Comment by kllrnohj

> Isn’t HLG using floating point(s)?

All transfer functions can generally work on either integer range or floating point. They basically just describe a curve shape, and you can have that curve be over the range of 0.0-1.0 just as easily as you can over 0-255 or 0-1023.

Extended sRGB is about the only thing that basically requires floating point, as it specifically describes 0.0-1.0 as being equivalent to sRGB and then has a valid range larger than that (you end up with something like -.8 to 2.4 or greater). And representing that in integer domain is conceptually possible but practically not really.

> Also DCI-P3 should fit in here somewhere, as it seems to be the most standardized color space for HDR.

BT2020 is the most standardized color space for HDR. DCI-P3 is the most common color gamut of HDR displays that you can actually afford, however, but that's a smaller gamut than what most HDR profiles expect (HDR10, HDR10+, and "professional" DolbyVision are all BT2020 - a wider gamut than P3). Which also means most HDR content specifies a color gamut it doesn't actually benefit from having as all that HDR content is still authored to only use somewhere between the sRGB and DCI-P3 gamut since that's all anyone who views it will actually have.