Image coding apparatus and image decoding apparatus

An image coding apparatus for coding coded data, the image coding apparatus comprising:

• a filter coefficient deriving circuit configured to derive a cross component filter coefficient from the coded data;
• a filter circuitry configured to apply an adaptive loop filter to a luminance image and a chrominance image, and output a filtered luminance image and a filtered chrominance image;
• a cross component filter circuit configured to derive an added value by using the luminance image and the cross component filter coefficient;
• a clipping circuit configured to derive a clipped value by clipping the added value within a range of a minimum value to a maximum value,
• wherein the minimum value is calculated by a formula −(1<<rangeCCBit), and the maximum value is calculated by a formula (1<<rangeCCBit)−1, wherein the rangeCCBit is a difference between a bit depth and a predetermined value;
• and
• an adding circuit configured to derive a modified filtered chrominance image by adding the clipped value to the filtered chrominance image.

An image decoding method for decoding coded data, the image decoding method comprising:

• deriving a cross component filter coefficient from the coded data;
• applying an adaptive loop filter to a luminance image and a chrominance image, and output a filtered luminance image and a filtered chrominance image;
• deriving an added value by using the luminance image and the cross component filter coefficient;
• clipping value by clipping the added value within a range of a minimum value to a maximum value,
• wherein the minimum value is calculated by a formula −(1<<rangeCCBit), and the maximum value is calculated by a formula (1<<rangeCCBit)−1, wherein the rangeCCBit is a difference between a bit depth and a predetermined value;
• and
• deriving a modified filtered chrominance image by adding the clipped value to the filtered chrominance image.