From the README:

                  MPEG-1 Video Software Encoder
                 (Version 1.5; February 1, 1995)

      Lawrence A. Rowe, Kevin Gong, Eugene Hung, Ketan Patel, Steve Smoot
        and Dan Wallach
     Computer Science Division-EECS, Univ. of Calif. at Berkeley

 This directory contains the freely distributed Berkeley MPEG-1 Video 
 Encoder.  The encoder implements the standard described in the ISO/IEC
 International Standard 11172-2.  The code has been compiled and tested 
 on the following platforms:

  DECstation 5000 and Alpha
  HP PA-RISC (HP/UX 9.X) (i.e., HP 9000/7XX and 9000/3XX)
  SGI Indigo running IRIX 5.0.1
  Sun Sparc (SunOS 4.X)

This is *not* bug-free software.  In particular, I've had problems using
odd-sized input frames.  Other than that, it works OK.