Video coding device, video coding method, and video decoding device

A video coding method executed by a video coding device,

• the video coding method comprising:
• dividing a coding target image contained in a video into a plurality of regions to generate region information that indicates the plurality of regions;
• generating reference constraint information that asymmetrically defines a reference constraint when information on a block in a second region is referred to from a block in a first region at one of boundaries between the first region and the second region among the plurality of regions, and a reference constraint when information on the block in the first region is referred to from the block in the second region at the one of boundaries;
• generating a determination result that indicates whether to refer to information on an adjacent block adjacent to a coding target block, based on a positional relationship between the coding target block and the adjacent block, and the reference constraint information;
• coding the coding target block in accordance with the determination result;
• and
• coding the region information, the reference constraint information, and one of coding results for the coding target block,
• by the video coding device.

A video decoding device comprising:

• a memory;
• and
• a processor coupled to the memory and configured to:
• decode a coded video to restore region information that indicates a plurality of regions in a coded image contained in the coded video, restores reference constraint information that asymmetrically defines a reference constraint when information on a block in a second region is referred to from a block in a first region at one of boundaries between the first region and the second region among the plurality of regions, and a reference constraint when information on the block in the first region is referred to from the block in the second region at the one of boundaries;
• restore a decoding target code that indicates coded blocks in the coded image;
• divides the coded image into the plurality of regions based on the region information;
• generate a determination result that indicates whether to refer to information on an adjacent block adjacent to one of the coded blocks, based on a positional relationship between the one of the coded blocks and the adjacent block, and the reference constraint information;
• and
• decode the decoding target code in accordance with the determination result.