Apparatus and method for filtering in video coding

The present disclosure relates a filter, to an encoder and a decoder using the filter, to a filtering method and a corresponding program, as well as to encoding and decoding using the filtering method or the filter. The filtering includes obtaining of an extended reconstructed block by extending the current reconstructed block to include at least padding samples from the current reconstructed block. After the padding, a current pixel of the extended reconstructed block and its neighboring pixels are loaded into a linear buffer and transformed with a 1D transform. The filtering is performed in frequency domain using a look-up table and the filtered pixels are transformed back.