The Fraps codec (FPS1) is put on the system when you install Fraps. If you’ve reinstalled Windows you will also need to reinstall Fraps in order to play back your movies. Please keep in mind that if you want to give your raw footage to another person they will also need to have Fraps installed.
Your media player may be having trouble keeping up with the large amount of data Fraps has written to disk. Fraps is optimised for processing large amounts of data, but many players are not. If they can’t read the data fast enough skips in the video and audio may be present.
This gaming codec is a lossless codec and used mainly for gaming. It has to capture the screen in a small a size as possible but retain the high quality video. Nobody watches gaming video in low quality formats.There are a number of gaming codecs for video capture. The 3IV1 codec as well as the BINK codec and the FPS1 codec are all gaming codecs.
You can read further on the develop history of this codec on the other page listed here. You can see who and why the codec was originally developed.