I don’t want to be rude, but you don’t understand my concern at all and it is very frustrating!!! :(
I had already figured out that PresetLevel does change the outcome.
HOWEVER: When people ask for more CLARITY on PARAMETERS we only get a dump of gst-inspect (which IS actually the insufficient documentation). Moreover: gst-inspect exposes TWO (2) separate paramters: QualityLevel AND PresetLevel. One of both (notably QualityLevel) does not have any effect on the encoded data.
So PLEASE: Communicate, publish, and document that (if?) QualityLevel is ignored and that there will be either a fix or it will be removed from module omxh265enc.