DivX

DivX stands for Digital Video Xtreme. It is known as a video codec which has good compression ratios while preserving a good quality based on the H.263 codec.
When DivX Inc. introduced the DivX6 format DivX became a container, too. The file extension for the DivX container is .divx (Still under developement) but normally the DivX encoded video will reside inside an AVI container.