I have a Panasonic plasma (P55VT50). It has been professionally calibrated for Rec.709 video. Anyone familiar with this display will know that it has the best black levels (other than the newer VT60s) available, and it’s easy to see the difference between black and almost black. Likewise, slight color differences are fairly easy to notice.
My Rec.709 test files were remuxes of the BluRays of The Bourne Identity and Iron Man. For Rec.2020/HDR, I used remuxes of the UHDs of these discs. Although I used my personal BluRays to make the 1080p remuxes, I downloaded the UHD remuxes because I don’t have a UHD drive in my PC. So, it’s possible there is something wrong with those remuxes, and I’ll check that once I get the UHD drive installed and rip my discs.
The Rec.709 files looked exactly the same when played by the Vero as when played by other devices (including the TV itself).
So far the only thing I have really tried on the Vero end is to force RGB output (echo 1 > /sys/class/amhdmitx/amhdmitx0/output_rgb) and that didn’t change anything (other than have the TV tell me it was now getting RGB instead of YUV), so it doesn’t look like its an EDID issue as some have. Nevertheless, here’s my EDID:
I read some of the other topics about forcing HDR to SDR, and it’s obvious that that conversion is happening even without forcing, as I don’t have the completely washed out colors you normally see with Rec.2020 on a Rec.709 display.
I tried changing some settings on the TV, and switching from the calibrated gamma to the built-in sRGB curve helped a lot, but I still ended up with crushed blacks and whites. White wasn’t too bright, but “almost white” was changed to white, just like “almost black” became black.
So, it seems to be down to LUT and other color conversion options. But, there are a lot of possible options, as shown in this thread:
So, where would be the best place to start? Since I know what “right” looks like in a pretty much absolute sense, I think I might be able to help you find out-of-the-box settings that will work best (assuming a calibrated display).
I’d also like to know if the setting changes in /sys/module/am_vecm/parameters need to be done while a video is running, and if they are persistent when stopping/starting videos.