The IAAFPlugin::CreateDescriptor implementation in the
CDCI codec sets the category class to
The JPEG, WAVE, and CDCI codecs all set their
categories to AUID_AAFCodecDef.
AUID_AAFDefObject is an abtract class type. If
something tries to create that object type it will fail (not
sure if anything actually does that). If that is not a
problem, then it would still be good to clean up the
inconsistency between the implementations.