HDRP10 is a video format converter for Unity HDRP that allows HDR video output via Windows HD Color.
Left: Standard dynamic range. Right: HDR enabled. You can see banding in the dark area of the left photo. I used Dell U2720QM HDR monitor and took these photos with an overexposure setting to emphasize the effect.
Please note that this is just a proof-of-concept implementation. I wouldn't recommend using it in a practical application.
Download this repository and copy Packages/jp.keijiro.hdrp10 into your
project's Packages directory.
Firstly, enable the HDR mode (Use display in HDR mode) in Player Settings.
HDRP10 only supports 10-bit HDR buffer, so set Swap Chain Bit Depth to Bit Depth 10.
Then add Hdrp10.FormatConversion to After Post Process (Project Settings
-> HDRP Default Settings -> Custom Post Process Orders).
Create a volume profile to disable Tonemapping and enable Format Conversion. Select Rec. 2020 ST 2084 in Format. You can also specify a paper-white brightness (in nits).
Optional: It's recommended increasing the color buffer precision in Color Buffer Format and Post-processing Buffer Format.
By disabling tonemapping, we get scene-linear images from HDRP with the Rec. 709 color primaries. The Format Conversion effect converts them using the Rec. 2020 color primaries, then apply the SMPTE ST 2084 transfer function (PQ).
This conversion process is implicitly done in the legacy (built-in) render pipeline but not in scriptable render pipelines. So I simply re-implemented it as a post-processing effect for HDRP.