divx movie managerWhat does the extension for a movie have to be for my PSP?

I have the latest software and i want to put a movie on,
my media manager doesn't work,
and i want to put a movie on and divx movie manageri have,
a lot of conversion programs.
what does the extension have to be ?
i have a divx one, i tried and it didn't workdivx movie manager,
and i also tried a avi file.
Did i do something wrong?

Please help, and thanks !!!!!
It has to be a MP4 file.