VLC 2.1.5 (all versions and 2.2.0) plays only audio not video
I've experienced something similar with VLC. Typically, I play vids in full screen on my second display connected to my MacBook. When I am not connected to the external display and I play a vid, VLC seems to want to still play in this dual display mode. So it's like it's playing on a ghost second display.

If this is your situation, the easiest solution is to simply press 'Escape'. That pulls the vid out of full screen mode (on the ghost second monitor) and displays it in windowed mode.

From there you should be good.

(P.S. I just wrote this same thing in another similar VLC post earlier today... Must be something in the air.)