What's this on my screen when playing videos?

[patrickg25]

Is this a fault or something? I have Lumia 625 and there's this like three edges of probably squares for, I'm guessing, buttons on screen. I'll put a pic...

 

[patrickg25]

Is this a fault or something? I have Lumia 625 and there's this like three edges of probably squares for, I'm guessing, buttons on screen. I'll put a pic...

Here's the URL OF THE PIC. On the right edge of the screen there's the lines. I hope you can see it clearly. http://tinypic.com/r/15mnqzn/8