The invention relates to an encoding device, a decoding device, an encoding method, and a decoding method. This encoding device is provided with: a circuit that, during operation, stores a first parameter in a
bitstream, said first parameter indicating whether or not a
syntax element associated with a chroma tool offset exists in a picture parameter set; when the first parameter indicates that the
syntax element exists in the picture parameter set, (i) in addition to the
syntax element, one or more second parameters used in a
deblocking filter process of a chroma sample of an image to be processed are stored in the
bitstream, and if the first parameter indicates that the syntax element exists in the picture parameter set, one or more second parameters used in the
deblocking filter process of the chroma sample of the image to be processed are stored in the
bitstream. The image encoding method includes the steps of: (i) performing a
deblocking filter process using one or more first parameters, (ii) performing the deblocking filter process using the one or more second parameters, (iii) encoding the image to be processed, and if the first parameters indicate that the syntax elements do not exist in the picture parameter set, encoding the image to be processed without storing the one or more second parameters in the bitstream. And (iii) encoding the image to be processed without storing the one or more second parameters in the bitstream if the first parameters indicate that the syntax elements do not exist in the picture parameter set.