Green Screen Video Editor Online - Remove and Replace a Background
Key out a green screen and put anything you like behind it: a solid colour, a photo, or another video. Click the screen in the preview to sample the exact colour your footage was shot against, then tune the edge until it looks right. Nothing is uploaded - the chroma key runs on your own device.
For best results and widest format support, use Chrome or Edge on a desktop computer. Other browsers use a different engine with limited codec support.
Drop your video here
or click to select a file
Works with MP4, MOV, WebM and MKV
🔒 Your files never leave your device - 100% private & secure
video.mp4
Click the screen in the preview to sample its exact colour.
How close to the screen colour still counts as background. Raise it if green is left over.
How soft the cutout edge is. Raise it if the outline looks jagged or cut out with scissors.
Removes the green light the screen throws onto hair and shoulders. Lower it if real greens go grey.
Drop a video into the box above or click to browse. MP4, MOV, MKV and WebM all work. The first frame appears on the stage with the key already applied, so you can see immediately how close the default is.
Click your screen to sample it
Click anywhere on the green in the preview and that exact colour becomes the key. This is the step that matters most: the green and blue presets are guesses about someone else's lighting, and one click on your own footage is the real answer.
Choose a background
A solid colour, an image, or another video. An image or video is fitted to your frame without being stretched, and a background video shorter than your clip loops to fill it.
Tune the edge, then export
Similarity decides how much of the screen counts as background, softness controls how hard the cutout edge is, and spill removes the green light bouncing off the screen onto your subject. Click Remove Green Screen and download the result.
What actually makes a key look good
The key itself is the easy part. What separates a convincing composite from an obviously fake one is the three things around it. Sampling the real colour comes first, because no two green screens are the same green - a painted cyclorama, a pop-up fabric backdrop and a bedsheet from a shop all key at different values, and lighting moves them further apart. Edge softness comes second: a hard on-off threshold gives you a jagged, aliased cutout that reads as a sticker laid over the background, and a few pixels of ramp fixes it. Spill suppression comes third and is the one most people never think of - a green screen is a big green light, and it throws green onto your subject's hair, shoulders and anything shiny. Remove the background and that rim is still there, glowing against the new one.
This tool does the keying on your graphics card rather than in JavaScript, which is why it can work through a whole clip rather than a still. The decision it makes is per pixel, and it is made on colour alone with brightness deliberately thrown away - that is what lets a screen that is brightly lit in the middle and shadowed at the edges still key as one surface.
Getting good footage to start with
No keyer rescues badly shot footage, so it is worth knowing what helps. Light the screen separately from your subject and as evenly as you can - the flatter the green, the smaller the range the key has to cover. Stand well away from it, because the further you are the less green bounces onto you and the less work spill suppression has to do. Avoid green or reflective clothing for the obvious reason. And shoot at the highest quality your camera offers: heavy compression smears colour detail around edges, which is exactly where the key needs it most, and it is why footage straight off a phone keys better than the same clip after a messaging app has been through it.
All of it runs on your device. The video is decoded, keyed and re-encoded using WebGL, WebAssembly and WebCodecs in your own browser - it is never uploaded to a server, there is no account, no watermark and no file size limit beyond your device's own memory.
Frequently Asked Questions
How do I remove a green screen from a video?
Load the video, click on the green in the preview to sample it, pick a background, and click Remove Green Screen. If the cutout looks rough, raise Similarity until the screen disappears completely, then raise Softness until the edge stops looking jagged. Those two sliders fix almost everything.
Can I use a blue screen instead?
Yes. There is a blue preset, and beyond that you can key on any colour at all by clicking it in the preview - the tool has no special knowledge of green. Blue is the traditional choice when your subject wears green, or for anything with fine detail, and it is worth remembering the spill will be blue rather than green.
What is chroma key?
Chroma key is the technique this tool uses, and the name film and television give it. Chroma means colour: every pixel is compared against one chosen colour, whatever matches becomes transparent, and the new background shows through the hole. "Green screen" is the same thing named after the colour it is usually shot against. So a chroma key tool, a green screen remover and a background replacer are three names for this page.
Can I put a video behind my subject rather than an image?
Yes. Choose Video as the background and pick a second file. Each frame of your clip is matched to the frame of the background at the same moment, so the two stay in step, and a background shorter than your footage loops to fill it. The background's own audio is ignored - the soundtrack that survives is the one from your main video.
Why is there still a green edge around my subject?
That is spill - the screen is a large green light, and it lands on hair, shoulders and anything shiny. Raise the Spill slider, which pulls the green channel back down to the level of the red and blue around it and neutralises the rim without touching genuinely green things elsewhere in the frame. If it is severe, the real fix is standing further from the screen next time.
Why are parts of my subject disappearing?
Similarity is set too high, so colours close to the key are being treated as background. Bring it down until the subject is solid again, then deal with any leftover screen by sampling the colour more precisely rather than by pushing the slider back up. Green or teal clothing will always fight a green key - that is the case for using a blue screen instead.
Does it work on an unevenly lit screen?
Better than you might expect, because the decision is made on colour alone with brightness thrown away - a shadowed corner of a green screen and a brightly lit one are far apart in RGB but almost identical once brightness is discounted. It is not magic, though. A screen with a genuinely different hue in one area, or one so dark it has lost its colour entirely, will need Similarity raised to the point where it starts eating the subject.
Do I need a real green screen?
You need a background that is one consistent colour and clearly different from everything you want to keep - a proper screen is easiest, but a plain painted wall or a well hung sheet works. What will not work is a normal room. This tool keys on colour, so it has no way to tell a person from the furniture behind them - to change the background of a video shot in an ordinary room you need background removal that finds the person rather than the colour, which is a different technique.
Does it change the audio or the length?
Neither. The soundtrack is copied across untouched wherever the output container can carry it, and the clip keeps its original length and frame rate. Only the picture changes.
Is my video uploaded anywhere?
No, and nor is your background image or video. Every step runs in your browser using WebGL, WebAssembly and WebCodecs - the files are read from disk, composited in memory and written back out locally. Nothing is sent to a server, there is no account, and no copy exists anywhere but your own device.