US 11,818,350 B2
Image coding method on basis of non-separable secondary transform and device therefor
Mehdi Salehifar, Seoul (KR); Seunghwan Kim, Seoul (KR); Jaehyun Lim, Seoul (KR); and Moonmo Koo, Seoul (KR)
Assigned to LG Electronics Inc., Seoul (KR)
Filed by LG Electronics Inc., Seoul (KR)
Filed on Jul. 14, 2022, as Appl. No. 17/864,666.
Application 17/864,666 is a continuation of application No. 17/316,049, filed on May 10, 2021, granted, now 11,627,320.
Application 17/316,049 is a continuation of application No. 16/901,857, filed on Jun. 15, 2020, granted, now 11,039,140, issued on Jun. 15, 2021.
Application 16/901,857 is a continuation of application No. PCT/KR2018/015812, filed on Dec. 13, 2018.
Claims priority of provisional application 62/599,021, filed on Dec. 15, 2017.
Prior Publication US 2022/0377336 A1, Nov. 24, 2022
Int. Cl. H04N 19/122 (2014.01); H04N 19/167 (2014.01); H04N 19/176 (2014.01); H04N 19/91 (2014.01)
CPC H04N 19/122 (2014.11) [H04N 19/167 (2014.11); H04N 19/176 (2014.11); H04N 19/91 (2014.11)] 14 Claims
OG exemplary drawing
 
1. A video decoding method performed by a decoding apparatus, comprising:
obtaining residual information for a target block from a bitstream;
deriving transform coefficients of the target block based on the residual information;
scanning (R+1)th to Nth transform coefficients among the transform coefficients of the target block;
deriving a non-separable transform index for the target block based on the scanning of the (R+1)th to Nth transform coefficients;
deriving residual samples of the target block based on an inverse transform for the transform coefficients of the target block, wherein the inverse transform is based on the non-separable transform index;
generating a reconstructed picture based on the residual samples; and
applying a deblocking filtering on the reconstructed picture,
wherein based on a case that a non-zero transform coefficient is included in the (R+1)th to Nth transform coefficients, a value of the non-separable transform index is derived as 0,
wherein based on a case that the non-zero transform coefficient is not included in the (R+1)th to Nth transform coefficients, the inverse transform based on a non-separable transform is performed for coefficients in a top-left target area of the target block based on a transform matrix related to the non-separable transform index,
wherein a size of the transform matrix is R×N,
wherein the N is a number of samples in the top-left target area, and
wherein the R is smaller than the N.