Video signal transmitting system in which digital video signal are divided into groups of predetermined frames. Digital video signals of at least one frame are intraframe coded and then transmitted. Remaining digital video signals are interframe coded with reference to the intraframe coded digital video signals, and intraframe coded digital video signals of a subsequent group of frames and are then transmitted. A motion vector from a predetermined reference frame is detected. Video signals are interframe coded by the motion vector to transmit the video signals. A motion vector from a first frame which is a plurality of frames away from the reference frame is converted to a motion vector for a one frame interval between the reference frame and the first frame. The motion vector is optimized, and is then transmitted.