikon d3100 if that has any relevance.

Lmaybe you have video effects on by accident