The Joint Collaborative Team on Video Coding (jct-vc) of itu-t wp3/16 and iso/iec jtc 1/ sc 29/ wg 11 held its tenth meeting during 11-20 July 2012 at the City Conference Centre (ccc), a k. a

5.9Non-deblocking loop filters

5.9.1Adaptive loop filter

The subsequent documents were discussed in the BoG on ALF (JCTVC-J0521).
JCTVC-J0036 ALF coefficient coding with a single k-table [K. Ugur (Nokia)]

Abstract:

This contribution proposes to remove position dependent coding of coefficients and instead use EG(0) for all the coefficients. Two versions of signed EG(0) VLC were tested – (1) Unsigned EG(0)+separate sign and (2) se(v). The results reportedly show that there is 0.0%–0.1% change in coding efficiency.

Benefit:

Luma & chroma coefficient coding consistent

Removes kes(v) parsing process entirely from the specification

Removes position dependency k-tables

Coding efficiency:

(1) 0.06% loss proposal 1 (Unsigned EG(0) + separate sign)

(2) 0.07% loss proposal 2 (se(v) – Signed Exp-Golobm coding)

Cross-check:

Originally, this was proposed by Nokia. Later, TI jointly proposed. TI and Nokia cross-checked the results individually.

Availability of text:

Available in the contribution.

Discussion:

kes(v) is used in other place, so no hardware reduction.

Current text has differences leading zero or leading one, but can be unified.

Same coding engine is used as coefficient level coding (but ALF coef. is signalled in APS).

There is no prediction in coding, therefore, EG(k) is preferable to compensate this.

Relation with JCTVC-J0346, see further discussion below.