HDTenEightyP/NetNews huggingface dataset:
From: nevries@accucx.cc.ruu.nl (Nico E de Vries)
Newsgroups: comp.compression.research
Subject: Re: how Huffman tree can be stored efficiently ?
Date: 2 Oct 92 17:01:08 GMT
Distribution: comp
Organization: Academic Computer Centre Utrecht

In <JT.92Sep30184832@fizyk1.fuw.edu.pl> jt@fuw.edu.pl (Jerzy Tarasiuk) writes:

>Hello,
>Most efficient algorithm to store information necessary to re-build
>Huffman decoding tree is put 256 bytes each specifying code size
>used to encode byte value which is index to the table, for exmple
>if use for 'a', 'b' and 'c' codes of lengths 4, 7 and 6, respectively
>then bytes at positions 97,98 and 99 should be 4,7,6; if '@' is not
>used in text which is compressed, then at position 64 can be 0.
>This information is not sufficient to rebuild original tree but is
>sufficient to build tree giving max compression (as original gives)
>so can put same algorithm for rebuilding in both comp and decomp.
>If there are no many long codes can think about using less then 8-bit
>bytes for this information (but is possible worst case when code
>sizes have range from 1 to 255 and such a packing is not possible...).
>Jerzy Tarasiuk

The idea to use code lengths for compact storage is quite common,
and of course quite good. Soem more idea's right "stolen" from
PKZIP 1.93a on this subject (and the PKZIP scheme is derived
from the AR002 scheme):
   - limit the code size to e.g. 15 (almost no harm to compression!)
   - use Huffman compression to compress the value's, there will be
     more long than short codes after all!
   - It even pays off to use an optimal tree for these Huffman
     codes and store this tree as well (wan't real fun? do this
     recursive multiple times :-).
   - run length encode the values, especially usefull for blocks
     of unused values
Some more tricks to improve the compression of the tree:
   - use some predictive model to make the tree rep even smaller
   - use a static dictionary of specific file's (general ones)
     helping the predictor
   - try to analyze tree's with familiar characteristics (e.g.
     if a single file is cut into pieces the tree's for those
     pieces will have properties in common)
Even using a neural network to do the predicting pays off.

Nico E. de Vries
 _ _
 O O  USENET nevries@cc.ruu.nl This text reflects MY opinions, nothing else.
  o   This text is supplied 'AS IS', no waranties of any kind apply.
 \_/  Don't waste your time on complaining about my hopeless typostyle.

"I own so many clocks that I need 1 hour to set them all one hour back
 for Winter time. Nevertheless it does not cost me any time."

Newsgroups: comp.compression.research
From: jt@fuw.edu.pl (Jerzy Tarasiuk)
Subject: how Huffman tree can be stored efficiently ?
Organization: Warsaw University Physics Dept.
Distribution: comp
Date: Wed, 30 Sep 1992 17:48:32 GMT

Hello,
Most efficient algorithm to store information necessary to re-build
Huffman decoding tree is put 256 bytes each specifying code size
used to encode byte value which is index to the table, for exmple
if use for 'a', 'b' and 'c' codes of lengths 4, 7 and 6, respectively
then bytes at positions 97,98 and 99 should be 4,7,6; if '@' is not
used in text which is compressed, then at position 64 can be 0.
This information is not sufficient to rebuild original tree but is
sufficient to build tree giving max compression (as original gives)
so can put same algorithm for rebuilding in both comp and decomp.
If there are no many long codes can think about using less then 8-bit
bytes for this information (but is possible worst case when code
sizes have range from 1 to 255 and such a packing is not possible...).
Jerzy Tarasiuk
Newsgroups: comp.compression.research
From: hugh@cs.toronto.edu ("D. Hugh Redelmeier")
Subject: Re: Fast decoders for variable-length codes
Keywords: variable-length code, decoder
Organization: Department of Computer Science, University of Toronto
Date: 3 Oct 92 03:10:52 GMT

edf@sm.luth.se (Ove Edfors) writes:
|  Is there anyone out there, who have information on fast decoders for
| variable-length codes, e.g. Huffman codes.

