Encoding method, decoding method, encoder, and decoder

A decoder, comprising:

• circuitry;
• and
• memory,
• wherein when the circuitry performs, using the memory, a normal inter prediction mode in which a plurality of motion vector precisions are selectively used,
• the circuitry:
• selects a motion vector precision for a current block from the plurality of motion vector precisions;
• generates, with reference to a motion vector of a neighboring block which has been processed in the current block, an intermediate motion vector (MV) predictor list in which one or more motion vector predictor candidates are registered, the one or more motion vector predictor candidates having a same motion vector precision;
• performs a rounding process on each of the one or more motion vector predictor candidates registered in the intermediate MV predictor list so that the one or more motion vector predictor candidates have the motion vector precision selected;
• selects a motion vector predictor from a final MV predictor list obtained by performing the rounding process;
• and
• performs a motion compensation process on the current block, using a motion vector which is an added value obtained by adding the motion vector predictor selected and a motion vector difference.

An encoding method for encoding video, the encoding method comprising:

• when performing a normal inter prediction mode in which a plurality of motion vector precisions are selectively used,
• selecting a motion vector precision for a current block from the plurality of motion vector precisions;
• generating, with reference to a motion vector of a neighboring block which has been processed in the current block, an intermediate motion vector (MV) predictor list in which one or more motion vector predictor candidates are registered, the one or more motion vector predictor candidates having a same motion vector precision regardless of the motion vector precision selected from the plurality of motion vector precisions;
• performing a rounding process on each of the one or more motion vector predictor candidates registered in the intermediate MV predictor list so that the one or more motion vector predictor candidates have the motion vector precision selected;
• selecting a motion vector predictor from a final MV predictor list obtained by performing the rounding process;
• and
• performing a motion compensation process on the current block, using a motion vector which is an added value obtained by adding the motion vector predictor selected and a motion vector difference.

A decoding method for decoding video, the decoding method comprising:

• when performing a normal inter prediction mode in which a plurality of motion vector precisions are selectively used,
• selecting a motion vector precision for a current block from the plurality of motion vector precisions;
• generating, with reference to a motion vector of a neighboring block which has been processed in the current block, an intermediate motion vector (MV) predictor list in which one or more motion vector predictor candidates are registered, the one or more motion vector predictor candidates having a same motion vector precision regardless of the motion vector precision selected from the plurality of motion vector precisions;
• performing a rounding process on each of the one or more motion vector predictor candidates registered in the intermediate MV predictor list so that the one or more motion vector predictor candidates have the motion vector precision selected;
• selecting a motion vector predictor from a final MV predictor list obtained by performing the rounding process;
• and
• performing a motion compensation process on the current block, using a motion vector which is an added value obtained by adding the motion vector predictor selected and a motion vector difference.