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 predicted sample;
• and
• storing or outputting prediction information including motion information or an intra prediction mode of a coding block to which the geometric partitioning mode is applied, and a prediction type capable of determining whether inter prediction or intra prediction is applied, wherein
• the deriving the motion information includes:
• controlling whether or not to derive motion information by bi-prediction on a basis of a predetermined condition,
• generating the motion compensation sample using the derived motion information, and
• storing the motion information in the buffer.

A program stored on a non-transitory computer-readable medium for causing a computer to function as an image decoding device, the image decoding device comprising a circuit and a buffe, wherein

• a first process derives motion information for a geometric partitioning mode to generate a motion compensation sample;
• a second process derives an intra prediction mode for the geometric partitioning mode to generate an intra predicted sample;
• and
• the buffer stores or outputs prediction information including motion information or an intra prediction mode of a coding block to which the geometric partitioning mode is applied, and a prediction type capable of determining whether inter prediction or intra prediction is applied, wherein
• the first process:
• controls whether or not to derive motion information by bi-prediction on a basis of a predetermined condition,
• generates the motion compensation sample using the derived motion information, and
• store the motion information in the buffer.