A GPL product, with the following description from the site:

mpeg2dec is an mpeg-1 and mpeg-2 video decoder. It is purposely kept simple : it does not include features like reading files from a DVD, output picture scaling, audio decoding, synchronisation, etc… The main purpose of mpeg2dec is to have a simple test bed for libmpeg2. mpeg2dec also includes a demultiplexer for mpeg-1 and mpeg-2 program streams, and output routines for a variety of different interfaces.

http://libmpeg2.sourceforge.net/