Issue with my videos viewed with Chrome

I'm making this video in the hopes that someone knows how to fix this issue. For all but my first 15 videos, the aspect ratio is messed up when viewed with Google Chrome. These videos will show streched horizontally with black bars on the top and bottom. Everything is fine when using Internet Explorer or Firefox. More and more people are using Chrome and brining this to my attention, but I have no idea how to fix it. The videos that are messed up are also done using multiple cameras, one is HD and my older one is not, so I'm not sure what could be causing this. Please let me know if you have any ideas.