Encoder and method for encoding

An encoder comprising:

• a plurality of first processors each configured to
• encode one of a plurality of slices obtained by dividing image information;
• and
• a second processor configured to:
• generate reduced image information by reducing the image information;
• determine that a first block is a preferential object block when it is determined, based on a direction of a motion vector of the first block, that the first block is a block to be encoded with reference to a block included in a second reduced slice adjacent to a first reduced slice among a plurality of reduced slices obtained by dividing the reduced image information, the first block being included in the first reduced slice;
• and
• perform, when it is determined that the first block is a preferential object block, a control to reduce a first quantization parameter used by one of the plurality of first processors to encode a block corresponding to the first block among a plurality of blocks included in a first slice corresponding to the first reduced slice.