JVET-O0300 AHG17: Clean-up of ALF Syntax Parameters [S. Paluri, J. Lim, S. Kim (LGE)]

This document proposes clean-ups of two Adaptive Loop Filter (ALF) Parameters, namely, alf_luma_fixed_filter_idx and alf_luma_fixed_filter_set_idx. Currently, both parameters use truncated binary (tb) binarizations. However, these two syntax elements have a maximum value of 15. Hence, there is no coding benefit obtained from TB binarization compared to fixed length coding (FLC). Using Truncated Binary binarization introduces more complexity than fixed length coding. Additionally FLC is especially useful for representing numbers when they are a power of two.

In the discussion, several experts expressed that the decoding of TB is so simple that there is no need to change.