[wonkey_monkey]

Originally Posted by ChaosKing

You can unconfuse yourself here http://avisynth.nl/index.php/Convert

Nope, still just as confusing. Nothing on the page indicates whether a change in bit depth should be expected or not with those functions. I've also added converttoy8 to the list, as you really shouldn't expect this after using it:

Originally Posted by pinterf

Perhaps once it did then from one point it didn't, when it was mapped directly to ConvertToYUV420 (and ...422, ...444). It should throw an error for non-8 bit colorspaces.

converttoyuy2 still does, presumably as it doesn't have a comparable function to be remapped to.