PURPOSE: To prevent a motion of a reproduced picture from being unnatural even when a picture with a large motion is continuously received by selecting a hierarchical layer position of a picture signal sent in response to an average of a motion vector magnitude of an entire current frame based on a magnitude of a detected motion vector.

CONSTITUTION: The resolution of a digitized picture input signal 100 is divided into plural layers by a down-sampler 101 and inputted to a multiplexer 105. Furthermore, a motion vector is detected for each unit block based on a current picture input signal and a decoded picture of a preceding frame and a predicted picture is generated based on the motion vector. Furthermore, a subtractor 114 generates a predicted error picture based on the current frame and the predicted picture and the prediction error picture is generated by an orthogonal transformation device 107 and a quantizer 108 and the orthogonal transformation device 107 and the quantizer 108 code the predicted error picture to provide an output. A layer discrimination device 104 obtains the mean value of the magnitude of the motion vector of the entire current frame based on the magnitude of the detected motion vector to select a hierarchy of the picture signal.