I use several for different uses and they all let you choose the codec and tune it noprobs, I use ZD soft Video recorder 2.1 with fantastic results, ZD soft did 3 good apps, ZD Soft Game Recorder, Soft Video Recorder, Screen Recorder, so the new version v3, does all 3 should be better, it is in most ways but I cant find out how to change the codec, i emailed their support asking where is it, as yet no reply, so i challenge software experts to find it, good luck.
thanks.
http://www.zdsoft.com/