A method for video processing includes applying a sub-block residual coding scheme to a current video block, wherein the residual of the current video block is split into a plurality of sub-blocks each having a size of M*N, determining at least one sub-block with non-zero coefficients based on characteristic associated with each of the plurality of sub-blocks; coding the residue of the current video block based on the derived at least one sub-block with non-zero coefficients.