METHOD AND APPARATUSES OF VIDEO ENCODING IN VIDEO ENCODING SYSTEM

Video encoding methods and apparatuses include receiving reconstructed video samples, determining an initial clipping setting for ALF coefficients, deriving clipping setting candidates from the initial clipping setting. ALF coefficients for the initial clipping setting and the clipping setting candidates are derived by solving inverse matrices, where partial intermediate results of solving ALF coefficients are shared by two or more clipping settings. A distortion value corresponds to the derived ALF coefficients for each clipping setting is computed, and final clipping indices for final ALF coefficients are determined according to the distortion values. ALF filtering is applied to the reconstructed video samples based on the final ALF coefficients and the final clipping indices.