The Visual-Meta approach is compatible with the Dublin Core Metadata Element Set through simply embedding it in full in the Visual-Meta Appendix.
Visual-Meta is Extensible for Computational Text, Rights Management and Provenance. Visual-Meta is Not A New Standard (it is BibTeX in a novel use, supported by JSON when that is useful), it builds seamlessly on the legacy PDF format by simply adding plain text metadata in an appendix, and basic Visual-Meta Is Quick & Easy To Add To Legacy Documents.
As more Visual-Meta is used, the openness and connectedness will increase, paving the way towards 5 star open data.