JPEGView/Independent JPEG Group/README.TXT

The Independent JPEG Group's JPEG software
==========================================

README for release 5alpha2 of 4-May-94
======================================

This archive contains an alpha-test release of the Independent JPEG Group's
free JPEG software.  THIS CODE IS NOT INTENDED FOR WIDESPREAD USE.  It has
some limitations and, no doubt, a few bugs.  If you want something more
trustworthy, please see the latest official release (available as described
under ARCHIVE LOCATIONS, below).

This software is the work of Tom Lane, Philip Gladstone, Luis Ortiz, Lee
Crocker, George Phillips, Ge' Weijers, and other members of the Independent
JPEG Group.


DOCUMENTATION ROADMAP
=====================

Please read at least the files install.doc (installation instructions) and
usage.doc (usage instructions).  Useful information can also be found in the
JPEG FAQ (Frequently Asked Questions) article; see ARCHIVE LOCATIONS below to
find out where to obtain the FAQ article.

This file contains the following sections:

OVERVIEW	General description of JPEG and the IJG software.
LEGAL ISSUES	Copyright, lack of warranty, terms of distribution. (READ THIS)
REFERENCES	Where to learn more about JPEG.
ARCHIVE LOCATIONS   Where to find newer versions of this software.
RELATED SOFTWARE    Other stuff you should get.
FILE FORMAT WARS    Software *not* to get.
TO DO		Plans for future IJG releases.

Other documentation files in the distribution are:

User documentation:
  install.doc	How to configure and install the IJG software.
  usage.doc	cjpeg/djpeg usage instructions.
  cjpeg.1	Unix-style man page for cjpeg (same info as usage.doc).
  djpeg.1	Unix-style man page for djpeg (same info as usage.doc).
  change.log	Version-to-version change highlights.
Programmer and internal documentation:
  libjpeg.doc	How to use the JPEG library in your own programs.
  example.c	Sample code for calling JPEG library.
  structure.doc	Overview of the JPEG library's internal structure.
  filelist.doc	Road map of IJG files.
  coderules.doc	Coding style rules. Please read if you contribute code to IJG.

If you want to understand how the JPEG code works, we suggest reading one or
more of the REFERENCES, then looking at the documentation files (in roughly
the order listed) before diving into the code.


OVERVIEW
========

This is an early test release of the rewritten IJG library, intended for the
hardy and adventurous only.  Consider yourself warned.

There's still a good deal of missing functionality in this release (see
change.log for the current status).  Still, the software is quite useful
within its limits, and it is noticeably faster than version 4.

----------

This archive contains C software to implement JPEG image compression and
decompression.  JPEG (pronounced "jay-peg") is a standardized compression
method for full-color and gray-scale images.  JPEG is intended for compressing
"real-world" scenes; cartoons and other non-realistic images are not its
strong suit.  JPEG is lossy, meaning that the output image is not necessarily
identical to the input image.  Hence you must not use JPEG if you have to have
identical output bits.  However, on typical images of real-world scenes, very
good compression levels can be obtained with no visible change, and amazingly
high compression levels are possible if you can tolerate a low-quality image.
For more details, see the references, or just experiment with various
compression settings.

We provide a set of library routines for reading and writing JPEG image files,
plus two simple applications "cjpeg" and "djpeg", which use the library to
perform conversion between JPEG and some other popular image file formats.
The library is intended to be reused in other applications.

This software implements JPEG baseline and extended-sequential compression
processes.  Provision is made for supporting all variants of these processes,
although some uncommon parameter settings aren't implemented yet.  For legal
reasons, we are not distributing code for the arithmetic-coding process; see
LEGAL ISSUES.  At present we have made no