Hi Adrian,
Thanks for the quick response. You didn't include the link, but I did go out and search for MS Windows Media Encoder and ended up at Expression Blend 4 Studio. I already have that but I did download and install Expression Encoder 4 Pro from that link, which apparently just added a DLL for screen capture.
Sorry for being so obtuse. When I tried to find a program that reconginzes the .PRX extension Microsoft claims ignorance and web searches don't do much better. If the capability is buried in Expression somewhere I'd expect it to claim ownership, but I'm definitely open to correction.
I tried some cut and paste into new .prx files to fake out PowerDirector but so far no luck.
All I want to do is to be able to get the equivalent to the YouTube_4_3 HD Quality (960x720) profile, which doesn't seem to exist in those supplied.
Thanks again for your help so far and in advance for any additional advice.
Best,
Richard