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!ChangeFSI/btpc/READMEJ
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
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File contents
BTPC uses the Independent JPEG Group's JPEG software in the file colmap.C only.
IJG require that their README file be distributed with any modified version of
their code. So here it is:
==========================================================================
The Independent JPEG Group's JPEG software
==========================================
README for release 6 of 2-Aug-95
================================
This distribution contains the sixth public release 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.
Serious users of this software (particularly those incorporating it into
larger programs) should contact IJG at jpeg-info@uunet.uu.net to be added to
our electronic mailing list. Mailing list members are notified of updates
and have a chance to participate in technical discussions, etc.
This software is the work of Tom Lane, Philip Gladstone, Luis Ortiz, Jim
Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi,
Ge' Weijers, and other members of the Independent JPEG Group.
IJG is not affiliated with the official ISO JPEG standards committee.
DOCUMENTATION ROADMAP
=====================
This file contains the following sections:
OVERVIEW General description of JPEG and the IJG software.
LEGAL ISSUES Copyright, lack of warranty, terms of distribution.
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 Usage instructions for cjpeg, djpeg, jpegtran,
rdjpgcom, and wrjpgcom.
*.1 Unix-style man pages for programs (same info as usage.doc).
wizard.doc Advanced usage instructions for JPEG wizards only.
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 the 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.
Please read at least the files install.doc and usage.doc. 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.
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 package 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; line drawings, cartoons and other non-realistic images
are not its strong suit. JPEG is lossy, meaning that the output image is not
exactly identical to the input image. Hence you must not use JPEG if you
have to have identical output bits. However, on typical photographic images,
very good compression levels can be obtained with no visible change, and
remarkably 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.
This software implements JPEG baseline, extended-sequential, and progressive
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
variants of JPEG; see LEGAL ISSUES. We have made no provision for supporting
the hierarchical or lossless processes defined in the standard.
We provide a set of library routines for reading and writing JPEG image files,
plus two sample 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.
In order to support file conversion and viewing software, we have included
considerable functionality beyond the bare JPEG coding/decoding capability;
for example, the color quantization modules are not strictly part of JPEG
decoding, but they are essential for output to colormapped file formats or
colormapped displays. These extra functions can be compiled out of the
library if not required for a particular application. We have also included
"jpegtran", a utility for lossless transcoding between different JPEG
processes, and "rdjpgcom" and "wrjpgcom", two simple applications for
inserting and extracting textual comments in JFIF files.
The emphasis in designing this software has been on achieving portability and
flexibility, while also making it fast enough to be useful. In particular,
the software is not intended to be read as a tutorial on JPEG. (See the
REFERENCES section for introductory material.) Rather, it is intended to
be reliable, portable, industrial-strength code. We do not claim to have
achieved that goal in every aspect of the software, but we strive for it.
We welcome the use of this software as a component of commercial products.
No royalty is required, but we do ask for an acknowledgement in product
documentation, as described under LEGAL ISSUES.
LEGAL ISSUES
============
In plain English:
1. We don't promise that this software works. (But if you find any bugs,
please let us know!)
2. You can use this software for whatever you want. You don't have to pay us.
3. You may not pretend that you wrote this software. If you use it in a
program, you must acknowledge somewhere in your documentation that
you've used the IJG code.
In legalese:
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, 1995, 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.
ansi2knr.c is included in this distribution by permission of L. Peter Deutsch,
sole proprietor of its copyright holder, Aladdin Enterprises of Menlo Park, CA.
ansi2knr.c is NOT covered by the above copyright and conditions, but instead
by the usual distribution terms of the Free Software Foundation; principally,
that you must include source code if you redistribute it. (See the file
ansi2knr.c for full details.) However, since ansi2knr.c is not needed as part
of any program generated from the IJG code, this does not limit you more than
the foregoing paragraphs do.
The configuration script "configure" was produced with GNU Autoconf. It
is copyright by the Free Software Foundation but is freely distributable.
It appears that the arithmetic coding option of the JPEG spec is covered by
patents owned by IBM, AT&T, and Mitsubishi. Hence arithmetic coding cannot
legally be used without obtaining one or more licenses. For this reason,
support for arithmetic coding has been removed from the free JPEG software.
(Since arithmetic coding provides only a marginal gain over the unpatented
Huffman mode, it is unlikely that very many implementations will support it.)
So far as we are aware, there are no patent restrictions on the remaining
code.
WARNING: Unisys has begun to enforce their patent on LZW compression against
GIF encoders and decoders. You will need a license from Unisys to use the
included rdgif.c or wrgif.c files in a commercial or shareware application.
At this time, Unisys is not enforcing their patent against freeware, so
distribution of this package remains legal. However, we intend to remove
GIF support from the IJG package as soon as a suitable replacement format
becomes reasonably popular.
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."
REFERENCES
==========
We highly recommend reading one or more of these references before trying to
understand the innards of the JPEG software.
The best short technical introduction to the JPEG compression algorithm is
Wallace, Gregory K. "The JPEG Still Picture Compression Standard",
Communications of the ACM, April 1991 (vol. 34 no. 4), pp. 30-44.
(Adjacent articles in that issue discuss MPEG motion picture compression,
applications of JPEG, and related topics.) If you don't have the CACM issue
handy, a PostScript file containing a revised version of Wallace's article
is available at ftp.uu.net, graphics/jpeg/wallace.ps.gz. The file (actually
a preprint for an article that appeared in IEEE Trans. Consumer Electronics)
omits the sample images that appeared in CACM, but it includes corrections
and some added material. Note: the Wallace article is copyright ACM and
IEEE, and it may not be used for commercial purposes.
A somewhat less technical, more leisurely introduction to JPEG can be found in
"The Data Compression Book" by Mark Nelson, published by M&T Books (Redwood
City, CA), 1991, ISBN 1-55851-216-0. This book provides good explanations and
example C code for a multitude of compression methods including JPEG. It is
an excellent source if you are comfortable reading C code but don't know much
about data compression in general. The book's JPEG sample code is far from
industrial-strength, but when you are ready to look at a full implementation,
you've got one here...
The best full description of JPEG is the textbook "JPEG Still Image Data
Compression Standard" by William B. Pennebaker and Joan L. Mitchell, published
by Van Nostrand Reinhold, 1993, ISBN 0-442-01272-1. Price US$59.95, 638 pp.
The book includes the complete text of the ISO JPEG standards (DIS 10918-1
and draft DIS 10918-2). This is by far the most complete exposition of JPEG
in existence, and we highly recommend it.
The JPEG standard itself is not available electronically; you must order a
paper copy through ISO. (Unless you feel a need to own a certified official
copy, we recommend buying the Pennebaker and Mitchell book instead; it's much
cheaper and includes a great deal of useful explanatory material.) In the US,
copies of the standard may be ordered from ANSI Sales at (212) 642-4900, or
from Global Engineering Documents at (800) 854-7179. (ANSI doesn't take
credit card orders, but Global does.) It's not cheap: as of 1992, ANSI was
charging $95 for Part 1 and $47 for Part 2, plus 7% shipping/handling. The
standard is divided into two parts, Part 1 being the actual specification,
while Part 2 covers compliance testing methods. Part 1 is titled "Digital
Compression and Coding of Continuous-tone Still Images, Part 1: Requirements
and guidelines" and has document number ISO/IEC IS 10918-1. Part 2 is titled
"Digital Compression and Coding of Continuous-tone Still Images, Part 2:
Compliance testing" and has document number ISO/IEC IS 10918-2.
