Replace Background

The Replace Background node cuts a subject out of a video and places them over a new background, image or video.

Inputs and outputs

Subject: a video containing the subject to cut out. This input only accepts videos.
Background: the new background, an image or a video.
Flow: an optional input that controls when this node runs. It can only be fed by the Trigger node or a logic node like Sequence or Router.
Video (output): the finished composited video.

Both Subject and Background are required. If either is missing, the run stops and tells you which one to connect or upload.

Aspect ratio: choose from 16:9, 9:16, 4:3, 3:4, 5:4, or 4:5. The longest edge renders at 1920 pixels.
Subject, Quality & Audio Settings: opens a panel with:
- Subject Position: where the cut-out subject sits over the new background, Full Frame, Bottom Center, Bottom Left, or Bottom Right.
- Quality: the cut-out model to use, General, People, High Quality, or Fast.
- "Keep Subject audio" and "Keep Background audio" toggles. The Background audio toggle only applies when your Background is a video.

Your Subject video can be up to 60 seconds long. Longer clips are cut off at that mark.