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CIB pdf toolbox technical guide (EN)

13. Generally valid Properties

13.1. XMP Metadaten

General
 Example
 Example for XMP metadata
General

Extensible Metadata Platform (XMP) is a format for embedding RDF into binary data. It is intended to integrate metadata in all relevant Adobe Systems applications according to a uniform schema.

The content of the XmpMetadataExtension property is described by the following detailed requirements, which result in particular from the specifications in the XMP and PDF/A specifications:

  • The attribute rdf:about must be set to "".
  • The content of the description elements and the necessary specification of an own namespace are arbitrary within the XMP specifications.
  • The string must be UTF-8 encoded.
  • According to the XMP specification only name-value pairs (properties) can be stored in XMP.
  • A value cannot itself be XML. However, structured values (signature area=Left,Top,Right,Bottom) and lists of values (Author=Thiel, Eisenschmid, Wissenbach) are supported by XMP. The available atomic data types are described in the XMP specification.
  • For PDF/A conformance: If the specified namespace is not one of the "XMP schemas" predefined in the XMP specification, then the description of the associated schema must also be provided. See the information in the PDF/A specification regarding metadata. This is not required for normal PDF.
  • The content of the „XmpMetadataExtension” is not checked for conformity.
  • - The caller makes sure that the property value is an XMP compliant string in UTF-8 encoding. The prefixing of the XMP header and the XMP termination is not allowed.
  • In the CIB documentServer this property must be encoded as CDATA section or with corresponding entities, and of course it must contain UTF-8.


Example

XmpMetadataExtension=”
<rdf:Description rdf:about=\”\” xmlns:xmpTGp=\”http://ns.adobe.com/xap/1.0/t/pg/\”>
<xmpTGp:NPages>25<xmpTGp:NPages>
</rdf:Description>
“

Example for XMP metadata

The green section describes the part that is the schema for the red individual content (=own property):

<rdf:Description rdf:about=”” xmlns:pdfaProperty=”http://www.aim.org/pdfa/ns/property/”>
<pdfaProperty:name>BackgroundFilename</pdfaProperty:name>
<pdfaProperty:valueType>Text</pdfaProperty:valueType>
<pdfaProperty:category>internal</pdfaProperty:category>
</rdf:Description>
 
<rdf:Description rdf:about=”” xmlns:pdfaSchema=”http://www.aim.org/pdfa/ns/schema/”>
<pdfaSchema:namespaceURI>
http://www.cib.de/schemas/xmp/pdfprops/1.0/
</pdfaSchema:namespaceURI>
<pdfaSchema:prefix>cibpdf</pdfaSchema:prefix>
<pdfaSchema:property>
<rdf:Seq>
<rdf:li>BackgroundFilename</rdf:li>
</rdf:Seq>
</pdfaSchema:property>
</rdf:Description>
 
<rdf:Description rdf:about=”” xmlns:cibpdf=”http://www.cib.de/schemas/xmp/pdfprops/1.0/”>
<cibpdf:DefaultBackgroundFilename>wert1</cibpdf:DefaultBackgroundFilename>               
</rdf:Description>