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Wojciech Mu³a · Guest

What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

TIA
w.

Industrial One · Guest

On Oct 7, 11:39 pm, Wojciech Mu³a
<wojciech_m...@poczta.null.onet.pl.invalid> wrote:
[quote]What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

TIA
w.
[/quote]
LZW was the first dictionary-based codec to the best of my knowledge.
It was an extension of the first algorithm ever invented (RLE) to
maximize its efficiency.

Industrial One · Guest

On Oct 7, 11:39 pm, Wojciech Mu³a
<wojciech_m...@poczta.null.onet.pl.invalid> wrote:
[quote]What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

TIA
w.
[/quote]
LZW was the first dictionary-based codec to the best of my knowledge.
It was an extension of the first algorithm ever invented (RLE) to
maximize its efficiency.

biject · Guest

On Oct 7, 7:03 pm, Industrial One <industrial_...@hotmail.com> wrote:
[quote]On Oct 7, 11:39 pm, Wojciech Mu³a

wojciech_m...@poczta.null.onet.pl.invalid> wrote:
What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

TIA
w.

LZW was the first dictionary-based codec to the best of my knowledge.
It was an extension of the first algorithm ever invented (RLE) to
maximize its efficiency.
[/quote]
LZW would have been more popular if didn>t have patent issue
problems fortunutly those early problems have gone away when the main
patent expired.. I have played around with it because it seems to me
that the original LZW as slick as it was lacked something just like
adaotive huffman and arithmetic which could be improved by making them
bijective.
LZW actually works pretty neat when I made it bijective. In many
ways I was surprised at the results and its an area where others could
easily make improvements since I do have working code for it on my
site I did it several years ago there is much more I wanted to do. But
my interests tend to drift once the hard part is done.

David A. Scott
--
My Crypto code
http://bijective.dogma.net/crypto/scott19u.zip
http://www.jim.com/jamesd/Kong/scott19u.zip old version
My Compression code http://bijective.dogma.net/
**TO EMAIL ME drop the roman "five" **
Disclaimer:I am in no way responsible for any of the statements
made in the above text. For all I know I might be drugged.
As a famous person once said "any cryptograhic
system is only as strong as its weakest link"

Thomas Richter · Guest

Industrial One wrote:
[quote]On Oct 7, 11:39 pm, Wojciech Mu³a
wojciech_m...@poczta.null.onet.pl.invalid> wrote:
What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

TIA
w.

LZW was the first dictionary-based codec to the best of my knowledge.
It was an extension of the first algorithm ever invented (RLE) to
maximize its efficiency.
[/quote]
LZ77 was the first one, LZW came later. LZW was, however, a very
practical implementation of the ideas behind LZ77. The patent goes back
to Terry Welch (sp?) who published the paper on this specific
implementation.

So long,
Thomas

Phil Carmody · Guest

Thomas Richter <thor@math.tu-berlin.de> writes:
[quote]Industrial One wrote:
On Oct 7, 11:39 pm, Wojciech MuÅ‚a
wojciech_m...@poczta.null.onet.pl.invalid> wrote:
What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

TIA
w.

LZW was the first dictionary-based codec to the best of my knowledge.
It was an extension of the first algorithm ever invented (RLE) to
maximize its efficiency.

LZ77 was the first one, LZW came later. LZW was, however, a very
practical implementation of the ideas behind LZ77. The patent goes
back to Terry Welch (sp?) who published the paper on this specific
implementation.
[/quote]
How far back to tunstall codes date back to?

Phil
--
The fact that a believer is happier than a sceptic is no more to the
point than the fact that a drunken man is happier than a sober one.
The happiness of credulity is a cheap and dangerous quality.
-- George Bernard Shaw (1856-1950), Preface to Androcles and the Lion

Wojciech Mu³a · Guest

Phil Carmody <thefatphil_demunged@yahoo.co.uk> wrote:

[quote]LZ77 was the first one, LZW came later. LZW was, however, a very
practical implementation of the ideas behind LZ77. The patent goes
[/quote]
LZW is slightly modified LZ78, not LZ77.

[quote]back to Terry Welch (sp?) who published the paper on this specific
implementation.

How far back to tunstall codes date back to?
[/quote]
Tunstall encoding was invented in 1968, LZW in 1984.

But - is tunstall encoding a dictionary-based scheme? IMHO no.

w.

Phil Carmody · Guest

Wojciech MuÅ‚a <wojciech_mula@poczta.null.onet.pl.invalid> writes:
[quote]Phil Carmody <thefatphil_demunged@yahoo.co.uk> wrote:
How far back to tunstall codes date back to?

Tunstall encoding was invented in 1968, LZW in 1984.
[/quote]
Thanks for that. Google failed to find that datum for me.

[quote]But - is tunstall encoding a dictionary-based scheme? IMHO no.
[/quote]
It>s not a sliding dictionary, or dynamically created, but
you are using a single output symbol to represent a possible
sequence of input symbols, and I think that makes it a
dictionary-based scheme.

I think it would be harder to define 'dictionary-based' in a way to
exclude Tunstall codes than to define it in a way that included
them. I.e. naturally they fall under the definition unless you go
out of your way to exclude them.

Phil
--
The fact that a believer is happier than a sceptic is no more to the
point than the fact that a drunken man is happier than a sober one.
The happiness of credulity is a cheap and dangerous quality.
-- George Bernard Shaw (1856-1950), Preface to Androcles and the Lion

Sportman · Guest

On Oct 8, 1:39 am, Wojciech Mu³a
<wojciech_m...@poczta.null.onet.pl.invalid> wrote:
[quote]What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?
[/quote]
Klaus Holtz associative memory search system see his history:
http://www.autosophy.com/history.htm

Original:
http://www.autosophy.com/FAIREdo.pdf

Similar:
http://www.autosophy.com/4366551l.htm

His patent was accepted later by his third try:
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4,366,551.PN.&OS=PN/4,366,551&RS=PN/4,366,551

jules Gilbert · Guest

On Oct 9, 6:42 pm, Sportman <sport...@gmail.com> wrote:
[quote]On Oct 8, 1:39 am, Wojciech Mu³a

wojciech_m...@poczta.null.onet.pl.invalid> wrote:
What kind of dictionary based encodings did exist before
Lempel-Ziv algorithm was invented?

Klaus Holtz associative memory search system see his history:http://www.autosophy.com/history.htm

Original:http://www.autosophy.com/FAIREdo.pdf

Similar:http://www.autosophy.com/4366551l.htm

His patent was accepted later by his third try:http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=P...
[/quote]
Actually, in the mid-70>s I used an on-line editor, part of WYLBUR, (a
system for the IBM-370,) that made use of a very simple and very local
dictionary that was line (text lines!,) oriented.

As I recall sometimes it was as good as 2:1, but usually not.


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