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diff --git a/jpg/README b/jpg/README deleted file mode 100644 index 0a23c19..0000000 --- a/jpg/README +++ /dev/null @@ -1,351 +0,0 @@ -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. |