data compression link collection

Newsgroup Posts

Interesting newsgroup posts, mostly to comp.compression and comp.compression.research. Note that nearly all of these posts are retrieved via the Deja News service. If something happens to Deja News, this topic will be not so useful.

LHA History Lesson

Published in Newsgroup Posts, LHA

A few notes about the ancient history of LHA on comp.compression.


Posted in February 22nd, 2004

Canonical Huffman Coder Construction

The first time I ever heard the phrase Canonical Huffman Coder was in reference to the technique used in PKZip to store Huffman tables. I don’t know where the technique originated, but it is basically a way to construct a Huffman table so that the actual codes don’t have to be stored when storing the table. This makes for some nice space savings when compared to a first-pass naïve implementation. (Like the ones I’ve done in the past.)

It turns out that somebody named Gareth was attempting to implement this code but was having a bit of trouble. His post to comp.compression brought out some useful help from some of the newsgroup regulars, and did a lot to shed light on the topic, and includes a reference to the paper that actually gave birth to the concept.

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Posted in March 13th, 2003

CRC Pointers

Somebody posting as thewhizkid complained to the comp.compression newsgroup that he just couldn’t figure out how to do a CRC calculation. He got a couple of good pointers here, including one to the zlib code, and another including a bit of Java that could do the job. I’ll add a pointer to my ancient-but-still-cogent article from DDJ,

File Verification Using CRC
to the mix. Between the three choices, I hope the poster was able to get a handle on the mysterious CRC.


Posted in March 12th, 2003

Why Can’t One Image Coder Rule?

Alex Ng posed the question on comp.compression: “In general, you cannot have one image coder can compress well for ALL
images. Why?”

This set off a lively and somewhat useful discussion, with lots of thoughtful posts from Thomas Richter and others. Always good to find some intelligent thought on the compression newsgroup.


Posted in March 7th, 2003

Free Specs from the ITU

According to Pete Fraser, you can download three free specifications from the ITU per year, after free registration. This is a great deal - these specs can run into the hundreds of dollars per copy, and if you aren’t near a university library, you may have no other way to get them.


Posted in September 15th, 2002

LZW Patent Expiration

This thread reveals the actual dates for the LZW patent expiration, including US, European, and Japanese patents.

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Posted in September 15th, 2002

A forum dedicated to the discussion of Wavelets. This link takes you to the French language version of the board - click on the “English” link on the left side of the page for English language discussion.

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Posted in June 5th, 2002

Distance Coding post

A post by Edgar Binder discussing his distance coding algorithm. Distance coding is used in place of the MTF stage in BWT compression.

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Posted in June 3rd, 2002

More PKWare DCL Decompression Code

C++ code posted to comp.compression that describes extraction from PKWare’s Data Compression Library.

Update: The author posted this correction to comp.compression:
There’s a bug in the code posted 2001-10-07 19:36:38 PST. To fix:
In the

void tcDecoder::Decode(char *apBuffer, unsigned int *apSize, unsigned int anBufferSize)

function after both

if (lnIndex == mnCurrentPos) lnIndex = lnStartIndex;


if (lnIndex == mnDictionarySize) lnIndex = 0;


Posted in April 22nd, 2002

Doom9’s MPEG Forum

This site is mostly oriented towards capturing and storing DVD - good advice on how to use various tools, codecs, hardware, etc. Very active site.


Posted in April 19th, 2002

The Edge - Archives

A huge disordered collection of links, newsgroup posts, and random conversations regarding data compression.


Posted in February 26th, 2002

Huffman codes and Fibonacci numbers by Alex Vinokur

A careful analysis of degenerate Huffman trees created when input counts follow a Fibonacci sequence, by Alex Vinokur. This post is from sci.math.

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Posted in February 14th, 2002

Slashdot Takes on MP3 and Competitors

Published in Newsgroup Posts, Audio

The folks at Slashdot are having a chat trying to decide what the best non-MP3 codec is for home music recording. Ogg Vorbis gets a lot of votes the last time I checked the thread, but WMA and MP3 have a fair number of adherents.


Posted in January 22nd, 2002

Jules Gilbert

Jules Gilbert has made a number of interesting and provocative posts to comp.compression. His claims have been met with vocal objections, but lack of public resolution will hamper the interested researcher.*compression*&as_uauthors=Jules%20Gilbert&hl=en

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Posted in December 5th, 2001

Teddy Turner Mixed Up In Compression Lawsuit

Teddy Turner, son of CNN mogul Ted Turner, was apparently named in a lawsuit in 1999 over an alleged misrepresentation of compression claims. A Florida company named Vision Tek claimed it could pump video over normal phone lines at high speeds, but was not able to satisy its investors, leading to a court case.


Posted in October 26th, 2001

What is mu-law encoding? Where can I get source for it?

Published in Newsgroup Posts, Speech

Part of the DSP FAQ, in our case it is an answer to a speech coding question.


Posted in September 24th, 2000

Mathematical Combinations and Compression

The comp.compression newsgroup regularly sees posts from folks with incredible compression claims. This one, started by Itai Bar-Haim, is remarkable not so much for its claims, but rather for the incredible length of the thread it spawned. All Atai said was that mathematical combinations have nothing to do with compression. So there.


Posted in June 27th, 2000

Alex Vinokur Newgroup Posts

Alex has collected a series of newsgroup discussions on Huffman coding.


Posted in May 26th, 2000

G. Orme on Music Compression

Published in Newsgroup Posts, Audio

A proposal on comp.compression for a new method of music compression.


Posted in May 2nd, 2000

Thoughts on Phil Katz Death

Published in Newsgroup Posts, People, Zip

Some reflection on the death of Phil Katz


Posted in May 2nd, 2000

BWT and different alphabet orders

A long thread dealing with a possible way to some improvement on BWT compression.


Posted in April 22nd, 2000

Paper on BWT for source estimation

A long and entertaining discussion of BWT compression in the comp.compression newsgroup.


Posted in April 11th, 2000

Motion compensation without side information for Wavelet Video

Charles Bloom gives a short bit of thought about just what the title says.


Posted in January 6th, 2000

A discussion on Audio Coding, January 1999.

Published in Newsgroup Posts, Audio

Charles Bloom thinks out loud about audio coding.


Posted in January 6th, 2000

A Fallacy in Model + Encoder

Charles Bloom thinks out loud about the canonical model + encoder of contemporary data compression.


Posted in January 6th, 2000

Notes on Low-N Quantum Information Theory

Charles Bloom thinks about quantum information theory.


Posted in January 6th, 2000

The 2nd law of stat-mech in info-theory

Charles Bloom puts that physics background into play in the world of information theory.


Posted in January 6th, 2000

More than one bit per bit?

Charles Bloom discusses the hopelessness of thinking you can get something for nothing.


Posted in January 6th, 2000

How Big is Nothing?

Charles Bloom puts the noggin to work on this question. It’s not as foolish as the title might make it sound.


Posted in January 6th, 2000

Complexity and Entanglement

Charles Bloom thinks out loud about complexity.


Posted in January 6th, 2000