Want to know how things are going in the world of PNG? Come check this page from time to time. See the current ratings for Stability, User Acceptance, Application Support, and so on.

http://www.libpng.org/pub/png/pngstatus.html

Another version of the PPMD program by Dmitry Shkarin. Readme says this includes a bug fix, and removal of one model.

ftp://ftp.nsk.su/.3/windows/compress/ppmde.zip

This page has a some Huffman compression code that has been adapted to implement a unique property that author refers to as one to one compression. In a nutshell, this property means that for any file X, F( F’( X ) ) == X. (F is either the compressor or decompressor, and F’ is its opposite number.)This is definitely not the case for most conventional compression algorithms.

http://bijective.dogma.net/

A library to perform adpative Huffman coding as described by Knuth in J. Alg. Nice clean looking C source code.

This link continues to be one of the most popular links at DataCompression.info. Reader Karl M. had this comment about the page: The program has a few problems converting from one-based to zero-based arrays. The code for incorporating the last symbol grabs an extra input bit, but since this is usually the EOT symbol, the bug doesn’t always cause problems..

http://www.xcf.berkeley.edu/~ali/K0D/Algorithms/huff/

This is a fairly small C program that was developed on the Amiga.

Note: I’m not sure why, but this page gets a very high number of ratings, nearly all very favorable, although Kate W. did claim: Parts missing from the source code, can’t build.

http://www.cbloom.com/src/adaphuff.zip

A nice tidy proof that the Huffman tree is an optimal prefix code for a given message. Note that a library reader finds that there is an error in the fixed-length codes listed in Table 1, a and b have duplicate values.

http://maths.abdn.ac.uk/~igc/tch/mx4002/notes/node59.html

A really nice set of programs and source code for all sorts of data compression. This area doesn’t appear to be actively maintained, so there are plenty of out-of-date files, but good stuff mixed in as well.

http://www.programmersheaven.com/zone22/mh142.htm

A very nice description of Huffman coding, as well as a few other types of coding. I believe this is part of a survey paper by Debra A. Lelewer and Daniel S. Hirschberg.

http://www.ics.uci.edu/~dan/pubs/DC-Sec3.html

The Data Compression Reference Center talks about Huffman coding. A short but fairly succint explanation.
This link points to an archived site, as the original has disappeared. Links on the archived page may or may not work properly.

http://web.archive.org/web/20020214075614/http://www.rasip.fer.hr/research/compress/algori
thms/fund/huffman/

Another java graphical demonstration of Huffman tree building.

http://www.ee.uwa.edu.au/~roberto/teach/itc314/java/Huffman/

This page describes Flexible Parsing, a proposed extension for dictionary based compression schemes. Yossi Matias, Nasir Rajpoot, and Cenk Sahinalp have a summary of their work on this page, along with links to three PS format papers that go into detail on the results. The authors summarize this improved technique as “looking one step ahead for the longest phrase in the dictionary instead of trying to find the longest possible phrase at hand.”

http://www.dcs.warwick.ac.uk/~nasir/work/fp/

An Optimizing Hybrid LZ77 RLE Data Compression Program, aka Improving Compression Ratio for Low-Resource Decompression by Pasi Ojala.

Presents a new literal tagging system, a fast exhaustive string
match algorithm, an optimal parsing algorithm, and results on
Calgary Corpus and Canterbury Corpus.

http://www.cs.tut.fi/~albert/Dev/pucrunch/

These folks deliver a tool called FLAM which uses a patented data compression algorithm to do something. The site has English and German language versions, but doesn’t seem to have any detailed information on FLAM.

http://www.limes-datentechnik.de/

This page contains a paper that describes a program that attempts to improve on Huffman compression by manipulation of the data stream.

http://www.ux.his.no/~karlsk/proj99/

A not very serious trashing of fractal compression.

http://graphics.cs.uiuc.edu/~jch/notfractal.html

The Independent JPEG Group is a source of free JPEG software. It is in wide use. Oddly enough, the groups home page doesn’t have anything interesting on it except a link to an ftp site, and a link to a couple of FAQs.

http://www.ijg.org/

by Xiaolin Wu, University of Western Ontario. A paper on the CALIC algorithm, first presented at DCC 96. This file is in PS format.

ftp://ftp.csd.uwo.ca/pub/from_wu/papers/dcc96.ps

by Xiaolin Wu, University of Western Ontario. A paper on high performance lossless image compression. I’m not sure if this paper was a predecessor to CALIC/JPEG-LS or not.

ftp://ftp.csd.uwo.ca/pub/from_wu/papers/paper0.ps

by Paul Glor Howard, Brown University, 1993. This thesis looks at statistical methods for performing data compression.

ftp://ftp.cs.brown.edu/pub/techreports/93/cs93-28.ps.Z

A collenction of links to graphics file format information.

http://www.ora.com/centers/gff/gff-faq/gff-faq1.htm#FILE_ARCS

The home page of the Encyclopaedia of Graphics File Formats.

http://www.ora.com/centers/gff/index.htm

Software for H.263, JPEG-LS, and JBIG-2. Follow the links to Software. Many publications as well.

http://spmg.ece.ubc.ca/

An article I wrote that describes how to take advantage of the zip classes included in Java’s 1.1 JDK. This includes some very simple programs that can create, view, and extract from zip files.

http://www.dogma.net/markn/articles/JavaZip/JavaZip.html

This article describes a relatively painless way to construct suffix trees. Once you have a suffix tree constructed, it is extremely easy to search for the longest match of a given string. This makes the suffix tree a nice data structure to use in macro replacement forms of data compression.

http://www.dogma.net/markn/articles/suffixt/suffixt.htm

AudioCatalyst is a commercial program that creates and playsback MP3 files. The recorder can rip tracks from music CDs and convert them to MP3 files in many different formats. A trial edition of the product is available at this web site.

http://www.xingtech.com/mp3/audiocatalyst/

by Balkenhol, Kurtz, and Shtarkov. A paper that was published at DCC 1999. Some thoughts about BWT and the context tree model, alphabet modification, modification of MTF, and Grouping of symbols.

NOTE:The file type would indicate that this is a compressed file, but it actually appears to be unencoded PS format.

http://www.techfak.uni-bielefeld.de/~kurtz/PS/balkenhol_BurrowsWheelerDcc99.ps.gz

by Bernhard Balkenhol, Stefan Kurtz, 1998. Yet another analysis of the algorithm. Any exciting conclusions? Click the rate link and you can tell me.

http://www.mathematik.uni-bielefeld.de/sfb343/preprints/pr98069.ps.gz

A description of the ARJ file format.

http://DataCompression.info/ArchiveFormats/arj.txt

A description of the CAB file format. This doc page includes some source.

http://DataCompression.info/ArchiveFormats/cab.zip

Xing makes consumer products that support various forms of digital audio. Xing Audio Catalyst is a popular program that supports both creation and playback of MP3 audio.

http://www.xingtech.com/