                          mpeg2encode / mpeg2decode
                          =========================
              MPEG-2 Encoder / Decoder, Version 1.2, July 19, 1996

                             Copyright (c) 1996 
                        MPEG Software Simulation Group

                     E-mail:   mssg@mpeg.org  (author contact)
                     Web:      http://www.mpeg.org/MSSG/
                     FTP:      ftp://ftp.mpeg.org/pub/mpeg/mssg/


Contents:
1. Overview
2. Introduction
3. Contacting the MPEG Software Simulation Group
4. Availability 
5. Installation
6. Acknowledgements
7. History of the technical report


1. Overview
===========

This directory contains our implementation of an ISO/IEC DIS 13818-2
codec.  It converts uncompressed video frames into MPEG-1 and MPEG-2
video coded bitstream sequences, and vice versa.

The files mpeg2enc.doc and mpeg2dec.doc in the doc/ directory contain
further information about the codec. The directory verify/ contains
a small set of verification pictures, a small bitstream, and Unix 
shell script to automatically test the output of the encoder and decoder.

A precompiled version of the programs for Win32s (Windows NT/95) will
be made available later date, although it is trivial to make a console
application from the encoder and decoder with most Win32s compilers
(such as Microsoft Visual C++).

Subdirectories src/mpeg2enc and src/mpeg2dec contain the source code
for the encoder and decoder, subdirectory par/ contains a couple of
example encoder parameter files for 25 and 30 frames/sec MPEG-2 and
MPEG-1 video.

Summary of changes since July 4, 1994 release:

This is only the second official release of our MPEG-2 video software.
Only minor bug corrections have been added to the encoder.  We still do
not implement scalable encoding, as this is mostly useful only for
academic research.

The decoder has been updated to meet the final MPEG specification,
although the old decoder will still reconstruct Main Profile and MPEG-1
bitstreams just fine.  The current decoder implements the most
important case of Spatial scalability, as well as SNR and Data
Partitioning.  Temporal scalability is not implemented.

2. Introduction
===============

MPEG-2 Video is a generic method for compressed representation of video
sequences using a common coding syntax defined in the document ISO/IEC
13818 Part 2 by the International Organization for Standardization
(ISO) and the International Electrotechnical Commission (IEC), in
collaboration with the International Telecommunications Union (ITU) as
Recommendation H.262.  The MPEG-2 concept is similar to MPEG-1, but
includes extensions to cover a wider range of applications.

The primary application targeted during the MPEG-2 definition process
was the all-digital transmission of interlaced broadcast TV quality
video at coded bitrates between 4 and 9 Mbit/sec.  However, the MPEG-2
syntax has been found to be efficient for other applications such as
those at higher bit rates and sample rates (e.g. HDTV). 

The most significant enhancement over MPEG-1 is the addition of syntax
for efficient coding of interlaced video (e.g. 16x8 block sizes for
motion compensation, field dct organization, Dual Prime prediction, et
al).  Several other more subtle enhancements (e.g. 10-bit DCT DC
precision, non-linear macroblock scale quantizer, intra VLC tables,
improved IDCT mismatch control) were adopted which have a moderate 
improvement in coding efficiency.... even for progressive video sequences.

Other key features of MPEG-2 are the scalable extensions which permit
the division of a continuous video signal into two or more coded bitstreams 
representing the video at different resolutions (spatial scalability), 
picture quality (SNR scalability and data partioning), or frame 
rates (temporal scalability).

The MPEG Software Simulation Group is currently developing MPEG
software with the purpose of providing aid in understanding the various
algorithms which comprise an encoder and decoder, and giving a sample
implementation based on advanced encoding models. The MPEG-2 software
project is an on-going development. Since the current version of the
encoder already employs a reasonable (and the most popular) subset of
the MPEG-2 signal coding toolkit (MPEG-1 and MPEG-2 Main Profile), and 
there appears to be sufficient public interest, we have decided to make 
a public release of the code.

