It might "officially" be 4K, but it's so heavily compressed that there are visible 8x8 blocks in the images, so it might as well be 8 times smaller - i.e. it has an effective resolution of 512x384
Take a look: http://imgur.com/YFsGb.png (I didn't change the image at all, except to crop it. I used mplayer to play it directly to png, and I made it a png so it's not jpeg artifacts.)
Interestingly the png of the 1080 is twice as large as the 4k version! Even though the 4k "officially" has twice the resolution in both directions (i.e. 4 times as many pixels).
High density or "retina display" monitors should be on their way soon, I've seen a 15 inch prototype display, not sure the resolution, but it was gorgeous. It will be interesting to see how web standards evolve to work well with these resolutions.
It seems since about 720p quality bottleneck is more in codec artefacts than in the resolution.
So for overall effects it would be probably better to give additional bandwidth to less lossy codec / settings than just to pure resolution (their first video "Life in the garden" has 28 MB in 720p and 91 MB in 4k resolution).
I don't have the gear to watch real 4k video properly, but watching the first video ( http://www.youtube.com/watch?v=N0m1XmvBey8&feature=PlayL... ), I wouldn't consider it 'real' 4k. I bumped the res to 'original' and saw highly visible encoding artifacts on a 1080p monitor. Artifacts that I absolutely would not expect to see on 4k source RED footage, never mind 2k. It's a nice marketing number, but like buying a camera by megapixels and ignoring lens quality, it's not truly indicative of quality.
Now we just need monitors, rather than projectors, that can actually display 4K content at its native resolution. Every LCD panel I've seen tops out at 2560x1600.
native resolution of 3840×2400 pixels (WQUXGA) on a screen with a diagonal of 22.2 inch (564 mm). This works out as over 9.2 million pixels, with pixel density of 204 pixels per inch (80 dpcm, 0.1245 mm pixel pitch)
Quad HD 3840x2160 prototypes have been shown, so we're getting close. Once 3D becomes a standard feature, TV makers may have to adopt quad HD to keep margins up.
I've got a 2560x1600 monitor, and honestly, the 4k video looked worse to me than 1080p. Blocky all over the place. If they can't raise the bitrate on the 4k videos, there's really no point to it.
Pure marketing stunt. Most Blurays are probably higher quality even if they are "only" 1080p. But they have bitrates hovering somewhere between 10 to 20 Mbps, while YouTube apparently uses <1Mbps even for 4k.
Incidentally it could be interesting to see some kind of visual quality vs bitrate vs resoltion -chart, ie what would be the optimal resolution for some bitrate.
YouTube wouldn't be what it is if they kept wondering how they'd monetize free video on the web. First they experiment, then they expand, then they take over. Even if money does not follow directly, it will eventually make its way into Google's core product: Adsense.
Youtube is pushing out of its niche and wants to become the place for storing and sharing any kind of video on the internet.
Note that Google has storage to burn, they've mastered high availability clustered network storage at a cost per gb far lower than the rest of the industry, they might as well try to use that for leverage. Also, google is a backbone internet provider, they don't pay for bandwith the same way that Microsoft or Apple might. Youtube bandwitch may cost them nothing, and even in a worst case scenario it only costs them rock bottom wholesale rates. Again, they're way ahead of the competition, so it makes sense for them to push.
So if I'm understanding this correctly, its a move to populate the site with high rez videos, so in a few years (or more) when monitor resolutions catch up, the site will be full of high rez content to watch?
Take a look: http://imgur.com/YFsGb.png (I didn't change the image at all, except to crop it. I used mplayer to play it directly to png, and I made it a png so it's not jpeg artifacts.)
For comparison here is the 1080 version: http://imgur.com/wkClm.png
Interestingly the png of the 1080 is twice as large as the 4k version! Even though the 4k "officially" has twice the resolution in both directions (i.e. 4 times as many pixels).