Method and device for entropy coding/decoding

An entropy decoding method, by a decoding apparatus, comprising:

• deriving a current luma transform block from a current coding block;
• deriving context information on a bin constituting a codeword of a syntax element cbf_luma that specifies whether a luma residual other than 0 is present in a current luma transform block;
• performing an arithmetic decoding on the bin based on the derived context information;
• and
• deriving a value of the syntax element cbf_luma based on the decoded bin,
• wherein the step of deriving the context information includes deriving the context information based on information on a transform depth (trafoDepth) of the current luma transform block,
• wherein a luma residual other than 0 is not present in the current luma transform block when the derived value of the syntax element cbf_luma is 0, and
• wherein at least one luma residual other than 0 is present in the current luma transform block when the derived value of the syntax element cbf_luma is 1.

A decoding apparatus performing an entropy decoding, comprising:

• an entropy decoding module for deriving a current luma transform block from a current coding block, for deriving context information on a bin constituting a codeword of a syntax element cbf_luma that specifies whether a luma residual other than 0 is present in a current luma transform block, for performing an arithmetic decoding on the bin based on the derived context information, and for deriving a value of the syntax element cbf_luma based on the decoded bin,
• a video reconstructing module for generating a reconstructed picture based on the value of the syntax element cbf_luma
• wherein the entropy decoding module derives the context information based on information on a transform depth (trafoDepth) of the current luma transform block,
• wherein a luma residual other than 0 is not present in the current luma transform block when the derived value of the syntax element cbf_luma is 0, and
• wherein at least one luma residual other than 0 is present in the current luma transform block when the derived value of the syntax element cbf_luma is 1.