Avoid an unintended black background in Duo video

Decide whether you need a still or a video

Transparent PNG or WebP is useful when a static phone needs to sit over another design. Native MP4 is an opaque video deliverable. If the scene was prepared with Transparent Bg for a still, review that choice before exporting motion.

A dark area inside the device is a separate issue. It may be part of the uploaded artwork or the folding screen treatment. Changing the outer scene background does not change those pixels.

Build the final backdrop into the video

Use a solid color or gradient that fits the destination and separates the phone from its surroundings. If the video will appear inside a dark website section, match its visual treatment deliberately rather than relying on transparency.

1. Turn off Transparent Bg for the video composition.
2. Choose a solid or gradient background in the scene controls.
3. Inspect the darkest phone edges against that background.
4. Play the entire sequence, including the fully open and closed poses.
5. Export Video with the intended preset and inspect the downloaded MP4 outside the editor.

Locate the remaining dark region

If black bars appear around the whole video, compare its aspect ratio with the player or publishing container. If bars are inside the screen, inspect the original source image or recording for baked-in margins. If softness or darkening occurs only while the phone folds, compare Fold animation at the same pose.

Keep a transparent still and an opaque video as separate deliverables when you need both. Do not rename one format to another or assume a file viewer’s black transparency backdrop is part of a PNG. Review the actual output type and the final placement together.