Google owned Youtube is testing new code for playing/embedding videos. The new code uses an iframe and actually embeds the video using HTML 5, meaning it doesn’t require flash, or any other plugins at all. Pretty cool!
Here’s an example of using the new embed code:
<iframe type=”text/html” width=”640″ height=”385″ src=”http://www.youtube.com/embed/VIDEO_ID” frameborder=”0″></iframe>
The video will only play in HTML5 if certain conditions are met, such as the user having opted in, and the video not containing ads.
Another interesting update for Youtube recently was support for 4k resolution videos. While 1080p is 1920×1080 resolution, 4k is a whopping 4096×3072! Unfortunately most processors/graphics cards can’t even handle it yet, mine certainly doesn’t 
To try it out just change the video mode on the Youtube player for applicable videos to ‘Original.’
Here’s both updates in action:
thanks