Extensions to the original JPEG standard are defined in Part 3, a new ISO
document. Part 3 is undergoing ISO balloting and is expected to be approved
by the end of 1995. IJG currently does not support any Part 3 extensions.
The JPEG standard does not specify all details of an interchangeable file
format. For the omitted details we follow the "JFIF" conventions, revision
1.02. A copy of the JFIF spec is available from:
Literature Department
C-Cube Microsystems, Inc.
1778 McCarthy Blvd.
Milpitas, CA 95035
phone (408) 944-6300, fax (408) 944-6314
A PostScript version of this document is available at ftp.uu.net, file
graphics/jpeg/jfif.ps.gz. It can also be obtained by e-mail from the C-Cube
mail server, netlib@c3.pla.ca.us. Send the message "send jfif_ps from jpeg"
to the server to obtain the JFIF document; send the message "help" if you have
trouble.
The TIFF 6.0 file format specification can be obtained by FTP from sgi.com
(192.48.153.1), file graphics/tiff/TIFF6.ps.Z; or you can order a printed
copy from Aldus Corp. at (206) 628-6593. The JPEG incorporation scheme
found in the TIFF 6.0 spec of 3-June-92 has a number of serious problems.
IJG does not recommend use of the TIFF 6.0 design (TIFF Compression tag 6).
Instead, we recommend the JPEG design proposed by TIFF Technical Note #2
(Compression tag 7). Copies of this Note can be obtained from sgi.com or
from ftp.uu.net:/graphics/jpeg/. It is expected that the next revision of
the TIFF spec will replace the 6.0 JPEG design with the Note's design.
Although IJG's own code does not support TIFF/JPEG, the free libtiff library
uses our library to implement TIFF/JPEG per the Note. libtiff is available
from sgi.com:/graphics/tiff/.
ARCHIVE LOCATIONS
=================
The "official" archive site for this software 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 will be archived
as graphics/jpeg/jpegsrc.v6.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.
Numerous Internet sites maintain copies of the UUNET files; in particular,
you can probably find a copy at any site that archives comp.sources.misc
submissions. However, only ftp.uu.net is guaranteed to have the latest
official version.
You can also obtain this software in DOS-compatible "zip" archive format from
the SimTel archives (ftp.coast.net:/SimTel/msdos/graphics/), or on CompuServe
in the GRAPHSUPPORT forum (GO GRAPHSUP), library 12 "JPEG Tools". Again,
these versions may sometimes lag behind the ftp.uu.net release.
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
RELATED SOFTWARE
================
Numerous viewing and image manipulation programs now support JPEG. (Quite a
few of them use this library to do so.) The JPEG FAQ described above lists
some of the more popular free and shareware viewers, and tells where to
obtain them on Internet.
If you are on a Unix machine, we highly recommend Jef Poskanzer's free
PBMPLUS image software, which provides many useful operations on PPM-format
image files. In particular, it can convert PPM images to and from a wide
range of other formats. You can obtain this package by FTP from ftp.x.org
(contrib/pbmplus*.tar.Z) or ftp.ee.lbl.gov (pbmplus*.tar.Z). There is also
a newer update of this package called NETPBM, available from
wuarchive.wustl.edu under directory /graphics/graphics/packages/NetPBM/.
Unfortunately PBMPLUS/NETPBM is not nearly as portable as the IJG software
is; you are likely to have difficulty making it work on any non-Unix machine.
A different free JPEG implementation, written by the PVRG group at Stanford,
is available from havefun.stanford.edu in directory pub/jpeg. This program
is designed for research and experimentation rather than production use;
it is slower, harder to use, and less portable than the IJG code, but it
is easier to read and modify. Also, the PVRG code supports lossless JPEG,
which we do not.
FILE FORMAT WARS
================
Some JPEG programs produce files that are not compatible with our library.
The root of the problem is that the ISO JPEG committee failed to specify a
concrete file format. Some vendors "filled in the blanks" on their own,
creating proprietary formats that no one else could read. (For example, none
of the early commercial JPEG implementations for the Macintosh were able to
exchange compressed files.)
The file format we have adopted is called JFIF (see REFERENCES). 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.
We recommend the use of TIFF/JPEG (TIFF revision 6.0 as modified by TIFF
Technical Note #2) for "high end" applications that need to record a lot of
additional data about an image. TIFF/JPEG is fairly new and not yet widely
supported, unfortunately.
The upcoming JPEG Part 3 standard defines a file format called SPIFF.
SPIFF is interoperable with JFIF, in the sense that most JFIF decoders should
be able to read the most common variant of SPIFF. SPIFF has some technical
advantages over JFIF, but its major claim to fame is simply that it is an
official standard rather than an informal one. At this point it is unclear
whether SPIFF will supersede JFIF or whether JFIF will remain the de-facto
standard. IJG intends to support SPIFF once the standard is frozen, but we
have not decided whether it should become our default output format or not.
(In any case, our decoder will remain capable of reading JFIF indefinitely.)
Various proprietary file formats incorporating JPEG compression also exist.
We have little or no sympathy for the existence of these formats. Indeed,
one of the original reasons for developing this free software was to help
force convergence on common, open format standards for JPEG files. Don't
use a proprietary file format!
TO DO
=====
In future versions, we are considering supporting some of the upcoming JPEG
Part 3 extensions --- principally, variable quantization and the SPIFF file
format.
Tuning the software for better behavior at low quality/high compression
settings is also of interest. The current method for scaling the
quantization tables is known not to be very good at low Q values.
As always, speeding things up is high on our priority list.
Please send bug reports, offers of help, etc. to jpeg-info@uunet.uu.net.
