FIG. 3 illustrates a flowchart of an exemplary video coding according to an embodiment of the present invention, where luma samples for the Cross-Component ALF processing are determined according to the chroma format.

FIG. 4 illustrates a flowchart of an exemplary video coding according to an embodiment of the present invention, where luma ALF and the Cross-Component ALF have the same filter coefficient precision.

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

In CC-ALF, one additional filter is added for chroma component and the filtered output will be the weighted sum of the original chroma filter and the additional filter. In one embodiment, only one additional filter tap with the input from the corresponding luma sample is added to the original chroma filter. In another embodiment, non-linear clipping operation can be also applied to this filter tap. That is, the clipping index can be signaled for this filter tap. In another embodiment, non-linear clipping operation cannot be applied to this filter tap, i.e. the clipping index cannot be signaled for this filter tap. In another embodiment, one flag is signalled in ALF filter parameters to indicate whether this filter tap is used or not.