If like me you purchased Porthole thinking it would solve your AIR Play issues here is a big warning!!
porthole is for Audio only,
if you watch videos the sound WILL NOT be in sync. Had I known this i would never have purchased it... But alas I did.
Here is the information directly from their site!
Now to get my money back!
Hey, my YouTube/Vimeo/etc video and audio are out of sync.
We know. It's quite hard to sync video playing on your Mac and audio streaming to your AirPlay device. Until we find a way around this, Porthole is for audio only.