IMAGE CODER

PROBLEM TO BE SOLVED: To reduce a circuit scale of an image coder where an HDTV signal and a normal television signal are coded simultaneously. SOLUTION: A normal television signal is coded at a frame rate of 30Hz, equal to that of an HDTV signal. Thus, a normal television signal coder 3 detects a motion vector with respect to an input frame of 30Hz. Detected motion vector information is used for a reference vector for searching a motion vector by a motion vector detection circuit 12 of a High Vision signal coder 4. Thus, in the motion vector detection processing by the High Vision signal coder 4, a moving direction and a moving distance of each macro block are easily checked only by checking matching with blocks close to the reference vector among the current input frames of the HDTV signal to considerably reduce the arithmetic operation for the detection of the motion vector.