Image encoding/decoding method and apparatus for performing in-loop filtering on basis of sub-picture structure, and method for transmitting bitstream

An image encoding apparatus comprising:

• a memory;
• and
• at least one processor connected to the memory, the at least one processor configured to:
• determine whether in-loop filtering is able to be performed across a boundary of a subpicture;
• and
• perform the in-loop filtering on a boundary of a current block based on a result of determination,
• wherein, based on the boundary of the current block being a boundary of a current subpicture including the current block, the in-loop filtering on the boundary of the current block is not performed, based on the first flag for the current subpicture specifying that the in-loop filtering is not able to be performed across the boundary of the current subpicture or the first flag for an adjacent subpicture adjacent to the boundary of the current block specifying that the in-loop filtering is not able to be performed across the boundary of the adjacent subpicture.

An apparatus for transmitting a bitstream for an image, the apparatus comprising:

• at least one processor configured to obtain the bitstream generated by an encoding apparatus;
• and
• a transmitter configured to transmit the bitstream;
• the bitstream is generated by:
• determining whether in-loop filtering is able to be performed across a boundary of a subpicture;
• and
• performing the in-loop filtering on a boundary of a current block based on a result of determination,
• wherein, based on the boundary of the current block being a boundary of a current subpicture including the current block, the in-loop filtering on the boundary of the current block is not performed, based on the first flag for the current subpicture specifying that the in-loop filtering is not able to be performed across the boundary of the current subpicture or the first flag for an adjacent subpicture adjacent to the boundary of the current block specifying that the in-loop filtering is not able to be performed across the boundary of the adjacent subpicture.