JPEG image compression FAQ, part 2/2 2/18/05 5:03 PM Part1 - Part2 - MultiPage JPEG image compression FAQ, part 2/2 There are reader questions on this topic! Help others by sharing your knowledge Newsgroups: comp.graphics.misc, comp.infosystems.www.authoring.images From: [email protected] (Tom Lane) Subject: JPEG image compression FAQ, part 2/2 Message-ID: <[email protected]> Summary: System-specific hints and program recommendations for JPEG images Keywords: JPEG, image compression, FAQ, JPG, JFIF Reply-To: [email protected] Date: Mon, 29 Mar 1999 02:24:34 GMT Sender: [email protected] Archive-name: jpeg-faq/part2 Posting-Frequency: every 14 days Last-modified: 28 March 1999 This article answers Frequently Asked Questions about JPEG image compression. This is part 2, covering system-specific hints and program recommendations for a variety of computer systems. Part 1 covers general questions and answers about JPEG. As always, suggestions for improvement of this FAQ are welcome. New since version of 14 March 1999: * Added entries for PIE (Windows digicam utility) and Cameraid (Macintosh digicam utility). * New version of VuePrint (7.3). This article includes the following sections: General info: [1] What is covered in this FAQ? [2] How do I retrieve these programs? Programs and hints for specific systems: [3] X Windows [4] Unix (without X) [5] MS-DOS [6] Microsoft Windows [7] OS/2 [8] Macintosh [9] Amiga [10] Atari ST [11] Acorn Archimedes [12] NeXT [13] Tcl/Tk [14] Other systems Source code for JPEG: [15] Freely available source code for JPEG Miscellaneous: [16] Which programs support progressive JPEG? [17] Where are FAQ lists archived? This article and its companion are posted every 2 weeks. If you can't find part 1, you can get it from the news.answers archive at rtfm.mit.edu (see "[17] Where are FAQ lists archived?"). This article changes frequently; get a new copy if the one you are reading is more than a couple months old. http://www.faqs.org/faqs/jpeg-faq/part2/ Page 1 of 12 JPEG image compression FAQ, part 2/2 2/18/05 5:03 PM Subject: [1] What is covered in this FAQ? This list describes programs that are of particular interest to JPEG users. For the most part, I concentrate on viewers, since a viewer program is the first thing you'll need. Some general image-editing programs are listed too, especially if they are useful as plain viewers (meaning that they can load and display an image as quickly and easily as a dedicated viewer). Programs that convert JPEG to and from other image file formats are also covered. I list only freeware and shareware programs that are available on the Internet by FTP. Commercial products are intentionally excluded, to keep the list to a reasonable size and to avoid any appearance of advertising. Also, I try to list only programs that are popular among Usenet users, as indicated by comments and recommendations in news articles. I have no access to many of the types of systems covered here, so I have to rely on what other people say about a program to decide whether to list it. If you have an opinion pro or con on any program, I'd appreciate hearing it. This FAQ also includes a few hints that are specific to a machine or program, and thus don't belong in the general discussion of part 1. Subject: [2] How do I retrieve these programs? Almost all the files mentioned in this FAQ are available by standard Internet FTP. If you don't know how to use FTP, please read the article "Anonymous FTP FAQ List", which you can get by sending e-mail to [email protected] with the single line "send faqs/ftp-list/faq" in the body. (See also "[17] Where are FAQ lists archived?") This section gives some quick reminders which are not meant as a substitute for reading the FTP FAQ. If you use a WWW browser such as Netscape or Lynx, it will do FTP for you. To retrieve a file described here as "site.name:/path/to/file ", tell the browser to open the URL "ftp://site.name/path/to/file ". (If you are reading this FAQ in the WWW FAQ archive, the file names should appear as links that you can just click on.) Depending on your browser, you may have to shift- click or take some other special action to instruct the browser to save the file to disk, rather than trying to display the file to you. If you do not have direct access to FTP, you can use an "ftpmail" server to obtain files by e-mail. See the FTP FAQ for details. Many of the pointers given here refer