By far the majority of digital objects in a Hydra repository would be expected to have accompanying descriptive metadata.  Hydra provides extensive functionality for dealing with MODS, but that particular schema is not a given. Hydra users are known to be working with a range of other metadata formats including Dublin Core (DC), EAD and PBCore.  It is possible to convert between formats; thus, for instance, one Hydra partner keeps all descriptive metadata as MODS but can create a DC representation or UKETD_DC from it on the fly.

Hydra provides for the storage of other types of metadata.  For instance, our approach to metadata provides for optional technical metadata – perhaps EXIF information for an image or format characterisation information from JHOVE(2).