It looks like the videos don’t play in Firefox until they are fully downloaded. That might be because of your server configuration but I can’t figure it out exactly. One thing to try is changing the filenames to mp4 instead of m4v.
Also, I noticed that your videos were recorded in SD at 720×480 with rectangular pixels. When they’re shown on a computer screen with square pixels they look slightly squished so the president looks fatter than he is. If you resize your videos to 640×480 when you convert them it should look a lot better.