A decoding method performed by a decoding apparatus, according to embodiments of the present document, may comprise the steps of: acquiring, via a bitstream, image information including residual information; generating reconstructed samples of a current picture on the basis of the residual information; and generating modified reconstructed samples by performing an in-loop filtering procedure on the reconstructed samples of the current picture, wherein whether or not the in-loop filtering procedure is performed across virtual boundaries is determined. The virtual boundaries can bring, to the decoding apparatus, advantages from a hardware perspective.