00000000 42 54 50 43 20 75 73 65 73 20 74 68 65 20 49 6e |BTPC uses the In| 00000010 64 65 70 65 6e 64 65 6e 74 20 4a 50 45 47 20 47 |dependent JPEG G| 00000020 72 6f 75 70 27 73 20 4a 50 45 47 20 73 6f 66 74 |roup's JPEG soft| 00000030 77 61 72 65 20 69 6e 20 74 68 65 20 66 69 6c 65 |ware in the file| 00000040 20 63 6f 6c 6d 61 70 2e 43 20 6f 6e 6c 79 2e 0a | colmap.C only..| 00000050 49 4a 47 20 72 65 71 75 69 72 65 20 74 68 61 74 |IJG require that| 00000060 20 74 68 65 69 72 20 52 45 41 44 4d 45 20 66 69 | their README fi| 00000070 6c 65 20 62 65 20 64 69 73 74 72 69 62 75 74 65 |le be distribute| 00000080 64 20 77 69 74 68 20 61 6e 79 20 6d 6f 64 69 66 |d with any modif| 00000090 69 65 64 20 76 65 72 73 69 6f 6e 20 6f 66 0a 74 |ied version of.t| 000000a0 68 65 69 72 20 63 6f 64 65 2e 20 53 6f 20 68 65 |heir code. So he| 000000b0 72 65 20 69 74 20 69 73 3a 0a 0a 3d 3d 3d 3d 3d |re it is:..=====| 000000c0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| * 00000100 3d 3d 3d 3d 3d 0a 0a 54 68 65 20 49 6e 64 65 70 |=====..The Indep| 00000110 65 6e 64 65 6e 74 20 4a 50 45 47 20 47 72 6f 75 |endent JPEG Grou| 00000120 70 27 73 20 4a 50 45 47 20 73 6f 66 74 77 61 72 |p's JPEG softwar| 00000130 65 0a 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |e.==============| 00000140 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000150 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0a 0a 52 45 |============..RE| 00000160 41 44 4d 45 20 66 6f 72 20 72 65 6c 65 61 73 65 |ADME for release| 00000170 20 36 20 6f 66 20 32 2d 41 75 67 2d 39 35 0a 3d | 6 of 2-Aug-95.=| 00000180 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 00000190 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0a |===============.| 000001a0 0a 54 68 69 73 20 64 69 73 74 72 69 62 75 74 69 |.This distributi| 000001b0 6f 6e 20 63 6f 6e 74 61 69 6e 73 20 74 68 65 20 |on contains the | 000001c0 73 69 78 74 68 20 70 75 62 6c 69 63 20 72 65 6c |sixth public rel| 000001d0 65 61 73 65 20 6f 66 20 74 68 65 20 49 6e 64 65 |ease of the Inde| 000001e0 70 65 6e 64 65 6e 74 20 4a 50 45 47 0a 47 72 6f |pendent JPEG.Gro| 000001f0 75 70 27 73 20 66 72 65 65 20 4a 50 45 47 20 73 |up's free JPEG s| 00000200 6f 66 74 77 61 72 65 2e 20 20 59 6f 75 20 61 72 |oftware. You ar| 00000210 65 20 77 65 6c 63 6f 6d 65 20 74 6f 20 72 65 64 |e welcome to red| 00000220 69 73 74 72 69 62 75 74 65 20 74 68 69 73 20 73 |istribute this s| 00000230 6f 66 74 77 61 72 65 20 61 6e 64 0a 74 6f 20 75 |oftware and.to u| 00000240 73 65 20 69 74 20 66 6f 72 20 61 6e 79 20 70 75 |se it for any pu| 00000250 72 70 6f 73 65 2c 20 73 75 62 6a 65 63 74 20 74 |rpose, subject t| 00000260 6f 20 74 68 65 20 63 6f 6e 64 69 74 69 6f 6e 73 |o the conditions| 00000270 20 75 6e 64 65 72 20 4c 45 47 41 4c 20 49 53 53 | under LEGAL ISS| 00000280 55 45 53 2c 20 62 65 6c 6f 77 2e 0a 0a 53 65 72 |UES, below...Ser| 00000290 69 6f 75 73 20 75 73 65 72 73 20 6f 66 20 74 68 |ious users of th| 000002a0 69 73 20 73 6f 66 74 77 61 72 65 20 28 70 61 72 |is software (par| 000002b0 74 69 63 75 6c 61 72 6c 79 20 74 68 6f 73 65 20 |ticularly those | 000002c0 69 6e 63 6f 72 70 6f 72 61 74 69 6e 67 20 69 74 |incorporating it| 000002d0 20 69 6e 74 6f 0a 6c 61 72 67 65 72 20 70 72 6f | into.larger pro| 000002e0 67 72 61 6d 73 29 20 73 68 6f 75 6c 64 20 63 6f |grams) should co| 000002f0 6e 74 61 63 74 20 49 4a 47 20 61 74 20 6a 70 65 |ntact IJG at jpe| 00000300 67 2d 69 6e 66 6f 40 75 75 6e 65 74 2e 75 75 2e |g-info@uunet.uu.| 00000310 6e 65 74 20 74 6f 20 62 65 20 61 64 64 65 64 20 |net to be added | 00000320 74 6f 0a 6f 75 72 20 65 6c 65 63 74 72 6f 6e 69 |to.our electroni| 00000330 63 20 6d 61 69 6c 69 6e 67 20 6c 69 73 74 2e 20 |c mailing list. | 00000340 20 4d 61 69 6c 69 6e 67 20 6c 69 73 74 20 6d 65 | Mailing list me| 00000350 6d 62 65 72 73 20 61 72 65 20 6e 6f 74 69 66 69 |mbers are notifi| 00000360 65 64 20 6f 66 20 75 70 64 61 74 65 73 0a 61 6e |ed of updates.an| 00000370 64 20 68 61 76 65 20 61 20 63 68 61 6e 63 65 20 |d have a chance | 00000380 74 6f 20 70 61 72 74 69 63 69 70 61 74 65 20 69 |to participate i| 00000390 6e 20 74 65 63 68 6e 69 63 61 6c 20 64 69 73 63 |n technical disc| 000003a0 75 73 73 69 6f 6e 73 2c 20 65 74 63 2e 0a 0a 54 |ussions, etc...T| 000003b0 68 69 73 20 73 6f 66 74 77 61 72 65 20 69 73 20 |his software is | 000003c0 74 68 65 20 77 6f 72 6b 20 6f 66 20 54 6f 6d 20 |the work of Tom | 000003d0 4c 61 6e 65 2c 20 50 68 69 6c 69 70 20 47 6c 61 |Lane, Philip Gla| 000003e0 64 73 74 6f 6e 65 2c 20 4c 75 69 73 20 4f 72 74 |dstone, Luis Ort| 000003f0 69 7a 2c 20 4a 69 6d 0a 42 6f 75 63 68 65 72 2c |iz, Jim.Boucher,| 00000400 20 4c 65 65 20 43 72 6f 63 6b 65 72 2c 20 4a 75 | Lee Crocker, Ju| 00000410 6c 69 61 6e 20 4d 69 6e 67 75 69 6c 6c 6f 6e 2c |lian Minguillon,| 00000420 20 47 65 6f 72 67 65 20 50 68 69 6c 6c 69 70 73 | George Phillips| 00000430 2c 20 44 61 76 69 64 65 20 52 6f 73 73 69 2c 0a |, Davide Rossi,.