Abstract: A loop filtering method and apparatus are provided. The loop filtering method includes: calculating blocking effect strength based on coding type information, which specifies the coding type of a block to be filtered, a motion vector of the block, and reference frame information, which identifies a reference frame; determining a filtering unit to be used for filtering the block based on the calculated blocking effect strength; and performing filtering on the block using the determined filtering unit. Accordingly, it is possible to provide high-quality HDTV images by determining whether to perform loop filtering and adjusting the degree of loop filtering in consideration of the characteristics of HDTV images.

Abstract: An integer transform method for image data compression in a video codec is provided. In compliance with the first Audio and Video Coding Standard (AVS) of China in which 8×8 DCT integer transform is adopted, an integer transform base selection method, which is used to evaluate the quality of transform bases with both de-correlation efficiency and energy concentration efficiency, is provided. Computation complexity is also considered in the selection procedure. Based on the method, two groups of 8×8 transform bases (5, 6, 4, 1) and (4, 5, 3, 1) are selected and a fast transform algorithm for these two groups is provided.

Abstract: A loop filtering method and apparatus are provided. The loop filtering method includes: calculating blocking effect strength based on coding type information, which specifies the coding type of a block to be filtered, a motion vector of the block, and reference frame information, which identifies a reference frame; determining a filtering unit to be used for filtering the block based on the calculated blocking effect strength; and performing filtering on the block using the determined filtering unit. Accordingly, it is possible to provide high-quality HDTV images by determining whether to perform loop filtering and adjusting the degree of loop filtering in consideration of the characteristics of HDTV images.