Valeria Metadata Model

Model structure

The Valeria metadata model currently supports these metadata fields:

The model uses structured terms where identity or semantics matter. Human-readable labels and names support presentation; canonical URIs are used for interoperable identity and controlled-vocabulary values. The VMC 3.0 JSON-LD serialization uses a versioned JSON-LD context that defines the VMC terms, and a JSON Schema that defines the document structure.

The following sections map VMC fields to standardized metadata properties and C2PA assertions. Compact IRIs such as dc:title identify properties in a target metadata or assertion vocabulary, not VMC field names.

Technical noteThe mappings are projections, not claims that source and target fields are semantically identical. Each projection should preserve the meaning of the source field within the vocabulary and structure of the target format.

The optional metadata.image.content_warning value is an authored declaration, not a JPEG Trust compliance result. nudity maps to the IPTC Content Warning term http://cv.iptc.org/newscodes/contentwarning/nudity. It is carried in the standard CV-Term About Image structure in XMP and signed CAWG metadata, with URI-valued CvId and CvTermId. There is no invented Iptc4xmpExt:ContentWarning property or legacy IIM mapping. VMC retains the authored code. Trust Profiles translate the extracted term into jpt:profile_label: Nude; an empty label does not establish suitability for every audience. Use null in a sidecar to remove an inherited warning. This field replaces the former nsfw boolean.

Conventional metadata

VMC can be mapped to conventional embedded metadata formats, such as XMP. The following table uses the namespace-qualified property names defined by the relevant XMP schemas.

The namespace prefixes used in this table are:

dc           http://purl.org/dc/elements/1.1/
xmpRights    http://ns.adobe.com/xap/1.0/rights/
photoshop    http://ns.adobe.com/photoshop/1.0/
Iptc4xmpExt  http://iptc.org/std/Iptc4xmpExt/2008-02-29/

Fields without a listed conventional mapping remain available in VMC but are not assigned an equivalent XMP property by this model.

C2PA provenance

C2PA assertions can carry both descriptive metadata and provenance. The assertion label and the property path are part of the mapping; they should not be conflated with ordinary embedded metadata.

Descriptive assertions

cawg.metadata uses CAWG/IPTC compact-IRI properties. The stds.schema-org.CreativeWork assertion uses the Schema.org JSON-LD context; for example, license expands to the Schema.org license property. The assertion label stds.schema-org.CreativeWork identifies the assertion type; it is not itself a VMC field.

Rights assertion

The current jpt.rights assertion is an ODRL rights expression. It records the licence, target, assigner, permitted reproduction/display/distribution actions, an attribution duty, and the configured prohibitions. A rights_statement is retained in VMC but is not currently projected into jpt.rights.

Publication provenance

The publication event is represented separately from descriptive metadata and rights:

metadata.source.digital_source_type is a source classification, not a creation action. A value such as the IPTC URI for “Created using Generative AI” expresses a declared digital source type; it does not by itself prove how, when, or by which system the image pixels were created. The model therefore does not use it to invent a c2pa.created action.