The encoder can also be used for generating good quality constant
bitrate MPEG-1 sequences and is (to our knowledge) the first publicly
available encoder based on the relatively sophisticated TM5 coding model.


3. Contacting the MPEG Software Simulation Group
================================================

We welcome any project-specific questions, comments, suggestions, bug
reports etc. They should be sent to the Internet E-mail address: 

      mssg@mpeg.org

which automatically forwards to the software authors.

4. Availability
===============

The most recent version of the codec source code is available by anonymous
ftp from:

  ftp://ftp.mpeg.org/pub/mpeg/mssg/

The directory contains the following files:

  mpeg2vidcodec_v12.tar.gz          codec source code and documentation
  mpeg2v12.zip                      source code and Win32s executables
 
You need gunzip (GNU zip/unzip) to uncompress the .gz and .zip archives.

5. Installation
===============

mpeg2decode and mpeg2encode have been compiled and tested on the following
platforms:

 - SUN SPARCstation 10, SunOS 4.1.3, (gcc compiler)
 - '386-PC, MSDOS 5.0, djgpp v1.11, gcc v2.5.7 and MS Visual C++ 4.0

The source code should compile without major modifications on other 32
bit systems with ANSI C compliant compilers. Systems with 16 bit 'int'
variables or segmented memory models are not supported.

Please report any modifications you had to apply in order to install the
programs on your system to the address mssg@mpeg.org      

The encoder and decoder are kept in separate sub-directories,
src/mpeg2dec contains the decoder, while src/mpeg2enc contains the
encoder sources.  The following installation procedure applies to both
the encoder and the decoder:


Step 1: edit Makefile
---------------------

You may have to set CC to your C compiler and CFLAGS to the flags required
by the compiler. It is sufficient to set these variables in the top directory
Makefile. They are propagated to the individual Makefiles of the encoder
and decoder. Any other changes have to be applied to the individual Makefiles,
however.

You can compile the decoder with or without X11 output. Please follow the
instructions in the top-level Makefile to activate X Window System support.

Step 2: edit src/mpeg2dec/config.h
----------------------------------

In most cases, no modification should be required. If your C library
doesn't accept "rb" / "wb" parameters in fopen() (required to disable
LF <-> CR/LF conversion on MSDOS systems), change the #defines RB and WB
to "r" and "w".


Step 3: make
------------

Type 'make' from the top directory (mpeg2). On a PC with DJGPP installed you
have to enter 'make pc' in the individual source directories to produce
.exe files.


Step 4: verification
--------------------

In the mpeg/verify directory, you can verify correct compilation of the
codec by typing 'make test'. No differences should be reported. The
only comparison which is allowed to fail is between test.m2v and
new.m2v, caused by floating point accuracy dependencies in the forward
DCT.


6. Acknowledgements
===================
Authors of the current release are:

  Stefan Eckart    <stefan@chromatic.com>
  Chad Fogg        <cfogg@chromatic.com>

420to422, 422to444 scaling filters:
  Cheung Auyeung   <auyeung@mot.com>

Windows 32s port:
  Sorin Papuc      <sop@compcore.com>

Special thanks are due to

 - J. Steurer, M. Oepen, IRT (Institut fuer Rundfunktechnik, Muenchen):
   for contributing motion estimation speed improvements (distance
   computation short-circuit in conjunction with spiral search, cf.
   dist1(), fullsearch())

 - Tristan Savatier <tristan@mpeg.org> for his help on numerous 
   improvements, suggestions, and features.

 Numerous users:
   for providing bug reports and Makefiles

7. History of Technical Report Project
======================================

The Technical Report, a document which primarily consists of
a C source code program, was initiated by the MPEG committee to: 

 - Provide an example of MPEG video syntax being intelligently employed 
   to generate good quality video bitstreams.
 - A reference tool for implementors
 - Aid in understanding the MPEG specification 
 - decoder which employs full arithmetic accuracy.

----
End of Readme file