CPC H04N 19/11 (2014.11) [H04N 19/176 (2014.11); H04N 19/61 (2014.11)] | 7 Claims |
1. An apparatus for decoding an image signal, comprising:
a memory;
at least one processor connected to the memory, the at least one processor configured to:
determine a modified intra prediction mode of a current block from an intra prediction mode, based on a ratio between a width and height of the current block and the intra prediction mode,
determine an inverse non-separable transform set based on the modified intra prediction mode, and
apply an inverse non-separable transform matrix selected from the inverse non-separable transform set to a top-left region of the current block determined based on the width and height of the current block,
wherein the at least one processor is further configured to determine an index of the inverse non-separable transform set related to the modified intra prediction mode,
wherein based on that the modified intra prediction mode is greater than or equal to 0 and less than or equal to 1, the index is determined as a first index value,
wherein based on that the modified intra prediction mode is greater than or equal to 2 and less than or equal to 12, the index is determined as a second index value,
wherein based on that the modified intra prediction mode is greater than or equal to 13 and less than or equal to 23, the index is determined as a third index value,
wherein based on that the modified intra prediction mode is greater than or equal to 24 and less than or equal to 44, the index is determined as a fourth index value,
wherein based on that the modified intra prediction mode is greater than or equal to 45 and less than or equal to 55, the index is determined as the third index value,
wherein based on that the modified intra prediction mode is greater than or equal to 56, the index is determined as the second index value, and
wherein based on that the modified intra prediction mode is less than 0, the index is determined as the second index value.
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