Apparatus for converting the scanning period of a video signal to a period not necessarily an integer times the original period

Apparatus for converting the scannng period of video signal, comprising:

• two frame buffer means each for storing a frame of video data;
• write-in means for executing a write-in operation including receiving a video signal having a first scanning period and generating a write-in address in accordance with the first scanning period to write a frame of video data from the video signal into one of said frame buffer means;
• read-out means for executing a repetitive read-out operation on a frame-by-frame basis including receiving a synchronizing signal having a second scanning period shorter than the first scanning period and generating a read-out address in accordance with the second scanning period to repetitively read out the video data from the other of said frame buffer means;
• and
• control means for controlling the operations of said read-out means and said write-in means so that when the write-in operation of said write-in means writing data to the one of said frame buffer means is finished, the read-out operation of said read-out means reading data from the other of said frame buffer means is also terminated, and subsequently the read-out operation of said read-out means to read data from the one of said frame buffer means is started from an address corresponding to a read-out address of the other of said frame buffer means at the finishing time of the write-in operation of the one of the said frame buffer means while the write-in operation of said write-in means to write data to the other of said frame buffer means is started.