Some information and assorted links regarding zlib.

http://gatekeep.cs.utah.edu/hppd/hpux/Misc/zlib-1.1.4/

The folks at Zeosync have been making some pretty bold claims regarding their yet-to-be-shown compressin tools. This patent application might open the door a bit.

http://l2.espacenet.com/dips/viewer?PN=WO0219536&CY=ep&LG=en&DB=EPD

This page has a Java applet that lets you experiment a bit with different quantization schemes for JPEG. There is lots of information here, I highly recommend that you follow the Help link to see what’s going on.

http://www.cs.sfu.ca/CourseCentral/365/li/interactive-jpeg/Ijpeg.html

An opportunity to look at a file when compressed with various JPEG quality factors.

http://www.cs.sfu.ca/CourseCentral/365/li/material/cgi-bin/whichjpeg.cgi

This example shows the effects of wavelet compression at various levels of quality and compares the wavelet compression result to the JPEG compression result.

http://www.cs.sfu.ca/CourseCentral/365/li/material/misc/wavelet.html

Dr. Keith Devlin writes an article in the UK Guardian explaining a bit about the technology behing the MP3 format.

http://www.guardian.co.uk/internetnews/story/0,7369,678607,00.html

This web site keeps links to free libraries and source code. If you like this, you might want to browse around in some of their other areas as well.

DataCompression.info user Andrew S. was not too impressed with this site: I tried one half of their links and they were all dead or directed to content not related to the topic.

http://www.thefreecountry.com/developercity/compression.shtml

A short tutorial on a few basic data compression concepts.

http://www.gnosis.cx/publish/programming/compression_primer.html

J. S. Vitter. “Design and Analysis of Dynamic Huffman Codes,” Journal of the ACM, 34(4), October 1987, 825-845. Full paper in PDF and Postscript format.

http://www.cs.duke.edu/~jsv/Papers/catalog/node60.html

Jeff Vitter’s Pascal implementation of his Adaptive Huffman algorithm. Naturally, this ACM submission is documented in a somewhat academic fashion.

http://www.cs.duke.edu/~jsv/Papers/catalog/node61.html

This paper by Paul Howard and Jeff Vitter goes over some of the basics of Arithmetic Coding, then outlines a coder that has increased efficiency by virtue of substituting table lookups for expensive arithmetic operations.

http://www.cs.duke.edu/~jsv/Papers/catalog/node64.html

This paper by Jyh-Han Lin and Jeff Vitter outlines new VQ algorithms based on linear programming. According to the abstract, the algorithm is the first known polynomial-time codebook design algorithm.

http://www.cs.duke.edu/~jsv/Papers/catalog/node67.html

by Paul Howard and Jeff Vitter. Here’s what they have to say about this paper from the abstract: Our algorithm, related to the PPM method, simplifies the modeling phase by eliminating the escape mechanism, and speeds up coding by using a combination of quasi-arithmetic coding and Rice coding. We provide details of the use of quasi-arithmetic code tables, and analyze their compression performance. Our Fast PPM method is shown experimentally to be almost twice as fast as the PPMC method, while giving comparable compression..

http://www.cs.duke.edu/~jsv/Papers/catalog/node68.html

EE Times reports that Europe’s ST Microelectronics is teaming up with 8X8 Inc. to produce chips aimed at the IP Telephony market. They are hoping to create chips that will be used in network video applications.8X8 will be supplying advanced compression and decompression algorithms for the chip vendor to sell in silicon.

http://www.eet.com/semi/news/OEG20020403S0026

Abale Zip is a royalty-free, robust and powerful Zip and Unzip component that costs much less than you would expect. It includes all the compression functionality you need in one easy to use ActiveX DLL that you distribute with your applications. The component works perfectly with VB, Delphi, ASP, C++Builder and Visual C++ and offers tons of sample applications to get you started. Looks like you can D/L a trial version, not clear from the web site if it’s crippled in any way. The web site works hard to explain that their component costs half of what you’ll pay for Xceedsoft’s product.

