QMC is internal codec and have no nedeed a external codec, you can go in expert mode and try the divx profil.
To make a little file you must select a video bitrate of 1500 and audio bitrate of 128k max.
Now, if you convert a dvd or other video file and keep a goop quality, you must keep a good ratio in the settings convertion.
But try to add (copy¦paste) the following setting in the field command line in expert mode : -flags +4mv+trell -aic 2 -cmp 2 -subcmp 2
This command line to keep a good quality ratio.
To help you follow the tutorial on the expert mode.
Have a nice day.
thx for donating