Um, doesn't Phil Harvey mention that this seems to be in XnView?

I'll ask this question at the XnView Newsgroup; I have seen that IPTC tags written with XnView are not shown in iTag, which uses the Adobe Toolkit. All other software shows them. The problem that XnView couldn't write XMP only occured after saving the files with Gimp before. I'm a little bit helpless finding out the real reason, so I try to look in every direction.

Best regards,
Christoph

Hello again,

here's what I wrote at the XnView Newsgroup:

http://newsgroup.xnview.com/viewtopic.php?f=36&t=28720

You can reproduce the problm as follows:

Open jpg in Gimp that has only exif-information. Resave it; XMP is created.
Now open the image in XnView, write an IPTC-Description and select the write XMP checkbox. Save.
IPTC is written, but XMP not. Phil Harvey said, that the reason exiftool didn't write the XMP-data is that there was a duplicate XMP-tag.

For gimp-2.9.1, I proposed a patch with a completly new approach (Bug 704796).
The patch is still not reviewed by the development team. Maybe it will be accepted.
That patch would solve those problems.
I ported the patch to 2.8.7 (because this is also my working version) and can be proposed after review.

Um, I was under the impression that we did talk about the patch, and agreed
on some changes...

Were can I get a precompiled version of gimp-2.9.1 and can you recommend it for "productive use"?

Best regards
Christoph

The nightly builds of GIMP 2.9 (master) and GIMP 2.8 can be found at http://nightly.darkrefraction.com/gimp/ (for Windows) and https://gimptest.flamingtext.com:9090/view/All%20Downloads/ (for Linux, 64 bit).
They are not for production use, but for early tests.

Okay, thanks for your reply! Seems like Gimp writes duplicate filds in XMP, which makes it impossible for other software to edit the data. Exiftool, XnView and iTag all report errors or simply don't write.
(http://newsgroup.xnview.com/viewtopic.php?f=36&t=28720&p=114414#p114414)
It would be great if Gimp would preserve the unedited XMP-data from files it rewrites.
I discovered an new error using XMP-Toolkit to read the metadata with iTag (http://www.itagsoftware.com/): On all images I edited with gimp I get the message: "Exiv2-Library cant't read the image. The embedded exif-data seems to be not correctly formatted".
Would be really great if there'd be a bugfix soon, because Gimp is my main workhorse ;-)! Anyway - great work!

Best regards,
Christoph

Please don't change the severity of bugs.

For me it's a critical bug, why shouldn't I set the severity to critical when there's the option? Corrupting metadata with the consequence that other software can't write XMP anymore is a really heavy bug.

Because every user calls their own bug "Critical" or "Urgent". That's
for the developers to decide, and we use the highest severities for
crashers. The metadata system is about to be replaced completely,
we are aware of its brokenness.

Okay, thank you Mitch and best regards

Fixed in master:

commit 21bed1e2fb438fa5721bddb0573a724ae0024455
Author: Hartmut Kuhse <onkelhatti@gimp.org>
Date:   Sat Oct 19 18:38:01 2013 +0200

    Completely rewrite metadata handling using gexiv2
    
    Based on original patches from Hartmut Kuhse and modified
    by Michael Natterer. Changes include:
    
    - remove libexif dependency and add a hard dependency on gexiv2
    - typedef GExiv2Metadata to GimpMetadata to avoid having to
      include gexiv2 globally
    - add basic GimpMetadata handling functions to libgimpbase
    - add image and image file specific metadata functions to libgimp,
      including the exif orientation image rotate dialog
    - port plug-ins to use the new APIs
    - port file-tiff-save's UI to GtkBuilder
    - add new plug-in "metadata" to view the image's metadata
    - keep metadata around as GimpImage member in the core
    - update the image's metadata on image size, resolution and precision
      changes
    - obsolete the old metadata parasites
    - migrate the old parasites to new GimpMetadata object on XCF load