Abstract: Object Known derivation, on a per intra prediction modes basis, of a template-based intra mode derivation based on a difference between a template prediction image and a template image has a problem that derivation of the template image and cost calculation require great computational resources. Solution Included are an intra prediction image generation unit configured to generate a template prediction image for an intra prediction mode candidate predetermined, a template cost derivation unit configured to derive a cost from the template prediction image and a template image corresponding to an image near a target block, and an intra prediction image generation unit configured to generate an intra prediction image by using a selected intra prediction mode, wherein the number of taps of an interpolation filter for the template prediction image is less than the number of taps of an interpolation filter for intra prediction.

Abstract: Object Known derivation, in units of intra prediction modes, of a template-based intra prediction mode based on a difference between a template prediction image and a template image has a problem that derivation of the template image and cost calculation require great computational resources. Solution An image decoding apparatus includes an intra prediction image generation unit configured to generate a template prediction image for a prescribed intra prediction mode candidate, a template cost derivation unit configured to derive a cost from the template prediction image and a template image corresponding to an image near a target block, and an intra prediction image generation unit configured to generate an intra prediction image by using a selected intra prediction mode, and a reference sample is sampled that is used to generate the template prediction image.