How to Convert Video files on a mac: Using VLC player and fixing common problems
If you are trying to convert less common video file formats on your mac computer like .avi, .mkv, .raw or .mpeg then you need a 3rd party program like VLC media player. Check out this quick tutorial for how to use VLC to convert files. Also you can see how to solve issues that I encountered like when the sound is missing from the video.