Patent ID: 7941864

Claim:
An audio-video output apparatus which outputs at least one of audio data and video data to a receiving apparatus using High-Definition Multimedia Interface (HDMI) communications, said audio-video output apparatus comprising: a list storage configured to hold an unauthorized apparatus list which contains information about an unauthorized apparatus; an authenticator, embodied in a processor, configured to perform a first apparatus authentication to verify whether or not the receiving apparatus is an authorized apparatus using the unauthorized apparatus list stored in said list storage, and to perform a second apparatus authentication at regular intervals to verify the receiving apparatus is an authorized apparatus; a list acquirer, embodied in a processor, configured to acquire another unauthorized apparatus list; an updater, embodied in a processor, configured to update the unauthorized apparatus list stored in said list storage to the unauthorized apparatus list acquired by said list acquirer when the unauthorized apparatus list acquired by said list acquirer is newer than the unauthorized apparatus list stored in said list storage; and an apparatus verifier, embodied in a processor, configured to, when the unauthorized apparatus list is updated by said updater, verify whether or not the receiving apparatus is an authorized apparatus using the updated unauthorized apparatus list, the verification being performed in parallel with the second apparatus authentication performed by said authenticator.