Exporting HDR Stills From A Video

Hey I'm pretty new here, both to the forums and Resolve, so this is probably a really easy question. I'm trying to pull 8K HDR screenshots out of 8K, 10 bit, 4:2:0, limited, Rec.2020, ST.2084 video but can't seem to get it right. After some googling I tried to export as a TIFF from the color tab, but the color of the image was muted and a far cry from the color of the original that doesn't need color correcting. So, the question is: How do I export 8K stills that maintain the already perfect color of the source in Resolve? I want to make sure I'm not sacrificing any color from Rec.2020 either.

I'll include a Mediainfo in tree mode of the source.

Edit #1: Here is a video sample of what I'm working with exported at 1080p instead of 8k from Resolve, all the color space and gamma settings are correct and it looks visually identical to the original apart from pixel count and bitrate. Link is through Discord because I don't know how else to get a 7 MB file to you guys with the forum's 2 MB limit. https://cdn.discordapp.com/attachments/ ... Sample.mp4

Edit #2: I have discovered a way to achieve my goal using HDR Shadowplay to screenshot the video. This method is kind of clunky since it requires me to hit the key combo on the right frame, I guess I could macro it 30x a second though... While we're on the subject, these screenshots are in the .JXR format with Rec.2020 color space and ST2084 gamma. I'd still like to know how to do this in Resolve though.

Rec2020 color space does not exist in the photo world. Resolve either exported an sRGB image or it actually embedded the color space you defined in the output section of your color management and your image viewer does not understand what to do with this.
Open the Tiff in Photoshop and check what color space is embedded in you Tiff.

Open the Tiff in Photoshop and check what color space is embedded in you Tiff.

The color space was RGB. Is there a specific color space I should be targeting? If that's even possible. I didn't see a color space option when exporting, and my timeline color space settings are all set properly.

Not only rec.2020 doesn't exist (yet?) in imagery encoding afaik.
HDR doesn't exist in stills. You can't view an image with HDR metadata.

If your purpose of grabbing that still is to create a thumbnail for a video you will have to convert that to sRGB.
I think it's best to perform a conversion within the project / grade and verify quality viewing it on an sRGB display before export rather than letting the export decide. If you merely tag/encode the image as sRGB it will look like it's a log image with dull colors.

If the purpose isn't a thumbnail and you actually need to maintain the most colors you can convert it to Display P3 instead.

Not only rec.2020 doesn't exist (yet?) in imagery encoding afaik.
HDR doesn't exist in stills. You can't view an image with HDR metadata.

Video is a sequence of stills, there is nothing inherently different in there besides standardised container and metadata for hdr. Nothing stops one from encoding image data with needed gamut and transfer function, problem is rather finding the viewer that interprets this data and sends it properly to screen. You can have hdr viewers in comp software for example, where outgoing signal specification is defined by viewer lut.

For a generic well supported container, ACES2065-1 linear exr-s, ACEScc/cct dpx or Alexa Wide Gamut/LogC dpx-s would be probably better for maintaining full gamut than something P3 based, if purpose is to stay in "video world". For stills world, Adobe Wide Gamut, Prophoto etc are also sufficiently wide gamuts, but here the question of transfer function rises, stills world isn't too keen on high dynamic range stuff.

...problem is rather finding the viewer that interprets this data and sends it properly to screen.

Technically definitely more true. I was kind of assuming the OP has little knowledge in this respect.
I guess we should take a step back and really ask what exactly the purpose is of grabbing that still in the first place.

Saving out a linear image file in ACES will indeed hold all captured information but we don't know what the image's purpose is.

Actually, there is an HDR PQ HEIF BT.2020 stills format.

It’s been around for years.

As for Rec.2020, it also exists in spite of there not being any displays that can reproduce 100% of the color space, just as DCI-P3 exists in spite of the fact that not even reference monitors costing $30,000 can reproduce 100% of that color space.

I was kind of assuming the OP has little knowledge in this respect.
I guess we should take a step back and really ask what exactly the purpose is of grabbing that still in the first place.

I do have very little experience working with stills and their properties. The purpose of the stills would be some wallpapers and single frame material to insert into other videos.

Actually, there is an HDR PQ HEIF BT.2020 stills format.

And it's been around for years.

As for Rec.2020, it also exists in spite of there not being any displays that can reproduce 100% of the color space, just as DCI-P3 exists in spite of the fact that not even reference monitors costing $30,000 can reproduce 100% of that color space.

That PQ BT.2020 format sounds like exactly what I need, but I still have no idea how I'd get a still to export to it in Resolve.

My monitor covers 98% of DCI-P3 and 83% of Rec.2020, but my footage doesn't need any grading so that's not that important.

Actually, the Canon R6 is shooting stills in that format, if you tell it so.