| 00000440 47 65 27 20 57 65 69 6a 65 72 73 2c 20 61 6e 64 |Ge' Weijers, and| 00000450 20 6f 74 68 65 72 20 6d 65 6d 62 65 72 73 20 6f | other members o| 00000460 66 20 74 68 65 20 49 6e 64 65 70 65 6e 64 65 6e |f the Independen| 00000470 74 20 4a 50 45 47 20 47 72 6f 75 70 2e 0a 0a 49 |t JPEG Group...I| 00000480 4a 47 20 69 73 20 6e 6f 74 20 61 66 66 69 6c 69 |JG is not affili| 00000490 61 74 65 64 20 77 69 74 68 20 74 68 65 20 6f 66 |ated with the of| 000004a0 66 69 63 69 61 6c 20 49 53 4f 20 4a 50 45 47 20 |ficial ISO JPEG | 000004b0 73 74 61 6e 64 61 72 64 73 20 63 6f 6d 6d 69 74 |standards commit| 000004c0 74 65 65 2e 0a 0a 0a 44 4f 43 55 4d 45 4e 54 41 |tee....DOCUMENTA| 000004d0 54 49 4f 4e 20 52 4f 41 44 4d 41 50 0a 3d 3d 3d |TION ROADMAP.===| 000004e0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================| 000004f0 3d 3d 0a 0a 54 68 69 73 20 66 69 6c 65 20 63 6f |==..This file co| 00000500 6e 74 61 69 6e 73 20 74 68 65 20 66 6f 6c 6c 6f |ntains the follo| 00000510 77 69 6e 67 20 73 65 63 74 69 6f 6e 73 3a 0a 0a |wing sections:..| 00000520 4f 56 45 52 56 49 45 57 20 20 20 20 20 20 20 20 |OVERVIEW | 00000530 20 20 20 20 47 65 6e 65 72 61 6c 20 64 65 73 63 | General desc| 00000540 72 69 70 74 69 6f 6e 20 6f 66 20 4a 50 45 47 20 |ription of JPEG | 00000550 61 6e 64 20 74 68 65 20 49 4a 47 20 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Par| 00003300 74 20 33 20 69 73 20 75 6e 64 65 72 67 6f 69 6e |t 3 is undergoin| 00003310 67 20 49 53 4f 20 62 61 6c 6c 6f 74 69 6e 67 20 |g ISO balloting | 00003320 61 6e 64 20 69 73 20 65 78 70 65 63 74 65 64 20 |and is expected | 00003330 74 6f 20 62 65 20 61 70 70 72 6f 76 65 64 0a 62 |to be approved.b| 00003340 79 20 74 68 65 20 65 6e 64 20 6f 66 20 31 39 39 |y the end of 199| 00003350 35 2e 20 20 49 4a 47 20 63 75 72 72 65 6e 74 6c |5. IJG currentl| 00003360 79 20 64 6f 65 73 20 6e 6f 74 20 73 75 70 70 6f |y does not suppo| 00003370 72 74 20 61 6e 79 20 50 61 72 74 20 33 20 65 78 |rt any Part 3 ex| 00003380 74 65 6e 73 69 6f 6e 73 2e 0a 0a 54 68 65 20 4a |tensions...The J| 00003390 50 45 47 20 73 74 61 6e 64 61 72 64 20 64 6f 65 |PEG standard doe| 000033a0 73 20 6e 6f 74 20 73 70 65 63 69 66 79 20 61 6c |s not specify al| 000033b0 6c 20 64 65 74 61 69 6c 73 20 6f 66 20 61 6e 20 |l details of an | 000033c0 69 6e 74 65 72 63 68 61 6e 67 65 61 62 6c 65 20 |interchangeable | 000033d0 66 69 6c 65 0a 66 6f 72 6d 61 74 2e 20 20 46 6f |file.format. Fo| 000033e0 72 20 74 68 65 20 6f 6d 69 74 74 65 64 20 64 65 |r the omitted de| 000033f0 74 61 69 6c 73 20 77 65 20 66 6f 6c 6c 6f 77 20 |tails we follow | 00003400 74 68 65 20 22 4a 46 49 46 22 20 63 6f 6e 76 65 |the "JFIF" conve| 00003410 6e 74 69 6f 6e 73 2c 20 72 65 76 69 73 69 6f 6e |ntions, revision| 00003420 0a 31 2e 30 32 2e 20 20 41 20 63 6f 70 79 20 6f |.1.02. A copy o| 00003430 66 20 74 68 65 20 4a 46 49 46 20 73 70 65 63 20 |f the JFIF spec | 00003440 69 73 20 61 76 61 69 6c 61 62 6c 65 20 66 72 6f |is available fro| 00003450 6d 3a 0a 20 20 20 20 20 20 20 20 4c 69 74 65 72 |m:. Liter| 00003460 61 74 75 72 65 20 44 65 70 61 72 74 6d 65 6e 74 |ature Department| 00003470 0a 20 20 20 20 20 20 20 20 43 2d 43 75 62 65 20 |. C-Cube | 00003480 4d 69 63 72 6f 73 79 73 74 65 6d 73 2c 20 49 6e |Microsystems, In| 00003490 63 2e 0a 20 20 20 20 20 20 20 20 31 37 37 38 20 |c.. 1778 | 000034a0 4d 63 43 61 72 74 68 79 20 42 6c 76 64 2e 0a 20 |McCarthy Blvd.. | 000034b0 20 20 20 20 20 20 20 4d 69 6c 70 69 74 61 73 2c | Milpitas,| 000034c0 20 43 41 20 39 35 30 33 35 0a 20 20 20 20 20 20 | CA 95035. | 000034d0 20 20 70 68 6f 6e 65 20 28 34 30 38 29 20 39 34 | phone (408) 94| 000034e0 34 2d 36 33 30 30 2c 20 20 66 61 78 20 28 34 30 |4-6300, fax (40| 000034f0 38 29 20 39 34 34 2d 36 33 31 34 0a 41 20 50 6f |8) 944-6314.A Po| 00003500 73 74 53 63 72 69 70 74 20 76 65 72 73 69 6f 6e |stScript version| 00003510 20 6f 66 20 74 68 69 73 20 64 6f 63 75 6d 65 6e | of this documen| 00003520 74 20 69 73 20 61 76 61 69 6c 61 62 6c 65 20 61 |t is available a| 00003530 74 20 66 74 70 2e 75 75 2e 6e 65 74 2c 20 66 69 |t ftp.uu.net, fi| 00003540 6c 65 0a 67 72 61 70 68 69 63 73 2f 6a 70 65 67 |le.graphics/jpeg| 00003550 2f 6a 66 69 66 2e 70 73 2e 67 7a 2e 20 20 49 74 |/jfif.ps.gz. It| 00003560 20 63 61 6e 20 61 6c 73 6f 20 62 65 20 6f 62 74 | can also be obt| 00003570 61 69 6e 65 64 20 62 79 20 65 2d 6d 61 69 6c 20 |ained by e-mail | 00003580 66 72 6f 6d 20 74 68 65 20 43 2d 43 75 62 65 0a |from the C-Cube.