# Remove a Video Background in the Concat Video Editor

> Concat cuts a person or object out of a clip with a small local model, a hand-painted mask or a chroma key, though the edges can show a soft halo that you need to check.

URL: https://concatvideoeditor.com/features/background-removal
Updated: 2026-10-18
Source: Concat Video Editor Guide, an independent guide. Not the official Concat website.

You can remove a video background in the Concat video editor without a green screen. Select a clip, tick Auto removal and a model of about 15 MB separates the subject from everything behind it on your own computer. Put a different clip on a lower track and the subject now stands in front of it.

![A speaker filmed against a white brick wall, before background removal](/images/ba-cutout-before.webp)

![The same speaker cut out by the Concat video editor and placed over a red running track](/images/ba-cutout-after.webp)

## How do you remove a video background in the Concat video editor?

1. Put the new background clip on one track and the clip with your subject on the track above it.
2. Select the subject clip. In the inspector, open the **Video** tab and then **Basic**.
3. Scroll to **Remove background** and tick it. Then tick **Auto removal**.
4. Leave **Subject** on **Auto**, the default, for a person talking to camera.
5. Adjust **Feather**, a percentage that softens the edge of the cutout.
6. Play the section back and check the edges around hair and hands.

In our test project the speaker sat on the upper track and a running track clip sat below, which gave the result above.

## What are the three removal modes?

The Concat video editor gives you three ways to cut out a subject, each a checkbox under Remove background.

| Mode | Best for |
|---|---|
| Auto removal | People or objects in normal footage. The model finds the subject for you |
| Custom removal | Shots where the model gets it wrong. You paint the mask yourself |
| Chroma key | Footage shot against a solid green or blue backdrop |

The Effects tab also has separate **Chroma Key** and **Luma Key** effects if you prefer to key a clip as an effect.

![Remove background section in the Concat inspector with Auto removal, Subject set to Auto, Feather, Custom removal and Chroma key](/images/feat-background-removal.webp)

## How do Custom removal and Chroma key work?

We tested both in Concat 0.2.7 on a clip we made with a solid green backdrop.

**Chroma key.** Tick **Chroma key** and Concat keys out the color in **Color**, which starts at 00b140, the standard chroma green. Three sliders tune it: **Similarity** (30% by default), **Softness** (10%) and **Spill** (50%). The key also appears as a Chroma Key card in the clip's **Effects** tab, where you can hide or remove it. Our green backdrop disappeared at the default settings and the clip on the lane below showed through.

![Chroma key settings in the Concat video editor with the key color 00b140, Similarity 30%, Softness 10% and Spill 50%](/images/feat-chroma-key.webp)

**Custom removal.** Tick **Custom removal** and four tools appear: a smart brush, a smart eraser, a plain brush and a plain eraser, with **Size** and **Feather** sliders. Paint over what you want to keep in the preview, watch the stroke count go up, then click **Apply**. Concat analyzes the clip from your strokes. One stroke across the subject was enough in our test, though a thin green fringe stayed on the edges. Ticking Custom removal turns Chroma key off, so pick one method per clip.

![Custom removal in the Concat video editor with smart brush, smart eraser, brush and eraser tools, Size, Feather, one stroke and the Apply button](/images/feat-custom-removal.webp)

## Does the footage get uploaded?

No. Like the captions and voice models in the Concat video editor, the cutout model runs locally and works offline after the download. That matters if you film people who did not agree to have their faces sent to a cloud service. The Concat app also adds no watermark to the export.

## How does it compare with background removal in CapCut?

The result you get is a similar idea: a person lifted out of a shot and placed over something else. The difference with Concat is the price and the privacy. CapCut puts 4K export behind a paid plan and can watermark exports that use Pro assets. Concat is free at any resolution it supports and the Concat video editor source is public on GitHub.

## What are the limits?

- **Soft edges.** In our test the speaker picked up a light halo against the red background. Try a lower Feather value first. Fine hair is hard for any model.
- **Busy backgrounds.** When the subject and the background share colors, expect to fix the mask with Custom removal.
- **One method per clip.** Auto removal, Custom removal and Chroma key are separate options, and switching to one turns the others off.
- **We did not time it.** Our test machine used software rendering, so we can't give a fair number for how fast a cutout previews or exports.

## Videos

### Video: Before and after: background removal in Concat

Raw footage on the left and the same moment exported from the Concat video editor with the speaker cut out over a new background on the right. (6 seconds, https://concatvideoeditor.com/videos/loop-cutout.mp4)

### Video: Remove a video background in the Concat video editor

Screen recording of Concat 0.2.7: put a new background on the lane below, tick Remove background on the speaker and Concat cuts the person out without a green screen. (12 seconds, https://concatvideoeditor.com/videos/demo-background-removal.mp4)

Steps shown:
1. Put the new background on the lane below
2. Select the speaker and tick Remove background
3. Concat cuts the person out, no green screen

## Questions people ask

### Do I need a green screen to remove a background in Concat?

No. Auto removal uses a model to find the subject in ordinary footage. Chroma key is there as a separate option for footage that was shot on a green or blue screen.

### Is background removal in Concat free?

Yes. It is part of the free app with no account, credits or watermark. The cutout model is about 15 MB and runs on your own computer.

### Can Concat remove the background from an object instead of a person?

Yes. The README describes background removal for people and objects. If the automatic result misses part of the object, Custom removal lets you paint the mask yourself.

### Why does my cutout have a soft glowing edge in Concat?

The cutout blends the border between subject and background. On strong colors that blend can show as a light halo. Try a different Feather value and check the preview over your real background.