Help with converting MPEG video for FCPX

So not exactly a FCP question, but I will be editing in it...

Another parent is giving me game videos on a key drive; my job is to catalog and edit the footage, perfect for FCPX. The files are MPEG-2 video which I converted with MPEG Streamclip. I'm finding two issues: the converted video has interlacing lines, and the files are about ten times the size of the originals. I'm hoping someone here has some experience since there's not a lot of documentation and lots of settings for MPEG Streamclip.

Thanks!

First, I don't think I've actually touched an MPEG-2 video clip in ages, but here's a little info.

MPEG-2 is mega compression, making very tiny, tiny files. When you convert to ProRes they're not mega-compressed any longer, and are actually easier for your CPU to process.

What you probably need to do is set MPEGStreamClip to give you progressive ProRes files, I'd think.