Internet Media Types (IMT or MIME type) values. These define computer media formats according to the RFC2045 and RFC2046 protocol specifications. MIME stands for Multipurpose Internet Mail Extensions. Only MIME types registered with the Internet Assigned Numbers Authority (IANA) are valid.
For digital library needs, MIME types not yet approved (such as application/vnd.rn-realmedia, audio/vnd.rn-realaudio, video/vnd.rn-realvideo, application/x-shockwave-flash, or audio/X-mp3) need to referenced from the local utformat scheme. Follow the convention of selecting a broad category of object format (e.g. audio) for the first part of the MIME type then use the file name suffix usually attached to files of this format.
In the context of the digital library, we offer a drop-down pick list of select, commonly encountered digital medium types. The picklist exposes the common term such as "PDF" rather than the actual mimetype "application/pdf" using the Dublin Core metadata field dcterm:medium.
In support of OAI-PMH harvesting by OAI providers such as the Mountain West Digital Library, these MIME values which are cataloged locally to the dcterms:medium field will be mapped to the Dublin Core Format field.
For more details see the Wikipedia article:
Internet media type
encoding-scheme; scheme=IMT