Video Blend

Node type: process:video_blend
Category: process

Description

Blend two videos frame by frame with an ffmpeg blend mode (lighten, multiply, screen, overlay and 19 more). Top Video is the upper layer, Bottom Video the base. Blends run on YUV planes, so modes like lighten and screen shift colors across the whole frame, not only where the top layer is bright: not a clean way to hide a region. The output ends with the shorter clip unless End With Shorter Clip is off. Flat price per run.

Pricing

• Cost: ~16 credits per generation
• Notes: fal bills this by compute time ($0.001 per compute second). Priced flat per run, which covers about 50 compute seconds; a 30 second 1080p blend should finish well inside that. Very long or 4K clips can cost fal more than the flat price.

Canvas ports

These appear as port handles on the left side of the node.

ID	Label	Details
top_video_url	Top Video	VIDEO (required) — The upper layer.
bottom_video_url	Bottom Video	VIDEO (required) — The base layer.

Sidebar config

These render as form fields in the right-side config panel when the node is selected.

ID	Label	Details
blend_mode	Blend Mode	TEXT · options: addition, average, burn, darken, difference, +18
opacity	Opacity	NUMBER · 0…1 — Opacity of the top layer, 0 to 1.
shortest	End With Shorter Clip	BOOLEAN

Outputs

ID	Label	Type
video	Blended Video	VIDEO

Colors shift: blends run in YUV, not RGB

The blend is computed on the video's YUV planes, so modes like lighten and screen act on the color channels too, not just brightness. Parts of the frame you expect to stay untouched change color. Measured: lighten with a black and white Segment Mask on top cut saturation by about 24% across the whole frame (skin went pink, grass grey, sky lavender). So this node is not a clean way to hide a face or any other region. Use it for looks where a color shift is fine.

A few modes worth knowing

• lighten keeps the brighter value on each plane.
• multiply darkens; screen brightens softly, which suits light leaks and glows laid over footage.
• normal with Opacity below 1 lays the top clip over the bottom at that opacity.

Length and frame size

The output ends when the shorter clip ends. Turn off End With Shorter Clip to run to the end of the longer one. Use two clips of the same frame size.

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Auto-generated from the Wireflow node registry.