| 摘要 |
A system controls access to a group of media items. A client device is operable by a user. A media server is coupled to at least one media data source,wherein the at least one media data source stores one or more media items for supply, by the media server, to the client device over a network. An authorisation server is coupled to an authorisation data source. The authorisation data source stores data identifying a group of media items of fixed group size N that are accessible by the user, each media item in said group having a different associated availability parameter value indicating a number of time periods M within which access to the media item is available,wherein the authorisation server is arranged to authorise the media server to supply a media item to the client device if said media item belongs to the group of media items. |
