User Activity

I am getting a continual problem on my videos. Too much noise. This can be seen here: https://www.youtube.com/watch?v=xODkPppDbcU'Noise" might not be the most accurate word - but what I meanis the "activity" that is ever-present. I see this even when...
I have taken some pix with my Powershot SX170 and they have much pixelization even tough it's anoutdoors pic and there shouldn't be a problem with the clarity. The settings I used are Auto and Live. Why am I not getting a clear, clean photo? Thanks.