US 11,736,735 B2
Systems and methods for applying adaptive loop filters in video coding
Frank Bossen, Vancouver, WA (US)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Filed by Sharp Kabushiki Kaisha, Osaka (JP)
Filed on Feb. 8, 2022, as Appl. No. 17/666,624.
Application 17/666,624 is a continuation of application No. 17/212,018, filed on Mar. 25, 2021, granted, now 11,284,115.
Claims priority of provisional application 63/003,241, filed on Mar. 31, 2020.
Prior Publication US 2022/0159306 A1, May 19, 2022
Int. Cl. H04N 19/00 (2014.01); H04N 19/80 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/117 (2014.01)
CPC H04N 19/80 (2014.11) [H04N 19/117 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11)] 2 Claims
OG exemplary drawing
 
1. A method of filtering a luma coding tree block and modifying a reconstructed sample value, the method comprising:
inputting a reconstructed luma picture sample array and a luma location of top-left of a current luma coding tree block;
determining filter indexes by using the luma location and the reconstructed luma picture sample array;
determining luma filter coefficients by using the filter indexes;
determining a variable applyAlfLineBufBoundary based on whether or not a bottom boundary of a current coding tree block is a bottom boundary of a current picture;
determining a current reconstructed sample value curr by using the reconstructed luma picture sample array;
determining a variable alfShiftY for a shift operation according to a vertical position of a luma sample and the variable applyAlfLineBufBoundary;
determining a sum value S by using the luma filter coefficients, the reconstructed luma picture sample array and the current reconstructed sample value curr;
determining a modified sum value being equivalent to a value of MS in the following equation,
MS=curr+((S+(1<<alfShiftY>>1))>>alfShiftY); and
calculating a modified reconstructed sample value by using the modified sum value.