Filter: openfx.net.sf.openfx.KeyerPlugin

Plugin Information

title: KeyerOFX
media types: Video experimental
description: A collection of simple keyers. These work by computing a foreground key from the RGB values of the input image (see the keyerMode parameter). This foreground key is is a scalar from 0 to 1. From the foreground key, a background key (or transparency) is computed. The function that maps the foreground key to the background key is piecewise linear:

  • it is 0 below A = (center+toleranceLower+softnessLower)
  • it is linear between A = (center+toleranceLower+softnessLower) and B = (center+toleranceLower) -it is 1 between B = (center+toleranceLower) and C = (center+toleranceUpper)
  • it is linear between C = (center+toleranceUpper) and D = (center+toleranceUpper+softnessUpper)
  • it is 0 above D = (center+toleranceUpper+softnessUpper)

Keyer can pull mattes that correspond to the RGB channels, the luminance and the red, green and blue colors. One very useful application for a luminance mask is to mask out a sky (almost always it is the brightest thing in a landscape). Conversion from A, B, C, D to Keyer parameters is: softnessLower = (A-B) toleranceLower = (B-C)/2 center = (B+C)/2 toleranceUpper = (C-B)/2 softnessUpper = (D-C)

See also:

  • https://web.archive.org/web/20220524000628/http://www.opticalenquiry.com/nuke/index.php?title=The_Keyer_Nodes#Keyer
  • http://opticalenquiry.com/nuke/index.php?title=Green_Screen
  • https://web.archive.org/web/20211023071843/http://opticalenquiry.com/nuke/index.php?title=Keying_Tips

version: 2
creator: mr.fantastic mrfantastic@firemail.cc
license: GPLv2
URL: https://openeffects.org/

Parameters

keyColor

title: Key Color
description: Foreground key color. foreground areas containing the key color are replaced with the background image.
type: color
readonly: no
required: no
animation: yes
default: #000000FF
widget: color

mode

title: Keyer Mode
description: The operation used to compute the foreground key.
type: string
readonly: no
required: no
animation: yes
default: Luminance
values:

  • Luminance
  • Color
  • Screen
  • None

luminanceMath

title: Luminance Math
description: Formula used to compute luminance from RGB values.
type: string
readonly: no
required: no
animation: yes

softnessLower

title: Softness (lower)
description: Width of the lower softness range [key-tolerance-softness,key-tolerance]. Background key value goes from 0 to 1 when foreground key is over this range.
type: float
readonly: no
required: no
animation: yes
minimum: -1
maximum: 0
default: -0.5

toleranceLower

title: Tolerance (lower)
description: Width of the lower tolerance range [key-tolerance,key]. Background key value is 1 when foreground key is over this range.
type: float
readonly: no
required: no
animation: yes
minimum: -1
maximum: 0
default: 0

center

title: Center
description: Foreground key value forresponding to the key color, where the background key should be 1.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 1
default: 1

toleranceUpper

title: Tolerance (upper)
description: Width of the upper tolerance range [key,key+tolerance]. Background key value is 1 when foreground key is over this range. Ignored in Screen keyer mode.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 1
default: 0

softnessUpper

title: Softness (upper)
description: Width of the upper softness range [key+tolerance,key+tolerance+softness]. Background key value goes from 1 to 0 when foreground key is over this range. Ignored in Screen keyer mode.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 1
default: 0.5

despill

title: Despill
description: Reduces color spill on the foreground object (Screen mode only). Between 0 and 1, only mixed foreground/background regions are despilled. Above 1, foreground regions are despilled too.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 2
default: 1

despillAngle

title: Despill Angle
description: Opening of the cone centered around the keyColor where colors are despilled. A larger angle means that more colors are modified.
type: float
readonly: no
required: no
animation: yes
minimum: 0
maximum: 180
default: 120

show

title: Output Mode
description: What image to output.
type: string
readonly: no
required: no
default: Intermediate
values:

  • Intermediate
  • Premultiplied
  • Unpremultiplied
  • Composite

sourceAlphaHandling

title: Source Alpha
description: How the alpha embedded in the Source input should be used
type: string
readonly: no
required: no
animation: yes
default: Ignore
values:

  • Ignore
  • Add to Inside Mask
  • Normal

mlt_origin

title: Top-Left Origin
description: Set to 1 to use MLT top-left image origin instead of the OFX bottom-left origin. Use for plugins that crash or produce incorrect output with negative row bytes.
type: boolean
readonly: no
required: no
minimum: 0
maximum: 1
default: 0
widget: checkbox

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