| CPC H04N 19/119 (2014.11) [H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11); H04N 19/96 (2014.11)] | 10 Claims |
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1. An image decoding method performed by an apparatus, the method comprising:
obtaining at least one coding unit including a current coding unit by hierarchically splitting a current image;
determining a code value for a difference quantization parameter for the current coding unit as a first value, when a first flag indicating whether signaling for the difference quantization parameter is to be enabled indicates that the signaling for the difference quantization parameter is enabled and a second flag indicating whether a predefined signaling scheme of the difference quantization parameter is to be used indicates that the predefined signaling scheme of the difference quantization parameter is used and a split flag indicating whether or not to split the current coding unit indicates that the current coding unit is split and a split type of the current coding unit is a ternary split type and a sum of a value resulting from applying log2 to a width of the current coding unit and a value resulting from applying log2 to a height of the current coding unit is equal to a value resulting from adding 1 to a value resulting from applying log2 to an area of a difference quantization parameter signaling unit;
obtaining the difference quantization parameter for the current coding unit based on information about a transform unit of the current coding unit, when the code value for the difference quantization parameter for the current coding unit is equal to the first value;
obtaining a quantization parameter for the current coding unit based on a predicted quantization parameter for the current coding unit and the difference quantization parameter for the current coding unit; and
obtaining a reconstructed block of the current coding unit, based on the quantization parameter for the current coding unit, wherein the split flag indicates one of a binary split type and the ternary split type when the split flag indicates that the current coding unit is split.
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