Image processing device and method with a scalable quantization matrix

An image processing device comprising:

• circuitry configured to
• set an initial difference coefficient that is a difference between a DC coefficient and a predetermined initial value, a replacement difference coefficient that is a difference between the DC coefficient and a (0, 0) coefficient located at the beginning of a first quantization matrix, and further difference coefficients each being a difference between two adjacent coefficients in a sequence of coefficients of the first quantization matrix arranged in scan order;
• quantize transform coefficient data using a second quantization matrix based on the first quantization matrix and generate quantized data;
• encode the quantized data to generate encoded data including the initial difference coefficient, and the difference coefficients;
• generate the encoded data including difference coefficients that are differences between coefficients of the first quantization matrix;
• generate the encoded data in a syntax in which the replacement difference coefficient and the difference coefficients are collectively included as a difference coefficient group, wherein the replacement difference coefficient and the difference coefficients are in the syntax of the encoded data in order of the replacement difference coefficient and the difference coefficients, and the circuitry is configured to encode the replacement difference coefficient and the difference coefficients in order of the replacement difference coefficient and the difference coefficients;
• and
• generate the encoded data including an initial difference value between the DC coefficient and an initial value set for a quantization matrix, wherein the initial difference value and the difference coefficient group are included in the syntax of the encoded data in order of the initial difference value and the difference coefficient group.