I've been uploading that format to YouTube and it takes a while to get the "HD' version up and running. SD shows up pretty fast after the upload, and the high quality shows up later.
I point out to friends to look for the "High Quality" option on the bottom right of the video screen so they will look for it.

However, several times the high quality/HD bogs down and doesn't buffer to keep the video showing non-stop. I tried to find some option to allow the video to fully buffer before starting to play but couldn't find any way to do that. Last night my HD stuff just would not play so I'm wondering if its a high traffic time of day and nothing was going to play non-stop in high quality.
Other times my HD videos play really nice and smooth and its a huge improvement over the SD version, especially when it comes to water scenes which are just awful in SD....

Anyone else having that problem?

Eileen