I downloaded Avid DNxHD codec separately, as I mentioned it, and installed it. After Effects still wouldn’t see it. It’s still gone from the Quicktime codec option menu. On both computers.
I’m using the full Avid version.
And like I said, this same thing happened in the EXACT same manner on two different computers. Installing codecs doesn’t solve this issue. Installing Avid again doesn’t solve it either. For some reason when I install Avid, then After Effects it on a CLEAN system for the first time, the codec is there. ONCE I delete Avid, that’s it, the codec is gone forever no matter how much installing and uninstalling I do.