HD is just a resolution - the size of the picture. You want to upload a 720p (1280x720) movie, and there's one of two ways to do that. You can either:
- Record at whatever you play in (1680x1050 in my case), then use a program like VirtualDub, and resize it to 1280x720. You'll want to make sure it's uncompressed, so the quality doesn't degrade in the resize.
- Or, you can set your in-game to 1280x720. Make sure you're not in windowed mode, or it won't resize. This typically makes it harder to see, especially on LCD's, but you can still play that way.
If you make modifications to your video (via something like Vegas or Premiere), make sure you select a 720p profile.
Luck is what happens when preparation meets opportunity. -Seneca
Everyone marvels at a square egg, but only the chicken understands the PAIN.