Let me test that for you, Geoff.
Hmmm, YouTube vids don't show up at all. I keep forgetting how this works. Will have to ask the Dungeonmaster.
Edit: I think I've got it. Remove the s from the https in the YouTube link. If that's not enough, put the link between <url> brackets, using the button with the small globe in the comment editor, and repeat the link in the first bracket: <url=link>.
Does the video I inserted still play automatically for you, Geoff?