posted this on March 30, 2010, 4:01 PM
This problem is caused by what's called "anamorphic" wide screen video. Basically, this is video that's designed to be played back in a 4:3 square (like a television) or 16x9 (like a movie screen, or a newer television). It's designed to be played back both ways, but the way it's designed it defaults to being played back 4:3.
That means that our system tries to play it back 4:3 too (largely because that's the format most video is encoded and uploaded in). The best way to solve this problem is to use different settings or different software to export your video. If your editing software has a checkbox or a setting anywhere labeled "anamorphic" you should uncheck this box (you may want to search your software's help for this term for additional help). If you can't find this setting you may want to try different software.