Xvid is an open source MPEG-4 video codec originally based on OpenDivX. Xvid was started by a group of volunteer programmers after the OpenDivX source was closed in July 2001.

Xvid features MPEG-4 Advanced Simple Profile features such as B-frames, quarter pixel motion compensation, global motion compensation, lumi masking, trellis quantization, and H.263, MPEG and custom quantization matrices.

The main competitor of Xvid is the DivX Codec (the word Xvid is DivX spelled backwards). While Xvid is open source, DivX is available as either a freeware binary, or the commercial version DivX(nbsp)Pro, which claims significantly better compression. Extensive testing has conclusively proved that DivX and DivX(nbsp)Pro are at the very best only even (and not better) with the speed and quality that can be achieved with Xvid.

• It is open-source, free software.
• Since version 1.0, it has been highly stable, and had very few bugs (all of which have been fixed immediately).
• Xvid will often encode faster than DivX.
• The Xvid source code can be compiled on many different operating systems and platforms, while DivX is officially available only for Windows and Mac(nbsp)OS. Avidemux is a multiplatform program, developed primarily on Linux.
• It is highly customizable and provides more encoding options than DivX.
• It is an excellent mid-range to high-range bitrate video codec, though it looks remarkably good at lower level bitrates too.
• As an MPEG-4 codec, it is compatible (among other MPEG-4 codecs) with DivX, which is an MPEG-4 codec, too.