My program "huf" quickly decodes Huffman codes.  It can be ftped from
ftp.cs.toronto.edu:/pub/hugh/huf*.

It uses a static code table, i.e. the code is the same for an entire
file.  This allows the decoder to "leap" into the code tree based on
the first n bits by using an auxilliary table with 2^n entries.

One reason that this is effective is that huf uses words as symbols,
not ASCII characters.  Thus each symbol is represented by a larger
string of bits.

I haven't thought hard about whether this technique would work well
with an adaptive Huffman program.

Hugh Redelmeier
hugh@mimosa.com or {utcsri, yunexus, utzoo, scocan}!redvax!hugh
When all else fails: hugh@csri.toronto.edu
+1 416 482-8253
From: edf@sm.luth.se (Ove Edfors)
Newsgroups: comp.compression.research
Subject: Fast decoders for variable-length codes
Summary: A request for information on fast decoding algorithms
Keywords: variable-length code, decoder
Date: 2 Oct 92 20:24:16 GMT
Organization: University of Lulea, Sweden


  Is there anyone out there, who have information on fast decoders for
variable-length codes, e.g. Huffman codes. I'm currently taking a closer
look at fast decoding, and I would be very grateful for any information
on the subject.
  Pointers to books, reports and articles on the subject are of particular
interest.

--------------------------------------------------------------------
Ove Edfors                          PHONE:    Int. +46 920 910 65
Div. of Signal Processing                     Dom.  0920 - 910 65
University of Lulea                 FAX:      Int. +46 920 720 43
S-951 87  LULEA                               Dom.  0920 - 720 43
SWEDEN                              E-MAIL:   edf@sm.luth.se
--------------------------------------------------------------------
From: keven@csugrad.cs.vt.edu (Keven Ring)
Newsgroups: comp.compression.research
Subject: Re: fractal compression
Date: 1 Oct 92 16:03:28 GMT
Distribution: comp
Organization: Virginia Tech Computer Science Dept, Blacksburg, VA

Look in the alt.fractals FAQ file.  I posted a message there about Fractal 
compression.  If you don't subscribe to that, try comp.compression.
This has the same article.
-- 
+-----------------------+"Frank-n-furter, it's all o-ver
|Keven Ring		|your mission is a failure. Your lifesyle's too extreme
|keven@csugrad.cs.vt.edu|I'm your new commander - You are now my prisoner
|VPI & SU		|We return to Transylvania.
Newsgroups: comp.compression.research
From: nevries@accucx.cc.ruu.nl (Nico E de Vries)
Newsgroups: comp.compression.research
Subject: Re: Fast decoders for variable-length codes
Keywords: variable-length code, decoder
Date: 5 Oct 92 13:37:56 GMT
Organization: Academic Computer Centre Utrecht

In <1309@my.sm.luth.se> edf@sm.luth.se (Ove Edfors) writes:

>  Is there anyone out there, who have information on fast decoders for
>variable-length codes, e.g. Huffman codes. I'm currently taking a closer
>look at fast decoding, and I would be very grateful for any information
>on the subject.
>  Pointers to books, reports and articles on the subject are of particular
>interest.

The common way is a lookup table. Always "snoop" X bits from the compressed
stream and use a table lookup to find out the value and the actual
length. Many sources (e.g. INFO-Zip UNZIP) us table lookup for Huffman
decompression.

Nico E. de Vries
 _ _
 O O  USENET nevries@cc.ruu.nl This text reflects MY opinions, nothing else.
  o   This text is supplied 'AS IS', no waranties of any kind apply.
 \_/  Don't waste your time on complaining about my hopeless typostyle.
From: davidsen@ariel.crd.GE.COM (william E Davidsen)
Newsgroups: comp.compression
Subject: Re: pkzip 3.05
Date: 6 Oct 92 13:48:28 GMT
Reply-To: davidsen@crd.ge.com (bill davidsen)
Organization: GE Corporate R&D Center, Schenectady NY

In article <rdippold.718146185@cancun>, rdippold@cancun.qualcomm.com (Ron Dippold) writes:

| This year?  Heck, in the summer of last year when I switched to ARJ, I
| was told that was a really stupid thing to do because "The new PKZIP
| is almost out."

