The descriptor formatMediaType identifies the general, high level nature of the content of a media item. It uses categories that show how content is presented to an observer, e.g., as a sound or text or moving image.
In identifying the general nature of the manner in which content is presented to an observer, the descriptor formatMediaType is a very high level view of the media type for a media item. Its meaning goes no deeper than to merely indicate if a media item is an animation, a moving image, a sound, or perhaps text (see the recommended picklist). The actual type of format is expressed through two other descriptors, formatPhysical and formatDigital (mime types).
Apply once within its container, pbcoreInstantiation (which itself can be applied multiple times for each rendition of a media item)