RECORDING MEDIUM HAVING RECORDED THEREON CODED INFORMATION USING PLUS AND/OR MINUS ROUNDING OF IMAGES

摘要

A computer-readable medium having stored thereon an image decoding program which, when executed by a computer, implements operations including: extracting motion vector information, and rounding method information from input information to be decoded; synthesizing a prediction image by performing motion compensation using the motion vector information and a reference image which is a previously decoded image; and synthesizing a decoded image by adding the prediction image to an error image; wherein a rounding method used for pixel value interpolation in performing the motion compensation for synthesizing the prediction image is one of a positive rounding method and a negative rounding method which is different from a one of a positive rounding method and a negative rounding method used for pixel value interpolation in performing the motion compensation for synthesizing a last prediction image.

主权项

1. An image decoder comprising
a memory to store a reference image which is a previously decoded image; and a synthesizer to receive an encoded bitstream including information of images, and execute motion compensation by synthesizing a predicted image of a current frame using motion vector information included in the encoded bitstream and the reference image; wherein the synthesizing a prediction image is performable using a positive rounding method and a negative rounding method for interpolating intensity values of pixels; wherein the interpolating intensity values of pixels is performed using a rounding method specified by the rounding method information; wherein the rounding method information is included in coded information of the currently decoded image; and wherein the rounding method information is included in a header section of the coded information of the currently decoded image.