Element Content Classes
Each XML document has exactly one single root element. It encloses all the other elements and is therefore the sole parent element to other elements. PBCore includes a number of root elements that can be used discretely: DescriptionDocument, CollectionDocument, and InstantiationDocument. Root elements are also called parent elements.
The Intellectual Content class provides descriptive metadata, including Title, Subject, Description, and Genre. The Intellectual Content for the asset contains no metadata concerning the physical or digital representation of the asset.
The Intellectual Property content class provides metadata concerning the creator, distributor, and publisher of the AV asset, along with rights information about its use..
The Extension content class provides options to split up PBCore documents and to include information from other metadata standards in a PBCore document.
The Instantiation content class contains all technical metadata about the physical or digital representation of the AV asset. This can include format, media type, duration, file size, data rate, aspect ratio, frame rate, and many other aspects of the media object. The Instantiation metadata includes the location of the physical or digital media object, which in the case of a streaming media file can be its full URL. In PBCore there can be many Instantiations for the same AV asset, all of which share the same Intellectual Content metadata.
Elements in an XML document must appear in a certain order and hierarchy. The hierarchy for a PBCore 2.1 pbcoreDescriptionDocument is as follows.
Within a pbcoreCollection, the hierarchy remains the same, but the pbcoreDescriptionDocument is contained inside a pbcoreCollection element. If a pbcoreInstantiationDocument is used as the root element, only the Instantiation elements may appear inside the document.
If pbcorePart or instantiationPart are used, all sub-elements must appear in the same order that they would within pbcoreDescriptionDocument (for pbcorePart) or pbcoreInstantiation (for instantiationPart.)