| 00003590 6d 61 69 6c 20 73 65 72 76 65 72 2c 20 6e 65 74 |mail server, net| 000035a0 6c 69 62 40 63 33 2e 70 6c 61 2e 63 61 2e 75 73 |lib@c3.pla.ca.us| 000035b0 2e 20 20 53 65 6e 64 20 74 68 65 20 6d 65 73 73 |. Send the mess| 000035c0 61 67 65 20 22 73 65 6e 64 20 6a 66 69 66 5f 70 |age "send jfif_p| 000035d0 73 20 66 72 6f 6d 20 6a 70 65 67 22 0a 74 6f 20 |s from jpeg".to | 000035e0 74 68 65 20 73 65 72 76 65 72 20 74 6f 20 6f 62 |the server to ob| 000035f0 74 61 69 6e 20 74 68 65 20 4a 46 49 46 20 64 6f |tain the JFIF do| 00003600 63 75 6d 65 6e 74 3b 20 73 65 6e 64 20 74 68 65 |cument; send the| 00003610 20 6d 65 73 73 61 67 65 20 22 68 65 6c 70 22 20 | message "help" | 00003620 69 66 20 79 6f 75 20 68 61 76 65 0a 74 72 6f 75 |if you have.trou| 00003630 62 6c 65 2e 0a 0a 54 68 65 20 54 49 46 46 20 36 |ble...The TIFF 6| 00003640 2e 30 20 66 69 6c 65 20 66 6f 72 6d 61 74 20 73 |.0 file format s| 00003650 70 65 63 69 66 69 63 61 74 69 6f 6e 20 63 61 6e |pecification can| 00003660 20 62 65 20 6f 62 74 61 69 6e 65 64 20 62 79 20 | be obtained by | 00003670 46 54 50 20 66 72 6f 6d 20 73 67 69 2e 63 6f 6d |FTP from sgi.com| 00003680 0a 28 31 39 32 2e 34 38 2e 31 35 33 2e 31 29 2c |.(192.48.153.1),| 00003690 20 66 69 6c 65 20 67 72 61 70 68 69 63 73 2f 74 | file graphics/t| 000036a0 69 66 66 2f 54 49 46 46 36 2e 70 73 2e 5a 3b 20 |iff/TIFF6.ps.Z; | 000036b0 6f 72 20 79 6f 75 20 63 61 6e 20 6f 72 64 65 72 |or you can order| 000036c0 20 61 20 70 72 69 6e 74 65 64 0a 63 6f 70 79 20 | a printed.copy | 000036d0 66 72 6f 6d 20 41 6c 64 75 73 20 43 6f 72 70 2e |from Aldus Corp.| 000036e0 20 61 74 20 28 32 30 36 29 20 36 32 38 2d 36 35 | at (206) 628-65| 000036f0 39 33 2e 20 20 54 68 65 20 4a 50 45 47 20 69 6e |93. The JPEG in| 00003700 63 6f 72 70 6f 72 61 74 69 6f 6e 20 73 63 68 65 |corporation sche| 00003710 6d 65 0a 66 6f 75 6e 64 20 69 6e 20 74 68 65 20 |me.found in the | 00003720 54 49 46 46 20 36 2e 30 20 73 70 65 63 20 6f 66 |TIFF 6.0 spec of| 00003730 20 33 2d 4a 75 6e 65 2d 39 32 20 68 61 73 20 61 | 3-June-92 has a| 00003740 20 6e 75 6d 62 65 72 20 6f 66 20 73 65 72 69 6f | number of serio| 00003750 75 73 20 70 72 6f 62 6c 65 6d 73 2e 0a 49 4a 47 |us problems..IJG| 00003760 20 64 6f 65 73 20 6e 6f 74 20 72 65 63 6f 6d 6d | does not recomm| 00003770 65 6e 64 20 75 73 65 20 6f 66 20 74 68 65 20 54 |end use of the T| 00003780 49 46 46 20 36 2e 30 20 64 65 73 69 67 6e 20 28 |IFF 6.0 design (| 00003790 54 49 46 46 20 43 6f 6d 70 72 65 73 73 69 6f 6e |TIFF Compression| 000037a0 20 74 61 67 20 36 29 2e 0a 49 6e 73 74 65 61 64 | tag 6)..Instead| 000037b0 2c 20 77 65 20 72 65 63 6f 6d 6d 65 6e 64 20 74 |, we recommend t| 000037c0 68 65 20 4a 50 45 47 20 64 65 73 69 67 6e 20 70 |he JPEG design p| 000037d0 72 6f 70 6f 73 65 64 20 62 79 20 54 49 46 46 20 |roposed by TIFF | 000037e0 54 65 63 68 6e 69 63 61 6c 20 4e 6f 74 65 20 23 |Technical Note #| 000037f0 32 0a 28 43 6f 6d 70 72 65 73 73 69 6f 6e 20 74 |2.(Compression t| 00003800 61 67 20 37 29 2e 20 20 43 6f 70 69 65 73 20 6f |ag 7). Copies o| 00003810 66 20 74 68 69 73 20 4e 6f 74 65 20 63 61 6e 20 |f this Note can | 00003820 62 65 20 6f 62 74 61 69 6e 65 64 20 66 72 6f 6d |be obtained from| 00003830 20 73 67 69 2e 63 6f 6d 20 6f 72 0a 66 72 6f 6d | sgi.com or.from| 00003840 20 66 74 70 2e 75 75 2e 6e 65 74 3a 2f 67 72 61 | ftp.uu.net:/gra| 00003850 70 68 69 63 73 2f 6a 70 65 67 2f 2e 20 20 49 74 |phics/jpeg/. It| 00003860 20 69 73 20 65 78 70 65 63 74 65 64 20 74 68 61 | is expected tha| 00003870 74 20 74 68 65 20 6e 65 78 74 20 72 65 76 69 73 |t the next revis| 00003880 69 6f 6e 20 6f 66 0a 74 68 65 20 54 49 46 46 20 |ion of.the TIFF | 00003890 73 70 65 63 20 77 69 6c 6c 20 72 65 70 6c 61 63 |spec will replac| 000038a0 65 20 74 68 65 20 36 2e 30 20 4a 50 45 47 20 64 |e the 6.0 JPEG d| 000038b0 65 73 69 67 6e 20 77 69 74 68 20 74 68 65 20 4e |esign with the N| 000038c0 6f 74 65 27 73 20 64 65 73 69 67 6e 2e 0a 41 6c |ote's design..Al| 000038d0 74 68 6f 75 67 68 20 49 4a 47 27 73 20 6f 77 6e |though IJG's own| 000038e0 20 63 6f 64 65 20 64 6f 65 73 20 6e 6f 74 20 73 | code does not s| 000038f0 75 70 70 6f 72 74 20 54 49 46 46 2f 4a 50 45 47 |upport TIFF/JPEG| 00003900 2c 20 74 68 65 20 66 72 65 65 20 6c 69 62 74 69 |, the free libti| 00003910 66 66 20 6c 69 62 72 61 72 79 0a 75 73 65 73 20 |ff library.uses | 00003920 6f 75 72 20 6c 69 62 72 61 72 79 20 74 6f 20 69 |our library to i| 00003930 6d 70 6c 65 6d 65 6e 74 20 54 49 46 46 2f 4a 50 |mplement TIFF/JP| 00003940 45 47 20 70 65 72 20 74 68 65 20 4e 6f 74 65 2e |EG per the Note.