2020.03.16 20:19 "Re: [Tiff] Old-Style JPEG Support", by Bob Friesenhahn

I'm having trouble working with some TIFF images that have the "Old JPEG Support" compression.

The tiffsplit package dumps the following message when I try to use it:

./tools/tiffsplit old-style-jpeg.tif
TIFFReadDirectory: Warning, Unknown field with tag 32931 (0x80a3) encountered.
TIFFReadDirectory: Warning, Unknown field with tag 32934 (0x80a6) encountered.
TIFFReadRawStrip: Compression scheme does not support access to raw uncompressed data.

Does

   ./tools/tiffcp -c jpeg old-style-jpeg.tif modern-jpeg.tif

work for you?

If this does not work (due to the same issue), then you might be forced to use tiffcrop instead.

So it looks like it should be available, but it isn't able to tiffsplit.

It seems that tiffsplit depends on being able to copy raw strips and preserve the original format.

Writing to old JPEG format is not supported.

On a Windows subsystem, I downloaded the binaries / dependencies from the GnuWin32 project and out of the gate it was able to tiffsplit the same image (with some warnings, but it still was able to work with it).

This is likely extremely old software and possibly dating to before Joris tried to make the old JPEG reader work better. If you run it without arguments, what version is reported?

My question is: how can I get something compiled on ubuntu to get a version of tiffsplit that can better work with these files that I'm having trouble with?

You should be focusing on converting files using old JPEG compression to a well-supported format. Old JPEG compression was replaced in 1995 by the current compression scheme.

Old versions of libtiff should still be available as source code so if an old version works better, then this could allow you "save" your files so they are likely to work reliably in the future.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt