This app doesn't play many file types. I tried looking for a way to communicate with Roku support but couldn't find an email address. I was hoping they might consider updating the channel to handle other video codecs. Anyone have any idea how to reach them?

This is as good a place as any to reach them.  RokuDale is the guy when it comes to RMP.  The "channels" have nothing to do with which codecs are supported.  It's entirely dependent on the firmware and Roku has apparently decided that what's supported now is good enough.  If you have a lot of media in an unsupported format you may want to consider Plex and its transcoding capability.

-JT

Roku itself has to be able to support the video codecs, can't be done via the app. Requires licensing costs to support certain formats. Roku would have to pay Microsoft for supporting AVI container. Typically old XviD based videos will use that AVI container rather than MP4. XviD is becoming a dead format anyways.

Thanks, that answers the question.