unreal.CompositePassColorKeyer

class unreal.CompositePassColorKeyer(outer: Object | None = None, name: Name | str = 'None')

Bases: CompositePassBase

Extracts alpha from a colored background (red, green or blue) using chroma keying. Supports clean-plate differencing, despill and denoising.

C++ Source:

  • Plugin: Composite

  • Module: Composite

  • File: CompositePassColorKeyer.h

Editor Properties: (see get_editor_property/set_editor_property)

  • alpha_threshold (Vector2f): [Read-Write] Thresholds any alpha value outside the specified range to zero or one respectively, with linear interpolation in-between.

  • blue_weight (float): [Read-Write] Weight of the foreground blue channel contributing to the key matte hardness.

  • chroma_shift (float): [Read-Write] Provided so users can compensate for upstream media whose chroma may be offset relative to luma with chroma-subsampled sources (such as 4:2:2 YUV captures).

    Applies a horizontal chroma shift, in input texels, to the foreground sampled by the color keyer pass. Center-pixel luma is preserved. Zero disables the shift.

  • clean_plate (Texture): [Read-Write] Clean plate background for calculating color differences per pixel, instead of the static key color. Resolution must match the composite actor render resolution.

  • clean_plate_countdown (float): [Read-Write] Setting that controls how long to delay before capturing a clean plate

  • denoise_method (CompositeDenoiseMethod): [Read-Write] Denoising method applied before the keyer.

  • despill_only (bool): [Read-Write] Only apply the despill algorithm controlled by DespillStrength, alpha is unmodified.

  • despill_strength (float): [Read-Write] Strength of the spill reduction, 0.0: none, 1.0: full.

  • devignette_strength (float): [Read-Write] Strength of the vignette removal. Used to improve plate uniformity & remove darker corners.

  • display_name (str): [Read-Write] The display name of the pass

  • green_weight (float): [Read-Write] Weight of the foreground green channel contributing to the key matte hardness.

  • invert_alpha (bool): [Read-Write] Invert the alpha key.

  • is_enabled (bool): [Read-Write] Whether or not the pass is active.

  • key_color (LinearColor): [Read-Write] Static background key color.

  • keyer_source (CompositeKeyerSource): [Read-Write] Source used by the keyer to derive the screen color: either a static key color or a clean plate texture.

  • plate_texture_preview_size (float): [Read-Write] Setting that determines how large to display the plate texture ‘picture-in-picture’ preview in the level editor when using the eye dropper color picker

  • preserve_vignette_after_key (bool): [Read-Write] When enabled, we undo devignetting before outputting the keyed plate.

  • red_weight (float): [Read-Write] Weight of the foreground red channel contributing to the key matte hardness.

  • screen_type (CompositeColorKeyerScreenType): [Read-Write] Type of screen color (required). The keyer works best against red, green or blue backgrounds.

  • visualization (CompositeColorKeyerVisualization): [Read-Write] Vizualize the alpha key or fill.

property alpha_threshold: Vector2f

[Read-Write] Thresholds any alpha value outside the specified range to zero or one respectively, with linear interpolation in-between.

Type:

(Vector2f)

property blue_weight: float

[Read-Write] Weight of the foreground blue channel contributing to the key matte hardness.

Type:

(float)

property chroma_shift: float

[Read-Write] Provided so users can compensate for upstream media whose chroma may be offset relative to luma with chroma-subsampled sources (such as 4:2:2 YUV captures).

Applies a horizontal chroma shift, in input texels, to the foreground sampled by the color keyer pass. Center-pixel luma is preserved. Zero disables the shift.

Type:

(float)

property clean_plate: Texture

[Read-Write] Clean plate background for calculating color differences per pixel, instead of the static key color. Resolution must match the composite actor render resolution.

Type:

(Texture)

property denoise_method: CompositeDenoiseMethod

[Read-Write] Denoising method applied before the keyer.

Type:

(CompositeDenoiseMethod)

property despill_only: bool

[Read-Write] Only apply the despill algorithm controlled by DespillStrength, alpha is unmodified.

Type:

(bool)

property despill_strength: float

none, 1.0: full.

Type:

(float)

Type:

[Read-Write] Strength of the spill reduction, 0.0

property devignette_strength: float

[Read-Write] Strength of the vignette removal. Used to improve plate uniformity & remove darker corners.

Type:

(float)

property green_weight: float

[Read-Write] Weight of the foreground green channel contributing to the key matte hardness.

Type:

(float)

property invert_alpha: bool

[Read-Write] Invert the alpha key.

Type:

(bool)

property key_color: LinearColor

[Read-Write] Static background key color.

Type:

(LinearColor)

property keyer_source: CompositeKeyerSource

either a static key color or a clean plate texture.

Type:

(CompositeKeyerSource)

Type:

[Read-Write] Source used by the keyer to derive the screen color

property preserve_vignette_after_key: bool

[Read-Write] When enabled, we undo devignetting before outputting the keyed plate.

Type:

(bool)

property red_weight: float

[Read-Write] Weight of the foreground red channel contributing to the key matte hardness.

Type:

(float)

property screen_type: CompositeColorKeyerScreenType

[Read-Write] Type of screen color (required). The keyer works best against red, green or blue backgrounds.

Type:

(CompositeColorKeyerScreenType)

property visualization: CompositeColorKeyerVisualization

[Read-Write] Vizualize the alpha key or fill.

Type:

(CompositeColorKeyerVisualization)