Give Plex connect a try and you gonna love it. I used to have WDTV live , then moved on to ATV3 , tried Airplay movies , Beamer ,converting everything to Itunes using Handbrake , Iflicks , Subler, Mp4tools etc this all was so much work.
Now with Plex connect , I have to do nothing , it plays everything and has been enjoying it since couple of months now. Only thing is you will have to do a small hack of Trailers app. And then just direct your Plex server to Folders you keep you media.
I second Plex... I use it on my Samsung TV as well as a jailbroken ATV2. Works great with ANY format I've thrown at it.