Patent ID: 6928118

Claim:
A video display apparatus for superposing a predetermined on-screen signal with a video signal, said video display apparatus comprising: OSD generating means for generating the predetermined on-screen signal and outputting the predetermined on-screen signal and an OSD period signal indicating an on-screen display period; a dual-port line memory for storing the on-screen signal and the OSD period signal which are outputted from said OSD generating means in synchronization with a write clock that is lower in speed than a dot clock of the video signal and increasing speeds of the on-screen signal and the OSD period signal to output the on-screen signal and the OSD period signal in synchronization with a read clock which is equal in speed to the dot clock of the video signal, such that a number of pixels of an on-screen display image is not changed between write and read operations; and switching means for receiving the video signal and the on-screen signal with the increased speed and selecting either the on-screen signal with the increased speed or the video signal based on the OSD period signal with the increased speed, such that the on-screen signal with the increased speed is outputted during the on-screen display period indicated by the OSD period signal with the increased speed and the video signal is outputted during a display period other than the on-screen display period.