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July 1998

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1998.07.21 14:03 "Re: Tiff2ps with JPEG", by Gerben Vos
1998.07.21 14:18 "Re: Tiff2ps with JPEG", by Tom Lane

1998.07.21 14:18 "Re: Tiff2ps with JPEG", by Tom Lane

Z9SLMANN@am.pnu.com writes:
>      I am attempting to use the tiff2ps utility in UNIX for TIFF images
>      stored with JPEG compression.  The TIFF images are scanned using a
>      variety of scanners and drivers.  I am getting an error message when I
>      try to create the postscript file - 'Old-Style JPEG compression
>      support is not configured'.

I'm afraid you're out of luck.  Libtiff only supports TIFF/JPEG per the
new Compression=7 style defined in TIFF Tech Note #2.  Evidently some of
your source files use one or another interpretation of the old
Compression=6 style.

Compression=6 is a real morass, not only because of the old spec's
ambiguities (which are described in the Tech Note), but because several
purported TIFF/JPEG writers write files that are compatible with *no*
defensible reading of the old spec.  To read their files you have to
ignore the specification and instead "just know" where to pull out the
data and what it means.

A generic reader that would handle everything that claims to be
old-style TIFF/JPEG may not even be possible.  It certainly wouldn't be
easy, and I would not expect it to work with any variant it hadn't been
specifically tested and debugged with.  None of the principal libtiff
contributors are interested in venturing into that morass.

If you just have one or two sources to deal with, you could decipher the
idiosyncracies of their particular interpretations of TIFF/JPEG and then
write some sort of conversion program to reformat the data as new-style
TIFF/JPEG.  See TIFF 6.0 Section 22 and Tech Note #2 for details
(they're available at ftp.sgi.com/graphics/tiff/ among other places).

I think a couple of people on this list have had to do something like
this already ... but of course their solutions are no more general-
purpose than I'm suggesting yours be.

			regards, tom lane
			organizer, Independent JPEG Group