Advanced Tone Mapping
Detailed tone mapping controls split between libplacebo built-in parameters and Void custom processing. This menu also shows parameter submenus for any loaded user shaders in the hdr/tonemapping category.
Libplacebo
Contrast Recovery
| Parameter | Default | Range | Step | Description |
|---|---|---|---|---|
| Contrast Recovery Strength | 0.30 | 0.0 -- 2.0 | 0.05 | Contrast recovery strength |
| Contrast Smoothness | 3.50 | 1.0 -- 10.0 | 0.10 | Contrast recovery smoothness |
Scene Detection (Peak Detection)
| Parameter | Type | Default | Range | Step | Description |
|---|---|---|---|---|---|
| Peak Detection | Toggle | On | -- | -- | Enable libplacebo HDR peak detection |
| Smoothing Period | Parameter | 20.0 | 1.0 -- 100.0 | 5.0 | Smoothing window in frames |
| Scene Threshold Low | Parameter | 5.50 | 0.0 -- 10.0 | 0.50 | Low threshold for scene change detection |
| Scene Threshold High | Parameter | 10.0 | 0.0 -- 20.0 | 0.50 | High threshold for scene change detection |
| Percentile | Parameter | 99.9 | 50.0 -- 100.0 | 1.0 | Peak percentile for detection |
| Black Cutoff | Parameter | 0.005 | 0.0 -- 1.0 | 0.001 | Black cutoff threshold |
Tone Mapping Constants
| Parameter | Default | Range | Step | Used By | Description |
|---|---|---|---|---|---|
| Knee Adaptation | 0.40 | 0.0 -- 1.0 | 0.05 | BT.2390 | Knee point ratio between source and target average |
| Knee Minimum | 0.10 | 0.0 -- 0.5 | 0.05 | BT.2390 | Knee point minimum as percent of PQ range |
| Knee Maximum | 0.80 | 0.5 -- 1.0 | 0.05 | BT.2390 | Knee point maximum as percent of PQ range |
| Knee Default | 0.40 | 0.0 -- 1.0 | 0.05 | BT.2390 | Default knee point without metadata |
| Knee Offset | 1.00 | 0.5 -- 2.0 | 0.10 | BT.2390 | BT.2390 knee point offset |
| Spline Contrast | 0.50 | 0.0 -- 1.5 | 0.05 | Spline | Preserves midtones vs highlights |
| Slope Tuning | 1.50 | 0.0 -- 10.0 | 0.10 | ST2094 | Tunes curve slope based on peak difference |
| Slope Offset | 0.20 | 0.0 -- 1.0 | 0.05 | ST2094 | Slope offset for spline function |
| Reinhard Contrast | 0.55 | 0.0 -- 1.0 | 0.05 | Reinhard | Local contrast at display peak |
| Linear Knee | 0.30 | 0.0 -- 1.0 | 0.05 | Linear | Knee point for legacy functions |
| Exposure | 1.00 | 0.0 -- 10.0 | 0.10 | Linear | Linear exposure gain for linear methods |
Void
The Void section contains three submenus: Exposure Control, Temporal Stability, and Tone Curve.
Exposure Control
| Parameter | Type | Default | Range | Step | Description |
|---|---|---|---|---|---|
| Exposure Anchor | Parameter | 0.30 | 0.10 -- 2.00 | 0.05 | EV midpoint as fraction of reference white; higher = brighter image |
| Auto-exposure Limit Neg (EV) | Parameter | Auto | -10.0 -- 0.0 or Auto | 0.10 | Negative EV limit; Auto uses adaptive range |
| Auto-exposure Limit Pos (EV) | Parameter | 0.0 | 0.0 -- 10.0 | 0.10 | Positive EV limit; 0.0 disables positive exposure compensation |
| Manual EV Mode | Toggle | Off | -- | -- | Enable manual exposure control |
| Manual EV | Parameter | 0.0 | -10.0 -- 10.0 | 0.10 | Exposure adjustment in stops |
Temporal Stability
| Parameter | Type | Default | Range | Step | Description |
|---|---|---|---|---|---|
| Mipmap Blur Iterations | Parameter | 2 | 1 -- 4 | 1 | Gaussian blur passes on 256x256 luminance map; more = smoother peaks, slower transients. Mipmap metering auto-enables when highlight contrast, highlight desaturation, or shoulder softening is active. |
| Mipmap Center Weight | Parameter | 1.50 | 0.0 -- 5.0 | 0.10 | Center-weighted metering emphasis; 0.0 = uniform, 5.0 = strong center |
