Sharks codecs comes with its own "settings app" for x86 and x64 which is essentially a "tweak tool" but more comprehensive and intuitive. You need both if you have an x64 system. Allows you specify which codecs and splitters will be used for which file types, among other things. Very good codecs and tools.
Tip: If you are going to use them, go into the properties of the settings app's .exe, compatibility tab, and set it to always "run as administrator."