Problem adding entries to XMP-IPTCExit::ArtworkOrObject using flattened tags

[Mac2]

I have some experience with ExifTool, but I cannot get this to work.
I start with a JPG file which has no XMP data yet.
I run the following commands in an .args file:

Code Select Expand

-XMP-iptcExt:ArtworkCreator=
-XMP-iptcExt:ArtworkSource=
-XMP-iptcExt:ArtworkTitle=

-XMP-iptcExt:ArtworkCreator=C1
-XMP-iptcExt:ArtworkCreator=C2
-XMP-iptcExt:ArtworkCreator=C1

-XMP-iptcExt:ArtworkSource=S1
-XMP-iptcExt:ArtworkSource=S2
-XMP-iptcExt:ArtworkSource=S1

-XMP-iptcExt:ArtworkTitle=T1
-XMP-iptcExt:ArtworkTitle=T2
-XMP-iptcExt:ArtworkTitle=T3
Fetching the result via

Code Select Expand

exiftool -xmp-iptcext:all image.jpg
yields

Code Select Expand

Artwork Creator                 : C1, C2, C1
Artwork Source                  : S1, S2, S1
Artwork Title                   : T1, T2, T3
which looks correct. But looking at the structured XMP output

Code Select Expand

exiftool -xmp-iptcext:all -struct -X image.jpg
I get

Code Select Expand

...
 <XMP-iptcExt:ArtworkOrObject>
  <rdf:Bag>
   <rdf:li rdf:parseType='Resource'>
    <XMP-iptcExt:AOCreator>
     <rdf:Bag>
      <rdf:li>C1</rdf:li>
      <rdf:li>C2</rdf:li>
      <rdf:li>C1</rdf:li>
     </rdf:Bag>
    </XMP-iptcExt:AOCreator>
    <XMP-iptcExt:AOSource>S1</XMP-iptcExt:AOSource>
    <XMP-iptcExt:AOTitle>T1</XMP-iptcExt:AOTitle>
   </rdf:li>
   <rdf:li rdf:parseType='Resource'>
    <XMP-iptcExt:AOSource>S2</XMP-iptcExt:AOSource>
    <XMP-iptcExt:AOTitle>T2</XMP-iptcExt:AOTitle>
   </rdf:li>
   <rdf:li rdf:parseType='Resource'>
    <XMP-iptcExt:AOSource>S1</XMP-iptcExt:AOSource>
    <XMP-iptcExt:AOTitle>T3</XMP-iptcExt:AOTitle>
   </rdf:li>
  </rdf:Bag>
 </XMP-iptcExt:ArtworkOrObject>
...

or, easier to read in JSON:

Code Select Expand

[{
  "SourceFile": "C:/data/Image Tests/Faces/B/A/Artwork.jpg",
  "ArtworkOrObject": [{
    "AOCreator": ["C1","C2","C1"],
    "AOSource": "S1",
    "AOTitle": "T1"
  },{
    "AOSource": "S2",
    "AOTitle": "T2"
  },{
    "AOSource": "S1",
    "AOTitle": "T3"
  }]
}]

which does not seem correct?

When I look in Adobe Photoshop at the metadata written by ExifTool, I get the expected (wrong) result:



How do I create 3 separate elements, each with its own Creator, Source and Title?
Where is my mistake?

[StarGeek]

I think this falls under the "Tricky" section on the Structured Information page.  And I'll admit I'm struggling to figure this out correctly.

But this works correctly I believe

Code Select Expand

C:\Programs\My_Stuff>type temp.txt
-XMP-iptcExt:ArtworkOrObject={AOCreator=C1}
-XMP-iptcExt:ArtworkOrObject={AOCreator=c2}
-XMP-iptcExt:ArtworkOrObject={AOCreator=c3}

-XMP-iptcExt:ArtworkSource=S1
-XMP-iptcExt:ArtworkSource=S2
-XMP-iptcExt:ArtworkSource=S3

-XMP-iptcExt:ArtworkTitle=T1
-XMP-iptcExt:ArtworkTitle=T2
-XMP-iptcExt:ArtworkTitle=T3

C:\Programs\My_Stuff>exiftool -P -overwrite_original  -@ temp.txt  y:\!temp\Test4.jpg
    1 image files updated

C:\Programs\My_Stuff>exiftool -G1 -a -s -xmp-iptcext:all -j -struct y:\!temp\Test4.jpg 
[{
  "SourceFile": "y:/!temp/Test4.jpg",
  "XMP-iptcExt:ArtworkOrObject": [{
    "AOCreator": ["C1"],
    "AOSource": "S1",
    "AOTitle": "T1"
  },{
    "AOCreator": ["c2"],
    "AOSource": "S2",
    "AOTitle": "T2"
  },{
    "AOCreator": ["c3"],
    "AOSource": "S3",
    "AOTitle": "T3"
  }]
}]
But of course, that probably isn't the best option for working in IMatch, as that would require trying to figure the correlation between the structured tag name and the flattened tag name.  I'm not sure there's a way to do that.

