I hadn't realized that YouTube worked best (seems according to PowerDirector) with a .WMV file.
After the process was finished, in my export directory there was the .WMV file as I expected, but also a .MPG file of almost the same size. That file had a suffix of _0 appended to my filename. When I check the properties, it's 720 x 480.
I didn't ask for that file to be created... how come it's there? And can it safely be deleted without affecting my project?
Thank you.