To propose an error concealment method for providing a higher image quality in the event of a decode error in a decoder of an H.264 coding system.

The method changes the values of a Filter Offset A and a Filter Offset B to a maximum or a higher value, this allows the values of an index A and an index B to be changed to a maximum or a higher value. Hence, if the difference between luminance values or color difference values is a little, the edges of the boundary are smoothed by possibly filtering it and, because of a very large difference between luminance values or color difference values at portions of the boundary of an essentially proper image, they are possibly not filtered to thereby obtain a good quality image.