Thought 1080p video on YouTube was big? Think bigger.

YouTube on Friday announced that its player now supports 4k, a standard resolution for films that measures 4096x3072 pixels. As YouTube Engineer Ramesh Sarukkai explained in the announcement on YouTube's official blog, "4K is nearly four times the size of 1080p," and it dwarfs even Imax, which projects films in the slightly smaller 2k format, with its 2048?1080-pixel resolution.

Of course, the proof of 4k's merits is in the pudding, which is why YouTube has a special playlist of five films that can be played back in their original 4k resolution. As Sarukkai warns, viewing these properly requires considerable bandwidth speed, as well as the right gear.

Speaking of which, even with a fast connection, home users will need the proper equipment to enjoy 4k videos in their native resolution. This means a large display, or 4k-capable projector--neither of which can be had on the cheap. It's also worth mentioning that while quite good-looking, streaming 4k video still has to jump through some of the same compression hoops that lower resolutions of HD video must do, meaning that they'll be playing at a much lower bit rate than you'd see, if you were to watch it from the source. On smaller videos, this can be less noticeable, but when blown up big, compression artifacts can be easier to spot.

1080p remains top size in most consumer HDTVs, as well as the service's previous resolution limit. Newer-model phones like the iPhone 4 and HTC Evo are just now becoming capable of shooting in the lesser 720p resolution, leaving 1080p and above to dedicated filming hardware.