Encoding device, decoding device, encoding method, and decoding method for coding efficiency

摘要

According to an embodiment, an encoding device includes a deriving unit and an encoding unit. The deriving unit is configured to derive a first reference value based on fixed point precision representing roughness of a weighting factor that is used for multiplying a reference image. The encoding unit is configured to encode a first difference value that is a difference value between the weighting factor and the first reference value and the fixed point precision. The weighting factor is included in a first range of predetermined bit precision having the first reference value at approximate center. The first difference value is in the predetermined range.

主权项

1. A decoding device comprising:
processing circuitry configured to: decode fixed point precision representing precision of a weighting factor that is used for multiplying a reference image; determine a first reference value based on the fixed point precision; decode the weighting factor by adding the first reference value to a first difference value that is a difference value between the weighting factor and the first reference value; determine a second reference value of an offset to be added to the reference image for correcting the pixel value, by subtracting a value obtained by both multiplying a median value of a maximum pixel value by the weighting factor and shifting to right for a bit or bits of the fixed point precision, from the median value; and decode the offset by adding the second reference value to a second difference value that is a difference value between the offset and the second reference value, wherein the first difference value is included in a first range of given bit precision, the first range having 0 at an approximate center, and the second difference value is included in a second range of given bit precision, the second range having a given value as approximate center.