Actually zip1.9 (not PKZIP) is out, and you can make a reasonable
argument for using either that or zoo2.10. Both are free, widely ported,
and source available. zip is a bit faster, and if you turn the
compression up (-9) it often does a better job. zoo has everything in
one program and supports generations, nice if you're not positive you
are done with the old version...

ARJ is useful only if you operate exclusively in the MS-DOS environment,
since ARJ compression is only available there (I've heard there's an
OS/2 version, never actually saw it). There are ARJ extractors for other
systems, but I don't believe there's a compressor.

-- 
bill davidsen, GE Corp. R&D Center; Box 8; Schenectady NY 12345
    Keyboard controller has been disabled, press F1 to continue.
Newsgroups: comp.compression,comp.compression.research
From: thomas@acadia.Kodak.COM (Thomas Kinsman)
Subject: WANTED: INFORMATION THEORY by ABRAMSON 
Followup-To: thomas@acadia.kodak.com
Keywords: BOOK REQUEST
Organization: Eastman Kodak Co., Rochester, NY
Date: Thu, 1 Oct 92 19:15:59 GMT

    Sorry to bother you all of you, but alt.books.technical just doesn't get read
    by enough of the right people.  Consider this a recomendation for a good book
    on INFORMATION THEORY and CODING.  I'm looking for the book:

    INFORMATION THEORY AND CODING, by NORMAN ABRAMSON
    Associate Professor of Electrical Engineering, Stanford University
    Published by McGRAW-HILL ELECTRONIC SCIENCE SERIES, 1963

    Fair price paid for a copy in good shape.

  Thomas B. Kinsman, thomas@acadia.kodak.com, Eastman Kodak Co., 716/477-2831 (w)
--
thomas@acadia.kodak.com    Voice: 716/477-2831(w)	     Fax: 716/722-0160
Thomas B. Kinsman, Eastman Kodak Co., Flr 3, Bldg 65, RL, Roch., NY 14650-1816
Newsgroups: comp.compression
From: bontchev@fbihh.informatik.uni-hamburg.de (Vesselin Bontchev)
Subject: Re: The hunt for latest versions of PKZip, Arj, Zoo.
Keywords: HELP
Reply-To: bontchev@fbihh.informatik.uni-hamburg.de
Organization: Virus Test Center, University of Hamburg
Date: 29 Sep 92 12:57:30 GMT

nevries@accucx.cc.ruu.nl (Nico E de Vries) writes:

> >Which is rather silly, because the encryption in ARJ is just TRIVIAL
> >to break, using a known-plaintext attack. The encryption on PKZIP (and

> I have heard this before (and actually I agree). Yet noone ever cracked
> $100.ARJ. Why???

Hey, what's $100.ARJ??? Is it an ARJ password breaking contest? Where
is it available from?

More exactly, I am able to do the following:

If you provide me with a passworded ARJ archive and a non-encrypted
version of the same file (or a non-compressed, your choice), then I am
able to tell you the password used, provided that it is shorter than
the half of the size of the compressed image (in bytes). As far as I
understand, this is called a known-plaintext attack.

In the everyday usage of ARJ (all files encrypted with one and the
same, probably short password), this means that if you happen to have
a non-encrypted version of one of the encrypted files in the archive,
it will allow you to decrypt the whole archive.

We have considered ARJ's encryption algorithm for exchanging encrypted
viruses with other anti-virus researchers, and have rejected it, since
it will be enough for the attacker to get a copy of one of the
infected files by other means (and the virus collections that float
around often contain one and the same files, not just one and the same
viruses), in order to recover the password, and possibly to recover
the whole further traffic.

But all this possibly belongs to sci.crypt.

