XMP Tag insert position

[DavidP]

Hi

my usecase is to use exif tool to insert a new xmp region tag (including Area,Type,Name,Description) into a jpeg file. But i do not know if there is already a xmp region tag present and if there is if it contains all necesarry subtags (Area,Type,Descrition...). Some other application might have already inserted some data and I only want to add my new data without changing the existing.


Example

-Add Joe to picture (some other application did that) without description

Code Select Expand

exiftool -RegionName+=Joe pic.jpg
exiftool -RegionAreaH+=0.2 pic.jpg
exiftool -RegionAreaW+=0.2 pic.jpg
exiftool -RegionAreaX+=0.5 pic.jpg
exiftool -RegionAreaY+=0.5 pic.jpg
exiftool -RegionAreaUnit+=normalize pic.jpg
exiftool -RegionType+=Face pic.jpg


-Add Sue to picture with description (i want to do that)

Code Select Expand

exiftool -RegionName+=Sue pic.jpg
exiftool -RegionAreaH+=0.1 pic.jpg
exiftool -RegionAreaW+=0.1 pic.jpg
exiftool -RegionAreaX+=0.2 pic.jpg
exiftool -RegionAreaY+=0.2 pic.jpg
exiftool -RegionAreaUnit+=normalize pic.jpg
exiftool -RegionType+=Face pic.jpg
exiftool -RegionDescription+=SuesFunnyFaceDescription


This results in the following xmp XML where you can see that Sues description ends up with Joe.       

Code Select Expand


<?xpacket begin='' id='W5M0MpCehiHzreSzNTczkc9d'?>
<x:xmpmeta xmlns:x='adobe:ns:meta/' x:xmptk='Image::ExifTool 10.17'>
<rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'>

<rdf:Description rdf:about=''
  xmlns:mwg-rs='http://www.metadataworkinggroup.com/schemas/regions/'
  xmlns:stArea='http://ns.adobe.com/xmp/sType/Area#'>
  <mwg-rs:Regions rdf:parseType='Resource'>
   <mwg-rs:RegionList>
    <rdf:Bag>
     <rdf:li rdf:parseType='Resource'>
      <mwg-rs:Area rdf:parseType='Resource'>
       <stArea:h>0.2</stArea:h>
       <stArea:unit>normalize</stArea:unit>
       <stArea:w>0.2</stArea:w>
       <stArea:x>0.5</stArea:x>
       <stArea:y>0.5</stArea:y>
      </mwg-rs:Area>
      <mwg-rs:Description>SuesFunnyFaceDescription</mwg-rs:Description>
      <mwg-rs:Name>Joe</mwg-rs:Name>
      <mwg-rs:Type>Face</mwg-rs:Type>
     </rdf:li>
     <rdf:li rdf:parseType='Resource'>
      <mwg-rs:Area rdf:parseType='Resource'>
       <stArea:h>0.1</stArea:h>
       <stArea:unit>normalize</stArea:unit>
       <stArea:w>0.1</stArea:w>
       <stArea:x>0.2</stArea:x>
       <stArea:y>0.2</stArea:y>
      </mwg-rs:Area>
      <mwg-rs:Name>Sue</mwg-rs:Name>
      <mwg-rs:Type>Face</mwg-rs:Type>
     </rdf:li>
    </rdf:Bag>
   </mwg-rs:RegionList>
  </mwg-rs:Regions>
</rdf:Description>
</rdf:RDF>
</x:xmpmeta>

Is there any way to make sure that all information is created in the same rdf:li section? Or if i knew that Joe is missing the description tag - can I specify that the Description should be added to the 2nd Element?

[Phil Harvey]

You seem to have two problems:

Is there any way to make sure that all information is created in the same rdf:li section

To be sure all elements of the RegionInfo structure are written together, write them as a structure:

exiftool -regionlist+="{Area={H=0.2,Unit=normalize,W=0.2,X=0.5,Y=0.5},Name=Joe,Type=Face}" pic.jpg

See Writing Structured Information for more information.

I only want to add my new data without changing the existing

This is tricky, and can't be easily done via the command line.  It could be done efficiently via a Perl script using the ExifTool API.

From the command line, a technique could be to fill all of the missing structure elements with dummy fields, then replace the one you want and delete the other dummy fields afterwards.

- Phil

[DavidP]

Hi Phil,

thank you for your reply. Inserting the data as structure was exactly the thing i was looking for.