What does "video output" mean in the context of media players?
Possible values are:
vdpau etc. Are these drivers?
They're APIs. "x11" is raw bit-blitting (old and slow, almost never what you want to use barring bugs in the other APIs); "xv" is the X Video extension (most cross-hardware compatible); "vdpau" is Video Decode and Presentation API for Unix (nVidia-only).