Avidemux 2.6.7 Linux Xvid settings

[Rhys]

Hello,
I wanted to edit some DVB-S recordings. I chose xvid4 as video codec, because it is the only one which works for my source files.
But I am confused about the configuration. I searched on the internet, but i could not find something helpful.
Most of the settings that were suggested i could not fin in avidemux 2.6.7 on Linux Mint 16, and for some settings in Avidemux  I could not find a description.

So my Question is: I get the options none, DCT, Qpel16, Qpel8 and Square for Macroblock decision. Where are the diffrences and what is the best for a DVB-S recording?

And what does the MotionEstimation option do? I can choose betwenn none, low, medium and full.

I hope someone can explain me.

P.S. I hope my english is not too bad.