Asymmetric deblocking in a video encoder and/or video decoder

An apparatus for filtering sample values, the apparatus comprising:

• processing circuitry;
• and
• a memory, wherein the apparatus is configured to:
• obtain a set of sample values, the set of sample values comprising the following sample values:
• p5, p4, p3, p2, p1, p0, q0, q1, q2, q3, q4, q5, q6, and q7;
• determine a value refP, wherein refP is equal to:
• (p5+p4+1)>>1;
• determine a value refQ, wherein
• i) when a maximum filter length value (maxLengthQ) is equal to 3, refQ is equal to:
• (q3+q2+1)>>1, or
• ii) when maxLengthQ is equal to 7, refQ is equal to:
• (q7+q6+1)>>1;
• determine a value refMiddle, wherein
• i) in the case that refQ is equal to (q3+q2+1)>>1, refMiddle is equal:
• to (p3+p2+p1+p0+q0+q1+q2+q3+4)>>3, or
• ii) in the case that refQ is equal to (q7+q6+1)>>1, refMiddle is equal to:
• (p5+p4+p3+p2+2*(p1+p0+q0+q1)+q2+q3+q4+q5+8)>>4);
• calculate a filtered sample value p0′, wherein p0′ is equal to:
• (refMiddle*f0+refP*(64−f0)+32)>>6, where f0=58;
• and
• calculate a filtered sample value q0′, wherein q0′ is equal to (refMiddle*g0+refQ*(64−g0)+32)>>6, where g0=59 or g0=53.