WMV AVI MKV RM RMVB XVID video file types are not supported by Apple iPad natively. What to do? You can convert them to .m4v, .mp4, or .mov file format which supported by Apple. However, it is not the best solution if you have lot of unsupported video files. Try the simple way, get a 3rd party video player that can support multiple video formats. Personally, I tested OPlayer HD for iPad. And it is working on RMVB video file with frame skipping enabled. Not 100% smooth but better than cannot watch at all.