---
title: "Video Blend"
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."
updated: 2026-10-03
---

# 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.

---

_Auto-generated from the Wireflow node registry._

---

Documentation index: fetch https://www.wireflow.ai/llms.txt for the full list of Wireflow docs.