Decoder

摘要

A ROM constituting a variable length coding table of 2 picture element range is provided. A motion vector within the range of 2 picture elements is given to the ROM to provide a VLC code corresponding to the motion vector within the range of 2 picture elements. In a calculation circuit, assuming that the value of a motion vector within the range of 4 picture elements is X, a quotient Y and a remainder Z are obtained by the division of X by 2. The quotient Y is supplied to the ROM whose output is added the remainder Z at an additional circuit to obtain a VLC code corresponding to the motion vector lying within the range of 4 picture elements. This is equivalent to the coding at the variable length coding for four-picture element range. By sending a flag indicating whether a motion vector range is 2 picture elements or 4 picture elements, the motion vector is correctly reproduced from the VLC code. By the use of the single table ROM, a motion vector within the range of 2 picture elements and 4 picture elements can be coded to reduce the load imposed on the hardware.