Streaming from iTunes

I have a bunch of TV shows in avi format that i have added to iTunes using reference files. They play fine in iTunes but i am wondering if i can stream these reference files to apple tv?

I also have some MKV movies which i would like to do the same thing with...

Also, i noticed airplay is enabled in iTunes now, if i have an apple TV can i airplay movies from iTunes to apple tv? if so can this only be done with mp4 files?

 

The only reason reference files to AVI/MKV movies works in iTunes is that you have additional codecs/plugins etc installed on your computer. The Apple TV does not have these additional installations so it won't play those reference files whether by syncing or streaming (AirPlay streaming from iTunes does work, but only on MP4/M4V videos).

You'll have to convert your files to an Apple TV-compatible format. Many MKVs can be losslessly converted using MKVTools or similar; AVIs are a bit trickier but can be converted lossily with Handbrake or whatever.