Hopefully, Phil will have a way.

[Phil Harvey]

Nested lists are a problem for the flattened tags.  Items are added to the lowest-level list as you have seen.  To do this properly you must write as a structure, either all at once using list notation:

Code Select Expand

-artworkorobject=[{AOCreator=C1,AOSource=S1,AOTitle=T1},{AOCreator=C2,AOSource=S2,AOTitle=T2},{AOCreator=C3,AOSource=S3,AOTitle=T3}]
or as separate items:

Code Select Expand

-artworkorobject={AOCreator=C1,AOSource=S1,AOTitle=T1}
-artworkorobject={AOCreator=C2,AOSource=S2,AOTitle=T2}
-artworkorobject={AOCreator=C3,AOSource=S3,AOTitle=T3}
- Phil

[StarGeek]

To do this properly you must write as a structure

Do any of the -list options give the names of structure components such as AOCreator, AOSource, or AOTitle?

I believe, and correct me if I'm wrong, Mac2 is extracting tag lists from exiftool for IMatch using -list*.  And my quick checks of the -list options doesn't seem to have structured tags details. So basically, is there a way to programmably extract a structure's details from exiftool or do the structures have to be researched and separately coded.

[Phil Harvey]

Do any of the -list options give the names of structure components such as AOCreator, AOSource, or AOTitle?

The -listx option gives you this information in the "tag id", preprended by the structure name.  For example, with -listx -f:

Code Select Expand

<tag id='ArtworkOrObject' name='ArtworkOrObject' type='struct' writable='true' flags='Bag,List'>
  <desc lang='en'>Artwork Or Object</desc>
 </tag>
 <tag id='ArtworkOrObjectAOCreator' name='ArtworkCreator' type='string' writable='true' flags='Flattened,List,Seq'>
  <desc lang='en'>Artwork Creator</desc>
  <desc lang='de'>Artwork Ersteller</desc>
  <desc lang='fr'>Créateur de l&#39;Illustration</desc>
 </tag>


I believe, and correct me if I'm wrong, Mac2 is extracting tag lists from exiftool for IMatch using -list*.  And my quick checks of the -list options doesn't seem to have structured tags details. So basically, is there a way to programmably extract a structure's details from exiftool or do the structures have to be researched and separately coded.

Complex XMP structures do make this difficult.

- Phil

[Mac2]

Thanks to both of you for providing insight and help.
#StarGeek is correct, I import the flattened tags into the database. I use -listx to retrieve information about groups and tags and store it into the database. For example, I have:

Code Select Expand

ArtworkOrObject           ArtworkOrObject (struct)
ArtworkOrObjectAOCreator  ArtworkCreator (string)
ArtworkOrObjectAOSource      ArtworkSource (string)
ArtworkOrObjectAOTitle      ArtworkTitle (lang-alt)
The database knows that ArtworkOrObject is a structure, but it does currently not know that ArtworkOrObjectAOCreator is part of a structure, or which.

When I understand Phil correctly, I could determine if and of which structure a tag belongs to by

a) finding all structure tags in the database (this currently finds 243 tags)
b) finding all tags which have an id that starts with the id of a structure =>
ArtworkOrObjectAOCreator
ArtworkOrObjectAOSource
...
c) "link" these flattened tags to the original structure tag in the database somehow

This would allow my code to know that when the user makes a modification to ArtworkOrObjectAOCreator that the output has to be written using the structure syntax if the user has provided more than one value.
So if the user changed ArtworkOrObject to  A;B;C, it would be written as

Code Select Expand

-XMP-iptcExt:ArtworkOrObject={AOCreator=A}
-XMP-iptcExt:ArtworkOrObject={AOCreator=B}
-XMP-iptcExt:ArtworkOrObject={AOCreator=C}

[Phil Harvey]

The database knows that ArtworkOrObject is a structure, but it does currently not know that ArtworkOrObjectAOCreator is part of a structure

If you use the -f option with -listx, the elements of a structure will have the "Flattened" tag set.  This allows you to identify which tags are part of a structure.

