How do I use a transparent WebM as an OBS Stinger transition?

A Stinger is a short video that plays while OBS switches scenes. Use a VP9 WebM with a real alpha channel so the animation composites over both scenes instead of painting a black rectangle. This is not the same as dropping a looping overlay into a scene.

Stinger vs overlay (do not mix these up)

OBS has two common places for transparent WebM. They solve different jobs:

• Stinger transition (this page): Lives in the Scene Transitions dock. It plays when you change scenes. The cut happens at a transition point you set.
• Media Source / Browser Source overlay: Lives in the Sources list. It sits on top of a scene—alerts, webcam frames, lower-thirds. That walkthrough is Can I use a transparent video overlay in OBS?

If you add the file as a Media Source, it will not fire on scene changes. If you only needed a persistent overlay, stop here and use the overlay guide.

What the WebM file needs

• Codec / pixels: VP9 WebM with yuva420p (alpha actually in the file)
• Length: Typically one or two seconds. Long stingers feel late on every scene change.
• Coverage: The animation should cover the frame at the moment you want the scene to swap—usually the peak of a wipe, slam, or logo hit.
• Do not use: Everyday H.264 MP4. It has no alpha, so OBS will show a black plate during the transition.

ExportAlpha is a file workflow: AI background removal, then true-alpha encode. Limits are 60 seconds, 1080p, and 200MB on upload. New accounts get 5 free processing seconds. It will not key your webcam live.

Add the Stinger in Scene Transitions

Typical OBS Studio setup (labels can vary slightly by version):

1. Find the Scene Transitions dock—not Sources.
2. Click + and choose Stinger.
3. Name it, then browse to your transparent .webm.
4. Set Transition Point Type to Time or Frame. Put the point where the graphic fully covers the old scene—often the middle of a one-second clip (for example 400–600 ms). You will tune this by watching a preview.
5. If the file has audio you want on the cut, enable monitoring/output for the stinger. Leave it off if the animation is silent.
6. Select that Stinger as the active transition, then switch scenes to test.

Do not add a Chroma Key filter to the stinger. If you need chroma key, the file does not have alpha—re-export it.

Transition point, not a source loop

Overlays often loop. Stingers should not. The file plays once per scene change. If the new scene appears too early or too late, change the transition point; do not convert the file into a Media Source to “fix” timing.

Track Matte is a different Stinger mode

OBS Studio 27+ can drive a Stinger with a Track Matte: a mask video that tells OBS where to show the outgoing scene versus the incoming scene. That is an advanced layout (often side-by-side or stacked in one file), not the basic transparent-WebM wipe this page covers. Official notes: Track Matte Stinger Transitions.

Black rectangle during the cut

• No alpha in the file: Re-export VP9 WebM with yuva420p. See why transparent video looks black.
• Wrong dock: You added a Media Source overlay instead of a Stinger.
• Transition point at 0: The scene swaps before the graphic covers the frame.

Frequently Asked Questions

How do I use a transparent WebM as an OBS Stinger transition?

Add a Stinger under Scene Transitions, point it at a VP9 WebM with alpha, and set the transition point to the cover frame. Test by switching scenes, not by showing the file as a source.

Is an OBS Stinger the same as a Media Source overlay?

No. Overlays stay on the scene. Stingers play on the cut. Use the Media Source / Browser Source guide for overlays.

Can I use this tool for live camera keying in OBS?

No. This is not a stream-keying plugin. You upload a file, get a transparent WebM or ProRes, then attach that file as a Stinger or overlay.

Sources

• OBS Track Matte Stinger Transitions (Stinger overlay + cut / matte modes): Official KB
• OBS Media Source (overlay files, not scene transitions): Official KB