How to Get Blender to Interpolate Missing Frames from a Mocap Track?

I’ve just started playing with motion capture with the eventual aim of using it for a music video. At the moment, I’m working on capturing the eyes, and of course, the tracking stops every time I blink or shut my eyes in the captured video.

The only way I’ve found to fill in the frames so far is to interpolate them by hand, so that when the eye reopens, there is not a sudden jump to the new position. It seems this should be quite easy for Blender to do, but I can’t find this function, or, as far as I can tell, any reference to one in the manual.

Any help would be most appreciated.