Systems and methods for video decoding with partial-block deblocking filtering for use by constrained directional enhancement filter

An apparatus for video decoding, the apparatus comprising:

• at least one memory configured to store video data;
• and
• at least one processor coupled to the at least one memory, the at least one processor configured to:
• apply a deblocking (DB) filter to a plurality of sub-blocks of a block of the video data to generate a DB-filtered plurality of sub-blocks, the plurality of sub-blocks being less than an entirety of sub-blocks within the block;
• apply the DB filter to at least two lines of pixels in an additional sub-block of the block to generate a DB-filtered portion of the additional sub-block, wherein the at least two lines of pixels in the additional sub-block are filtered without filtering an entirety of the additional sub-block using the DB filter and the at least two lines of pixels are adjacent to one another, and wherein the additional sub-block is adjacent to at least one of the plurality of sub-blocks;
• and
• apply a constrained directional enhancement filter (CDEF) to the DB-filtered plurality of sub-blocks and the DB-filtered portion of the additional sub-block to generate a CDEF-filtered plurality of sub-blocks.