Image information encoding method and encoder, and image information decoding method and decoder

摘要

It is an object of the present invention to provide a method and apparatus capable of correcting a phase shift of a color-difference signal, caused by a motion estimation and compensation, to improve the quality of output image of compressed image information. With the present invention, decompression including motion compensation is made of a string of image compressed-codes by breaking (38) an input image signal in a format of 4 : 2 : 0 including a luma signal and chroma signal into macro-blocks and making motion estimation and compensation of the input image signal in units of a macro-block, wherein, when a current macro-block is a field macro-block and when a reference field has a different parity from a current field, the phase of the chroma signal by 1/4 of the value mv of the vertical component in motion vector information.