An audio codec uses one or more access points to broadcast or unicast a performance to a mobile digital media device that is registered and therefore is authorized to receive the performance. Prior to receiving, the mobile digital media device is authenticated by replying to an RFID query from one or...http://www.google.com.hk/patents/US7693978?utm_source=gb-gplus-share專利 US7693978 - Distributing live performances
