Method and apparatus for deriving rice parameter in video/image coding system

A video encoding method performed by an encoding apparatus, the method comprising:

• generating at least one of information representing a level value of a target transform coefficient in a current transform block or information representing a residual level value;
• deriving a rice parameter for at least one of the information representing the level value of the target transform coefficient or the information representing the residual level value based on a neighboring transform coefficient of the target transform coefficient;
• deriving a bin string for at least one of the information representing the level value of the target transform coefficient or the information representing the residual level value based on the rice parameter;
• and
• encoding the bin string,
• wherein the rice parameter is derived based on the number of available neighboring transform coefficients for the target transform coefficient and a level value of the available neighboring transform coefficient for the target transform coefficient.

A computer-readable digital storage medium including information causing a decoding apparatus to perform a video decoding method, the video decoding method comprising:

• obtaining residual information for a current transform block from a bitstream, the residual information including at least one of information representing a level value of a target transform coefficient in the current transform block or information representing a residual level value;
• deriving a rice parameter for at least one of the information representing the level value of the target transform coefficient or the information representing the residual level value based on a neighboring transform coefficient of the target transform coefficient;
• deriving a bin string for at least one of the information representing the level value of the target transform coefficient or the information representing the residual level value based on the rice parameter;
• and
• deriving the level value of the target transform coefficient based on the bin string,
• wherein the rice parameter is derived based on the number of available neighboring transform coefficients for the target transform coefficient and a level value of the available neighboring transform coefficient for the target transform coefficient.