I could determine if and of which structure a tag belongs to by

a) finding all structure tags in the database (this currently finds 243 tags)
b) finding all tags which have an id that starts with the id of a structure =>
ArtworkOrObjectAOCreator
ArtworkOrObjectAOSource
...
c) "link" these flattened tags to the original structure tag in the database somehow

I understand that this is not ideal.  The "Flattened" flag should help a bit here.  We could maybe think about making this easier somehow.  Would it help to add a "struct" element that points up to the containing structure (ie. "flags='Flattened,List,Seq' struct='ArtworkOrObject'")?

- Phil

[StarGeek]

a) finding all structure tags in the database (this currently finds 243 tags)
b) finding all tags which have an id that starts with the id of a structure =>
ArtworkOrObjectAOCreator
ArtworkOrObjectAOSource
...
c) "link" these flattened tags to the original structure tag in the database somehow

Unfortunately, there are structures where this falls apart, usually due to shortened flattened name tags and structures within sturctures.  The most obvious being MWG:RegionInfo, where most of the tags don't contain the name of the parent structure, which doesn't contain the name of its parent structure.

We could maybe think about making this easier somehow.  Would it help to add a "struct" element that points up to the containing structure (ie. "flags='Flattened,List,Seq' struct='ArtworkOrObject'")?

I like this idea, but then I'm not the one coding for it.  I once had the thought of making a simple autohotkey gui for inputting structures, but that would had to have been hard coded.

[Phil Harvey]

Unfortunately, there are structures where this falls apart, usually due to shortened flattened name tags and structures within sturctures.

True the tag names may be shortened, but not the ID's.

- Phil

[StarGeek]

True the tag names may be shortened, but not the ID's.

Ah, yes, I didn't take the time to look closer at the -listx output for these. My mistake.

[Mac2]

I understand that this is not ideal.  The "Flattened" flag should help a bit here.  We could maybe think about making this easier somehow.  Would it help to add a "struct" element that points up to the containing structure (ie. "flags='Flattened,List,Seq' struct='ArtworkOrObject'")?

I know about the Flattened tag. My code parses it but so far did not have a use for it.

I like your idea of structure members having a 'pointer' to their containing parent element. This would work as well for nested structures, where code just could follow the parent chain to determine all containing structures until there is no parent anymore.

This would make it easy to 'collect' all values for a structured tag from its flattened tags in the database and then dynamically producing the optimal input for ExifTool during write-back.

[Phil Harvey]

OK.  Will do.  The -listx -f output will look like this for ExifTool 12.50:

Code Select Expand

<tag id='ArtworkOrObject' name='ArtworkOrObject' type='struct' writable='true' flags='Bag,List'>
  <desc lang='en'>Artwork Or Object</desc>
 </tag>
 <tag id='ArtworkOrObjectAOCreator' name='ArtworkCreator' type='string' writable='true' flags='Flattened,List,Seq' struct='ArtworkOrObject'>
  <desc lang='en'>Artwork Creator</desc>
  <desc lang='de'>Artwork Ersteller</desc>
  <desc lang='fr'>Créateur de l&#39;Illustration</desc>
 </tag>
Where the "struct" attribute is the ID of the parent structure tag.  For nested structures you will have to work your way up the hierarchy as you mentioned.  Cyclical references shouldn't be a problem since ExifTool already breaks those.

Adding this "struct" attribute makes the Flattened flag redundant, but I'll have to leave it in for backward compatibility.

- Phil

[Mac2]

That is excellent! Thank you very much.
I will use this to enhance future versions of my software.

I've always had the pending to-do for a dynamic structured tag editor (mainly for XMP/IPTC), to allow for easy input of repeatable structures. This will make this easier to implement in a generic way.

[Mac2]

One more question:
When I use -f -t -l -listx, I get results like this:

Code Select Expand

<tag id='ArtworkOrObjectAOCreator' name='ArtworkCreator' type='string' writable='true' flags='Flattened,List,Seq'>
but when writing the structure, the tag must be named AOCreator.

Code Select Expand

XMP-iptcExt:ArtworkOrObject={AOCreator=ABC}
Where does AOCreator come from?

Is is the right way to derive it from the tag id by removing the name of the containing struct:
"ArtworkOrObjectAOCreator" => "AOCreator" ?

[StarGeek]

Where does AOCreator come from?

Is is the right way to derive it from the tag id by removing the name of the containing struct:
"ArtworkOrObjectAOCreator" => "AOCreator" ?

Yes, I believe that's what Phil was saying above when he corrected me above in this post.  The tag ID will be the Structure name+Structure element, so as you say, remove the structure name to get the element.