OP, what game are you tryign to rercord ?
i make uber 1337 CSS videos ( lol ) and all i use is frpasm btu i record demos ( recordign the code of the game ) then record form them. ( so i dont lag out whn boom headshoting noobs lol.
Divx is a no no... you can edit it !!!
try and get Siony Sound forge, and experiment with the different file types, or 'virtual dub' does *** same... and its free.
more info though plz, your OP annoyed me