Don't have the slightest idea if this will work or not but give these a try to demux/mux the AVI's which may or may not fix them as they commonly remove crap out of AVI's even sometimes making them playable:
What I'm wondering is that recuva seems to make some changes to all (!) the AVI files. All the files were exported by Adobe Premiere, so absolutely WITHOUT this use of UNDF codec. I do not understand where it's coming from.
I find another tool, AVImedic, which noticed that the file it self and the index are ok, but 0,1% of the file, in the HEADER, is an small problem.
When I could find an other copy which is ok AVImedic can make an 'repairpatch' for al my files.
Because of the size of the this old files (1 Gb is the smallest) and in this time HDU were much more expensive I do not have an backup of it.
So still in big problems to solve the whole recovery action with REVUCA.