When embedding videos from YouTube…

Grab the Embed code fom the "SHARE" tab on the videos page.  Depending on where you want the video to be placed, you may want to adjust the SIZE of the embedded player before you copy the embed code. 
Below is a custom player, sized at 356 Wide x 200 High

Of course, you can embed a larger-sized player if desired, but sometimes lower-resolution videos look bad when displayed too large.  Be sure to test your video's appearance before pushing it live.
 

(If 'Blurred Lines' isn't a Summer Jam – I don't know what is…)

That above example is 560 x 315 – you'll notice the right-side of the player doesn't appear on the page… the MAXIMUM width for page content on your FLEX website is 475 pixels.  In order to get the biggest-size video player for Flex pages, use a CUSTOM SIZE player at 475 x 267 (used below)

Those videos were all grabbed from YouTube.  If you are creating local content, we suggest uploading the video to YouTube and using the embed code.  Players from other video providers also use embed codes, and they should work in Flex.

Vimeo works

However Kaltura DOES NOT