| 00003950 20 20 6c 69 62 74 69 66 66 20 69 73 20 61 76 61 | libtiff is ava| 00003960 69 6c 61 62 6c 65 0a 66 72 6f 6d 20 73 67 69 2e |ilable.from sgi.| 00003970 63 6f 6d 3a 2f 67 72 61 70 68 69 63 73 2f 74 69 |com:/graphics/ti| 00003980 66 66 2f 2e 0a 0a 0a 41 52 43 48 49 56 45 20 4c |ff/....ARCHIVE L| 00003990 4f 43 41 54 49 4f 4e 53 0a 3d 3d 3d 3d 3d 3d 3d |OCATIONS.=======| 000039a0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 0a 0a 54 68 65 20 |==========..The | 000039b0 22 6f 66 66 69 63 69 61 6c 22 20 61 72 63 68 69 |"official" archi| 000039c0 76 65 20 73 69 74 65 20 66 6f 72 20 74 68 69 73 |ve site for this| 000039d0 20 73 6f 66 74 77 61 72 65 20 69 73 20 66 74 70 | software is ftp| 000039e0 2e 75 75 2e 6e 65 74 20 28 49 6e 74 65 72 6e 65 |.uu.net (Interne| 000039f0 74 0a 61 64 64 72 65 73 73 20 31 39 32 2e 34 38 |t.address 192.48| 00003a00 2e 39 36 2e 39 29 2e 20 20 54 68 65 20 6d 6f 73 |.96.9). The mos| 00003a10 74 20 72 65 63 65 6e 74 20 72 65 6c 65 61 73 65 |t recent release| 00003a20 64 20 76 65 72 73 69 6f 6e 20 63 61 6e 20 61 6c |d version can al| 00003a30 77 61 79 73 20 62 65 20 66 6f 75 6e 64 0a 74 68 |ways be found.th| 00003a40 65 72 65 20 69 6e 20 64 69 72 65 63 74 6f 72 79 |ere in directory| 00003a50 20 67 72 61 70 68 69 63 73 2f 6a 70 65 67 2e 20 | graphics/jpeg. | 00003a60 20 54 68 69 73 20 70 61 72 74 69 63 75 6c 61 72 | This particular| 00003a70 20 76 65 72 73 69 6f 6e 20 77 69 6c 6c 20 62 65 | version will be| 00003a80 20 61 72 63 68 69 76 65 64 0a 61 73 20 67 72 61 | archived.as gra| 00003a90 70 68 69 63 73 2f 6a 70 65 67 2f 6a 70 65 67 73 |phics/jpeg/jpegs| 00003aa0 72 63 2e 76 36 2e 74 61 72 2e 67 7a 2e 20 20 49 |rc.v6.tar.gz. I| 00003ab0 66 20 79 6f 75 20 61 72 65 20 6f 6e 20 74 68 65 |f you are on the| 00003ac0 20 49 6e 74 65 72 6e 65 74 2c 20 79 6f 75 0a 63 | Internet, you.c| 00003ad0 61 6e 20 72 65 74 72 69 65 76 65 20 66 69 6c 65 |an retrieve file| 00003ae0 73 20 66 72 6f 6d 20 66 74 70 2e 75 75 2e 6e 65 |s from ftp.uu.ne| 00003af0 74 20 62 79 20 73 74 61 6e 64 61 72 64 20 61 6e |t by standard an| 00003b00 6f 6e 79 6d 6f 75 73 20 46 54 50 2e 20 20 49 66 |onymous FTP. If| 00003b10 20 79 6f 75 20 64 6f 6e 27 74 0a 68 61 76 65 20 | you don't.have | 00003b20 46 54 50 20 61 63 63 65 73 73 2c 20 55 55 4e 45 |FTP access, UUNE| 00003b30 54 27 73 20 61 72 63 68 69 76 65 73 20 61 72 65 |T's archives are| 00003b40 20 61 6c 73 6f 20 61 76 61 69 6c 61 62 6c 65 20 | also available | 00003b50 76 69 61 20 55 55 43 50 3b 20 63 6f 6e 74 61 63 |via UUCP; contac| 00003b60 74 0a 68 65 6c 70 40 75 75 6e 65 74 2e 75 75 2e |t.help@uunet.uu.| 00003b70 6e 65 74 20 66 6f 72 20 69 6e 66 6f 72 6d 61 74 |net for informat| 00003b80 69 6f 6e 20 6f 6e 20 72 65 74 72 69 65 76 69 6e |ion on retrievin| 00003b90 67 20 66 69 6c 65 73 20 74 68 61 74 20 77 61 79 |g files that way| 00003ba0 2e 0a 0a 4e 75 6d 65 72 6f 75 73 20 49 6e 74 65 |...Numerous Inte| 00003bb0 72 6e 65 74 20 73 69 74 65 73 20 6d 61 69 6e 74 |rnet sites maint| 00003bc0 61 69 6e 20 63 6f 70 69 65 73 20 6f 66 20 74 68 |ain copies of th| 00003bd0 65 20 55 55 4e 45 54 20 66 69 6c 65 73 3b 20 69 |e UUNET files; i| 00003be0 6e 20 70 61 72 74 69 63 75 6c 61 72 2c 0a 79 6f |n particular,.yo| 00003bf0 75 20 63 61 6e 20 70 72 6f 62 61 62 6c 79 20 66 |u can probably f| 00003c00 69 6e 64 20 61 20 63 6f 70 79 20 61 74 20 61 6e |ind a copy at an| 00003c10 79 20 73 69 74 65 20 74 68 61 74 20 61 72 63 68 |y site that arch| 00003c20 69 76 65 73 20 63 6f 6d 70 2e 73 6f 75 72 63 65 |ives comp.source| 00003c30 73 2e 6d 69 73 63 0a 73 75 62 6d 69 73 73 69 6f |s.misc.submissio| 00003c40 6e 73 2e 20 20 48 6f 77 65 76 65 72 2c 20 6f 6e |ns. However, on| 00003c50 6c 79 20 66 74 70 2e 75 75 2e 6e 65 74 20 69 73 |ly ftp.uu.net is| 00003c60 20 67 75 61 72 61 6e 74 65 65 64 20 74 6f 20 68 | guaranteed to h| 00003c70 61 76 65 20 74 68 65 20 6c 61 74 65 73 74 0a 6f |ave the latest.o| 00003c80 66 66 69 63 69 61 6c 20 76 65 72 73 69 6f 6e 2e |fficial version.| 00003c90 0a 0a 59 6f 75 20 63 61 6e 20 61 6c 73 6f 20 6f |..You can also o| 00003ca0 62 74 61 69 6e 20 74 68 69 73 20 73 6f 66 74 77 |btain this softw| 00003cb0 61 72 65 20 69 6e 20 44 4f 53 2d 63 6f 6d 70 61 |are in DOS-compa| 00003cc0 74 69 62 6c 65 20 22 7a 69 70 22 20 61 72 63 68 |tible "zip" arch| 00003cd0 69 76 65 20 66 6f 72 6d 61 74 20 66 72 6f 6d 0a |ive format from.