The Independent JPEG Group's JPEG software
This distribution contains MS-DOS executable copies of version 4 of the
Independent JPEG Group's free JPEG software. You are welcome to redistribute
this software and to use it for any purpose, subject to the conditions under
LEGAL ISSUES, below.
This version of the software runs ONLY on MS-DOS machines with 386 or 486 CPUs
and at least 1Mb free extended memory. It requires a VCPI-compatible memory
manager (such as QEMM or 386MAX), and therefore it will NOT run under Windows
or OS/2 (DESQview is OK though). If you don't have a compatible system, use
the vanilla DOS version, posted separately. But if you do have a compatible
system, this code runs up to twice as fast as the vanilla version.
For usage instructions, see the file USAGE. Useful information can also be
found in the JPEG FAQ (Frequently Asked Questions) article, posted regularly
in the Usenet news.answers newsgroup.
Please report any problems with this software to [email protected]
Put the CJPEG.EXE and DJPEG.EXE files someplace handy. You may also want to
add a line to your AUTOEXEC.BAT file to define the directory in which the
programs will create temporary files; it should look something like this:
Make sure that the indicated directory is on a disk with plenty of free space;
if the programs create temporary files at all, the files will be large
(several megabytes for typical images). If you haven't set GO32TMP, the
programs will look at your TMP or TEMP variables (in that order), and will
create files in the current directory if none of these are defined.
If you have installed DJ Delorie's DJGPP (version 1.09), you can save some
disk space by removing the GO32 DOS extender from CJPEG.EXE and DJPEG.EXE.
See the DJGPP documentation for details.
ABOUT JPEG FILE FORMATS
CAUTION: Handmade Software's shareware PC program GIF2JPG produces files that
are totally incompatible with our programs (and everyone else's too). They
use a proprietary format that is an amalgam of GIF and JPEG representations.
However, you can force GIF2JPG to produce compatible files with its -j switch,
and their decompression program JPG2GIF can read our files (at least ones
produced with our default option settings).
The file format we have adopted is called JFIF. This format has been agreed
to by a number of major commercial JPEG vendors, and we expect that it will
become the de facto standard. JFIF is a minimal representation; work is also
going forward to incorporate JPEG compression into the TIFF 6.0 standard, for
use in "high end" applications that need to record a lot of additional data
about an image. We intend to support TIFF 6.0 in the future. We hope that
these two formats will be sufficient and that other, incompatible JPEG file
formats will not proliferate.
Indeed, part of the reason for developing and releasing this free software is
to help force rapid convergence to de facto standards for JPEG file formats.
SUPPORT STANDARD, NON-PROPRIETARY FORMATS: demand JFIF or TIFF 6.0!
The authors make NO WARRANTY or representation, either express or implied,
with respect to this software, its quality, accuracy, merchantability, or
fitness for a particular purpose. This software is provided "AS IS", and you,
its user, assume the entire risk as to its quality and accuracy.
This software is copyright (C) 1991, 1992, Thomas G. Lane.
All Rights Reserved except as specified below.
Permission is hereby granted to use, copy, modify, and distribute this
software (or portions thereof) for any purpose, without fee, subject to these
(1) If any part of the source code for this software is distributed, then this
README file must be included, with this copyright and no-warranty notice
unaltered; and any additions, deletions, or changes to the original files
must be clearly indicated in accompanying documentation.
(2) If only executable code is distributed, then the accompanying
documentation must state that "this software is based in part on the work of
the Independent JPEG Group".
(3) Permission for use of this software is granted only if the user accepts
full responsibility for any undesirable consequences; the authors accept
NO LIABILITY for damages of any kind.
Permission is NOT granted for the use of any IJG author's name or company name
in advertising or publicity relating to this software or products derived from
it. This software may be referred to only as "the Independent JPEG Group's
We specifically permit and encourage the use of this software as the basis of
commercial products, provided that all warranty or liability claims are
assumed by the product vendor.
We are required to state that
"The Graphics Interchange Format(c) is the Copyright property of
CompuServe Incorporated. GIF(sm) is a Service Mark property of
The source code from which this software was generated is freely available.
The "official" archive site for the source code is ftp.uu.net (Internet
address 22.214.171.124 or 126.96.36.199). The most recent released version can
always be found there in directory graphics/jpeg. This particular version is
jpegsrc.v4.tar.Z. If you are on the Internet, you can retrieve files from
UUNET by anonymous FTP. If you don't have FTP access, UUNET's archives are
also available via UUCP; contact [email protected]
for information on
retrieving files that way.
The source code will also appear in the SIMTEL20 archives and on CompuServe,
but I don't have exact locations yet. These copies will be ZIP files which
may be easier for PC users to deal with.
You are welcome to use the source code in other JPEG-related programs.
The conditions for doing so may be found in LEGAL ISSUES, above.
The executables in this package were compiled using DJ Delorie's DJGPP version
1.09, a freely available 32-bit C compiler and DOS extender. (You can obtain
source and executables for DJGPP from barnacle.erc.clarkson.edu; look in
directory pub/msdos/djgpp.) Note that the user interface used by these
programs differs from the Unix-style user interface found in the main IJG