Open source MPEG-4 video codec (library)

 Xvid (formerly XviD) is an open source MPEG-4 video codec, implementing MPEG-4
 Simple Profile, Advanced Simple Profile, and Advanced Video Coding standards.
 It is written in C with assembler optimizations for quality and speed
 (including MMX, SSE, and 3Dnow! code for i386 and AltiVec for PowerPC), and is
 especially optimized towards offline, multi-pass compression for storage and
 archival purposes.
 .
 This package contains the shared library.