Here's one from my library, made it a few months ago to auto get the best version of a video from youtube.

Not too much to write on this one, you pass in the url of a youtube video (the normal web url) - it'll first try and load the HD version, then the HQ version and finally falls back to the "normal" quality version; the class extends mx.controls.VideoDisplay so you have all the normal methods.

Further, it only does all the detection stuff if the url is a youtube video, if it isn't then it loads the video as per usual, so it can be used as a replacement class for VideoDisplay without any negative effects or strange functionality.

no demo, just the source. Uses Flex 3 and ActionScript 3

hope it's of use to somebody!

Source: CleverVideo.as

Usage:

video : CleverVideo = new CleverVideo( 'http://www.youtube.com/watch?v=_OBlgSz8sSM' );
addChild( video );