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Matte Morphology

Matte Morphology · screenshot coming soon

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What this node does

Matte Morphology reshapes a matte using morphological operations. Erode pulls the matte edge inward (shrink), dilate pushes it outward (grow), and open/close are the combined operations that clean up noise: open (erode then dilate) removes small stray specks, close (dilate then erode) fills small holes. You control the amount separately in the horizontal and vertical directions. Input and output are COMFYTV_VIDEO. It runs as a live fx-preview filter (emits an fx spec and passes through), so you can preview the reshaped matte without a full render.

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When to use it

  • A key leaves a fringe of background around the subject — erode a pixel or two to trim it.
  • The matte has holes or speckles — use close/open to clean them.
  • You need to choke or spread the matte before compositing with Key Mix.

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Parameters

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op

The morphological operation: erode (default, shrink), dilate (grow), open (remove small specks), or close (fill small holes).

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size_x

Horizontal size of the operation, in pixels. Range 0–64, default 1. 0 means no effect on that axis.

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size_y

Vertical size of the operation, in pixels. Range 0–64, default 1. 0 means no effect on that axis.

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Outputs

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Tips

  • Start with erode at size 1–2 to trim a thin background halo; more than a few pixels starts eating real edges.
  • Use close to seal pinholes in a subject, open to drop isolated noise dots.
  • Set size_x and size_y independently when the matte problem is directional (e.g. horizontal motion blur).
  • To interoperate with native ComfyUI nodes, insert a Bridge. See bridges.md.
  • Matte Monitor — see the matte defects before and after morphing.
  • Key Mix — composite with the cleaned matte.
  • Keyer / PIK Keyer / Select0r — produce the matte.