Patent ID: 11943474
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An apparatus for decoding a video signal, comprising:
a memory configured to store the video signal; and
a processor coupled with the memory,
wherein the processor is configured to:
obtain an intra prediction mode of a current block from the video signal;
determine a modified intra prediction mode from the intra prediction mode for the current block based on a width and a height of the current block and the intra prediction mode;
determine a non-separable transform set index based on the modified intra prediction mode;
derive a non-separable transform matrix based on the non-separable transform set index and a non-separable transform index; and
apply the non-separable transform matrix to the current block,
wherein the processor is configured to determine the modified intra prediction mode by adding 65 to the intra prediction mode, when (i) the width is larger than the height, (ii) the intra prediction mode is equal to or larger than 2, and (iii) the intra prediction mode is smaller than a first reference value,
wherein the processor is configured to determine the modified intra prediction mode by subtracting 67 from the intra prediction mode, when (i) the height is larger than the width, (ii) the intra prediction mode is larger than a second reference value, and (iii) the intra prediction mode is equal to or smaller than 66, and
wherein the processor is configured to determine the non-separable transform set index:
as 1 when the modified intra prediction mode is smaller than 0,
as 0 when the modified intra prediction mode is equal to or larger than 0 and equal to or smaller than 1,
as 1 when the modified intra prediction mode is equal to or larger than 2 and equal to or smaller than 12,
as 2 when the modified intra prediction mode is equal to or larger than 13 and equal to or smaller than 23,
as 3 when the modified intra prediction mode is equal to or larger than 24 and equal to or smaller than 44,
as 2 when the modified intra prediction mode is equal to or larger than 45 and equal to or smaller than 55, and
as 1 when the modified intra prediction mode is equal to or larger than 56 and equal to or smaller than 80.