Are there any free codec movie converters?

I have a movie that I made on windows movie maker but I need to convert into an itunes file to share it. I also just got an ipad last week and am trying to transfer all my things over including the video. I’ve downloaded a bunch of random video converters but they only do 60% for free or the first half for free and then charge. I literally only need it for this one time because in the future I’m going to use imovie (which I actually prefer anyways).

Thanks!