How to ensure my high quality videos are displayed as such on youtube?

My original videos are clear and sharp but when viewed on youtube they are "dumbed down" with lots of "lossiness" to the imagery. On the other hand, I can see high quality video is possible when I see videos like this: a href="http://www.youtube.com/watch?v=7FsLqFIkYI0&feature=related" rel="nofollow"http://www.youtube.com/watch?v=7FsLqFIkY…/a