How to rotocopy mask video footage easily ?

Im buying syntheyes to mix real footage with 3d , but sometimes after we got the shoot analized and exported to blender how do i mask certain objects ?

Rotoscoping ok , but frame by frame ? or can i motion track masc in syntheyes ?

is there an automated way to mask in blender ?

check this out:
(look for open source)
i hope it is of any help to you