Air Video can stream videos in almost any format to your iPhone, iPad and iPod touch. You don't need to copy your videos to the device just to watch them. It works extremely well.
http://www.inmethod.com
I want to see it it will work on the xpenology build.
I'm not even sure it's possible. I have used it for several years now on my WHSv1 and have recently built a nice new nas. I'm going to miss being able to stream mkvs to my ipad/iPhone.
I did some research and found someone has releases Jar files of the server but after that I'm lost as to what to do with them. (Or if it would work at all)
Here is a link to the jar files if anyone wants to try it out? Or just tell me flat out it won't work so I can try to find something else
http://www.inmethod.com/forum/posts/list/1856.page