You'll want to install QT6. It's good. mpeg4 is good.
.wmv's have all kinds of intellectual property flags and other BS in them... basically... it was microsoft's way of placating the recording industry.
There are hack software to convert them out there... you just need to dig it up, since most of it is technically illegal (circumvention clause in the DMCA).
Cleaner will more than likely not be enhanced per say because it uses its own built in encoding algorithms to squeeze a bit more performance/compression out of the video than the standard QT algorithms (which, by themselves, are still quite powerful).
For $30, QT Pro is easily the most bang for the buck of any software out there.