Decoding device and encoding device

The invention provides a decoding device and an encoding device. The decoding device is provided with: a processing circuit; and a memory connected with the processing circuit. The processing circuit uses the memory to perform luminance filtering processing on a first boundary between a first luminance block and a second luminance block and perform color difference filtering processing on a second boundary between a first color difference block and a second color difference block. In the luminance filtering process, the values of a plurality of luminance samples included in the first luminance block and the second luminance block arranged in a direction orthogonal to the first boundary are changed using a restriction process in which the amount of change in the values of the plurality of luminance samples does not exceed respective first threshold values set asymmetrically with respect to the first boundary, and in the color difference filtering process, the values of a plurality of color difference samples i