is the UPnP-server ("master" device) that provides media library information and streams media-data (like audio/video/picture/files) to UPnP clients on the network. It is a computer system or a similar digital appliance that stores digital media, such as photographs, movies, or music and shares these with other devices.
UPnP AV media servers provide a service to UPnP AV client devices, so called control points, for browsing the media content of the server and request the media server to deliver a file to the control point for playback.