need help wiith the TMPGEnc 4.0 XPress

屁屁zzz

can anyone please help me with the TMPGEnc 4.0 XPress,when i covert the rmvb to mpg, the files are so big,how can i size it down.
6 v: L: \+ D, A5 c" |5 @' {tvb now,tvbnow,bttvbthank you so much!!!