BACKGROUND

1. Technical Field

The present disclosure relates to an encoder, a decoder, an encoding method, and a decoding method.

2. Description of the Related Art

There has been H.265 as the video coding standard. H.265 is also referred to as High-Efficiency Video Coding (HEVC).

SUMMARY

An encoder according to an aspect of the present disclosure includes circuitry and memory. Using the memory, the circuitry: in inter prediction for a current block, determines a base motion vector, and writes, in an encoded signal, a delta motion vector representing (i) one direction among a plurality of directions including a diagonal direction and (ii) a distance from the base motion vector; and encodes the current block using the delta motion vector and the base motion vector.

A decoder according to an aspect of the present disclosure includes circuitry and memory. Using the memory, the circuitry: in inter prediction for a current block, determines a base motion vector, and parses a delta motion vector representing (i) one direction among a plurality of directions including a diagonal direction and (ii) a distance from the base motion vector; and decodes the current block using the delta motion vector and the base motion vector.

Note that these general and specific aspects may be implemented using a system, a device, a method, an integrated circuit, a computer program, a computer-readable recording medium such as a CD-ROM, or any combination of systems, devices, methods, integrated circuits, computer programs or recording media.

Additional benefits and advantages of the disclosed embodiments will be apparent from the Specification and Drawings. The benefits and/or advantages may be individually obtained by the various embodiments and features of the Specification and Drawings, which need not all be provided in order to obtain one or more of such benefits and/or advantages.

