what difference between drm and x11?

I createa linux based app which use decode/encoder, from the example,I need create libva hardware handler and there are two options.  X11 or DRM. but what the difference between these options. for Haswell intel chipset, which is the best option?

BTW. what the minimum linux kernel version needed in order to support Mediasdk, We currnelty have  SLES development machine and 3.0.93 kernel.. does it too old to support Mediasdk full feature?