How would I do a Super Nintendo-like pixelated fade-in effect?

I know, I know, this has probably been done in 8 billion games by now, but I still want to know how to do it. The effect at the start of a lot of stages in Super Nintendo games where it starts with big chunky pixels and they get smaller and smaller until they are the right size.

I’m guessing it is just some simple filter I can do to a camera or using a UI canvas or something?

I’m talking about what happens about 8 seconds into this video:

Where would I start with this?

PS. I’m making a 2D SNES style game if that wasn’t obvious.

I would look into the functions and variables you can tweak on the Texture class. I haven’t done an effect like this before but perhaps the mipMapBias? You’ll have to experiment with it.