Qf in MeGUI

[Vytenis]

I always used to look at Qf value in programs like Gspot or GKnot. But I can't find it in MeGUI. How should I estimate movies to be encoded quality? Only bitrate? But quality depends on frame size too.
Staxrip gives suggestion to set bitrate lower - excess bitrate won't make movie better or resize (make smaller) frame.
I miss this feature in MeGui or I just do not know how to use it properly?

[Vytenis]

I found thread http://forum.doom9.org/showthread.php?t=116582 that partially answers my question.
I think my question should be moved to MeGUI feature request thread either.