Patent ID: 7639742

Claim:
An image information encoding method of an image information encoder, in which image information is compression-encoded by breaking an input image signal including a brightness signal and color-difference signal into blocks and making motion estimation and compensation of the input image signal in units of a block, the method comprising: shifting, with a phase correction unit of the image information encoder, for motion estimation and compensation, a phase of the color-difference signal in a reference image block adaptively based on a selected motion estimate mode and a selection between values mv of vertical components in motion vector information in which the values mv approximate the motion estimation so that the reference image block upon comparison coincides in phase of the color-difference signal with an input image block, wherein the input image signal is an interlaced image in a format of 4:2:0, and the motion estimate mode includes a frame motion estimate/compensate mode and field motion estimate/compensate mode, either of which is selected for each macro block as an encoding unit including the blocks, the motion estimate mode is the field motion estimate/compensate mode, when, of first and second fields forming together a frame, one for a reference image and the other for an input image are the same as each other, the color-difference signal is phase-shifted by ½ of the value mv of the vertical component in motion vector information, when the reference image is the second field while the input image is the first field, the color-difference signal is phase-shifted by mv/2−¼ of the value mv of the vertical component in motion vector information, and when the reference image is the first field while the input image is the second field, the color-difference signal is phase-shifted by mv/2+¼ of the value mv of the vertical component in motion vector information.