CPC H04N 19/105 (2014.11) [H04N 19/109 (2014.11); H04N 19/167 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/46 (2014.11)] | 13 Claims |
1. An image decoding method, comprising:
determining an inter-component prediction mode of a chroma component block based on an inter-component prediction mode list and predetermined index information, wherein the inter-component prediction mode list is configured with k inter-component prediction modes;
downsampling reference samples for inter-component prediction of the chroma component block based on the determined inter-component prediction mode;
classifying the downsampled reference samples into a first group and a second group, wherein the first group represents a minimum value group of first downsampled reference samples having relatively small values among the downsampled reference samples and the second group represents a maximum value group of second downsampled reference samples having relatively large values among the downsampled reference samples;
obtaining a first average value between the first downsampled reference samples in the first group and a second average value between the second downsampled reference samples in the second group;
calculating a difference between the first average value and the second average value;
deriving a parameter of a linear prediction model based on the difference between the first average value of the first group and the second average value of the second group; and
performing the inter-component prediction on the chroma component block by using the parameter of the linear prediction model,
wherein a filter for the downsampling is variably determined depending on whether a top boundary of a luma component block corresponding to the chroma component block is on a top boundary of a coding tree unit (CTU) to which the luma component block belongs.
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