Image coding apparatus, image coding method, and program, and image decoding apparatus, image decoding method, and program

An image decoding apparatus configured to decode encoded data generated by encoding image data, the image decoding apparatus comprising:

• an acquiring unit configured to acquire information on a minimum area size related to a quantization parameter and information on a block size of a block included in an image;
• and
• a decoding unit configured to decode a difference value for a quantization parameter capable of being shared in decoding processes for a block group including a plurality of blocks,
• wherein a size of each of the plurality of blocks is smaller than the minimum area size,
• wherein the plurality of blocks includes at least both of a first block and a second block processed subsequent to the first block,
• wherein the decoding unit is configured to decode the difference value in processing of the first block, in a case where the first block contains a coefficient value not equal to 0 and a split flag for the first block indicates that the first block is not split, and
• wherein the decoding unit is configured to decode the difference value in processing of the second block, in a case where the second block contains a coefficient value not equal to 0 and the difference value has not been decoded in the processing of the first block and a split flag for the second block indicates that the second block is not split.

A method for an image encoding apparatus, comprising:

• determining a block size of a block included in an image;
• encoding information on a minimum area size related to a quantization parameter;
• and
• encoding a difference value for a quantization parameter capable of being shared in encoding processes for a block group including a plurality of blocks,
• wherein a size of each of the plurality of blocks is smaller than the minimum area size,
• wherein the plurality of blocks includes at least both of a first block and a second block processed subsequent to the first block,
• wherein the encoding the difference value encodes the difference value in processing of the first block, in a case where the first block contains a coefficient value not equal to 0 and a split flag for the first block indicates that the first block is not split, and
• wherein the encoding the difference value encodes the difference value in processing of the second block, in a case where the second block contains a coefficient value not equal to 0 and the difference value has not been encoded in the processing of the first block and a split flag for the second block indicates that the second block is not split.

A non-transitory computer-readable storage medium storing instructions for causing a computer to perform a process comprising:

• determining a block size of a block included in an image;
• encoding information on a minimum area size related to a quantization parameter;
• and
• encoding a difference value for a quantization parameter capable of being shared in encoding processes for a block group including a plurality of blocks,
• wherein a size of each of the plurality of blocks is smaller than the minimum area size,
• wherein the plurality of blocks includes at least both of a first block and a second block processed subsequent to the first block,
• wherein the encoding the difference value encodes the difference value in processing of the first block, in a case where the first block contains a coefficient value not equal to 0 and a split flag for the first block indicates that the first block is not split, and
• wherein the encoding the difference value encodes the difference value in processing of the second block, in a case where the second block contains a coefficient value not equal to 0 and the difference value has not been encoded in the processing of the first block and a split flag for the second block indicates that the second block is not split.

A method for an image decoding apparatus, comprising:

• acquiring information on a minimum area size related to a quantization parameter and information on a block size of a block included in an image;
• and
• decoding a difference value for a quantization parameter capable of being shared in decoding processes for a block group including a plurality of blocks,
• wherein a size of each of the plurality of blocks is smaller than the minimum area size,
• wherein the plurality of blocks includes at least both of a first block and a second block processed subsequent to the first block,
• wherein the decoding the difference value decodes the difference value in processing of the first block, in a case where the first block contains a coefficient value not equal to 0 and a split flag for the first block indicates that the first block is not split, and
• wherein the decoding the difference value decodes the difference value in processing of the second block, in a case where the second block contains a coefficient value not equal to 0 and the difference value has not been decoded in the processing of the first block and a split flag for the second block indicates that the second block is not split.

Anon-transitory computer-readable storage medium storing instructions for causing a computer to perform a process comprising:

• acquiring information on a minimum area size related to a quantization parameter and information on a block size of a block included in an image;
• and
• decoding a difference value for a quantization parameter capable of being shared in decoding processes for a block group including a plurality of blocks,
• wherein a size of each of the plurality of blocks is smaller than the minimum area size,
• wherein the plurality of blocks includes at least both of a first block and a second block processed subsequent to the first block,
• wherein the decoding the difference value decodes the difference value in processing of the first block, in a case where the first block contains a coefficient value not equal to 0 and a split flag for the first block indicates that the first block is not split, and
• wherein the decoding the difference value decodes the difference value in processing of the second block, in a case where the second block contains a coefficient value not equal to 0 and the difference value has not been decoded in the processing of the first block and a split flag for the second block indicates that the second block is not split.