I Can read tags from DNG, but cannot change them. Can delete group.

[snahl]

Hi Phil
trying to change (delete) application specific tags in a DNG file.
Exiftool reads the tags for me as follows:

exiftool -a -s -G1 -XMP-lrt:all IMG113800.DNG

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[XMP-lrt]       Width                           : 2640
[XMP-lrt]       Height                          : 1760
[XMP-lrt]       ExposureBeforeDeflicker         : -1.0
[XMP-lrt]       ReferenceBoxX1                  : 0.118489586
[XMP-lrt]       ReferenceBoxX2                  : 0.16536458
[XMP-lrt]       ReferenceBoxY1                  : 0.25390625
[XMP-lrt]       ReferenceBoxY2                  : 0.72265625
[XMP-lrt]       ReferenceKeyFrame               : false
[XMP-lrt]       Aperture                        : 8.0
[XMP-lrt]       ShutterSpeed                    : 0.8
[XMP-lrt]       Iso                             : 100


...but to change or delete them specific tags is not possible.

exiftool -XMP-lrt:ReferenceBoxX1=0 -XMP-lrt:ReferenceBoxX2=0 -XMP-lrt:ReferenceBoxY1=0 -XMP-lrt:ReferenceBoxY2=0 IMG113800.DNG

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Warning: Tag 'ReferenceBoxX1' does not exist
Warning: Tag 'ReferenceBoxX2' does not exist
Warning: Tag 'ReferenceBoxY1' does not exist
Warning: Tag 'ReferenceBoxY2' does not exist
Nothing to do.


...likewise to delete a single tag is not possible - for example:
exiftool -XMP-lrt:ReferenceBoxX1= IMG113800.DNG

Latest Version 9.25 is installed so the -m option as described here seems not to be the solution:
https://exiftool.org/forum/index.php/topic,4920.0.html

However I can delete the whole group

exiftool -XMP-lrt:all= IMG113800.DNG

What is it that I am doing wrong?
Thanks for advice.
Greetings, Hans.

[Phil Harvey]

Hi Hans,

You aren't doing anything wrong.  Here is a list of all writable XMP tags.

       "ExifTool will extract XMP information even if it is not listed in these tables,
        but other tags are not writable unless added as user-defined tags in the
        ExifTool config file."

What software writes these lrt tags?  Would it be worthwhile adding these to ExifTool?  If so, I'll need a sample, and some documentation would be useful too.

- Phil

[snahl]

Hi Phil,

thanks for your prompt reply. Sent you a PM with a sample file attached.

Regarding the config-file, would that be done with a statement using 'XMP-xxx:NewXMPxxxTag1'  ?

What software writes these lrt tags?

The software is called LRTimelapse2.

Would it be worthwhile adding these to ExifTool?

That is up to you to decide. I am sure the code-writer (and maybe some the users) would not object, I really don't know.

Looking forward to receiving your feedback.
Thanks, Hans.

[Phil Harvey]

Hi Hans,

Thanks, I got the sample.

Attached is a config file that will allow you to write these.

           To activate this file, rename it to ".ExifTool_config" and
           place it in your home directory or the exiftool application
           directory.  (On Windows and Mac systems this must be done via
           the command line since the GUI's don't allow filenames to begin
           with a dot.  Use the "rename" command in Windows or "mv" on the
           Mac.)  This causes ExifTool to automatically load the file when
           run.  Your home directory is determined by the first defined of
           the following environment variables:

               1. EXIFTOOL_HOME
               2. HOME
               3. HOMEDRIVE + HOMEPATH
               4. (the current directory)

           Alternatively, the -config option of the exiftool application
           may be used to load a specific configuration file (note that
           it must be the first option on the command line):

               exiftool -config xmp-lrt.config ...

- Phil

[snahl]

...your fast!
works just fine.

Thank you, Phil.