| Spatial Blur Radius | Parameter | 2 | 0 -- 4 | 1 | Gaussian blur radius for histogram input (0 = off); reduces pixel noise before metering |
| Center-Weighted | Toggle | Off | -- | -- | Weight center pixels higher in histogram; reduces edge/letterbox influence |
| Window Size | Parameter | 8 | 1 -- 16 | 1 | Sliding window size for harmonic mean; larger = more stable, slower response |
| Decay Factor | Parameter | 0.85 | 0.50 -- 0.99 | 0.01 | Exponential decay weight for harmonic mean; higher = older frames matter more |
| EMA Alpha | Parameter | 0.20 | 0.01 -- 1.0 | 0.01 | EMA smoothing on top of windowed mean; higher = faster response |
| Transition Blend | Parameter | 0.50 | 0.1 -- 1.0 | 0.05 | Blend rate for gradual transitions; higher = faster adaptation |
| Cut Blend | Parameter | 0.30 | 0.1 -- 1.0 | 0.05 | Blend rate after hard scene cuts; higher = faster scene change response |
| EV Change Threshold | Parameter | 2.00 | 0.0 -- 10.0 | 0.05 | Instant scene cut if EV delta >= threshold |
Tone Curve
| Parameter | Type | Default | Range | Step | Description |
|---|---|---|---|---|---|
| Reference White (nits) | Parameter | 203 | 1 -- 10000 | 1.0 | Target brightness |
| Contrast Ratio | Parameter | 1000 | 100 -- 1000000 | 50.0 | Display contrast |
| Use Contrast Control | Toggle | Off | -- | -- | Use contrast_ratio for output black (true) or measured min (false) |
| Curve Type | Selector | Spline | BT.2390 / Suzuki / Reinhard / Hable / Mobius / Spline / Reinhard-Dark | -- | Tone curve algorithm for the Void mapper |
| H-K Effect | Parameter | 1.0 | 0.0 -- 1.0 | 0.05 | Helmholtz-Kohlrausch compensation |
| Highlight Desaturation | Parameter | 0.00 | 0.0 -- 1.0 | 0.05 | Desaturate highlights toward white; reduces saturated color blow-out |
| Highlight Contrast | Parameter | 0.00 | 0.0 -- 4.0 | 0.05 | Pull down highlights before tone curve; preserves detail in specular regions |
| Shoulder Softening | Parameter | 0.00 | 0.0 -- 2.0 | 0.10 | Mipmap-modulated curve softening; locally softens tone curve shoulder |
| Highlight Gradient | Parameter | 1.5 | 1.0 -- 4.0 | 0.10 | EV pulldown gradient exponent; 1.0 = linear, 2.0 = quadratic |
| Shadow Weight | Parameter | 0.46 | 0.0 -- 1.0 | 0.02 | Suzuki shadow adjustment (Suzuki curve only) |
| Highlight Weight | Parameter | 0.04 | 0.0 -- 1.0 | 0.02 | Suzuki highlight adjustment (Suzuki curve only) |
| Contrast Bias | Parameter | 0.00 | -1.0 -- 1.0 | 0.05 | Suzuki midtone contrast (Suzuki curve only) |
| Mobius Knee | Parameter | 0.30 | 0.05 -- 0.95 | 0.05 | Mobius linear knee point; below knee = linear, above = compressed (Mobius curve only) |
| Spline Contrast | Parameter | 0.50 | 0.0 -- 1.5 | 0.05 | Spline contrast tuning; higher = more contrast at pivot (Spline curve only) |
Specular-Gated Local Adaptation
| Parameter | Default | Range | Step | Description |
|---|---|---|---|---|
| Specular Slope Min | 0.10 | 0.0 -- 1.0 | 0.02 | Slope below which specularity = 1.0; lower = tighter specular gate |
| Specular Slope Max | 0.40 | 0.0 -- 1.0 | 0.02 | Slope above which specularity = 0.0; higher = wider specular gate |
| Specular Max Darken | 1.00 | 0.1 -- 4.0 | 0.10 | Max local darkening in stops; higher = more aggressive highlight compression |
| Specular Min % | 1.0 | 0.0 -- 100.0 | 0.50 | Min % of frame above ref_white to enable local adaptation; 0 = always active |
| Specular Area Min % | 5.0 | 0.0 -- 50.0 | 1.0 | Full highlight effect below this % of frame |
| Specular Area Max % | 30.0 | 0.0 -- 100.0 | 1.0 | No highlight effect above this % of frame |
Menu Path
Main Menu > HDR Settings > Advanced Tone Mapping