3d alone works. You put either "Use3DLayers" or its short version "3d" (it's a readarg template).

About playback speed, i assume you use mplayer. If so, since audio driver is absent from this release, in the meanwhile, just add -ao null. Else mplayer seems to pick up some filesave audio id or so (haven't checked on efika yet), which would make playback very slow.

Of course, don't expect to read much more than 640x480 movies anyway (nor demanding codecs like h264), but below it should be fine.