[sheppaul]

Originally Posted by Arm3nian

Maybe madshi can explain why he calls it image doubling, I'm sure he has his reasons.

It's from intrinsic properties of Nnedi3 filter. The filter is designed for that purpose.

http://avisynth.nl/index.php/Nnedi3
nnedi3 is also very good for enlarging images by powers of 2,