Image decoding device, image decoding method, and program

An image decoding method comprising:

• deriving motion information for a geometric partitioning mode to generate a motion compensation sample;
• deriving an intra prediction mode for the geometric partitioning mode to generate an intra prediction sample, wherein
• the deriving of the intra prediction mode comprising:
• deriving a plurality of the intra prediction modes on the basis of adjacent reference samples or adjacent reference blocks adjacent to the block to be decoded, and
• selecting, with use of a signaled index, one or a plurality of intra prediction modes from an intra prediction mode candidate list including the plurality of derived intra prediction modes to generate the intra prediction sample.

A program stored on a non-transitory computer-readable medium for causing a computer to function as an image decoding device comprising a circuit:

• the circuit:
• derives motion information for a geometric partitioning mode to generate a motion compensation sample;
• and
• derives an intra prediction mode for the geometric partitioning mode to generate an intra prediction sample,
• the circuit:
• derives a plurality of the intra prediction modes on the basis of adjacent reference samples or adjacent reference blocks adjacent to the block to be decoded, and
• selects, with use of a signaled index, one or a plurality of intra prediction modes from an intra prediction mode candidate list including the plurality of derived intra prediction modes to generate the intra prediction sample.