Remove background from video with AI: what Sume covers

Sume does not ship a video background-removal or matting endpoint. Sume RMBG 1.0 takes a public HTTPS image_url, so it works on stills only. For video, the closest options are a prompt edit through video_to_video and a crop. Adobe's September 2026 Firefly notes describe a Remove Background for video clips that works across the whole clip without frame-by-frame masking; Sume has no equivalent.

Sume facts are from Video Router, Video frames and Video filter, read 2026-09-30.

What does RMBG 1.0 take?

The OpenAPI description reads: "Sume RMBG 1.0 background-removal request. Provide a public HTTPS image_url." There is no video_url field. You can pull a still from a clip with video frames, remove its background, and use the result as an image, but that gives you one cut-out, not a matted video.

Can a prompt change the background of a clip?

Yes, as an edit, not a matte. The gemini-omni-flash-1.1 model on Video Router accepts video_url as the edit source, and the prompt describes the edit. The docs' own example is "Replace the bottle with an apple. Keep everything else the same." You would describe the background change the same way and review the result. The output is a new generated video, so it can differ from the source in ways a mask would not.

What about cropping the background out?

If the background is a border, video filter's crop op takes a rectangle as fractions of the source frame (x, y, width, height). That removes pixels outside the rectangle; it cannot cut around a moving subject.

What should I do for a transparent or masked result?

Sume does not return a transparent video. If you need a matte, do that step in an editor, then bring the result back as a Sume-hosted clip for trimming or assembly. For stills, see remove backgrounds from images in bulk. Frame extraction is capped at 24 frames per call, so it is a way to get references, not a per-frame matting pipeline.