PURPOSE: To reduce moving vector information to be transmitted by switching and performing motion compensation interframe forecasting and motion compensation interfield forecasting, block by block.

CONSTITUTION: A TV signal from a terminal 1 is inputted to a delay circuit 3 and the 1st and the 2nd vector detector 31 and 38. The 1st and the 2nd vector detectors 31 and 38 output an interfield moving vector and an interframe moving vector, respectively. Those outputs are supplied to a discriminating circuit 37 to make a code length comparison between both vectors. According to the comparison result, a selector 33 selects the interfield or interframe moving vector, which is supplied to an encoder 30. The variable length encoded moving vector from the encoder 30 is multiplexed by a multiplexer 11 with a forecasting error signal from an encoder 9 to transmit the resulting signal through a buffer memory 13.