Why are the videos I've recorded to YouTube suddenly showing up in 4:3 format instead of 16:9?

Episode 967 (2:16:33)

Shawn from Detroit, MI
Macbook Pro

Shawn has been using the camera on his MacBook Pro to record and upload to YouTube. However, recently it's gone from 16:9 to 4:3. Leo says that it could be the software that Shawn is recording from. He's been using the recording utility with Flash. It sounds like this is a known bug in that Flash utility, so Leo recommends using iMovie for recording.

Leo also says that going with Google+ Hangouts Live on Air will automatically record to YouTube, so he could eliminate the middleman. The future is HTML5. In fact, he can go to YouTube's HTML5 page, and they recently turned on the ability to record with it.