1. A method of removing a blocking phenomenon using properties of two blocks in a loop filtering system, comprising: determining whether at least one of a first block and a second block has non-zero transform coefficient information, and the second block being adjacent to the first block, determining a filter strength value in consideration of a presence of the non-zero transform coefficient information, determining coefficients, for pixels on a block boundary between the first and second blocks, based on the filter strength value, calculating values of the pixels based on the determined coefficients, the calculating including performing a bit shift operation, and wherein the pixels on the block boundary are at least two pixels in the first block and at least two pixels in the second block, wherein the bit shift operation uses an integer wherein the integer is greater than 1.