Inaccurate HDR color over Decklink Mini Monitor 4K

Hi, I'm not sure if this is an issue with Resolve or the Decklink Mini Monitor 4K or something else, but when outputting HDR REC 2020 over HDMI, the color is muted and greenish. compared to how it renders and plays back on other devices.

Here are a couple screen grabs of my measurements of Ryan Masciola's HDR test patterns (Diversified Video Solutions) as output from an Xbox One S and displayed on a Sony A8F OLED HDR TV. I also downloaded the exact same patterns from his site (and confirmed they are the same HVEC files as were burned on the UHD disc) and displayed them through Resolve in Rec 2020 ST084 color space with HDR metadata output. The results are very different! I know the test pattern disc is pretty close because the Sony OLEDs don't come with CMS because they are meant to be that color-accurate and theses results confirm that.

My best solution has been to make a monitor LUT to make up the difference, but I'd love to have this one get figured out if there's a piece of hardware or software in the mix that is causing this.

UHD test pattern disc (proper readings)

UHD DIsc.JPG (868.6 KiB) Viewed 1563 times

Resolve readings:

Resolve Output.JPG (889.4 KiB) Viewed 1563 times

Does the TV either:
1) be capable of tru hdr2020/2084
Or
2) understand the signal correctly and map it to the TV gamut (probably close to 709)?

Those TVs don't use Rec.709 gamut for UHD signals, but P3. They are typically around 95%+ of P3 gamut.

Chad, your Sony TV is definitely not so accurate as you think by default, but this is irrelevant.
When you play same clip over TV or Resolve it should look the same and this is most important here.

Do both TV inputs use the same picture profile?
Try also manually forcing Rec.2020 in TV settings for both inputs. Maybe some auto setting doesn't properly work.
Do you see that TV is switching into Rec.2020 mode in case of Resolve signal? Is there any info provided by TV about current signal type?

Hey Andrew and Walter, thanks for your thoughts! I can't believe I've been struggling with this for so long and I haven't tried forcing the TV into both HDR gamma and color space. I assumed because it picked up the HDR metadata and switched over that it was using the REC 2020 space, but it looks like it switched into HDR10 mode with REC709 color space, which would explain the desaturated look.

A couple interesting points though: The color saturation sweeps mostly lined up to the Xbox One S signal, but had a few luma inconsistencies. It's hard to tell with this kind of TV if that's a result of Max FALL (the TV darkening over time) or the signal itself.

Also, when connecting through my Onkyo receiver (TN-NR777) there is the same characteristic bending of both the cyan and yellow colors similar to what I saw before, along with a few other slight variations (blue luma). The strange thing is the receiver has a standby mode where even when it is switched off, it still passes the signal along, so it doesn't seem like it should be manipulating the signal at all, yet it comes our differently. I'm using all the same new 18Gbps Monoprice HDMI cable for all connections. Thankfully, it's close enough to where I can just make a simple monitor LUT in Resolve and be on my way, but it's worth trying to understand what might be happening there. Here's the sweep results from routing through the Onkyo.

Screen Shot 2019-02-17 at 6.37.47 PM.jpg (621.85 KiB) Viewed 1299 times

Thanks again for helping me troubleshoot this. Glad to be up and running!

It may be related to some HDR metadata presence/absence as you said.
I would advice you to buy one of the HDFury boxes to be able to monitor exactly what HDR metadata goes to your TV and if needed adjust it.

It may be related to some HDR metadata presence/absence as you said.
I would advice you to buy one of the HDFury boxes to be able to monitor exactly what HDR metadata goes to your TV and if needed adjust it.

I saw that happen with version 12.5