Sigmoidization
Apply a sigmoid transfer curve during upscaling to reduce ringing and other scaling artifacts.
When upscaling in linear light, sharp luminance transitions (such as bright edges against dark backgrounds) can overshoot, producing halos and ringing. Sigmoidization transforms the image into a perceptually more uniform space before scaling, then inverts the transform afterward. This compresses the extremes of the luminance range so that scaling filters behave more gently across high-contrast edges.
Default: Off
Parameters
Sigmoid Center
| Property | Value |
|---|---|
| Default | 0.75 |
| Range | 0.0 – 1.0 |
| Step | 0.05 |
The midpoint of the sigmoid curve. Values closer to 1.0 shift the transition region toward the highlights, giving more precision in bright areas. Values closer to 0.0 shift it toward the shadows. The default of 0.75 is a good general-purpose choice that slightly favours highlight detail.
Sigmoid Slope
| Property | Value |
|---|---|
| Default | 6.5 |
| Range | 1.0 – 20.0 |
| Step | 0.5 |
Controls the steepness of the sigmoid curve. Higher values produce a sharper S-curve, which compresses the extremes more aggressively and reduces ringing further — but may also reduce contrast in the midtones. Lower values produce a gentler curve closer to linear light scaling.
Recommended Settings
- Sharp filters (Lanczos, EWA Lanczos) — enable sigmoidization to tame ringing on high-contrast edges.
- Soft filters (Bilinear, Gaussian) — sigmoidization is less necessary but will not hurt.
- Downscaling — sigmoidization primarily benefits upscaling; it has little effect when downscaling.
Menu Path
Main Menu > Video Settings > Sigmoidization