CPC H04N 19/647 (2014.11) [H04N 19/124 (2014.11); H04N 19/13 (2014.11); H04N 19/176 (2014.11); H04N 19/70 (2014.11); H04N 19/91 (2014.11); H04N 19/513 (2014.11); H04N 19/619 (2014.11); H04N 19/64 (2014.11)] | 14 Claims |
1. An image decoding method performed by a decoding apparatus, comprising:
deriving transform coefficients for a current block based on residual information received from a bitstream;
deriving dequantized transform coefficients for the current block based on the transform coefficients;
deriving residual samples for the current block based on the dequantized transform coefficients; and
generating a reconstructed picture based on the residual samples for the current block,
wherein the current block includes a low frequency transform coefficient region including at least one non-zero transform coefficient and a region including only one or more zero transform coefficients other than the low frequency transform coefficient region,
wherein the residual information includes last significant coefficient prefix information and last significant coefficient suffix information on a position of a last non-zero transform coefficient among the transform coefficients for the current block,
wherein the last significant coefficient prefix information includes column position prefix information and row position prefix information,
wherein a maximum value of the column position prefix information is determined based on a width of the low frequency transform coefficient region,
wherein a maximum length of a first codeword for the column position prefix information is determined based on the width of the low frequency transform coefficient region,
wherein a maximum value of the row position prefix information is determined based on a height of the low frequency transform coefficient region, and
wherein a maximum length of a second codeword for the row position prefix information is determined based on the height of the low frequency transform coefficient region.
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