| CPC H04N 19/196 (2014.11) [H04N 19/12 (2014.11); H04N 19/176 (2014.11); H04N 19/463 (2014.11); H04N 19/60 (2014.11); H04N 19/70 (2014.11)] | 13 Claims |

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1. A method of decoding an image, the method comprising:
determining whether an inverse transform is skipped for a current block;
decoding, based on a rice parameter, information on a residual coefficient of the current block;
reconstructing the residual coefficient based on the information; and
obtaining a residual sample of the current block from the residual coefficient,
wherein the rice parameter for the residual coefficient is obtained by:
deriving an initial sum of absolute value variable based on a sum of absolute values of reference residual coefficients;
obtaining a shifting parameter based on the initial sum of absolute value variable;
obtaining a sum of absolute value variable by updating the initial sum of absolute value variable based on the shifting parameter;
obtaining, based on the sum of absolute value variable, an initial rice parameter from a rice parameter mapping table; and
obtaining the rice parameter by updating the initial rice parameter based on the shifting parameter,
wherein the shifting parameter is one of a plurality of shifting parameter candidates, and
wherein a selection of the one from the plurality of shifting parameter is based on an interval to which the initial sum of absolute value variable belongs among a plurality of intervals.
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