Encoding device, encoding method, decoding device, decoding method, and generation method

An encoding method comprising:

• dividing an encoding unit of an image into a plurality of regions;
• generating, for each boundary that partitions each of the plurality of regions along a direction which crosses a line, a boundary header used to identify the boundary;
• generating a piece of trajectory information representing a displacement of the boundary associated with progress of the line;
• and
• when generating encoded data including the generated boundary headers and the generated pieces of trajectory information, changing, in accordance with the number of boundaries, a manner in which the generated boundary headers and the generated pieces of trajectory information are aligned.

A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute a method, the method comprising:

• dividing an encoding unit of an image into a plurality of regions;
• generating, for each boundary that partitions each of the plurality of regions along a direction which crosses a line, a boundary header used to identify the boundary;
• generating a piece of trajectory information representing a displacement of the boundary associated with progress of the line;
• and
• when generating encoded data including the generated boundary headers and the generated pieces of trajectory information, changing, in accordance with the number of boundaries, a manner in which the boundary headers and the pieces of trajectory information are aligned.

A decoding device configured to decode encoded data including a boundary header used to identify a boundary that partitions each of a plurality of regions obtained by dividing an encoding unit of an image along a direction which crosses a line, and a piece of trajectory information representing a displacement of the boundary associated with progress of the line and output the image, comprising:

• a separation unit configured to separate the encoded data into the boundary headers and the pieces of trajectory information;
• a decision unit configured to decide, in accordance with the number of boundaries, whether to store all the boundary headers in a holding unit all at once;
• and
• a decoding unit configured to decode, for each line, the line based on the boundary header held by the holding unit.

A decoding method of decoding encoded data including a boundary header used to identify a boundary that partitions each of a plurality of regions obtained by dividing an encoding unit of an image along a direction which crosses a line, and a piece of trajectory information representing a displacement of the boundary associated with progress of the line and outputting the image, the method comprising:

• separating the encoded data into the boundary headers and the pieces of trajectory information;
• deciding, in accordance with the number of boundaries, whether to store all the boundary headers in a holding unit all at once;
• and
• decoding, for each line, the line based on the boundary header held by the holding unit.

A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute a decoding method of decoding encoded data including a boundary header used to identify a boundary that partitions each of a plurality of regions obtained by dividing an encoding unit of an image along a direction which crosses a line, and a piece of trajectory information representing a displacement of the boundary associated with progress of the line and outputting the image, the method comprising:

• separating the encoded data into the boundary headers and the pieces of trajectory information;
• deciding, in accordance with the number of boundaries, whether to store all the boundary headers in a holding unit all at once;
• and
• decoding, for each line, the line based on the boundary header held by the holding unit.

A method of generating encoded data including a boundary header used to identify a boundary that partitions each of a plurality of regions obtained by dividing an encoding unit of an image along a direction which crosses a line, and a piece of trajectory information representing a displacement of the boundary associated with progress of the line, the method comprising:

• if the number of boundaries is larger than a predetermined number, generating a first bit string representing the predetermined number of boundary headers;
• arranging a second bit string representing the trajectory information corresponding to a first line next to the first bit string;
• and
• arranging at least one bit string representing the remaining boundary headers next to the second bit string.