I saw in another thread that the RNS 850 should play m4v video files, however I haven't been successful. It will play DVDs just fine, and plays mp3s and m4a's. My m4v are DVD rips converted to m4v using Handbrake with the AppleTV 2 profile, which uses the h.264 codec. Owner's manual (pg 212) says this should work. My bitrates are below 2000 as well.