According to one embodiment, a video server reads a first type of video signal for one screen from a memory address related to a screen based on a clock pulse if first information in order to read the first type of video signal from the memory device with the first predetermined time interval and the clock pulse are received, and reads a second type of video signal for integral multiple screens from the playback controller in order to read the second type of video signal from the memory device with a changing point of the clock pulse level if the second information from the playback controller in order to read the second type of video signal from the memory device with the first predetermined time interval and the clock pulse are received.