Metadata registry

MusicBrainz is a project by the MetaBrainz Foundation that aims to create a collaborative music database that is similar to the freedb project. MusicBrainz was founded due to the restrictions placed on the Compact Disc Database (CDDB), a database for software applications to look up audio CD information on the Internet. MusicBrainz has expanded its goals beyond serving as a CD metadata repository, evolving into a structured online database for music information, including details about artists, performers, and songwriters.

system of descriptive information for an arrangement or division of objects into groups based on characteristics, which the objects have in common

Schema.org is a reference website that publishes documentation and guidelines for using structured data mark-up on web-pages (in the form of microdata, RDFa or JSON-LD). Its main objective is to standardize HTML tags to be used by webmasters for creating rich results (displayed as visual data or infographic tables on search engine results) about a certain topic of interest. It is a part of the semantic web project, which aims to make document mark-up codes more readable and meaningful to both humans and machines.

standard for metadata registries