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Keyer

Keyer · screenshot coming soon

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What this node does

Keyer builds a matte from your footage using one of several strategies: key on luminance (brightness), on a specific color, on a green/blue screen, or pass through with none. Unlike a one-slider chroma key, it gives you a full keying curve — a center point plus separate tolerance and softness for the darker (lower) and brighter (upper) sides — so you can shape exactly which values are kept. It also has an angular despill for cleaning screen fringe. Input and output are COMFYTV_VIDEO. It has a ▶ Run. Like PIK Keyer, it picks its mode automatically: wire any of the side inputs (in/out mask or background) to run the full render; leave them empty and it runs a fast, previewable single-image key.

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When to use it

  • You want to key on brightness (e.g. isolate highlights or shadows) rather than a color.
  • A screen key needs asymmetric handling — tighter on one side of the threshold than the other.
  • You need finer edge shaping than Chroma Key offers, but without a clean plate.

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Parameters

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mode

The keying strategy: luminance (default), color, screen, or none.

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key_color

The reference color for color/screen modes. Hex, default #000000.

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The keying curve (softness_lower, tolerance_lower, center, tolerance_upper, softness_upper)

These five shape which values become the matte, from dark to bright:
  • softness_lower — feather below the lower tolerance. Range -1.0–0.0, default -0.5.
  • tolerance_lower — how far below center is still fully kept. Range -1.0–0.0, default 0.0.
  • center — the value the key is centered on. Range 0.0–1.0, default 1.0.
  • tolerance_upper — how far above center is still fully kept. Range 0.0–1.0, default 0.0.
  • softness_upper — feather above the upper tolerance. Range 0.0–1.0, default 0.5.
Widen the tolerances to keep more; increase the softness values to feather the transition.

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despill / despill_angle

Spill suppression strength and its hue angle. despill ranges 0.0–2.0, default 1.0 (0 = off). despill_angle ranges 0–180 degrees, default 120 (green). Set the angle toward your screen hue.

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output

matte (default) for a grayscale mask, alpha for real transparency, premult for premultiplied RGB, or composite to render over the background. (alpha needs the VP9 encoder — use matte if it errors.)

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Side inputs (optional)

  • video — the plate to key.
  • in_mask — force areas fully opaque (keep).
  • out_mask — force areas fully transparent (remove).
  • bg_video — background used when output is composite.

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Outputs

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Tips

  • For a luma key, start with mode=luminance, set center where the split should be, and open the tolerances/softness until the matte looks right.
  • Wiring a side input switches to full-render mode; with none it stays a live-previewable key.
  • To interoperate with native ComfyUI nodes, insert a Bridge. See bridges.md.
  • Chroma Key — simpler single-color key.
  • PIK Keyer — clean-plate / IBK-style keyer for the hardest screens.
  • Select0r — color-space region keyer (RGB/ABI/HCI) with shape and edge controls.
  • Matte Monitor — visualize how clean the resulting matte is.