Viz Artist

Version 3.9.0 | Published December 13, 2017 ©

Chroma Keyer

This Shader clear regions in a video defined by a color. The color-space of this Shader is YUV, which is defined as following:

The luminance (Y) component determines the brightness of the color, while the U and V components determine the color itself (the chroma). Luminance (Y) ranges from 0.0 (dark) to 1.0 (bright). U and V ranges from -0.5 to 0.5.

Note: This plug-in is located in: Built Ins -> Shader -> Effects

This section contains information on the following topics:

Chroma Keyer Properties


  • Video: Sets the input video channel for keying. Be sure that for the set video channel the “Keying Mode” has been set to M-Zone (see Keying Mode).

  • Blend: Sets the alpha for the key signal

  • Fit: Select Screen or Object

  • Invert: Flips the key signal.

  • Sampling Filter

    • Nearest: Color information is taken from one pixel.

    • 1D-Filter: Color information is taken after applying a 1D-linear filter.

    • 2D-Filter: Color information is taken after applying a 2D-linear filter.

  • Luminance: Sets the luminance.
    Basic parameters for first method:


  • HueAngle: Selects the color to key in YUV space.

  • OpeningAngle: Tolerance for the color in YUV space.

  • KeyGain: Gradient for borders to neighboring colors (1=soft, 10=sharp).

  • SatMin: Lower saturation limit for keyed colors.

  • SatMinGrad: Gradient for lower saturation limit (0=sharp, 1=soft).

  • SatMax: Upper saturation limit for keyed colors.

  • SatMaxGrad: Gradient for upper saturation limit (0=sharp, 1=soft).
    Basic parameters for second method:


  • U-Color: U-value for color keying.

  • V-Color: V-value for color keying.

  • UV-Diameter: All colors between the reference UV and this diameter will be removed.

  • UVGradient: Gradient for fade out at diameter border (0=sharp, 1=soft).
    Removing keying from Highlights and Shadows:


  • LumMin: Lower luminance limit for keyed colors.

  • LumMinGrad: Gradient for lower luminance limit (0=sharp, 1=soft).

  • LumMax: Upper luminance limit for keyed colors.

  • LumMaxGrad: Gradient for upper luminance limit (0=sharp, 1=soft).
    Sampling reference point:


  • UVRangeCheck: This option can be used to get an information of the sampled color

  • URangeMin: Defines the minimum UColor that should be accepted

  • URangeMax: Defines the minimum UColor that should be accepted

  • VRangeMin: Defines the minimum UColor that should be accepted

  • VRangeMax: Defines the minimum UColor that should be accepted

  • SampleTrustiness: Percentage of samples in the limited UV-Color space

  • Pos. X: X-coordinate for sampling.

  • Pos. Y: Y-coordinate for sampling.

    Note: The origin of the coordinate system is in the upper left corner.

  • Width: Sets number of pixels in x-direction.

  • Height: Sets number of pixels in y-direction.

  • Sample at Pos: If enabled Pos. X and Pos. Y will be replaced by XY-coordinates of the object center. If disabled the XY-coordinates will be set by values in the interface.

  • Get Sample: Sample another time the reference point.

See Also