Derivation process of boundary filtering strength, and deblocking filtering method and apparatus using the derivation process

A deblocking filtering method comprising:

• a bS derivation process by a deblocking filtering apparatus for neighboring two blocks;
• and
• a process for applying filtering by the deblocking filtering apparatus with respect to pixel values of the two blocks according to the derived bS,
• wherein the bS derivation process comprises:
• determining whether at least one of two neighboring blocks is intra-coded;
• if neither of the blocks are intra-coded, determining whether at least one of the two blocks contains a transformed coefficient;
• if neither of the two blocks do contain a transformed coefficient, determining whether motion compensation for the two blocks is performed based on different reference frames or otherwise the absolute difference between the horizontal or vertical components of the two motion vectors of the two blocks is greater than or equal to 1;
• and
• if motion compensation for the two blocks is performed based on the identical reference frame and the absolute difference between the horizontal or vertical components of the two motion vectors of the two blocks is less than 1, determining whether the two blocks are coded by IC (illumination compensation) mode,
• wherein the determining whether the two blocks are coded by IC mode comprises determining whether both of the blocks are coded by IC mode and the blocks have different illumination change values, or only one of the two blocks is coded by IC, and,
• if both of the blocks are coded by IC mode and the blocks have different illumination change values, the bS of deblocking filtering for the boundary between both of the blocks is derived using a difference of illumination change values of the two blocks;
• and if only one of the two blocks is coded by IC mode, the bS of deblocking filtering for the boundary between both of the blocks is derived using the illumination change value of the block.