Supplier of data comrpession libraries to use with FoxPro. Includes FOXSQZ, an archiving and compression library, COMP5, a compression library, and JavaSQZ, a data compression library for Java.

http://ourworld.compuserve.com/homepages/masterw/

mgzip is a program that makes use of SMP machines and zlib to use as many processors as you have to quickly compress files into gzip compatible format. mgzip only compresses; gunzip must be used to uncompress the resultant file. I have been able to compress files three times faster than standard gzip on a 4 processor Alpha 4100 using three worker threads. Currently, mgzip will compile and run on Digital Unix 4.0[BD], Linux with a suitable pthread library, and AIX 4.3. Porting to other Unices with pthread libraries should be an easy task, and may be as simple as compiling.

http://www.lemley.net/mgzip.html

A Technical Documentation bulleting from TI that answers the question “What is a Compressed Postscript (.psz) File?”

http://www.ti.com/sc/docs/psheets/psform.htm

WSQ by Aware is our implementation of the Federal Bureau of Investigation’s Wavelet Scalar Quantization fingerprint compression standard. WSQ by Aware is the industry’s highest performing implementation of the FBI’s Wavelet Scalar Quantization (WSQ) digital fingerprint compression algorithm. WSQ is a wavelet transform-based compression standard, developed by the FBI for compression of digital fingerprint images.

http://www.aware.com/products/compression/wsq.html

A company that makes PhotoJazz, a lossless compression plug in package that they describe as having Breakthrough lossless photo-quality compression of stills and movies for archival, print, and the Internet. Version 2.0 supports Mac and Windows, Photoshop, QuickTime, and Quark. You can download the Reader for free and try it out.

http://www.bitjazz.com

Bob Carpenter has created a nice Java package that implements a PPM/arithmetic coding compression system. This page includes links to the source code, javadocs, and a fair amount of tutorial material. Very complete!

http://www.colloquial.com/ArithmeticCoding/

bwtzip is an ongoing project, distributed under the GNU General Public License, to implement a Burrows-Wheeler compressor in standard, portable C++. It is research-grade in that it is highly modularized and abstracted, so that it is simple to swap out parts of the compressor without affecting anything else. This makes it easy to experiment with different algorithms at different stages of compression.

Looks like Steven T. Lavavej released a new version of bwtzip in early February, 2003. A wide variety of improvements, most of them in implementation - not visible to the end user. A description of recent changes is found here

http://stl.caltech.edu/bwtzip.html

These guys are claiming a quantum leap in image compression! It looks like you can get a 30 day free trial of this product. The affiliate marketing program for MyPhotoZip is kind of goofy, see more about it at ecomecom.net.

Visitor Tim A had this to say: A demo of MyPhotoZip is available on CNET, ZDNet (possibly others). My first impression is that it’s very similar to JP2. Lossless compression performance is virtually identical on a few test images. Nothing special to talk about

Donald J. was a bit more enthusiastic: I have run several tests on this product and the quality compared to JPEG is far superior. For a raw TIFF image of 10 MB or more the file size can be compressed as much as 1000 to 1 while still maintaining decent quality if you adjust the color portion to a higher number.

http://myphotozip.com

A pure Ada decompression library. You can extract files from zip archives using this library, although you can’t create them.

Release 11 shipped in November of 2002.

http://www.mysunrise.ch/users/gdm/unzipada.htm

This wrapper class provides you with simple access to the gzip compression methods in zlib. You can compress and decopress to/from memory (including strings) to files. Looks promising. Release 1.1 was released 12/2002, although I can’t tell what if anything has changed.

http://www.codeproject.com/cpp/cgzip.asp

Jürgen is the proprietor of

www.data-compression.info,
an excellent resource for developers and researchers. Jürgen has a good supply of links to papers, conferences, books, etc. on the site, as well as executables and source for ABC, a freeware BWT compressor he wote in Delphi.

http://www.data-compression.info/JuergenAbel/

Will McKee wrote some Huffman code in C++. Take a look.

Update: Will reports that he has improved the documentation in this package, as well as adding a new function.

http://www.cjkware.com/wamckee/huffman.zip

Will McKee has released this as freeware - includes complete source to a string substitution compressor. From the description it sounds as though it’s variant on LZSS, but I’ll defer to anyone willing to do a real analysis.

http://www.cjkware.com/wamckee/mcdag.zip

Nellymoser is the leading provider of proprietary speech and audio software technology and solutions in the areas of compression, modification, synchronization and conversion. Our products improve speech and audio quality and efficiency in bandwidth-constrained environments while creating more immersive, interactive environments for your applications and services.

http://www.nellymoser.com/

The Asao libraries from Nellysoft have been designed specifically to address the need for a very small footprint, low bandwidth speech and audio compression. Asao will operate at a variety of bit rates (12/16/24/32 Kbps). This new technology can be rapidly harnessed for applications such as streaming over mobile data networks, Internet radio and embedded platforms such as toys and other consumer devices.