Regards,
Vesselin
-- 
Vesselin Vladimirov Bontchev          Virus Test Center, University of Hamburg
Tel.:+49-40-54715-224, Fax: +49-40-54715-226      Fachbereich Informatik - AGN
< PGP 2.0 public key available on request. > Vogt-Koelln-Strasse 30, rm. 107 C
e-mail: bontchev@fbihh.informatik.uni-hamburg.de    D-2000 Hamburg 54, Germany
Newsgroups: comp.compression
From: htomita@magnus.acs.ohio-state.edu (Hideo Tomita)
Subject: Pls. help with .tar files
Organization: The Ohio State University
Date: Sat, 26 Sep 1992 18:35:10 GMT

Thank you in advnace.

Hideo Tomita
P. S. I am on Ultrix4.2.

Newsgroups: comp.compression
From: markm@wri.com
Subject: Wanted:  Stuffit for UNIX
Reply-To: markm@wri.com
Organization: Wolfram Research, Inc.
Date: Tue, 29 Sep 1992 15:44:17 GMT


Hello all,

I'm looking for source code for a version of Stuffit (not Deluxe or Classic,  
just something like 1.5.1) which will run on a Unix machine and recursively  
descend directory structures.  If anyone knows the whereabouts of such a beast,  
please let me know.

Thanks!
--Mark Moline
markm@wri.com
Newsgroups: comp.compression
From: bontchev@fbihh.informatik.uni-hamburg.de (Vesselin Bontchev)
Subject: Re: The hunt for latest versions of PKZip, Arj, Zoo.
Reply-To: bontchev@fbihh.informatik.uni-hamburg.de
Organization: Virus Test Center, University of Hamburg
Date:  2 Oct 92 19:47:27 GMT

lvv@lvvhq.adam.kiev.ua (Leonid Volnitsky) writes:

> >   > I have heard this before (and actually I agree). Yet noone ever cracked
> >   > $100.ARJ. Why???
> >
> >   Hey, what's $100.ARJ??? Is it an ARJ password breaking contest? Where
> >   is it available from?
> >
> >   More exactly, I am able to do the following:

> Moreover, I've rigistrator for ARJ 2.30 :-)

I have one too, and also a program that helps you create
"authenticated" ARJ and ZIP archives. Computes the "secret number" in
just a few seconds for ARJ and less than a minute for ZIP.

But this is completely unrelated to the encryption problem. It just
shows that the authentication in ARJ is just as easy to break as the
one in PKZIP. I was originally speaking about the -encryption- methods
in those archivers. The one used in ARJ is -extremely- weak, while the
one used in PKZIP is just not very strong.

Regards,
Vesselin
-- 
Vesselin Vladimirov Bontchev          Virus Test Center, University of Hamburg
Tel.:+49-40-54715-224, Fax: +49-40-54715-226      Fachbereich Informatik - AGN
< PGP 2.0 public key available on request. > Vogt-Koelln-Strasse 30, rm. 107 C
e-mail: bontchev@fbihh.informatik.uni-hamburg.de    D-2000 Hamburg 54, Germany
From: kpatel@roger-rabbit.cs.berkeley.edu (KETAN DASHARATH PATEL)
Newsgroups: comp.compression
Subject: MPEG software and problems with XING
Date: 29 Sep 1992 17:31:05 GMT
Organization: University of California at Berkeley
NNTP-Posting-Host: roger-rabbit.cs.berkeley.edu


We are developing a PD software MPEG decoder and it is almost
done. We think we can achieve at least 10 frames/second on an
HP 700 series and we are shooting for 20 (I'm not sure where 
we`ll get the factor of two). 

A comment on XING and there *claim* to MPEG fame. As far as I
can tell, XING mpeg data consists of nothing but I frames which
means that they are not using mpeg to any extent to which it was
intended. It is tantamount to JPEG encoding each frame separately.
With just I frames there is no motion estimation or temporal 
prediction.  

