Image decoding method for residual data coding in image coding system, and apparatus therefor

An image encoding method, performed by an encoding apparatus, the method comprising:

• deriving prediction samples and residual samples of a current block;
• deriving transform coefficients for the residual samples of the current block;
• generating syntax elements for a first transform coefficient to an n-th transform coefficient of the current block, wherein the syntax elements are syntax elements according to a first residual data coding structure of Transform Skip Residual Coding (TSRC);
• generating syntax elements for an n+1th transform coefficient to a last transform coefficient of the current block, wherein the syntax elements are syntax elements according to a second residual data coding structure of the TSRC;
• encoding image information including prediction related information of the current block, the syntax elements according to the first residual data coding structure and the syntax elements according to the second residual data coding structure,
• wherein a number of context-coded syntax elements for the first transform coefficient to the n-th transform coefficient is equal to a maximum number of context coded bins of the current block, and
• wherein the syntax elements according to the second residual data coding structure include coefficient level information and a sign flag for a transform coefficient.

A non-transitory computer-readable storage medium storing a bitstream generated by a method, the method comprising:

• deriving prediction samples and residual samples of a current block;
• deriving transform coefficients for the residual samples of the current block;
• generating syntax elements for a first transform coefficient to an n-th transform coefficient of the current block, wherein the syntax elements are syntax elements according to a first residual data coding structure of Transform Skip Residual Coding (TSRC);
• generating syntax elements for an n+1th transform coefficient to a last transform coefficient of the current block, wherein the syntax elements are syntax elements according to a second residual data coding structure of the TSRC;
• encoding image information including prediction related information of the current block, the syntax elements according to the first residual data coding structure and the syntax elements according to the second residual data coding structure;
• and
• generating the bitstream including the image information,
• wherein a number of context-coded syntax elements for the first transform coefficient to the n-th transform coefficient is equal to a maximum number of context coded bins of the current block, and
• wherein the syntax elements according to the second residual data coding structure include coefficient level information and a sign flag for a transform coefficient.