The online version of IM-QT on the QT2.0 CD defines the interface for the SetMediaDataRef function to be:
pascal OSErr SetMediaDataRef(Media theMedia, short index, Handle dataRef,
OSType dataRefType);
which is also what the prototype in the include file says.But the actual description for the "index" field says:
"Contains a pointer to a short integer. The Movie Toolbox returns the index value that is assigned to the new data reference...This is wrong. SetMediaDataRef returns a short, not a pointer (as defined in the APIs).