METHOD AND APPARATUS FOR CODING ADAPTIVE-LOOP FILTER COEFFICIENTS
Disclosed is a method and apparatus for encoding adaptive-loop filter (“ALF”) coefficients. An encoder or decoder codes the ALF coefficients by using k-variable Exp-Golomb codewords where k is larger than 0, and k is the same for each coefficient. This eliminates the need for a k-parameter mapping table.
1 . A method for coding a plurality of adaptive-loop filter coefficients, the method comprising:
binarizing each of the plurality of adaptive-loop filter coefficients using k-variable Exp-Golomb codewords for which k is larger than 0; and
coding each of the plurality of adaptive-loop filter coefficients with k-variable Exp-Golomb codewords for which k is greater than 0.
2 . The method of claim 1 wherein the value of k used for coding each of the plurality of adaptive-loop filter coefficients is the same for each of the plurality of adaptive-loop filter coefficients.
3 . The method of claim 1 :
wherein the value of k used for binarizing each of the plurality of adaptive-loop filter coefficients is selected from a group consisting of: 1, 2, 3, 4, and 5; and
wherein the value of k used for coding each of the plurality of adaptive-loop filter coefficients is selected from a group consisting of: 1, 2, 3, 4, and 5.
4 . The method of claim 1 wherein each of the plurality of adaptive-loop filter coefficients is a Luma adaptive-loop filter coefficient.
5 . The method of claim 4 :
wherein the value of k used for binarizing each of the plurality of adaptive-loop filter coefficients is selected from a group consisting of: 1, 2, 3, 4, and 5; and
wherein the value of k used for coding each of the plurality of adaptive-loop filter coefficients is selected from a group consisting of: 1, 2, 3, 4, and 5.
6 . The method of claim 1 wherein each of the plurality of adaptive-loop filter coefficients is a Chroma adaptive-loop filter coefficient.
7 . The method of claim 6 :
wherein the value of k used for binarizing each of the plurality of adaptive-loop filter coefficients is selected from a group consisting of: 1, 2, 3, 4, and 5; and
wherein the value of k used for coding each of the plurality of adaptive-loop filter coefficients is selected from a group consisting of: 1, 2, 3, 4, and 5.
8 . A method for coding a plurality of adaptive-loop filter coefficients, the method comprising:
binarizing the plurality of adaptive-loop filter coefficients using fixed-length codewords, all of which have a length that is equal to or greater than 4 bits; and
coding each of the plurality of adaptive-loop filter coefficients using fixed-length codewords, all of which have a length that is equal to or greater than 4 bits.
9 . The method of claim 8 :
wherein the length of each of the fixed-length codewords used to binarize the plurality of adaptive-loop coefficients is selected from a group consisting of: 4 bits, 5 bits, 6 bits, 7 bits, and 8 bits; and
wherein the length of each of the fixed-length codewords used to code the plurality of adaptive-loop coefficients is selected from a group consisting of: 4 bits, 5 bits, 6 bits, 7 bits, and 8 bits.
10 . The method of claim 8 wherein each of the plurality of adaptive-loop filter coefficients is a Luma adaptive-loop filter coefficient.
11 . The method of claim 10 :
wherein the length of each of the fixed-length codewords used to binarize the plurality of adaptive-loop coefficients is selected from a group consisting of: 4 bits, 5 bits, 6 bits, 7 bits, and 8 bits; and
wherein the length of each of the fixed-length codewords used to code the plurality of adaptive-loop coefficients is selected from a group consisting of: 4 bits, 5 bits, 6 bits, 7 bits, and 8 bits.
12 . The method of claim 8 wherein each of the plurality of adaptive-loop filter coefficients is a Chroma adaptive-loop filter coefficient.
13 . The method of claim 12 :
wherein the length of each of the fixed-length codewords used to binarize the plurality of adaptive-loop coefficients is selected from a group consisting of: 4 bits, 5 bits, 6 bits, 7 bits, and 8 bits; and
wherein the length of each of the fixed-length codewords used to code the plurality of adaptive-loop coefficients is selected from a group consisting of: 4 bits, 5 bits, 6 bits, 7 bits, and 8 bits.
14 . An encoder for encoding a plurality of original video pixels of an original predictive unit, the encoder comprising:
an adaptive-loop filter configured to minimize the coding distortion between input and output pictures, wherein the adaptive-loop filter has a plurality of filter coefficients, wherein each of the filter coefficients is binarized using k-variable Exp-Golomb codewords for which k is larger than 0, and wherein each of the filter coefficients is coded using k-variable Exp-Golomb codewords for which k is greater than 0.