JVET-AN0164 Non-EE2: ALF coefficient coding group extension [I. Jumakulyyev, D. Buğdayci Sansli, J. Lainema (Nokia)]

In this contribution, ALF coefficient coding group extension is proposed to improve ALF coefficient coding efficiency. The method proposes to extend the coding groups of coefficients.

The coding efficiency and runtimes of the proposed method over ECM-18.0 is reported as below {for Y, U, V, EncT, DecT}:

AI {0.00%, -0.01%, 0.00%, 99.9%, 100.0%}

RA { -0.02%, 0.01%, -0.03%, 100.1%, 100.0%}

LDB { -0.06%, 0.06%, 0.02%, 99.9%, 99.9%}

It was commented that some of the gain may be due to retraining, which according to proponents is however necessary to get the full benefit of the method.

Is applied to both luma and chroma.

The BVI-D dataset was used for training.

It was agreed to investigate this in an EE, and also to compare against an anchor that is retrained without the group extension approach.