Unhappy 4k & 2k video at youtube doesn't work

Hello..

I'm wondering why note pro 12.2 doesn't support 4k & 2k YouTube video ; I'm using the UC browser HD and I changed sitting at the browser to desktop on that be able to used to from YouTube video any reserosation up to 1080p but higher like 1440p and 2160p doesn't work at note pro 12.2.... note pro 12.2 should be able to working 4k & 2k reserosation...as my knowledge.

anyone have faced that issue? If there is any suggestions would be a appreciated.

cheers.