Ketan Patel
kpatel@cory.berkeley.edu


Newsgroups: comp.compression,comp.compression.research,alt.comp.compression,comp.dsp
From: provine@enel.ucalgary.ca (Joseph Provine)
Subject: 1-D DCT data compression code
Summary: Request for 1-D DCT code
Date: Sat, 03 Oct 92 21:35:41 GMT
Organization: ECE Department, U. of Calgary, Calgary, Alberta, Canada
Keywords: 1-D, DCT, compression, coding

Are there source codes available for 1-D data compression by DCT out there?
Can anyone provide me with the pointer to the code, if it exists?
Both reversible and irreversible coding desirable.
Thanks in advance

Joseph Provine
provine@enel.ucalgary.ca



Newsgroups: comp.compression
From: roelofs@pan.arc.nasa.gov (Cave Newt)
Subject: LHa 1.01u for Unix (was: Re: Lha for Unix)
Organization: University of Chicago
Date: Fri, 2 Oct 92 16:21:30 GMT

gt8741b@prism.gatech.edu (Chris Adams) writes:

>Does anyone know where Lha for Unix is archived?  All I have been able to find
>is Lharc, which uses the -lh1- method, where Lha uses -lh5-.  Lha is compatible
>with Lha 2.13 for MS-DOS.  I received the source via email from someone last
>spring, but now I need the source again.

I just sent a cleaned-up, (at least partially) bug-fixed version
to Keith Petersen of the Simtel20 archives.  It's LHa 1.01u, and
it's on Simtel or any of its mirror sites (see just about any posting
in comp.binaries.ibm.pc.archives for full site names).  The actual
filespec is probably something like pd8:[misc.unix]lha101u.tar-z on
Simtel, something similar on the mirrors.

Greg Roelofs
From: craig@kralizec.zeta.org.au (Craig Dewick)
Newsgroups: comp.compression
Subject: Re: Wanted: Stuffit for UNIX
Date: 30 Sep 92 10:00:58 GMT
Organization: Kralizec Dialup Unix Sydney: +61-2-837-1183 V.32

markm@wri.com writes:


>I'm looking for source code for a version of Stuffit (not Deluxe or Classic,  
>just something like 1.5.1) which will run on a Unix machine and recursively  
>descend directory structures.  If anyone knows the whereabouts of such a beast,  

I'm also after something like this. I need to decompress some sound
file from a Mac system, and they're compressed with Stuffit. Bit hard
to use without decompressing them first!!
-- 
 Craig Dewick               |      - Railway Preservation Industries P/L -
 Send email to:             |      actively supporting the preservation of
 craig@kralizec.zeta.org.au |           Australia's railway heritage.
Newsgroups: comp.compression
From: luosu@parlo.su.OZ.AU (Luo Su Huai)
Subject: Wanted: head and shoulder image and speech sample data
Reply-To: luosu@parlo.su.OZ.AU (Luo Su Huai)
Organization: University of Sydney, Australia
Date: Tue, 29 Sep 1992 02:45:19 GMT

 
Hello,all,
I am doing some work on synthesizing human face image through speech for my 
Ph.D thesis. Now I urgently need the sample data,both in image and in speech.
The data should be several minutes of head and shoulder image and corresponding
speech. I need a male speaking some sentences( with the words known). And
both the digital image and speech data can be acccessed frame by frame(prefer 
20ms/f).  Could anyone please offer me any information about how to get this?
Thanks very much in advance.

Luo Suhuai
School of Electrical Engineering
University of Sydney
NSW 2006,Sydney,Australia
luosu@ee.su.oz.au





 


Newsgroups: comp.compression
From: davidm@sfsuvax1.sfsu.edu (David Morgenstern)
Subject: Request for Information
Organization: California State University, Sacramento
Date: Mon, 5 Oct 1992 23:15:24 GMT


Dear Compressors:

I've been given the assignment to report on Higher Education kinda
news for MacWeek. This is a very wide-ranging area, but I'm
focusing on new projects from universities, technologies that are
starting to be used in the academic environment, and anything else
that looks interesting. It doesn't have to be all Macintosh,
although that helps! 

My first report covered the SUIT cross-platform C-language graphic
software, the Tripwire security software for UNIX, and the EndNote
TagLink (a commercial program) support for the TAGS bibliographic
file format developed by the UC Library. 

I'd like to hear about what you're working on, if there's something
you think that people should know about, a new technology, or a new
tool. If a colleague is doing something interesting, can you pass
this on to them?  Any other news that might be of interest to
MacWeek readers is always welcome!
 
