mpeg decoder 22 at the mixer 27 the mixing time of the graphic image is determined based on pts presentation time stamp relation between corresponding atvef data tp and a v data tps through the above explained operations pl data for supplementary service information can be provided for a digital television set along with a v contents written in a recording medium like as digital television broadcast programs according to atvef or dase standard the pl interpreter 34 of the hd dvd player 200 may transmit all tps included in reproduced presentation data through only isochronous channel of the interfacing unit 35 without checking pid of each tp in this case of not separating the interfacing unit 28 of the digital television set 300 further conducts the functions of checking and separating that is it checks pid if every tps received through the isochronous channel and separates a v data tp and atvef data one based on their pids a digital television set may equip with an addition element not figured to conduct the checking and separating instead of the function integrated interfacing unit the separated a v data and atvef data tps are to the mpeg decoder 22 and the pl separator 23 respectively the a v data tps are decoded to original video and sound data by the mpeg decoder 22 and the atvef data tps are converted to a corresponding graphic image through sequential processes of the pl separator 23 the pl interpreter 25 and the graphic.