Problems when converting TIFF files that contain tag 37724

[rwruck]

Hi,

there seems to be a problem when converting TIFF files when the source contains the Photoshop ImageSourceData tag (37724).
I've used a command line like this (IM 6.7.2.0) to compress a TIFF file:

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convert -compress JPEG source.tif destination.tif

Reading the input file shows the usual warnings:

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source.tif: unknown field with tag 37724 (0x935c) encountered. `TIFFReadDirectory' @ warning/tiff.c/TIFFWarnings/707

That's not a problem so far, but when writing the output file, there are errors:

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destination.tif: Unknown tag 37724. `TIFFSetField' @ error/tiff.c/TIFFErrors/497

The output file is written BUT it does not contain the 37724 tag AND convert exits with code 1 which indicates a failure.
Looking at tiff.c, there's the following code which seems to be intended for handling this tag:

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    if (LocaleCompare(name,"tiff:37724") == 0)
      (void) TIFFSetField(tiff,37724,(uint32)GetStringInfoLength(profile),
        GetStringInfoDatum(profile));

This does not work, because 37724 is a custom tag. You'd have to register it using TIFFSetTagExtender as outlined here: http://www.asmail.be/msg0054585832.html

I'd assume that the declaration of the ImageSourceData tag would be something like

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{ 37724, -1, -1, TIFF_UNKNOWN, FIELD_CUSTOM, 1, 1, "ImageSourceData" }

[magick]

We can reproduce the problem you posted and will get a patch into ImageMagick 6.7.3-5 Beta within a few days. Thanks.

Can you post a URL to one of your TIFF images with the 37724 tag so we can test our solution?

[rwruck]

Thanks for the quick reply.

Here is an image: http://www.rw-it.net/public/37724/test.tiff

Here is a patch I made that works for me: http://www.rw-it.net/public/37724/patch ... iff.c.diff

[magick]

We have the patch in ImageMagick 6.7.3-5 Beta and the Subversion trunk. For now we treat the 37724 tag as a binary blob. In the future, we'll add code to decode the blob and extract the metadata.