| 00003ce0 74 68 65 20 53 69 6d 54 65 6c 20 61 72 63 68 69 |the SimTel archi| 00003cf0 76 65 73 20 28 66 74 70 2e 63 6f 61 73 74 2e 6e |ves (ftp.coast.n| 00003d00 65 74 3a 2f 53 69 6d 54 65 6c 2f 6d 73 64 6f 73 |et:/SimTel/msdos| 00003d10 2f 67 72 61 70 68 69 63 73 2f 29 2c 20 6f 72 20 |/graphics/), or | 00003d20 6f 6e 20 43 6f 6d 70 75 53 65 72 76 65 0a 69 6e |on CompuServe.in| 00003d30 20 74 68 65 20 47 52 41 50 48 53 55 50 50 4f 52 | the GRAPHSUPPOR| 00003d40 54 20 66 6f 72 75 6d 20 28 47 4f 20 47 52 41 50 |T forum (GO GRAP| 00003d50 48 53 55 50 29 2c 20 6c 69 62 72 61 72 79 20 31 |HSUP), library 1| 00003d60 32 20 22 4a 50 45 47 20 54 6f 6f 6c 73 22 2e 20 |2 "JPEG Tools". | 00003d70 20 41 67 61 69 6e 2c 0a 74 68 65 73 65 20 76 65 | Again,.these ve| 00003d80 72 73 69 6f 6e 73 20 6d 61 79 20 73 6f 6d 65 74 |rsions may somet| 00003d90 69 6d 65 73 20 6c 61 67 20 62 65 68 69 6e 64 20 |imes lag behind | 00003da0 74 68 65 20 66 74 70 2e 75 75 2e 6e 65 74 20 72 |the ftp.uu.net r| 00003db0 65 6c 65 61 73 65 2e 0a 0a 54 68 65 20 4a 50 45 |elease...The JPE| 00003dc0 47 20 46 41 51 20 28 46 72 65 71 75 65 6e 74 6c |G FAQ (Frequentl| 00003dd0 79 20 41 73 6b 65 64 20 51 75 65 73 74 69 6f 6e |y Asked Question| 00003de0 73 29 20 61 72 74 69 63 6c 65 20 69 73 20 61 20 |s) article is a | 00003df0 75 73 65 66 75 6c 20 73 6f 75 72 63 65 20 6f 66 |useful source of| 00003e00 0a 67 65 6e 65 72 61 6c 20 69 6e 66 6f 72 6d 61 |.general informa| 00003e10 74 69 6f 6e 20 61 62 6f 75 74 20 4a 50 45 47 2e |tion about JPEG.| 00003e20 20 20 49 74 20 69 73 20 75 70 64 61 74 65 64 20 | It is updated | 00003e30 63 6f 6e 73 74 61 6e 74 6c 79 20 61 6e 64 20 74 |constantly and t| 00003e40 68 65 72 65 66 6f 72 65 20 69 73 0a 6e 6f 74 20 |herefore is.not | 00003e50 69 6e 63 6c 75 64 65 64 20 69 6e 20 74 68 69 73 |included in this| 00003e60 20 64 69 73 74 72 69 62 75 74 69 6f 6e 2e 20 20 | distribution. | 00003e70 54 68 65 20 46 41 51 20 69 73 20 70 6f 73 74 65 |The FAQ is poste| 00003e80 64 20 65 76 65 72 79 20 74 77 6f 20 77 65 65 6b |d every two week| 00003e90 73 20 74 6f 0a 55 73 65 6e 65 74 20 6e 65 77 73 |s to.Usenet news| 00003ea0 67 72 6f 75 70 73 20 63 6f 6d 70 2e 67 72 61 70 |groups comp.grap| 00003eb0 68 69 63 73 2c 20 6e 65 77 73 2e 61 6e 73 77 65 |hics, news.answe| 00003ec0 72 73 2c 20 61 6e 64 20 6f 74 68 65 72 20 67 72 |rs, and other gr| 00003ed0 6f 75 70 73 2e 20 20 59 6f 75 20 63 61 6e 0a 61 |oups. You can.a| 00003ee0 6c 77 61 79 73 20 6f 62 74 61 69 6e 20 74 68 65 |lways obtain the| 00003ef0 20 6c 61 74 65 73 74 20 76 65 72 73 69 6f 6e 20 | latest version | 00003f00 66 72 6f 6d 20 74 68 65 20 6e 65 77 73 2e 61 6e |from the news.an| 00003f10 73 77 65 72 73 20 61 72 63 68 69 76 65 20 61 74 |swers archive at| 00003f20 0a 72 74 66 6d 2e 6d 69 74 2e 65 64 75 2e 20 20 |.rtfm.mit.edu. | 00003f30 42 79 20 46 54 50 2c 20 66 65 74 63 68 20 2f 70 |By FTP, fetch /p| 00003f40 75 62 2f 75 73 65 6e 65 74 2f 6e 65 77 73 2e 61 |ub/usenet/news.a| 00003f50 6e 73 77 65 72 73 2f 6a 70 65 67 2d 66 61 71 2f |nswers/jpeg-faq/| 00003f60 70 61 72 74 31 20 61 6e 64 0a 2e 2e 2e 2f 70 61 |part1 and..../pa| 00003f70 72 74 32 2e 20 20 49 66 20 79 6f 75 20 64 6f 6e |rt2. If you don| 00003f80 27 74 20 68 61 76 65 20 46 54 50 2c 20 73 65 6e |'t have FTP, sen| 00003f90 64 20 65 2d 6d 61 69 6c 20 74 6f 20 6d 61 69 6c |d e-mail to mail| 00003fa0 2d 73 65 72 76 65 72 40 72 74 66 6d 2e 6d 69 74 |-server@rtfm.mit| 00003fb0 2e 65 64 75 0a 77 69 74 68 20 62 6f 64 79 0a 20 |.edu.with body. | 00003fc0 20 20 20 20 20 20 20 73 65 6e 64 20 75 73 65 6e | send usen| 00003fd0 65 74 2f 6e 65 77 73 2e 61 6e 73 77 65 72 73 2f |et/news.answers/| 00003fe0 6a 70 65 67 2d 66 61 71 2f 70 61 72 74 31 0a 20 |jpeg-faq/part1. | 00003ff0 20 20 20 20 20 20 20 73 65 6e 64 20 75 73 65 6e | send usen| 00004000 65 74 2f 6e 65 77 73 2e 61 6e 73 77 65 72 73 2f |et/news.answers/| 00004010 6a 70 65 67 2d 66 61 71 2f 70 61 72 74 32 0a 0a |jpeg-faq/part2..| 00004020 0a 52 45 4c 41 54 45 44 20 53 4f 46 54 57 41 52 |.RELATED SOFTWAR| 00004030 45 0a 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |E.==============| 00004040 3d 3d 0a 0a 4e 75 6d 65 72 6f 75 73 20 76 69 65 |==..Numerous vie| 00004050 77 69 6e 67 20 61 6e 64 20 69 6d 61 67 65 20 6d |wing and image m| 00004060 61 6e 69 70 75 6c 61 74 69 6f 6e 20 70 72 6f 67 |anipulation prog| 00004070 72 61 6d 73 20 6e 6f 77 20 73 75 70 70 6f 72 74 |rams now support| 00004080 20 4a 50 45 47 2e 20 20 28 51 75 69 74 65 20 61 | JPEG. (Quite a| 00004090 0a 66 65 77 20 6f 66 20 74 68 65 6d 20 75 73 65 |.few of them use| 000040a0 20 74 68 69 73 20 6c 69 62 72 61 72 79 20 74 6f | this library to| 000040b0 20 64 6f 20 73 6f 2e 29 20 20 54 68 65 20 4a 50 | do so.) The JP| 000040c0 45 47 20 46 41 51 20 64 65 73 63 72 69 62 65 64 |EG FAQ described| 000040d0 20 61 62 6f 76 65 20 6c 69 73 74 73 0a 73 6f 6d | above lists.som| 000040e0 65 20 6f 66 20 74 68 65 20 6d 6f 72 65 20 70 6f |e of the more po| 000040f0 70 75 6c 61 72 20 66 72 65 65 20 61 6e 64 20 73 |pular free and s| 00004100 68 61 72 