An inputted image is divided into a plurality of blocks, prediction errors are generated from pixels to be referred to, an orthogonal transform is performed on the prediction errors, transform coefficients are generated, quantization coefficients are generated by quantizing the generated transform coefficients by using a quantization matrix, the quantization coefficient is coded, the quantization matrix is coded, the quantization matrix is coded when the quantization matrix is not the same as a predetermined quantization matrix, and correspondence information indicating that the quantization matrix is the same as the predetermined quantization matrix is coded when the quantization matrix is the same as the predetermined quantization matrix.
CODING METHOD AND DECODING MEHTOD OF A QUANTIZATION MATRIX