http://www.abale.com

I’m not familiar with this directory, but they do have a good list of data compression links here.

http://directory.ansme.com/computers/96710.html

An archive manager that has some built in functionality that helps you with your backup requirements. Automatic archiving in the trusty Zip format.

http://www.jspayne.com/filearchiver/

GZIPSite is a tool that can compress your web site and allow it to load as much as 50% faster.

http://www.applet.dk/

These guys use compression to increase messaging throughput on your network. Looks like they work with Microsoft Exchange, as well as having a general purpose product for ISPs.

http://www.quikcat.com/

I guess this is where you go to register or get support for your copy of RAR or WinRAR.

http://www.rarreg.com/

Rarissimo is a file utility to automatically compress and/or uncompress files, companion for the award winning compression program WinRAR. Distinguishable from other compression solutions by its ability to fully preserve NTFS alternate streams. This feature provides automatic compression/uncompression for Macintosh files stored on NT volumes preserving their filenames and peculiar structures - it means for example that you can use Rarissimo to send and receive Macintosh files using any standard FTP process (and not only Mac-based programs).

DataCompression.info user Marie M. said: This utility is very specialized so not easy to find. It is a great help to transfer Mac files without a special Mac ftp utility.

http://peccatte.karefil.com/Software/Rarissimo/RarissimoEN.htm

ColdCompress presents an easy to use GUI for creating .tar.gz archives on Mac OS X Server.

http://www.stepwise.com/Software/ColdCompress/index.html

MacRAR is the only RAR tool for Macintosh. Based upon Eugene Roshal’s sources and including a Mac interface, the package is delivered as shareware.

http://macrar.free.fr/

shcodec is order-0 32-bit canonical static huffman codec. It encodes an alphabet of 256 symbols with minimum-redundancy or length-restricted codes (basic method: Alistair Moffat and Jyrki Katajainen, modified by Artur A. Pessoa). shcodec uses efficient method for tree packing: on text files packed tree size is approx 68 bytes, on binary files this value is about 132 bytes. Memory requirements are very small: 1280 bytes for encoding and only 574 bytes for decoding! shcodec uses extremely fast and simple SHIFT-OR method for encoding, and CANONICAL-DECODE with a cache for small codewords for decoding.

Update: Alexander has added SH-SFX to the web page - a program for creating Win32 SFXs from files compressed with shcodec.

http://webcenter.ru/~xander/

Welcome to media.xiph.org, a repository for freely-redistributable test sets. We use these to test our codecs, and hope you will too. This site includes a partial mirror of the Video Quality Experts Group test sequences as well.

http://media.xiph.org

Guido Vollbeding has posted a number of items related to the IGJ code. Includes ways to crop, rotate, and merge JPEG files.

http://jpegclub.org/

Bill has links to some of his papers here, citations for all.

http://www.scms.rgu.ac.uk/staff/smc/researchcoord/staff_publications/wjt.html

The author of this code created this visualization executable for a seminar.

DCL reader Drew D. downloaded the code, executed it, and had this to say about it: The program is an executable for windows with a dll and some gif’s. The program seems to require a screen size greater than 800×600 to view the fixed size window. The program is a bit cryptic to me since I only have a basic understanding of Arithmetic encoding but it offers nice step by step encoding with some statistical information. It also allows for the modifying of input types and reading from a file..

http://www.bodden.de/download.php?cat=ac&file=acvis_exe.zip

EllTech makes a compression library that supports zip files, plus a bunch of other formats, including ARC, ARJ, tarballs, etc.

Update! EllTech’s products were acquired by BeCubed Software. Compression Plus 5.0 appears to still be available.

http://www.becubed.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=B&Product_Code=080150

Privately held Pulsent is promising a new video compression technique that can stream video across the net with only half the bandwidth of MPEG2. They’ve not only created a new algorithm but are also developing the chips to support it.

http://story.news.yahoo.com/news?tmpl=story&u=/cn/20020325/tc_cn/show_time_for_new_video_c
ompression&cid=70