Apparatus and method for filtering in video coding

An apparatus of a video encoder or a video decoder, comprising:

• a memory comprising instructions;
• and
• one or more processors in communication with the memory, wherein the one or more processors are configured to, when executing the instructions, carry out operations comprising:
• scanning, according to a predefined scan template, to obtain a current pixel of a block and neighboring pixels of the current pixel, wherein the block is a reconstructed block or a predicted block, and wherein the predefined scan template is defined as a set of spatial or raster offsets relative to a position of the current pixel inside the reconstructed block or the predicted block;
• obtaining spectrum components by performing transform for the current pixel and the neighboring pixels of the current pixel, wherein the transform is a Hadamard transform;
• obtaining filtered spectrum components based on a filtering parameter and the spectrum components when an absolute value of at least one of the spectrum components is less than a threshold;
• obtaining filtered pixels by performing inverse transform for the filtered spectrum components;
• and
• generating a filtered block based on the filtered pixels.