Maybe doing any factory reset would solve of your problem.

Guys, I'm having this weird issue with my LG K10 New. I don't really know much about phone hardware/software so I'm not sure if it is related to it, but basically, the videos I watch in the cellphone are kinda grainy and pixelated, even in HD. And it's weird because it only happen in videos... Not in pictures, not in games, not even in the display itself, only videos.

I tested videos in Youtube App, Vidme Website, Facebook and even downloaded a video and watched by the phone's default video player.

I'm not sure what this is, I didn't find any people with this same issue on web so I'm not sure if it is happening only to me.

Any hints?