ExifTool Forum

ExifTool => Newbies => Topic started by: nafetslesierk on December 17, 2012, 08:46:47 AM

Title: XMP query - actually rhymes...
Post by: nafetslesierk on December 17, 2012, 08:46:47 AM
Hi!

Why does this work,

exiftool abc.pdf -xmp-bibtex:volume
-> Volume: 89

but this does not:

exiftool abc.pdf -xmp-bibtex:volume="123"
-> "Warning: Tag 'xmp-bibtex:Volume' does not exist
-> Nothing to do.

Cheers

Stefan
Title: Re: XMP query - actually rhymes...
Post by: Phil Harvey on December 17, 2012, 09:04:29 AM
Hi Stefan,

ExifTool will extract any XMP information that exists, even if it hasn't been pre-defined.  But ExifTool can only write tags that have been pre-defined.  You can create user-defined tags to write anything you want.  See the XMP-xxx example in the sample config file (https://exiftool.org/config.html).

- Phil
Title: Re: XMP query - actually rhymes...
Post by: nafetslesierk on December 17, 2012, 09:07:30 AM
THANKS!
Will fiddle around a bit...
Best
Stefan
Title: Re: XMP query - actually rhymes...
Post by: Phil Harvey on December 17, 2012, 09:21:30 AM
I have expanded this paragraph in the XMP tag name documentation (https://exiftool.org/TagNames/XMP.html) in an attempt to clear this up in the documentation:

       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.  For example, the "pdfx" namespace
       doesn't have a predefined set of tag names because it is used to store
       application-defined PDF information, so although this information will
       be extracted, it is only writable if the corresponding user-defined tags
       have been created.

- Phil