Adaptive loop filtering for chroma components

An apparatus configured to perform adaptive loop filtering in a video coding process comprising:

• a memory configured to store a block of pixels;
• a video coder configured to:
• determine a status of a coding unit-level luma adaptive loop filtering flag independently from that of a coding unit-level chroma adaptive filtering flag;
• determine whether to perform luma adaptive loop filtering on the block of pixels, based at least in part on the coding unit-level luma adaptive loop filtering flag;
• determine whether to perform chroma adaptive loop filtering on the block of pixels, based at least in part on the coding unit-level chroma adaptive filtering flag, independently of determining whether to perform luma adaptive loop filtering;
• perform luma adaptive loop filtering for luma components of the block of pixels responsive to determining to perform luma adaptive loop filtering;
• perform chroma adaptive loop filtering for chroma components of the block of pixels responsive to determining to perform chroma adaptive loop filtering;
• and
• derive filter coefficients for both the luma adaptive loop filtering and chroma adaptive loop filtering based on one of a block-based classification mode and a region-based classification mode.

An apparatus configured to perform adaptive loop filtering in a video coding process comprising:

• means for determining a status of a coding unit-level luma adaptive loop filtering flag independently from that of a coding unit-level chroma adaptive loop filtering flag;
• means for determining whether to perform luma adaptive loop filtering on a block of pixels, based at least in part on the coding unit-level luma adaptive loop filtering flag;
• means for determining whether to perform chroma adaptive loop filtering on the block of pixels, based at least in part on the coding unit-level chroma adaptive loop filtering flag, independently of determining whether to perform luma adaptive loop filtering;
• means for performing luma adaptive loop filtering for luma components of the block of pixels responsive to determining to perform luma adaptive loop filtering;
• means for performing chroma adaptive loop filtering for chroma components of the block of pixels responsive to determining to perform chroma adaptive loop filtering;
• and
• means for deriving filter coefficients for both the luma adaptive loop filtering and chroma adaptive loop filtering based on one of a block-based classification mode and a region-based classification mode.

A non-transitory computer-readable storage medium storing instructions that, when executed, causes one or more processors of a device configured to perform adaptive loop filtering in a video coding process to:

• determine a status of a coding unit-level luma adaptive loop filtering flag independently from that of a coding unit-level chroma adaptive loop filtering flag;
• determine whether to perform luma adaptive loop filtering on a block of pixels, based at least in part on the coding unit-level luma adaptive loop filtering flag;
• determine whether to perform chroma adaptive loop filtering on the block of pixels, based at least in part on the coding unit-level chroma adaptive loop filtering flag, independently of determining whether to perform luma adaptive loop filtering;
• perform luma adaptive loop filtering for luma components of the block of pixels responsive to determining to perform luma adaptive loop filtering;
• perform chroma adaptive loop filtering for chroma components of the block of pixels responsive to determining to perform luma adaptive loop filtering;
• and
• derive filter coefficients for both the luma adaptive loop filtering and chroma adaptive loop filtering based on one of a block-based classification mode and a region-based classification mode.