to popular central archive sites, such as ftp.simtel.net for DOS software or sumex-aim.stanford.edu for Mac. These sites are often overloaded, and are likely to refuse your connection request when they are busy. You can try again at a less popular time of day, or you can look for a "mirror site". Most central archive sites have groups of mirror sites that keep copies of their files. Find out the name of the mirror site closest to you, and visit that site instead; it's good net citizenship and you'll get faster response. Check the FAQs for the newsgroups specific to your system type to find lists of mirror sites. (The archive site may list some mirror sites in its connection-refused error message. Unfortunately, some FTP programs won't show you the whole message. WWW browsers are often bad about this.) If you are able to reach the archive site, but the file you want doesn't exist, most likely it's been replaced by a newer version. Get a directory listing of the directory that's supposed to contain the file, and look for a file with a similar name but a higher version number. In a WWW browser, you can get a directory listing by removing the file name, that is opening the URL consisting of everything up to and including the last slash. (If you find an out-of-date reference in a *current* version of the JPEG FAQ, I'd appreciate hearing about it by e-mail.) Practically all of the files listed here are compressed archive files. This means you need to retrieve them in binary mode. (WWW browsers do this automatically, but many older FTP programs must be told to use binary mode.) Once you've got the archive file, you'll need a decompressor/dearchiver to extract the program and documentation files inside it. Check the FAQs for your system type to find out where to get dearchiver programs. Subject: [3] X Windows XV is an excellent viewer for JPEG, GIF, and many other image formats. It can also do format conversion and some simple image manipulations. Current release is 3.10a, available from http://www.trilon.com/xv/ or from http://www.faqs.org/faqs/jpeg-faq/part2/ Page 2 of 12 JPEG image compression FAQ, part 2/2 2/18/05 5:03 PM ftp://ftp.cis.upenn.edu/pub/xv/. Shareware, $25. HINT: if you have an 8-bit display then you need to "lock 8-bit mode" to get decent display of JPEG images. (But do NOT do this if you intend to resave the image, because it'll be written from the 8-bit version, thus costing you image quality.) You can set this mode to be default by adding "xv.force8: true" to your .Xdefaults file. To override that default for editing, say "xv -24". Another excellent choice is John Cristy's free ImageMagick package, currently at release 4.1; see http://www.wizards.dupont.com/cristy/ImageMagick.html. This software handles many image processing and conversion tasks. The ImageMagick package provides a C/C++-callable library and a set of command line processing/display programs. Perl and Python interfaces to the ImageMagick library are also available. Both of the above are large, complex packages. If you just want a simple image viewer, try xloadimage or xli. xloadimage views and converts many image file types including JPEG. Version 4.1 has better JPEG support than prior versions and is easier to install. xloadimage is free and available from ftp://ftp.x.org/R5contrib/. xli is a variant version of xloadimage; xli is slightly better as an interactive viewer, but it can't be used as a converter, and it supports fewer file formats. xli is also free and available from ftp://ftp.x.org/contrib/applications/. Subject: [4] Unix (without X) If you want a command-line JPEG conversion program, see the IJG source code described in section 15. (This code is included as a subdirectory in most of the X programs described above, although they may not have the latest version.) Non-X viewers are hard to come by, since they are very hardware dependent. Linux users with VGA/SVGA displays may like zgv. Version 3.1 is available from sunsite.unc.edu:/pub/Linux/apps/graphics/viewers/svga/zgv-3.1-bin.tar.gz. (Several other alternatives are available in the same directory.) If you use a less popular platform, you're probably out of luck. Subject: [5] MS-DOS This covers plain DOS; for Windows or OS/2 programs, see the next sections. NOTE ABOUT SIMTEL FILES: The best-known Internet collection of PC-related programs is the Simtel archives (named for the original archive site, now defunct).