JVET-Q0494 CE5-related: Joint clip operation for CCALF and chroma ALF [T.-C. Ma, X. Xiu, Y.-W. Chen, H.-J. Jhu, X. Wang (Kwai Inc.)]
Initially presented in BoG, further review Track B Wednesday 15 January 1705 (chaired by JRO)
According to Core Experiment (CE5) common base software, when both chroma ALF and CCALF are enabled, range clipping operations are performed on modified chroma samples separately in each of the two modules to prevent overflow or underflow. In this contribution, it is proposed to perform only one range-clipping operation after chroma samples processed by ALF and CCALF. The proposed change is implemented based on CE5 software. Simulation results show that the proposed change results in a BD-rate change (YUV) of 0.00%, 0.00%, 0.00% for AI, 0.00%, 0.00%, 0.00% for RA, XXX%, XXX%, XXX% for LDB, respectively.
There are minor deviations (not bit exact) for RA classes Ax.
The proposal requires some text changes to cover the cases CCALF on/off
The benefit in implementation appears minor.
No action.