Safari Youtube Video Without Flash and 4k Video on rMBP

[macNewbie02]

Hi,

Is it possible to watch youtube videos without flash running?

EDIT: It seems like this tutorial works.
https://forums.macrumors.com/threads/1403890/

However, it seems as though 4k videos still lag. If I download the video and play it via Quick Time it plays perfectly.

This only plays with no lag on 4k via Quick Time.

http://www.youtube.com/watch?v=N0m1XmvBey8

Can you play it using html5?

Have you tried it yourself?

Thanks.