Fraps doesn't use any special codecs. It just records raw, uncompressed video, which is why the files are huge. Bandicam, OBS, and software from Nvidia are three that I know of that record and compress files automatically, though I can't attest to their quality because I don't use them.
Ah, okay. Thanks for clearing that up. Boyfriend was trying to figure it out a few months ago and found someone say it had a special codec. I just took that as a good enough reason, I suppose.