An AV system that executes image recognition of an identification mark 9 provided on headphones 8 in a seat side shot image taken with a camera 2,calculates the coordinate position of the identification mark 9 in the shot image, decides from the coordinate position of the identification mark 9 as to which one of a plurality of seats a user wearing the headphones 8 sits on, and transmits audio data which corresponds to video data to be displayed on the display screen facing the seat, as to which a decision is made that the user sits on, to the headphones 8 to be produced as audio output.