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-The Independent JPEG Group's JPEG software
-==========================================
-
-README for release 8d of 15-Jan-2012
-====================================
-
-This distribution contains the eighth 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.
-
-This software is the work of Tom Lane, Guido Vollbeding, Philip Gladstone,
-Bill Allombert, Jim Boucher, Lee Crocker, Bob Friesenhahn, Ben Jackson,
-Julian Minguillon, Luis Ortiz, George Phillips, Davide Rossi, Ge' Weijers,
-and other members of the Independent JPEG Group.
-
-IJG is not affiliated with the ISO/IEC JTC1/SC29/WG1 standards committee
-(also known as JPEG, together with ITU-T SG16).
-
-
-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.
-ACKNOWLEDGMENTS Special thanks.
-FILE FORMAT WARS Software *not* to get.
-TO DO Plans for future IJG releases.
-
-Other documentation files in the distribution are:
-
-User documentation:
- install.txt How to configure and install the IJG software.
- usage.txt Usage instructions for cjpeg, djpeg, jpegtran,
- rdjpgcom, and wrjpgcom.
- *.1 Unix-style man pages for programs (same info as usage.txt).
- wizard.txt Advanced usage instructions for JPEG wizards only.
- change.log Version-to-version change highlights.
-Programmer and internal documentation:
- libjpeg.txt How to use the JPEG library in your own programs.
- example.c Sample code for calling the JPEG library.
- structure.txt Overview of the JPEG library's internal structure.
- filelist.txt Road map of IJG files.
- coderules.txt Coding style rules --- please read if you contribute code.
-
-Please read at least the files install.txt and usage.txt. Some 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 encoding, decoding,
-and transcoding. JPEG (pronounced "jay-peg") is a standardized compression
-method for full-color and gray-scale images.
-
-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.
-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) 1991-2012, Thomas G. Lane, Guido Vollbeding.
-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 Unix configuration script "configure" was produced with GNU Autoconf.
-It is copyright by the Free Software Foundation but is freely distributable.
-The same holds for its supporting scripts (config.guess, config.sub,
-ltmain.sh). Another support script, install-sh, is copyright by X Consortium
-but is also freely distributable.
-
-The IJG distribution formerly included code to read and write GIF files.
-To avoid entanglement with the Unisys LZW patent, GIF reading support has
-been removed altogether, and the GIF writer has been simplified to produce
-"uncompressed GIFs". This technique does not use the LZW algorithm; the
-resulting GIF files are larger than usual, but are readable by all standard
-GIF decoders.
-
-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 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 http://www.ijg.org/files/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 and Jean-loup Gailly, published by
-M&T Books (New York), 2nd ed. 1996, ISBN 1-55851-434-1. 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 currently available 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).
-Although this is by far the most detailed and comprehensive exposition of
-JPEG publicly available, we point out that it is still missing an explanation
-of the most essential properties and algorithms of the underlying DCT
-technology.
-If you think that you know about DCT-based JPEG after reading this book,
-then you are in delusion. The real fundamentals and corresponding potential
-of DCT-based JPEG are not publicly known so far, and that is the reason for
-all the mistaken developments taking place in the image coding domain.
-
-The original JPEG 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 numbers ISO/IEC IS
-10918-1, ITU-T T.81. Part 2 is titled "Digital Compression and Coding of
-Continuous-tone Still Images, Part 2: Compliance testing" and has document
-numbers ISO/IEC IS 10918-2, ITU-T T.83.
-IJG JPEG 8 introduces an implementation of the JPEG SmartScale extension
-which is specified in two documents: A contributed document at ITU and ISO
-with title "ITU-T JPEG-Plus Proposal for Extending ITU-T T.81 for Advanced
-Image Coding", April 2006, Geneva, Switzerland. The latest version of this
-document is Revision 3. And a contributed document ISO/IEC JTC1/SC29/WG1 N
-5799 with title "Evolution of JPEG", June/July 2011, Berlin, Germany.
-
-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. JFIF 1.02 has been adopted as an Ecma International Technical Report
-and thus received a formal publication status. It is available as a free
-download in PDF format from
-http://www.ecma-international.org/publications/techreports/E-TR-098.htm.
-A PostScript version of the JFIF document is available at
-http://www.ijg.org/files/jfif.ps.gz. There is also a plain text version at
-http://www.ijg.org/files/jfif.txt.gz, but it is missing the figures.
