Converting .avi and .mkv to a readable format for the Droid X

[Gryffen Spark]

Is there a particular program people use to convert .avi and .mkv files to .mpg or whatever a Droid X needs the format to be in. I'm getting really frustrated because no matter what I try, my X decides to not play them. What format do they need to be in and how can I convert them without having to pay $50 for some program?

 

[pyro6128]

use handbrake, and make the file an mp4

edit: you can also download the app "rock player", it will play most files

 

[pool_shark]

Mine plays avi's just fine. I use magic dvd ripper.