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1994-12-17
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The Independent JPEG Group's JPEG software
==========================================
This distribution contains MS-DOS executable copies of version 5a 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 PCs with 386 or better CPUs.
It is compiled to use 386 32-bit mode, and it runs 25% to 50% faster than
the plain 16-bit DOS version. It will run in a Windows or OS/2 DOS window
as well as under plain MS-DOS. You'll need at least a megabyte of extended
or expanded memory to get decent performance. (For older machines, use the
plain DOS version of the IJG software, which should be available from the
same place you got this package.)
For usage instructions, see the file usage.doc. Useful information can also
be found in the JPEG FAQ (Frequently Asked Questions) article, posted
regularly in the Usenet newsgroups comp.graphics and news.answers.
Please report any problems with this software to jpeg-info@uunet.uu.net.
INSTALLATION
============
On most MS-DOS setups, the programs should run as-is. Try just typing
"cjpeg" or "djpeg" and see if you get a screenful of help info. If not,
you may have a conflict with your extended or expanded memory manager.
Get the file oak.oakland.edu:/SimTel/msdos/djgpp/djgpp.faq for the latest
information on resolving such problems. If all else fails, you can always
use the non-386 version of the IJG programs.
For best results, you should set the environment variable GO32TMP to point
to a temporary directory on a hard disk with plenty of free space. For
example,
set GO32TMP=c:/temp
(Notice you should use forward slash "/" before a directory name, not
backslash "\" as is more common on DOS.) You can put this command in your
AUTOEXEC.BAT file so that you don't have to enter it by hand in future.
If you don't set GO32TMP, the programs will try to create work files in the
current directory. This may lead to unexpected "Insufficient memory"
errors, especially if you happen to be cd'ed to a floppy.
If you have DJGPP 1.12 or later installed, you can save some disk space by
re-stubbing these programs with exe2coff/coff2exe. This will remove the
built-in copies of go32 and instead use the go32 you already have. (Note:
rdjpgcom and wrjpgcom are not compiled with DJGPP and cannot be restubbed.)
The programs' "-dct float" option will not work if you don't have a math
coprocessor. You could get DJGPP and install its math emulator, but it
will run so slowly that you may as well not bother.
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. (Version 2.0 of
GIF2JPG produces compatible files by default.)
The file format we have adopted is called JFIF. This format has been agreed
to by a number of major commercial JPEG vendors, and it has become the de
facto standard. JFIF is a minimal or "low end" representation. Work is also
going forward to incorporate JPEG compression into the TIFF standard, for use
in "high end" applications that need to record a lot of additional data about
an image. We intend to support TIFF 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/JPEG!
LEGAL ISSUES
============
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, 1993, 1994, 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
conditions:
(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.
These conditions apply to any software derived from or based on the IJG code,
not just to the unmodified library. If you use our work, you ought to
acknowledge us.
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
software".
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
CompuServe Incorporated."
SOURCE CODE
===========
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 192.48.96.9). The most recent released version can always be found
there in directory graphics/jpeg. This particular version is archived as
graphics/jpeg/jpegsrc.v5a.tar.gz. If you are on the Internet, you
can retrieve files from ftp.uu.net by standard anonymous FTP. If you don't
have FTP access, UUNET's archives are also available via UUCP; contact
help@uunet.uu.net for information on retrieving files that way.
The source is also available in the SimTel archives (graphics/jpgsrc5a.zip)
and on CompuServe (GRAPHSUP library 15, file jpgs5a.zip). These copies are
ZIP files which may be easier for PC users to deal with.
Note that the user interface used here differs from the Unix-style user
interface found in the main IJG distribution. Source code for the DOS user
interface is in file jpegaltui.v5a.tar.gz at ftp.uu.net.
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 DJGPP 1.12m2.
DJGPP is a DOS version of the free GNU C compiler. You can obtain it
via Internet from oak.oakland.edu: /SimTel/msdos/djgpp/ (or other SimTel
archive sites).
The JPEG FAQ (Frequently Asked Questions) article is a useful source of
general information about JPEG. It is updated constantly and therefore
is not included in this distribution. The FAQ is posted every two weeks
to Usenet newsgroups comp.graphics, news.answers, and other groups. You
can always obtain the latest version from the news.answers archive at
rtfm.mit.edu. By FTP, fetch /pub/usenet/news.answers/jpeg-faq/part1 and
.../part2. If you don't have FTP, send e-mail to mail-server@rtfm.mit.edu
with body
send usenet/news.answers/jpeg-faq/part1
send usenet/news.answers/jpeg-faq/part2