I don't understand but a bit of what you're explaining...
You've asked about MPEG compression technology. The Guide I pointed you to speaks to the various technologies used in MPEG-4 codecs.
- Unlike my explanations, the Guide's explanations are simple, understandable, and shown with example images to make the concepts even easier to understand.
The guide is written in plain and easy to understand English ... or French, or German, or Japanese.
...To figure out the compressability will I have to encode over and over again ?
No.
- AutoGK does a compression test for you as part of any multipass encoding.
- GK has a semi-automatic compression test, which is usually run only once. Subsequent tests in GK are only needed if you change the compressibility of the content. That would happen if you select different codec features/options, or change preprocessing filters/settings.
...I'll try to get info on (Auto)GK...
Start
here.