"AUTO" uses the MaxCLL/FALL metadata that the JVC receives. If the HDR Optimizer is used it will send modified MaxCLL/FALL. Otherwise (and always from the 203) the JVC will get MaxCLL/FALL metadata off the disc and that can be anything from fairly good to non-existent. The other JVC settings ignore MaxCLL/FALL.Hi, i tested 1 movie side by side on Panasonic UB9000 and OPPO 203 and i think on HDR "AUTO" UB9000 looks more bether then on OPPO 203. On UB9000 i was have enabled HDR Optimilizer.
So, to do a proper comparison you should have the HDR Optimizer off and use the same (non-AUTO) setting for both. I suspect that you would not see any obvious differences.
Or, if you want to see whether the HDR Optimizer adds something to the JVC processing vs the 203 (which just passes through the HDR metadata), then you should use "AUTO" for the Panasonic and one of the JVC non-AUTO settings for the 203.