P
Peterwimmer
Guest
Took the time today to find out how the new RTX HDR feature upscales from SDR. Here's what I've found:
Depending on your monitor's peak brightness setting, here are some good paper-white/mid-gray values to use, as recommended by the ITU:
UPDATE:
Nv driver 551.86 mentions the following bugfix:
AUTO HDR muss aus ein in Windows aber das reguläre HDR auf AN. Ich habe es einfach global aktiviert. AUTO HDR hat ausgedient da RTX HDR Haushoch überlegen ist.
Für OLED Bildschirme heißt das;
Max Helligkeit: 1000
Mittlere Graustufe : 75 diese variiert von Display zu Display, aber 75 scheint auf gängigen Oled Displays nahe dem Optimum.
Kontrast: 25
Sättigung: -50
Diese Einstellungen sind für Puristen die dem Original so nah wie möglich kommen wollen.
Fantastisches Feature!
- Saturation -50 is true neutral with sRGB primaries. The default Saturation value of 0 boosts all colors. Would have rather preferred a vibrancy slider here, which would only affect more vivid colors. Simple saturation scalers can add unnecessary color to things that aren't supposed to be colorful.
- The base tone curve when Contrast is 0 is pure gamma 2.0. If you want RTX HDR to have midtones and shadows that match conventional SDR, set Contrast to +25, which matches a gamma of 2.2. For gamma 2.4/BT1886, set Contrast to +50.
- Note that the SDR curve that Windows uses in HDR is not a gamma curve, but a piecewise curve that is flatter in the shadows. This is why SDR content often looks washed out when Windows HDR is enabled. Windows' AutoHDR also uses this flatter curve as its base, and it can sometimes look more washed out compared to SDR. Nvidia RTX HDR uses a gamma curve instead, which should be a better match with SDR in terms of shadow depth.
- Mid-gray sets the scene exposure, and it's being represented as the luminance of a white pixel at 50% intensity. Most of you are probably more familiar with adjusting HDR game exposure in terms of paper-white luminance. You can calculate the mid-gray value needed for a particular paper-white luminance using the following:midGrayNits = targetPaperWhiteNits * (0.5 ^ targetGamma)You'll notice that mid-gray changes depending on targetGamma, which is 2.0 for Contrast 0, 2.2 for Contrast +25, or 2.4 for Contrast +50. The default RTX HDR settings sets paper white at 200 nits with a gamma of 2.0.
- Example: If you want paper-white at 200 nits, and gamma at 2.2, set Contrast to +25 and midGrayNits = 200 * (0.5 ^ 2.2) = 44 nits.
- Example: If you want paper-white at 100 nits and gamma at 2.4 (Rec.709), set Contrast to +50 and midGrayNits = 100 * (0.5 ^ 2.4) = 19 nits.
| Category | Value |
|---|---|
| Mid-Gray | 44 nits (=> 200 nits paper-white) |
| Contrast | +25 (gamma 2.2) |
| Saturation | -50 |
Depending on your monitor's peak brightness setting, here are some good paper-white/mid-gray values to use, as recommended by the ITU:
| Peak Display Brightness | Recommended Paper White | Mid-gray value (Contrast +0) | Mid-gray value (Contrast +25) | Mid-gray value (Contrast +50) |
|---|---|---|---|---|
| 400 nits | 101 nits | 25 | 22 | 19 |
| 600 nits | 138 nits | 35 | 30 | 26 |
| 800 nits | 172 nits | 43 | 37 | 33 |
| 1000 nits | 203 nits | 51 | 44 | 38 |
| 1500 nits | 276 nits | 69 | 60 | 52 |
| 2000 nits | 343 nits | 86 | 75 | 65 |
UPDATE:
Nv driver 551.86 mentions the following bugfix:
AUTO HDR muss aus ein in Windows aber das reguläre HDR auf AN. Ich habe es einfach global aktiviert. AUTO HDR hat ausgedient da RTX HDR Haushoch überlegen ist.
Für OLED Bildschirme heißt das;
Max Helligkeit: 1000
Mittlere Graustufe : 75 diese variiert von Display zu Display, aber 75 scheint auf gängigen Oled Displays nahe dem Optimum.
Kontrast: 25
Sättigung: -50
Diese Einstellungen sind für Puristen die dem Original so nah wie möglich kommen wollen.
Fantastisches Feature!
