Coverting MKV to MPG (free?) Help!

Ive been searching and searching on google and on here and found some helpful things about converting a mkv to apple tv, however all of the programs that I have found have all been paid programs. Are there any that are free? If so, which is the best paid program to use?
Thanks!

northy124 said:

Does no one search?

Get HandBrake

Click to expand...

I have searched, I have handbrake and tried it, but I get invalid source.

I hold the huge MKV converting thread that is like 16 pages, and saw that handbreak would work, but I still can figure it out.

northy124 said:

Are you sure your using 0.9.3?

Click to expand...

Just updated. Thanks!