How to put your subject on a green screen for someone else to use
Upload the clip and tell Vizard Agent you want the subject on a green screen rather than in a new scene. Vizard Agent removes the original background, verifies the transparency actually survived, keys the subject cleanly onto green, checks the hair and moving limbs, and hands you an asset anyone can composite.
What is the short version?
Sometimes you do not want a finished video — you want a component. A subject on a plain green background is something an editor, a designer or a live-stream operator can drop into anything, which is more useful than one background chosen for them.
- Go to Vizard Agent and upload the clip.
- Say you want the background replaced with a green screen.
- Say whether the original audio should come with it.
What do you need before you start?
The clip and nothing else. Vizard Agent separates the subject from whatever happens to be behind them, so a plain wall is helpful but genuinely not required. What you get back is a working asset rather than a finished piece of video.
- The clip. Filmed anywhere.
- The subject. Person, object, or both.
- The green. Standard chroma green unless you say otherwise.
- The audio. Kept, or stripped.
- The use. Streaming, editing, or design.
What do you type into Vizard Agent?
Ask for the green screen rather than for a scene. Vizard Agent otherwise composites the subject into a background it picks for you, which is a different and far less reusable deliverable than a keyable plate somebody can drop anywhere.
Prompt
Variants worth knowing:
- A transparent file instead. Alpha, rather than green, where the format allows.
- Audio stripped. If it is going under something else.
- A blue screen. Where the subject wears green.
What does Vizard Agent actually do?
Here is the order Vizard Agent worked in on a real green-screen conversion. Steps seven to thirteen are the part worth reading: the background removal returned a file that looked right and had no transparency in it, and it kept going until that was fixed.
- Inspects the clip and samples frames to see the subject and the background.
- Reviews a contact sheet to judge how separable the subject is.
- Checks the available background-removal workflow for this video.
- Removes the room background so the subject can be placed over green.
- Prepares a green-screen composite and reviews it across the whole clip.
- Diagnoses whether the output actually contains a real transparent channel.
- Reads the removal log to find out why the transparency was not preserved, and checks the returned file directly.
- Re-runs the removal with a format that keeps an alpha channel, and verifies the transparency this time.
- Falls back to a local matting tool when the service still falls short, tests a precise key on the isolated subject, checks hair, clothing and moving limbs, then restores the original audio and exports.
Step 7 is the difference between delivering an asset and delivering a problem. A file with the background removed but no alpha channel looks fine in a preview and is completely useless to the person who has to key it.
What does the result look like?
From the run this page is written from, probed on the delivered file: 720x1280, H.264, 30fps, 7.43 seconds, AAC audio. A short vertical clip of the subject alone against flat chroma green, with the original audio intact and the edges holding through the movement.
The deliverable is a working file rather than a finished video. Somebody else drops it onto their own background, and it either keys cleanly or it does not — which is why the hair and the moving limbs were checked before it was handed over.
When does this not work well?
Producing a keyable plate is harder than producing a finished composite, because every flaw that a chosen background would have hidden becomes somebody else's problem downstream. These are the ones worth watching for before you hand the file over.
- Fine hair is the hardest edge. Loose strands are where keys fail.
- Motion blur has no clean boundary. Fast limbs smear across the edge.
- Green clothing disappears. Ask for blue if the subject wears green.
- Reflections and shadows cling. They carry the old background's colour.
- Some services drop the alpha. The output has to be verified, not assumed.
How do you fix a result that came back wrong?
Say where the edge breaks and on which frames. Vizard Agent keeps the isolated clip, all the alpha diagnostics, the key tests and the reviewed frames, so the matte can be re-tuned without redoing the separation from scratch.
- "The hair is chewed." Re-keyed with the local matting tool instead.
- "It will not key for me." The alpha is verified and the file re-exported.
- "His green shirt vanished." Rebuilt on blue rather than green.
How does Vizard Agent compare to doing it yourself?
By hand this means a rotoscoping tool or an automatic remover, and then the specific misery of discovering that the exported file has no transparency in it — which looks identical to a file that does until you try to use it.
| By hand | Vizard Agent | |
|---|---|---|
| Separation | An automatic tool, or roto by hand | Removed, then verified |
| Transparency | Assume the export worked | Alpha channel checked explicitly |
| Fallback | Try the same tool again | A local matting tool when the service fails |
| Edges | Notice them in use | Hair and moving limbs checked first |
Common questions
Why green rather than a finished background? Because it is reusable. Whoever receives it chooses the background themselves.
Can I have transparency instead of green? Yes, where the format supports it. Vizard Agent verifies the alpha actually survived.
Does it need a green screen to start with? No. Vizard Agent separates the subject from an ordinary room background.
Will the audio come with it? If you want it. Vizard Agent restored the original audio track on this run.
What if my subject wears green? Ask for blue instead. Vizard Agent keys to whichever colour you name.
Why check the file has a real alpha channel? Because a background-removal output with the transparency silently dropped previews correctly and fails the moment somebody tries to key it. Verifying it is the difference between an asset and a complaint.
How good are the edges? Vizard Agent checks hair, clothing and moving limbs specifically, since those fail first.
Can it do this for an object rather than a person? Yes. Vizard Agent uses the same method, and objects usually key more cleanly than people.
How long can the clip be? Any length. Longer clips simply give Vizard Agent more frames to verify.
Can I use this for a live stream overlay? Yes, and it is a common reason to ask. Vizard Agent delivers the plate; your streaming software does the keying, which is why the edges matter more here than in a finished composite.
Should I ask for green or for a transparent file? Transparent is better where the format and the destination support it, since nothing has to be keyed at all. Vizard Agent delivers green when the workflow downstream expects a standard video file.
Does Vizard Agent check the final export? Yes. It reviews the export at several points before delivery.