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Date: Thu, 27 Jan 94 11:55:02 TAN
From: ndr@tazboy.Jpl.Nasa.Gov (Niles Ritter)
Message-Id: <9401271855.AA14945@tazboy.JPL.NASA.GOV>
To: dkelly@etsinc.com
Subject: Re:  JPEG support
Cc: tiff@sgi.sgi.com, tiffjpeg@cs.columbia.edu
Sender: tiff-owner@sgi.sgi.com

Dwight Kelly writes,

>  Has anyone added JPEG compress/decompress support to the libtiff library?

The problem is that the JPEG implementation, as specified in the TIFF 6.0
Documentation from Aldus, has some ambiguities/design flaws, particularly
in the "restart intervals" issues. One can create a functional JPEG-in-TIFF
(for example, by merging the libtiff and the IJG's libjpeg codes), but you
inevitably have to break something in the specs, and usually something
in the TIFF libs as well. Also, you have no guarantee that other peoples
JPEG-TIFF code will have made the same compromises, and so there is no
"standard" yet.

I've got some intermediate modules that merge libtiff/libjpeg, but, 
There is a mailing list dedicated to trying to resolve these issues for
the next TIFF specs called tiffjpeg@cs.columbia.edu. Tom Lane
(Tom_Lane@G.GP.CS.CMU.EDU) runs the list; you can contact him or
subscribe directly by sending e-mail to listserver@cs.columbia.edu
with the body of the message:

    subscribe tiffjpeg YOUR_FULL_NAME_HERE

Like everyone else, I'm waiting for the next, internally consistent, set 
of TIFF-JPEG specs to be settled on and published. The end is not
yet apparently in sight (Any news, Tom?)


  --Niles Ritter.