65 77 61 72 65 20 76 69 65 77 65 72 73 |hareware viewers| 00004110 2c 20 61 6e 64 20 74 65 6c 6c 73 20 77 68 65 72 |, and tells wher| 00004120 65 20 74 6f 0a 6f 62 74 61 69 6e 20 74 68 65 6d |e to.obtain them| 00004130 20 6f 6e 20 49 6e 74 65 72 6e 65 74 2e 0a 0a 49 | on Internet...I| 00004140 66 20 79 6f 75 20 61 72 65 20 6f 6e 20 61 20 55 |f you are on a U| 00004150 6e 69 78 20 6d 61 63 68 69 6e 65 2c 20 77 65 20 |nix machine, we | 00004160 68 69 67 68 6c 79 20 72 65 63 6f 6d 6d 65 6e 64 |highly recommend| 00004170 20 4a 65 66 20 50 6f 73 6b 61 6e 7a 65 72 27 73 | Jef Poskanzer's| 00004180 20 66 72 65 65 0a 50 42 4d 50 4c 55 53 20 69 6d | free.PBMPLUS im| 00004190 61 67 65 20 73 6f 66 74 77 61 72 65 2c 20 77 68 |age software, wh| 000041a0 69 63 68 20 70 72 6f 76 69 64 65 73 20 6d 61 6e |ich provides man| 000041b0 79 20 75 73 65 66 75 6c 20 6f 70 65 72 61 74 69 |y useful operati| 000041c0 6f 6e 73 20 6f 6e 20 50 50 4d 2d 66 6f 72 6d 61 |ons on PPM-forma| 000041d0 74 0a 69 6d 61 67 65 20 66 69 6c 65 73 2e 20 20 |t.image files. | 000041e0 49 6e 20 70 61 72 74 69 63 75 6c 61 72 2c 20 69 |In particular, i| 000041f0 74 20 63 61 6e 20 63 6f 6e 76 65 72 74 20 50 50 |t can convert PP| 00004200 4d 20 69 6d 61 67 65 73 20 74 6f 20 61 6e 64 20 |M images to and | 00004210 66 72 6f 6d 20 61 20 77 69 64 65 0a 72 61 6e 67 |from a wide.rang| 00004220 65 20 6f 66 20 6f 74 68 65 72 20 66 6f 72 6d 61 |e of other forma| 00004230 74 73 2e 20 20 59 6f 75 20 63 61 6e 20 6f 62 74 |ts. You can obt| 00004240 61 69 6e 20 74 68 69 73 20 70 61 63 6b 61 67 65 |ain this package| 00004250 20 62 79 20 46 54 50 20 66 72 6f 6d 20 66 74 70 | by FTP from ftp| 00004260 2e 78 2e 6f 72 67 0a 28 63 6f 6e 74 72 69 62 2f |.x.org.(contrib/| 00004270 70 62 6d 70 6c 75 73 2a 2e 74 61 72 2e 5a 29 20 |pbmplus*.tar.Z) | 00004280 6f 72 20 66 74 70 2e 65 65 2e 6c 62 6c 2e 67 6f |or ftp.ee.lbl.go| 00004290 76 20 28 70 62 6d 70 6c 75 73 2a 2e 74 61 72 2e |v (pbmplus*.tar.| 000042a0 5a 29 2e 20 20 54 68 65 72 65 20 69 73 20 61 6c |Z). 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Don't.use a| 00004cd0 20 70 72 6f 70 72 69 65 74 61 72 79 20 66 69 6c | proprietary fil| 00004ce0 65 20 66 6f 72 6d 61 74 21 0a 0a 0a 54 4f 20 44 |e format!...TO D| 00004cf0 4f 0a 3d 3d 3d 3d 3d 0a 0a 49 6e 20 66 75 74 75 |O.=====..In futu| 00004d00 72 65 20 76 65 72 73 69 6f 6e 73 2c 20 77 65 20 |re versions, we | 00004d10 61 72 65 20 63 6f 6e 73 69 64 65 72 69 6e 67 20 |are considering | 00004d20 73 75 70 70 6f 72 74 69 6e 67 20 73 6f 6d 65 20 |supporting some | 00004d30 6f 66 20 74 68 65 20 75 70 63 6f 6d 69 6e 67 20 |of the upcoming | 00004d40 4a 50 45 47 0a 50 61 72 74 20 33 20 65 78 74 65 |JPEG.Part 3 exte| 00004d50 6e 73 69 6f 6e 73 20 2d 2d 2d 20 70 72 69 6e 63 |nsions --- princ| 00004d60 69 70 61 6c 6c 79 2c 20 76 61 72 69 61 62 6c 65 |ipally, variable| 00004d70 20 71 75 61 6e 74 69 7a 61 74 69 6f 6e 20 61 6e | quantization an| 00004d80 64 20 74 68 65 20 53 50 49 46 46 20 66 69 6c 65 |d the SPIFF file| 00004d90 0a 66 6f 72 6d 61 74 2e 0a 0a 54 75 6e 69 6e 67 |.format...Tuning| 00004da0 20 74 68 65 20 73 6f 66 74 77 61 72 65 20 66 6f | the software fo| 00004db0 72 20 62 65 74 74 65 72 20 62 65 68 61 76 69 6f |r better behavio| 00004dc0 72 20 61 74 20 6c 6f 77 20 71 75 61 6c 69 74 79 |r at low quality| 00004dd0 2f 68 69 67 68 20 63 6f 6d 70 72 65 73 73 69 6f |/high compressio| 00004de0 6e 0a 73 65 74 74 69 6e 67 73 20 69 73 20 61 6c |n.settings is al| 00004df0 73 6f 20 6f 66 20 69 6e 74 65 72 65 73 74 2e 20 |so of interest. | 00004e00 20 54 68 65 20 63 75 72 72 65 6e 74 20 6d 65 74 | The current met| 00004e10 68 6f 64 20 66 6f 72 20 73 63 61 6c 69 6e 67 20 |hod for scaling | 00004e20 74 68 65 0a 71 75 61 6e 74 69 7a 61 74 69 6f 6e |the.quantization| 00004e30 20 74 61 62 6c 65 73 20 69 73 20 6b 6e 6f 77 6e | tables is known| 00004e40 20 6e 6f 74 20 74 6f 20 62 65 20 76 65 72 79 20 | not to be very | 00004e50 67 6f 6f 64 20 61 74 20 6c 6f 77 20 51 20 76 61 |good at low Q va| 00004e60 6c 75 65 73 2e 0a 0a 41 73 20 61 6c 77 61 79 73 |lues...As always| 00004e70 2c 20 73 70 65 65 64 69 6e 67 20 74 68 69 6e 67 |, speeding thing| 00004e80 73 20 75 70 20 69 73 20 68 69 67 68 20 6f 6e 20 |s up is high on | 00004e90 6f 75 72 20 70 72 69 6f 72 69 74 79 20 6c 69 73 |our priority lis| 00004ea0 74 2e 0a 0a 50 6c 65 61 73 65 20 73 65 6e 64 20 |t...Please send | 00004eb0 62 75 67 20 72 65 70 6f 72 74 73 2c 20 6f 66 66 |bug reports, off| 00004ec0 65 72 73 20 6f 66 20 68 65 6c 70 2c 20 65 74 63 |ers of help, etc| 00004ed0 2e 20 74 6f 20 6a 70 65 67 2d 69 6e 66 6f 40 75 |. to jpeg-info@u| 00004ee0 75 6e 65 74 2e 75 75 2e 6e 65 74 2e 0a |unet.uu.net..| 00004eed
.