Possible issues with using MPlayer on OpenBSD: all arches: The GUI is deprecated so we stripped it from the build. You can use x11/gnome-mplayer or x11/smplayer instead. i386: win32 codecs were disabled in OpenBSD's build, as the open-source codecs are now of decent quality. arm: You may encounter slow video output. In this case you can disable the X.Org screen rotation in /etc/X11/xorg.conf. Depending on the video you are playing you may want to pass the -framedrop or the -hardframedrop option to mplayer. In order to improve vorbis performance on ARM, try using the tremor codec. This can be achieved using '-ac tremor'. See the package description for a list of FLAVORs and their meaning.