CPC H04N 19/117 (2014.11) [H04N 19/136 (2014.11); H04N 19/172 (2014.11); H04N 19/196 (2014.11); H04N 19/82 (2014.11)] | 20 Claims |
1. A method for in-loop filtering by performing adaptive loop filtering on a reconstructed frame of a video stream, implemented by an encoding device or a decoding device, the method comprising:
forming differences between at least one of luma and chroma components of a pixel of the reconstructed frame and the at least one of luma and chroma components of neighboring pixels in a connected area of the pixel;
clipping the differences according to respective clipping levels;
forming a weighted sum of the clipped differences; and
adding the weighted sum to the at least one of luma and chroma components of the pixel to determine a filtered respective component of the pixel,
wherein the respective clipping levels are chosen from a same set of clipping levels for the luma and chroma components when luma bit depth, BitDepthLuma, is same as chroma bit depth, BitDepthChroma;
wherein the set of clipping levels for the luma and chroma components is determined according to the following equations:
Lim(i,j)=[1<<(BitDepthLuma−ShiftConst[Idx(i,j)])] for luma component
Lim(i,j)=[1<<(BitDepthChroma−ShiftConst[Idx(i,j)])] for chroma components
Idx(i,j)=0,1,2,3
ShiftConst[0]=0,ShiftConst[1]=3,ShiftConst[2]=5,ShiftConst[3]=7
Or
ShiftConst[0]=0,ShiftConst[1]=2,ShiftConst[2]=4,ShiftConst[3]=6
through variation of the bit depth of the luma component BitDepthLuma and the chroma components BitDepthChroma as well as an index Idx(i,j).
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