Software for for multi-media management, as well as discovery and control of capable devices over network (known as DLNA- or also UPnP-clients/servers)
A DLNA capable device can cover one or more of the following functions:
- act as a server to provide content
- act as a client to access a DLNA server
- act as a control-point to deal with the two above
- act as a media renderer (which a control-point can address to have media "played")
While the definition of DLNA is pretty lose when it comes to supported formats, most of todays apps/devices support more formats than the DLNA specification "prescribes". For details, follow up to the linked Wikipedia articles.