Register Guidelines E-Books Search Today's Posts Mark Forums Read

Go Back   MobileRead Forums > E-Book Formats > Kindle Formats

Notices

Reply
 
Thread Tools Search this Thread
Old 03-25-2008, 06:08 PM   #1
slayda
Retired & reading more!
slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.slayda ought to be getting tired of karma fortunes by now.
 
slayda's Avatar
 
Posts: 2,743
Karma: 884247
Join Date: Sep 2006
Location: North Alabama, USA
Device: Kindle 1, iPad 4, iPhone 5
Does anyone know the Mobipocket compression?

Does anyone know the Mobipocket compression algorithms, or are they proprietary? Im interested in compression methods. If you don't know them, do you know where to find documentation on them?
slayda is offline   Reply With Quote
Old 03-25-2008, 06:52 PM   #2
wallcraft
reader
wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.wallcraft ought to be getting tired of karma fortunes by now.
 
wallcraft's Avatar
 
Posts: 6,979
Karma: 5183568
Join Date: Mar 2006
Location: Mississippi, USA
Device: Kindle 3 and Fire
MobiPockect's highest level of compression isn't formally documented anywhere, but the python programs mobi2oeb and mobihuff.py decompress DRM-free MOBI books.
wallcraft is offline   Reply With Quote
Old 03-25-2008, 09:29 PM   #3
tompe
Grand Sorcerer
tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.
 
Posts: 7,144
Karma: 4315826
Join Date: Oct 2007
Location: Link÷png, Sweden
Device: Nexus 7, Nexus 5, iPad 2, Kindle PW
Quote:
Originally Posted by wallcraft View Post
MobiPockect's highest level of compression isn't formally documented anywhere, but the python programs mobi2oeb and mobihuff.py decompress DRM-free MOBI books.
And if somebody took these programs and wrote a high level specification it would be very good ...
tompe is offline   Reply With Quote
Old 03-26-2008, 07:49 AM   #4
igorsk
Wizard
igorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfoldedigorsk reads XML... blindfolded
 
Posts: 3,443
Karma: 52235
Join Date: Sep 2006
Location: Belgium
Device: PRS-500/505/700, Kindle, Cybook Gen3, Words Gear
Python is not that hard to read
igorsk is offline   Reply With Quote
Old 03-26-2008, 12:08 PM   #5
tompe
Grand Sorcerer
tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.
 
Posts: 7,144
Karma: 4315826
Join Date: Oct 2007
Location: Link÷png, Sweden
Device: Nexus 7, Nexus 5, iPad 2, Kindle PW
Quote:
Originally Posted by igorsk View Post
Python is not that hard to read
No. The hard part is to get a mathematical description of the method. I would like to do a clean room implementation since I am a bit unsure of the legal status of Python code and the legal status of an implementation based in the Python code. Also it would be much easier to re-implement it in Perl from a more high level description.
tompe is offline   Reply With Quote
Old 03-26-2008, 02:55 PM   #6
kovidgoyal
creator of calibre
kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.
 
kovidgoyal's Avatar
 
Posts: 26,438
Karma: 5383257
Join Date: Oct 2006
Location: Mumbai, India
Device: Various
It's just huffman coding, a public domain algorithm, with a few implementation winkles. Frankly, I don't see any difference between "a mathematical description" and a "source code description" since both use a language to describe an algorithm.
kovidgoyal is offline   Reply With Quote
Old 03-26-2008, 02:59 PM   #7
tompe
Grand Sorcerer
tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.tompe ought to be getting tired of karma fortunes by now.
 
Posts: 7,144
Karma: 4315826
Join Date: Oct 2007
Location: Link÷png, Sweden
Device: Nexus 7, Nexus 5, iPad 2, Kindle PW
Quote:
Originally Posted by kovidgoyal View Post
It's just huffman coding, a public domain algorithm, with a few implementation winkles. Frankly, I don't see any difference between "a mathematical description" and a "source code description" since both use a language to describe an algorithm.
The python code is based on copyrighted code that has probably been accessed in a way that somebody can have legal opinions about. If I just copy the Python code it I am not sure it can be GPL:ed. And I am very unsure if the GPL notice in the Python code is correct.

A mathematical description from which I do an implementation were I do not look at existsing copyrighted code is definitely unproblematic.
tompe is offline   Reply With Quote
Old 03-26-2008, 03:06 PM   #8
kovidgoyal
creator of calibre
kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.kovidgoyal ought to be getting tired of karma fortunes by now.
 
kovidgoyal's Avatar
 
Posts: 26,438
Karma: 5383257
Join Date: Oct 2006
Location: Mumbai, India
Device: Various
You're assuming the python code was written looking at copyrighted code rather than reverse engineering? On what basis? For a mathematical description, just google huffman coding.
kovidgoyal is offline   Reply With Quote
Old 03-30-2010, 12:38 AM   #9
jonj
Junior Member
jonj began at the beginning.
 
Posts: 2
Karma: 10
Join Date: Mar 2010
Device: Kindle
Question Compressing to Mobi or PRC

Thanks for the good start on decompression. I am kind of new to these algorithms and compression in general. My language of choice is C#. If I wanted to learn how to create a .mobi or .prc from original HTML/images/etc. in C# does anyone here have advice on how to begin?
jonj is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Cover Image Compression. Ichi Calibre 3 01-04-2010 07:38 AM
Unsupported Compression Method on the jetBook? Dr. Drib Ectaco jetBook 6 08-24-2009 03:12 AM
MOBI Output Compression? sirbruce Calibre 6 06-14-2009 08:10 PM
MOBI Output Compression? sirbruce Calibre 4 03-27-2009 11:51 AM
ePub compression gonzule ePub 3 10-25-2008 04:35 PM


All times are GMT -4. The time now is 12:24 PM.


MobileRead.com is a privately owned, operated and funded community.