Your Mac comes with QuickTime Player, which does a great job of playing a lot of video content. Lovely.
But if you spend a lot of time doing stuff with video, you’ll know there are times when QuickTime lets you down. There are formats it just won’t play, even if you have Perian installed (which was number 4 in our list of 50 Mac Essentials).
When those moments arise, VLC will come to your aid.