colorlevels

Adjust video input frames using levels.

The filter accepts the following options:

rimin

gimin

bimin

aimin

Adjust red, green, blue and alpha input black point. Allowed ranges for options are [-1.0, 1.0]. Defaults are 0.

rimax

gimax

bimax

aimax

Adjust red, green, blue and alpha input white point. Allowed ranges for options are [-1.0, 1.0]. Defaults are 1.

Input levels are used to lighten highlights (bright tones), darken shadows (dark tones), change the balance of bright and dark tones.

romin

gomin

bomin

aomin

Adjust red, green, blue and alpha output black point. Allowed ranges for options are [0, 1.0]. Defaults are 0.

romax

gomax

bomax

aomax

Adjust red, green, blue and alpha output white point. Allowed ranges for options are [0, 1.0]. Defaults are 1.

Output levels allows manual selection of a constrained output level range.

preserve

Set preserve color mode. The accepted values are:

‘none’

Disable color preserving, this is default.

‘lum’

Preserve luminance.

‘max’

Preserve max value of RGB triplet.

‘avg’

Preserve average value of RGB triplet.

‘sum’

Preserve sum value of RGB triplet.

‘nrm’

Preserve normalized value of RGB triplet.

‘pwr’

Preserve power value of RGB triplet.

Examples

• Make video output darker:

  colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
  

• Increase contrast:

  colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
  

• Make video output lighter:

  colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
  

• Increase brightness:

  colorlevels=romin=0.5:gomin=0.5:bomin=0.5