MPEG-1 Video Software Encoder
                 (Version 1.1; August 9, 1993)

     Lawrence A. Rowe, Kevin Gong, Ketan Patel, 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:

 HP PA-RISC (HP/UX 8.X, X11R4) (i.e., HP 9000/7XX and 9000/3XX)
 Sun Sparc (SunOS 4.X, X11R5)
 DECstation 5000 and Alpha

If you decide to port the code to a new architecture, please let
us know so that we can incorporate the changes into our sources.

This directory contains everything required to build the encoder
and run it.  We have included source code, makefiles, binaries
for selected platforms, documentation, and test data.  Installation 
instructions are given in the file named src/INSTALL.  A man 
page is given in the file doc/mpeg_encode.1. 

The encoder will accept any input file format as long as you provide 
a script to convert the images to PPM or YUV format.  Input file
processing is described in the file doc/INPUT.FORMAT.  Options to control 
input file processing and compression parameters are specified in 
a parameter file.  Very little error processing is done when reading 
this file.  We suggest you start with the sample parameter file 
examples/template.param and modify it.  See also examples/default.param.

We have also provided a Tcl/Tk script, named encode.tcl, that can 
be used to set parameters interactively (see the misc/ directory).
The misc/ directory contains utility you might find useful including:
programs to do PPM/YUV conversion and programs to convert Parallax
XVideo JPEG files into PPM or YUV frames.

The motion vector search window can be specified, including half-pixel
block matching, in the parameter file.  We have implemented several 
search algorithms for P-frames including: 1) exhaustive search, 
2) subsampled search, and 3) logarithmic search.  We have also implemented
several alternatives for B-frame block matching including: 1) interpolate
best forward and best backward block, 2) find backward block for best
forward or vice-versa (called CROSS2), and 3) exhaustive cross product
(i.e., go out for coffee and a donut!). The search algorithms are controlled
by options in the parameters file.  For tips on choosing the right search
technique, see doc/TIPS.

We have done some tuning to produce a reasonable encoder, but there are
many more optimizations that we would like to incorporate.  These 
extensions are listed in the file EXTENSIONS.  If you succeed in 
implementing any of them, please let us know! We have established 
several mailing lists for messages about the Berkeley MPEG work:

mpeg-list-dist@CS.Berkeley.EDU
   General information on the MPEG-1 decoder and encoder for 
   everyone interested should be sent to this list.

mpeg-list-request@CS.Berkeley.EDU
   Requests to join or leave the list should be sent to this
   address. The subject line should contain the single word
   ADD or DELETE.

mpeg-bugs@CS.Berkeley.EDU
   Problems, questions, or patches should be sent to this address.

Our future plans include porting the encoder to run on other
platforms and completing a portable parallel version of the code
that will run on a network of workstations.  Vendors or other 
organizations interested in supporting this research or discussing 
other aspects of this project should contact Larry Rowe at 
Rowe@CS.Berkeley.EDU (+1 510-642-5117).

ACKNOWLEDGEMENTS:

We gratefully thank Hewlett-Packard and Fujitsu who provided financial
support for this work.  We also want to thank the following people for 
their help:

    Jef Poskanzer who developed the pbmplus package.
    ---------
    Copyright (C) 1989, 1991 by Jef Poskanzer.

    Permission to use, copy, modify, and distribute this software and its
    documentation for any purpose and without fee is hereby granted, provided
    that the above copyright notice appear in all copies and that both that
    copyright notice and this permission notice appear in supporting
    documentation.  This software is provided "as is" without express or
    implied warranty.
    ---------

    Eiichi Kowashi of Intel and Avideh Zakhor of U.C. Berkeley who
    provided valuable suggestions on motion vector searching.

    Chad Fogg of the University of Washington who has helped us 
    understand many issues in MPEG coding and decoding.