Depends on what was uploaded originally, to varying degrees. But it's worth a try.
I was watching a Rory Gallagher vid yesterday at full screen and it was little blurry. There was no "watch in high quality" link on the page (which gives a better pic but no stereo), but I thought to try the &fmt=18 trick, anyhow and I got a very high rez picture. Soundtrack was originally mono, so no stereo but worth the minor trouble.
I've been uploading higher rez vids and, above a certain rez, they appear with he high quality link. If there's much stereo content (like I dueted with myself), then I'll add a link into the info with the whole URL in it.
I don't think you can embed the high quality, though.
