Any way to import Camtasia produced AVI's

I have used Camtasia for screen capture. I especially like the very small files sizes. Now I’d like to import camtasia avi’s to blender. While I can import other uncompressed AVIs easily the camtasia avis (using techsmith codec) don’t seem to be supported.
I’ve tried all sort of ways to get them show on Blender (2.78c), fraserver from VirtualDub etc to no avail.
Has anyone managed to import these avi’s somehow other than re-rendering to something less uncompressed? The Techsmith codec is really good for small sizes, everything else I’ve tried is way, way bigger.