Thanks,

David Morgenstern, davidm@sfsuvax1.sfsu.edu 
-- 
 David Morgenstern, BMUG CheerLeader davidm@sfsuvax1.sfsu.edu
    "Miracles do occur - but they rarely provide food." 
         --  Talmud: Shabbat, 53b
From: hob@soda.berkeley.edu (Bing Ho)
Newsgroups: comp.compression
Subject: Convert pkzip 1.1 to zip 1.9?
Date: 26 Sep 1992 10:05:46 GMT
Organization: U.C. Berkeley, CS Undergraduate Association
Distribution: world
NNTP-Posting-Host: soda.berkeley.edu

I am interested in converting a large number of pkzip 1.1 archives
(about 100-200 megabytes) into the new zip archive format found in
zip 1.9.  I am interested in some automated solution where I can
specify all .zip files in a subdirectory and they will be converted
overnight.

Does anybody have a program or batch files that can do this (they
must be able to convert internal .zip files as well, preserve
volume labels, comments, and directories)

Thanks for any help.


-- 
Bing Ho  hob@soda.berkeley.edu
Xref: sparky comp.compression:3442 news.answers:3271
From: nevries@accucx.cc.ruu.nl (Nico E de Vries)
Newsgroups: comp.compression
Subject: Re: arj239.exe/arj
Date: 1 Oct 92 23:37:37 GMT
Organization: Academic Computer Centre Utrecht

In <1992Sep29.182906.14002@tamsun.tamu.edu> henrik@stat.tamu.edu (Henrik Schmiediche) writes:

>...
>I can confirm that arj239 is a official Beta test release of arj 2.4
>sceduled to be released soon. The main purpose of this release is not
>increased compression, but increased speed and ofcourse a few new
>switches.... 

Lets send Jung a present for his 1000th switch :-)

>    - Henrik

Nico E. de Vries
 _ _
 O O  USENET nevries@cc.ruu.nl This text reflects MY opinions, nothing else.
  o   This text is supplied 'AS IS', no waranties of any kind apply.
 \_/  Don't waste your time on complaining about my hopeless typostyle.

"I own so many clocks that I need 1 hour to set them all one hour back
 for Winter time. Nevertheless it does not cost me any time."
From: blom@husc8.harvard.edu (Eric Blom)
Newsgroups: comp.compression
Subject: ARJ 2.39 FTP site
Summary: The latest version of ARJ is available in Germany.
Keywords: ARJ FTP ftp 2.39a 2.39 2.40
Date: 4 Oct 92 19:04:34 GMT
Article-I.D.: husc8.blom.718225474

For those of you who are interested, ARJ 2.39a is available for FTP at
"ftp.germany.eu.net" in the "pub/comp/msdos/arcers" directory.  I didn't
stay on very long to see what other arcers were online, but I imagine the
selection is pretty good.

Again, ARJ 2.39a is FASTER than 2.30.  Much faster.

Sorry about not including my address in my previous post.  I can be
reached either as "blom@husc8.harvard.edu" or as "71172.2515@compuserve.com"
Newsgroups: comp.compression
From: griffita@fraser.sfu.ca (David Stuart Griffiths)
Subject: Re: Lha for Unix
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Thu, 1 Oct 1992 00:18:26 GMT

gt8741b@prism.gatech.edu (Chris Adams) writes:

>Does anyone know where Lha for Unix is archived?  All I have been able to find
>is Lharc, which uses the -lh1- method, where Lha uses -lh5-. Lha is compatible
>with Lha 2.13 for MS-DOS.  I received the source via email from someone last
>spring, but now I need the source again.

You can pick it up from "amiga.physik.unizh.ch" in the "/amiga/LhA"
directory.  It's in with some other Amiga stuff, but it is the Unix
version.
-- 

------------------------------------------------------------------------------
David Griffiths  / / Internet: griffita@sfu.ca  
____________    / /   Fidonet: David Griffiths @ 1:153/765.0 or 1:153/910.0
 DLG "Pro"  \ \/ /   Broadcast TV @ British Columbia Institute of Technology
>The Best!<  \/\/      "Where semesters are long and courses are hard..."
------------------------------------------------------------------------------



Newsgroups: comp.compression