IMAGE ENCODING AND DECODING METHOD AND APPARATUS

摘要

PURPOSE: A method and an apparatus for encoding and decoding an image are provided to generate an inversely proportional value to a variable td based on an offset value by arithmetic right shift of the absolute value of the variable td, and compute a scaling factor based on the variable td and the inversely proportional value to the variable td, thereby enhancing image encoding/decoding efficiency. CONSTITUTION: A prediction block generator (111,112) determines whether to scale a motion vector of a reference block based on a reference picture of a current block and a picture order count (POC) value of a reference picture of the reference block which is used for inter prediction of the current block. If it is determined to perform the scaling, the prediction block generator computes variables td and tb based on POC difference between the said pictures, produces an offset value by an arithmetic right shift of the absolute value of the variable td by a binary digit 1, produces an inversely proportional value to the variable td using the offset value, and calculates a scaling factor based on the variable td and the inversely proportional value of the variable td. [Reference numerals] (111) Motion prediction unit; (112) Motion compensation unit; (120) Intra prediction unit; (130) Conversion unit; (140) Quantization unit; (150) Entropy encoding unit; (160) Inverse quantization unit; (170) Inverse conversion unit; (180) Filter unit; (190) Reference image buffer; (AA) Input image; (BB) Inter; (CC) Intra; (DD) Bit stream