H.264 encoder with CLEAR options for specifying minimum & maximum video bitrate? I almost never get stuck with things like this and kinda figure things out myself... but I'm at a complete loss here. 

I've used Handbrake, X-Media Recode, and lots of other encoders and they're great.. but they just don't have clearly defined options for maximum and minimum bitrate control in VBR. That, or I just can't find the options. Is there a GUI I could use for this? Or is it only possible through command-line in x264 core? I've only been able to work with constant bitrate so far and I REALLY need to use variable bitrate.

I found these extra options and I think they might be for variable bitrate.. but experimenting and encoding with that still produces a result with constant bitrate:

VBV buffer size, VBV maximum bitrate, VBV initial buffer and Bitrate variance.

Any help would be appreciated.
From http://ffmpeg.org/ffmpeg.html , you can do this in CLI.. not sure about GUI.


  ‘-maxrate bitrate’
  
  Set max video bitrate (in bit/s). Requires -bufsize to be set. 
  
  ‘-minrate bitrate’
  
  Set min video bitrate (in bit/s). Most useful in setting up a CBR encode   
  
  
    Eg: "ffmpeg -i myfile.avi -b:v 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v"