1. An image decoding apparatus, comprising: circuitry configured to: generate a difference image based on a difference between a first motion compensation image and a second motion compensation image; increase a resolution of the difference image; filter, by a filtering process, at least one motion compensation image based on the difference image that has the increased resolution and based on a correlation in a time direction that is included in the first motion compensation image and the second motion compensation image, wherein each of the first motion compensation image and the second motion compensation image is in a first layer; and generate a prediction image in a second layer based on the filtering process on the at least one motion compensation image.