http://www.nellymoser.com/products/audio_compression_asao_fst.htm

The Sase libraries fron Nellysoft offer flexible compression options for both embedded and data packets based compression implementations It can operate in either a single bit rate or a multi-rate mode, offering compression rates (1.8/3.2/6.4 Kbps) to suit your application or the changing environment of packet based networks. Sase has the ability to switch bit rates on-the-fly to better handle changing network condition. At 3.2 Kbps Sase offers near toll quality, as you would expect when more bits are added the speech quality improves at 6.4 Kbps.

http://www.nellymoser.com/products/compression_fst.htm

David Scott presents an implementation of Vitter’s dynamic Huffman compressor, adapted so that it is bijective. Don’t know what bijective means? Check out David’s home page for more details.

http://bijective.dogma.net/compress2vh.htm

The folks at SpeedProject in Germany have created a developer’s toolkit that gives you full access to the SQX format archives created by their Squeez and SpeedCommander utilities. The toolkit and DLLs are completely free.

http://www.sqx-archiver.org/

This is a preliminary shot at creating an open source BWT compression engine. Things look very preliminary at this point with just a couple of files available for download and not much message traffic.

http://sourceforge.net/projects/bwtcoder/

Google’s directory entry point for test images used in data compression.

http://directory.google.com/Top/Computers/Algorithms/Compression/Test_Images/

This dynamic Huffman coder from Karl Malbrain is written in C and includes weight scaling. It is modeled on the Vitter algorithm.

A DataCompression.info user notes that this site has been undergoing continual changes, and perhaps would benefit from some sort of “last modified on” field.

http://www.geocities.com/malbrain/vitter_c.html

A nice set of lecture notes by Iain Richardson. The notes have a good level of detail, so there is value here even without the lecture.

http://www.vcodex.fsnet.co.uk/videocoding2b.pdf

1997, Robert Giegerich, Stefan Kurtz. We review the linear time suffix tree constructions by Weiner, McCreight, and Ukkonen. We use the terminology of the most recent algorithm, Ukkonen’s online construction, to explain its historic predecessors. The submitter of this paper indicates that it has user-friendly terminology, always welcome in Journal papers.

http://citeseer.nj.nec.com/giegerich97from.html

This is the data compression standard that implements the LZJH algorithm, and is used in V.90 and V.92 modems. The ITU wants to charge you a few bucks for this standard, but if you believe the post from Pete Fraser (listed elsewhere on DataCompression.info) you can get three free standards per year. Maybe this ought to be one of them.

http://www.itu.int/rec/recommendation.asp?type=items&lang=e&parent=T-REC-V.44-200011-I

SEQUITUR is a method for inferring compositional hierarchies from strings. It detects repetition and factors it out of the string by forming rules in a grammar. The rules can be composed of non-terminals, giving rise to a hierarchy. It is useful for recognizing lexical structure in strings, and excels at very long sequences.

http://sequence.rutgers.edu/sequitur/

PlusV is a brand new audio compression enhancement technology that allows audio files to be compressed in as little as 64 or even 48 kbits/s. PlusV is not a compression scheme of its own, it is an extension that can be applied to existing audio formats. When combined with the MP3 technology, MP3+V files are fully compatible with existing MP3 files and decoders. To get full audio quality out of PlusV files, you just need a PlusV capable decoder, like a PlusV capable WinAmp plugin.

http://www.plusv.org/

IP*Works! Zip allows developers to easily integrate compression and decompression functionality into web or desktop applications using popular file and data compression standards including Zip, Tar, Gzip and Jar standards for compression. All IP*Works! Zip components have been built from the ground up entirely in native .NET and Java code, combining exceptional speed, excellent data compression, and extreme portability across platforms.

The components feature password support, file deletion within an archive, streaming compression and decompression, and more. IP*Works! Zip is currently available as fully-managed 100% C# .NET components, or pure Java beans.

http://www.nsoftware.com/products/ipworkszip.aspx

BICOM is a freely available open source compressor. It uses a souped-up PPM algorithm, and is completely bijective.

Reader comment:
Wow this is hot! …a bijective compressor
using full size Rijndael encryption…

http://www3.sympatico.ca/mt0000/bicom/bicom.html

Szip is a freeware portable general purpose lossless compression program. It has a high speed and compression, but high memory demands (up to 20MB) too. The compression is done using a variant of blocksorting, which explains its rather high memory requirements.

Update: Michael Schindler has at long last posted the source code for szip.

http://www.compressconsult.com/szip/

The abstract for a paper on calculation of Huffman codes. The paper isn’t here, but the source code is. Alistair says that if you sort your array of counts, you can create the Canonical Huffman tree in memory.

http://www.cs.mu.oz.au/~alistair/abstracts/mk95%3Awads.html