Leave it to Fletch to get all sceintifical and stuff!
But what he said is true. You might want to try to get Cleaner 5.2. It is the most all around useful compression utility I've ever seen. You will be able to choose from all the MPEG formats 1,2,3 & 4 as well as WM8 & Real 9 & Quicktime 6. You can encode a few different ones and see what works best for you.
Get the 5.0 download
here