@terrym@tassie and Hendrik...
Thank you. Where's that 'beer' emoji?
I don't understand these settings, so, I do not touch them. I am very capable of a 'wonder what happens if I click that' attitude, but not when it comes to video playback...
marko, in the same dialog terrym@tassie showed above, in the JRVR settings under Scaling, you are currently using Jinc as the Upscaling Algorithm, maybe move that up to a different setting - they are roughly ordered in performance/quality order. Worst case you end up with one of the two built-ins which are a lot faster.
As a second step, maybe go to the Processing tab and disable Debanding. It has little effect on high quality content but can cost a bunch of time.
Working through your reply, I tried this first, and things improved greatly. Render average came down to around 17ms, but there was still a steady increase in the dropped frames count.
Then, I read the next bit...
If you want a single easy option, you could also swap to the Performance preset on the JRVR General page. Although swapping the upscaler should do the job.
What graphics card is that system using?
The CPU performance from the benchmark looks fine, but it doesn't measure graphics performance.
and I was like, wait a minute...
Graphics is provided by the Intel thing on the chip (my technical jargon is impressive huh?
) so I selected that performance preset, clicked the load button, turned on that HDR setting in Windows display settings, and now, it's all good again.
Average render times are below 10ms, some dropped frames right at the beginning, then it's stable, and looks fine. Even the SDR to HDR step is stable and looks fine too.
Thank you, again, for the steer.
Final thoughts...
1. I've no idea what got changed, or when, nor how. I don't touch those settings, they're dark magic to me
2. After selecting a preset, and hitting that load button, it would be handy to know what preset is loaded. An indicator somewhere that shows "Loaded preset: [Performance]" and, if a setting subsequently changes, that should change to "Loaded preset: [Performance (modified)]"
This might have been enough to get me there on my own
-marko