Black squares during videos

[ZephiriusJixx]

Often when I'm watching a video that has darker parts in it, little blocks switch back and forth between being fully black and grayish. These blocks are bigger than the pixels, and it happens with all the videos I've put on it.

Mostly the videos look great, but these blacks get a bit annoying.
Other than that I also get a little bit of ghosting in the credits, but that doesn't bother me as much.

Anyone else have a problem with their screens like this?

[Ennex]

This sounds like the common artifacting that happens with most compression codecs... and yes, it shows up more on complete black areas for some reason. How are your videos compressed, by the way?

[ZephiriusJixx]

Just noticed if you change the option under settings for videos, from sharpen to soften, you don't get the big black squares everywhere, might make some blacks a little less dark, but actually all the dark shapes become a bit sharper counter intuitively.