Hello, a played a little with the rotobezier tool and came up with this:

the first part shows the video with the rotobezier in action.
the second is the original video without the mask.

is in spanish because i only wanted show it to my friends, but then i discovered that the rotobezier tool is almost into oblivion, so thats the reasson i share this to you.

Is VERY easy (tedious but easy…)
there are some good quality tutorials, just search for rotoscoping in blender c: