Encoder, decoder, encoding method, and decoding method

A decoding method, comprising:

• in prediction residual decoding of a current block,
• decoding a plurality of flags by Context-Based Adaptive Binary Arithmetic Coding (CABAC) decoding, each of the plurality of flags relating to a coefficient included in the current block;
• determining a base level;
• calculating a prediction absolute value of the coefficient based on a sum of absolute values of five neighboring coefficients in the current block;
• deriving a rice parameter based on a difference between the prediction absolute value and the base level, wherein
• if the difference is below a first value, the rice parameter is set to zero,
• if the difference is equal to or larger than the first value and smaller than a second value, the rice parameter is set to one;
• decoding a remainder value of the coefficient using the derived rice parameter, wherein the remainder value and the base level are used to obtain an absolute value of the coefficient;
• and
• decoding a sign flag indicating whether the coefficient has a positive value or a negative value if the absolute value of the coefficient is more than zero.