"instantiationPhysical is used to identify the format of a particular instantiation as it exists in a physical form that occupies physical space (e.g. a tape on a shelf). This includes physical digital media, such as a DV tape, audio CD, or authored DVD, as well as analog media.
Best practice: PBCore provides a controlled vocabulary for media objects, though any controlled vocabulary can be used so long as it is referenced. For digital storage carriers that contain file-based media, such as data CDs, LTO tapes or hard drives, use instantiationDigital to convey the mime type of the file instead of describing the carrier.
The Video vocabulary provides terms for physical media formats for analog and digital video."