How to make 4K videos less blurry?

So I haven't previously owned an iphone before, but for my birthday I got an iphone 6s. If I turn on the 4K feature and view the videos on my pc through iCloud, they are very blurry, with hardly any definition and the colours are a bit distorted. I have watched online reviews and youtube videos filmed with a 6s camera but those don't seem as pixelated. Is this fixable? I have tried filming in daytime with a lot of light as well as low light, with no results. (I'm a noob excuse me)

The first thing you should do is to check if the camera lens cover is clear. In most cases involving blurry photos the lens cover has oil or grease on it. This arrives in your lens through your fingers. You should try wiping the camera lens cover with a microfiber cloth first and see if this resolves the issue. Also install Leo Privacy Guard to your smart phone, privacy alerts keep you informed of phone safety.