Compression

Compression

Post by Peter Bjurstr? » Tue, 22 Jul 2003 21:07:55



Is ZIP compression and Flate compression identical?

Thanks
Peter

 
 
 

Compression

Post by Aandi Inst » Tue, 22 Jul 2003 21:27:09



>Is ZIP compression and Flate compression identical?

No.  See the PDF Reference for full details and/or refererences.
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Compression

Post by Andreas Lobinge » Tue, 22 Jul 2003 21:29:01


Aloha,

"Peter Bjurstr?m" schrieb:

Quote:> Is ZIP compression and Flate compression identical?

No, but gzip and therefore zlib are almost identical.

Wishing a happy day
                LOBI

 
 
 

Compression

Post by Peter Bjurstr? » Tue, 22 Jul 2003 21:52:38




> >Is ZIP compression and Flate compression identical?

> No.  See the PDF Reference for full details and/or refererences.

I have been reading the PDF Reference from cover to cover and as far as I
understand there is no ZIP compression/filter supported in the PDF. Altough
do I often see applications (for example PitStop) that has options to do ZIP
compression but no Flate compression on for example images. So I thought
when you say ZIP in PDF you mean Flate.

Peter

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Compression

Post by Aandi Inst » Wed, 23 Jul 2003 01:21:33






>> >Is ZIP compression and Flate compression identical?

>> No.  See the PDF Reference for full details and/or refererences.

>I have been reading the PDF Reference from cover to cover and as far as I
>understand there is no ZIP compression/filter supported in the PDF.

That is correct, technically. "ZIP" is the user interface name for
FlateDecode.  

Quote:>do I often see applications (for example PitStop) that has options to do ZIP
>compression but no Flate compression on for example images. So I thought
>when you say ZIP in PDF you mean Flate.

Yes.  And this is quite separate from LZW.
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Compression

Post by Peter Bjurstr? » Wed, 23 Jul 2003 03:50:20







> >> >Is ZIP compression and Flate compression identical?

> >> No.  See the PDF Reference for full details and/or refererences.

> >I have been reading the PDF Reference from cover to cover and as far as I
> >understand there is no ZIP compression/filter supported in the PDF.

> That is correct, technically. "ZIP" is the user interface name for
> FlateDecode.

Confusing...

Quote:

> >do I often see applications (for example PitStop) that has options to do
ZIP
> >compression but no Flate compression on for example images. So I thought
> >when you say ZIP in PDF you mean Flate.

> Yes.  And this is quite separate from LZW.

As a paranthese. About five years ago a studied the LZW compression and
discovered writing an encoder/decoder for LZW was suprisinlgy easy. I then
contacted Unisys since they own the patent on LZW. After a maybe twenty
e-mails, when they asked for the size of my shoes, I gave up. When will this
patent expire?

Peter

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Compression

Post by Jos Verno » Wed, 23 Jul 2003 04:12:25


Quote:> As a paranthese. About five years ago a studied the LZW compression and
> discovered writing an encoder/decoder for LZW was suprisinlgy easy. I then
> contacted Unisys since they own the patent on LZW. After a maybe twenty
> e-mails, when they asked for the size of my shoes, I gave up. When will
this
> patent expire?

I*but... AFAIK...

The main US patent expired about a month ago.

Patents in a number of other countries are still valid (though whether they
are enforcable is open to debate).

Jos

 
 
 

Compression

Post by Peter Bjurstr? » Wed, 23 Jul 2003 05:34:40



Quote:> > As a paranthese. About five years ago a studied the LZW compression and
> > discovered writing an encoder/decoder for LZW was suprisinlgy easy. I
then
> > contacted Unisys since they own the patent on LZW. After a maybe twenty
> > e-mails, when they asked for the size of my shoes, I gave up. When will
> this
> > patent expire?

> I*but... AFAIK...

What do you mean by IANAL?

Kind regards
Peter

 
 
 

Compression

Post by Maarten Snee » Wed, 23 Jul 2003 06:09:05






> > I*but... AFAIK...

> What do you mean by IANAL?

I Am Not A Lawyer

HTH

Maarten

 
 
 

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