Why is the video on my Nikon d3100 noisy?

Why does the video that I take on my Nikon d3100 have a lot of noise. I've played with all of the settings and haven't had any luck. I'm recording in full HD, 1080p at 24fps. The video clips that I see online of videos shot with this camera don't have any noise and look great, what's going on?

Here is a sample video that I took, I realize that it is a little dark but it's just as noisy in bright conditions. Make sure to watch it in HD and full screen to clearly see the noise.

I did not see noise, I saw a video that was poorly focused for the video it was taking