XVID

Xvid, also spelled XviD, is a free and open-source video codec library that implements the MPEG-4 Part 2 standard. It originated in the early 2000s as a fork of the OpenDivX project and became one of the most widely used MPEG-4 Part 2 encoders. The library provides both encoding and decoding functionality and is designed to be portable across platforms including Windows, Linux, and macOS.

Xvid supports the MPEG-4 Part 2 Simple and Advanced Simple Profiles, enabling features such as B-frames, motion compensation, and quantization for efficient compression. Encoders built on the Xvid library typically offer options for rate control, including constant quantizer and variable bitrate modes, as well as two-pass encoding for improved quality, along with settings for motion search range and macroblock processing.

Usage and containers: While commonly paired with the AVI container, Xvid can be used with other containers via compatible muxers. It has long been favored for standard-definition video and has remained popular in legacy video collections and certain niche applications.

Licensing and status: Xvid is released under the GNU General Public License. Development activity has slowed in recent years, with official updates being infrequent, though the codebase remains usable and is included in many legacy toolchains and portable media players. It competes with proprietary DivX and newer codecs such as H.264/AVC.

See also: DivX, MPEG-4 Part 2, OpenDivX.