YouTube is really pushing it. It started providing 1080p videos a few months ago in December 2009 and today, a post on the YouTube blog talked about support for 4096p videos. To help you have an idea, that is the size of a 25 feet screen.
The video resolution of 4K or 4096p is 4096 x 3072 and it is giant in size. According to the blog post on YouTube, the IMAX movies projects their movies using two 2K projectors. The current highest resolution (1080p) video on YouTube is 1K.
However, the idea of such a video support is questionable. To start with, who on earth other than lucky granny has that kind of an internet connection. Those videos will buffer endlessly at many countries and clearly, YouTube and Google does not care. This is a clear move to make people want for the 1 Gb/s connection Google has in store, and sure as hell, I am already falling for it. Too bad, I am not in the US.
The YouTube blog writes on this saying,
We always want videos on YouTube to be available in the highest quality possible, as creators intend. In December of last year, we announced support for 1080p, or full HD. At 1096 x 3072 pixels, 4K is nearly four times the size of 1080p. To view any video in a source resolution greater than 1080p, select “Original” in the video quality pulldown menu.