-
-The TIFF 6.0 file format specification can be obtained by FTP from
-ftp://ftp.sgi.com/graphics/tiff/TIFF6.ps.gz. 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
-http://www.ijg.org/files/. 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.
-
-
-ARCHIVE LOCATIONS
-=================
-
-The "official" archive site for this software is www.ijg.org.
-The most recent released version can always be found there in
-directory "files". This particular version will be archived as
-http://www.ijg.org/files/jpegsrc.v8d.tar.gz, and in Windows-compatible
-"zip" archive format as http://www.ijg.org/files/jpegsr8d.zip.
-
-The JPEG FAQ (Frequently Asked Questions) article is a source of some
-general information about JPEG.
-It is available on the World Wide Web at http://www.faqs.org/faqs/jpeg-faq/
-and other news.answers archive sites, including the official news.answers
-archive at rtfm.mit.edu: ftp://rtfm.mit.edu/pub/usenet/news.answers/jpeg-faq/.
-If you don't have Web or FTP access, 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
-
-
-ACKNOWLEDGMENTS
-===============
-
-Thank to Juergen Bruder for providing me with a copy of the common DCT
-algorithm article, only to find out that I had come to the same result
-in a more direct and comprehensible way with a more generative approach.
-
-Thank to Istvan Sebestyen and Joan L. Mitchell for inviting me to the
-ITU JPEG (Study Group 16) meeting in Geneva, Switzerland.
-
-Thank to Thomas Wiegand and Gary Sullivan for inviting me to the
-Joint Video Team (MPEG & ITU) meeting in Geneva, Switzerland.
-
-Thank to Thomas Richter and Daniel Lee for inviting me to the
-ISO/IEC JTC1/SC29/WG1 (also known as JPEG, together with ITU-T SG16)
-meeting in Berlin, Germany.
-
-Thank to John Korejwa and Massimo Ballerini for inviting me to
-fruitful consultations in Boston, MA and Milan, Italy.
-
-Thank to Hendrik Elstner, Roland Fassauer, Simone Zuck, Guenther
-Maier-Gerber, Walter Stoeber, Fred Schmitz, and Norbert Braunagel
-for corresponding business development.
-
-Thank to Nico Zschach and Dirk Stelling of the technical support team
-at the Digital Images company in Halle for providing me with extra
-equipment for configuration tests.
-
-Thank to Richard F. Lyon (then of Foveon Inc.) for fruitful
-communication about JPEG configuration in Sigma Photo Pro software.
-
-Thank to Andrew Finkenstadt for hosting the ijg.org site.
-
-Last but not least special thank to Thomas G. Lane for the original
-design and development of this singular software package.
-
-
-FILE FORMAT WARS
-================
-
-The ISO/IEC JTC1/SC29/WG1 standards committee (also known as JPEG, together
-with ITU-T SG16) currently promotes different formats containing the name
-"JPEG" which is misleading because these formats are incompatible with
-original DCT-based JPEG and are based on faulty technologies.
-IJG therefore does not and will not support such momentary mistakes
-(see REFERENCES).
-There exist also distributions under the name "OpenJPEG" promoting such
-kind of formats which is misleading because they don't support original
-JPEG images.
-We have no sympathy for the promotion of inferior formats. Indeed, one of
-the original reasons for developing this free software was to help force
-convergence on common, interoperable format standards for JPEG files.
-Don't use an incompatible file format!
-(In any case, our decoder will remain capable of reading existing JPEG
-image files indefinitely.)
-
-Furthermore, the ISO committee pretends to be "responsible for the popular
-JPEG" in their public reports which is not true because they don't respond to
-actual requirements for the maintenance of the original JPEG specification.
-
-There are currently distributions in circulation containing the name
-"libjpeg" which claim to be a "derivative" or "fork" of the original
-libjpeg, but don't have the features and are incompatible with formats
-supported by actual IJG libjpeg distributions. Furthermore, they
-violate the license conditions as described under LEGAL ISSUES above.
-We have no sympathy for the release of misleading and illegal
-distributions derived from obsolete code bases.
-Don't use an obsolete code base!
-
-
-TO DO
-=====
-
-Version 8 is the first release of a new generation JPEG standard
-to overcome the limitations of the original JPEG specification.
-More features are being prepared for coming releases...
-
-Please send bug reports, offers of help, etc. to jpeg-info@jpegclub.org.