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ExifTool Forum

ExifTool => Newbies => Topic started by: Jom on July 28, 2022, 11:42:05 AM

Title: About the values of some tags
Post by: Jom on July 28, 2022, 11:42:05 AM
1.
exif:ImageUniqueID
The standard says the following "An identifier assigned uniquely to each image. It is recorded as a 32 character ASCII string, equivalent to hexadecimal notation and 128- bit fixed length.", but ExifTool allowed me to write a string much longer than 32 characters.
Is this normal behavior or should I control the length of the string myself?

2.
XMP-plus:ImageFileConstraints
XMP-plus:CreditLineRequired
XMP-plus:CopyrightStatus
What value should I pass to ExifTool for these tags?
In the standard, the values are specified as full URLs (example - http://ns.useplus.org/ldf/vocab/CS-PRO), but in the ExifTool specification only shortened (example - CS-PRO).

-XMP-plus:CopyrightStatus="http://ns.useplus.org/ldf/vocab/CS-PRO"
or
-XMP-plus:CopyrightStatus="CS-PRO"
?
Title: Re: About the values of some tags
Post by: Phil Harvey on July 28, 2022, 11:46:30 AM
1. Often ExifTool allows you to write whatever you want to a string-type tag.  Adding constraints increases complaints.  And when constraints are applied, they can often be avoided with the -n option.

2.  This is FAQ 6 (https://exiftool.org/faq.html#Q6).

- Phil
Title: Re: About the values of some tags
Post by: Jom on July 28, 2022, 12:16:36 PM
Tell me, please, do you know of cases when restrictions were violated and this led to incorrect interaction with the software, for example in my case with 32 characters in Exif?
Title: Re: About the values of some tags
Post by: Phil Harvey on July 28, 2022, 01:00:06 PM
This is a loaded question...

I know of many cases where software interacts badly with some perfectly valid tag values.

- Phil
Title: Re: About the values of some tags
Post by: Jom on July 28, 2022, 01:09:51 PM
Thanks.
Title: Re: About the values of some tags
Post by: Jom on July 28, 2022, 02:13:24 PM
There is one more question.
Why does ExifTool write only CS-PRO if the standard value is http://ns.useplus.org/ldf/vocab/CS-PRO ?

Code Select
PS D:\_temp> exiftool -XMP-plus:CopyrightStatus='Protected' .\IMG_1744.CR2
    1 image files updated
PS D:\_temp> exiftool -XMP-plus:CopyrightStatus -n .\IMG_1744.CR2
Copyright Status                : CS-PRO
PS D:\_temp>
Title: Re: About the values of some tags
Post by: StarGeek on July 28, 2022, 02:26:06 PM
Look at the raw XMP and you'll see that is what exiftool is writing.
Code Select
C:\>exiftool -G1 -a -s -xmp -b y:\!temp\Test4.jpg
<?xpacket begin='�' id='W5M0MpCehiHzreSzNTczkc9d'?>
<x:xmpmeta xmlns:x='adobe:ns:meta/' x:xmptk='Image::ExifTool 12.42'>
<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>

 <rdf:Description rdf:about=''
  xmlns:plus='http://ns.useplus.org/ldf/xmp/1.0/'>
  <plus:CopyrightStatus>http://ns.useplus.org/ldf/vocab/CS-PRO</plus:CopyrightStatus>
 </rdf:Description>
</rdf:RDF>
</x:xmpmeta>
<?xpacket end='w'?>
Title: Re: About the values of some tags
Post by: Jom on July 28, 2022, 03:24:41 PM
I understand, ExifTool adding to end of URL entering value.
Need only adding or CC-PRO (with -n) or Protected.
If I added full URL, I get this:

Code Select
<plus:CopyrightStatus>http://ns.useplus.org/ldf/vocab/http://ns.useplus.org/ldf/vocab/CS-PRO</plus:CopyrightStatus>
Thanks.
Title: Re: About the values of some tags
Post by: Phil Harvey on July 28, 2022, 09:30:23 PM
This is explained in the first paragraph of the XMP PLUS tags documentation (https://exiftool.org/TagNames/PLUS.html#XMP), and the table shows the conversions that ExifTool uses.

- Phil
Title: Re: About the values of some tags
Post by: Jom on July 28, 2022, 10:20:03 PM
When you don't know what to look for, you may not notice the first paragraph. :)
When you are looking for the value of an option, then everything is simple, but when an unexpected incomprehensible behavior of the program, you run firstly to the forum. :-\
Thanks.
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