A method of filtering reconstructed video data including inputting a reconstructed luma picture sample array, setting a luma location corresponding to a current chroma sample to a location defined by a horizontal location in the chroma sample multiplied by a sub-width value and a vertical location in the chroma sample multiplied by a sub-height value, deriving luma sample locations inside the reconstructed luma picture sample array by using the luma location, and deriving a variable by using cross-component filter coefficients and the reconstructed luma picture sample array defined by at least one of the luma sample locations. The variable is modified by using a current chroma block of samples.