It all goes down to VLC, FFMPEG, MENCODER open-source projects. Do they support drm locked wmv video files. Don't hold your breath may not come any time soon. This is what drm does, it locks you to a very strict environment. Jailbreak may be possible with some internet tools but most countries consider them illegal tools.
So yes, you have a rights to playback purchased movies, but within strict limits seller gave to you. Usually this means its PC playback and that's it.