Its FOURCC code is MLCY
This codec does not produce lossy formats.
The latest versions of the MLC codec featured several improvements: added support for HDYC colorspace; better compression in modes using motion estimation; inner data format modified and not providing backward compatibility; added support for UYUY colorspace at input side and converted to YUY2 at output etc.
MLC Codec is easy to install, you just need to open InstallMLC.exe and follow the instructions.
It is compatible with Windows XP and as a freeware program it is distributed under the GNU GPL license.