Disclosed is a luminescent substance which has the structure EA3N2Si2O4:D, wherein EA= and D=Eu, provides red emission, and is characterized by great stability and a simple production process. As marks representing characteristic points of an AV stream, a mark of the type indicating a point and a mark of the type indicating a section are provided. A downward moving plate in cooperation with a pair of laterally moving plates to control the movement of the rotors. In this way, an electronic musical instrument using the fuel battery can operate for a long time as compared to the conventional electronic musical instruments using a dry battery or storage battery. The subsequent markers can be rendered when a condition associated with the subsequent marker is satisfied. The video is cataloged according to predefined or user definable metadata.