Xvid is a video codec library that uses the MPEG-4 Part 2 Advanced Simple Profile standard. It is distributed for free under the GNU General Public License.
Since the codec is open source, it has been compiled for a wide range of platforms such as Windows, Mac OS X, Linux and BSD. The software compresses and decompresses video files to the MPEG-4 standard and works in tandem with a video player, and it is also possible to write video compressed with Xvid to a DVD or VCD for direct play. The compression does cause a drop from the original video quality, but the designers attempt to only lose data that is imperceptible to the human eye.