W3C home > Mailing lists > Public > public-respimg@w3.org > September 2013

Re: Compressive images test

From: Frédéric Kayser <f.kayser@free.fr>
Date: Fri, 20 Sep 2013 00:43:03 +0200
Cc: Chris Lilley <chris@w3.org>
Message-Id: <3C9A9303-BBE6-4456-A9D7-52BA0ACF7DEA@free.fr>
To: public-respimg@w3.org
Yep, but to my knowledge this "Group" consist of only one member: Guido Vollbeding.
He is on bad terms with the lijbpeg-turbo team:
https://bugzilla.redhat.com/show_bug.cgi?id=639672#c7

Thomas Richter (JPEG member, thorfdbg) expressed his views on what he is doing:
http://encode.ru/threads/1598-Quo-Vadis-JPEG-Another-update?p=30279&viewfull=1#post30279

I've exchanged a couple of email with him, because I wanted to merge contiguous DQT markers in a single one (Photoshop does it) he answered that this would brake SmartScale (this non-standard extension has been introduced in version 8 of his libjpeg).
This SmartScale feature has never be and will never be part of the JPEG specs, now read what some other have to say about it:
http://www.libjpeg-turbo.org/About/SmartScale
http://hardwarebug.org/2010/02/01/ijg-swings-again-and-misses/

Using the latest features introduced in IJGs libjpeg will produce non standard files that should no longer be called JPEGs, it's a pity since v6 was known to be an excellent implementation of the most commonly used parts of the JPEG 10918-1 specs.

Now if you want the a full implementation (including 12 bits components, arithmetic coding, original lossless and hierarchical modes) you can use this one:
https://github.com/thorfdbg/libjpeg

Or stick to libjpeg-turbo for pure speed without fancy non standard features.
http://sourceforge.net/projects/libjpeg-turbo/

Regards
-- 
Frédéric Kayser


Chris Lilley wrote :

> Hello Frédéric,
> 
> Thursday, September 19, 2013, 7:29:04 PM, you wrote:
> 
>> Beware of libjpeg versions higher than 7 since this project has been
>> "hijacked" by a single man and many new features are not in line
>> with the official JPEG team and are not part of the specs (a really
>> sad story),
> 
> Huh? The maintainer is still the Independent JPEG Group, no?
> 
> http://www.infai.org/jpeg/
> 
> 
> "The current version is release 9 of 13-Jan-2013."
> http://www.ijg.org/
> 
> -- 
> Best regards,
> Chris                            mailto:chris@w3.org
> 
> 
Received on Thursday, 19 September 2013 22:43:34 UTC

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