Click the image or video in the timeline you want to edit.
On the right, open the Appearance panel.
Set Corner radius:
Enter a pixel value for how rounded the corners should be.
Example: 10 or 20 for slightly rounded corners.
Example: 100 for very rounded corners.
The preview updates as you type so you can tune the look.
Tips
Small values (10–20px) keep corners subtle.
Larger values feel more playful or modern.
On a square asset, a radius of 50% can make a circle (depending on aspect ratio).
Use similar values across clips for a consistent look.