Replace a green-screen background: three Sume routes compared

For a clip shot on green, the Sume route that matches the job is the catalog Format sume-green-screen, called at POST /v1/formats/sume/sume-green-screen/runs. For a clip that already has a real background that you want to change, use the Gemini Omni video edit in the Video Router. ByteDance lists green-screen background replacement as a Seedance 2.5 editing feature (read 2026-10-05), but Sume's docs list seedance-2.5 as a text, image and reference generator with a 4 to 30 second range, not as an editing route. Do not send a source video to Seedance on Sume and expect a keyed result.

Route 1: the catalog Format

The Format catalog lists sume-green-screen among the slugs you can call at the reserved sume handle with any key that carries formats:write. The page does not describe what it takes, so read it first: GET /v1/formats/sume/sume-green-screen returns a description and an io profile with input_kind and output_kind. If io is null, the Format predates registration and the description is all you have. The run, its media and its spend belong to your key, and the call is the same contract as every other Format: Idempotency-Key, an optional generation_spend_cap_usd, and a receipt you poll.

Route 2: an Omni video edit

gemini-omni-flash-1.1 has a video_to_video capability. You send video_url and a prompt that gives the edit instruction. The docs example replaces a bottle with an apple. The same fields are the way to ask for a different background, but the docs show an object swap only, so test one clip before you commit a batch. Three rules from the page matter: video_url cannot be sent with image_url, end_image_url or any reference_*_urls; the request takes no aspect_ratio and no duration; and resolution is optional with a default of 720p. Google describes video references of up to 3 seconds for the model (read 2026-10-05); the edit source limit is not stated on the Sume page, so use a short clip.

curl -X POST https://api.sume.com/v1/video-router/generate \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: bg-swap-001" \
  -d '{
    "model": "gemini-omni-flash-1.1",
    "prompt": "Replace the green background with a sunlit kitchen. Keep the person and product unchanged.",
    "video_url": "https://example.com/greenscreen-clip.mp4",
    "resolution": "720p",
    "mode": "async"
  }'

Route 3: a filter program, checked for free

POST /v1/video-filter/check validates a filtergraph without a job, credits or an encode, and returns diagnostics for an unknown filter instead of a 400. A real encode costs $0.02 per job at the public rate, and the source must be a media.sume.com clip, so import it first. The docs list the allowlisted filter families as tone, blur, geometry, fade and internal compositing, and do not list a keying filter by name. Send your graph to /check and let the diagnostics tell you whether a keyer is accepted before you design around it.

Which one for which clip

Pick by what you start with and what you want back.

Whichever route you choose, write the first test as a one-clip job with its own idempotency key and a low spend cap, and look at the edges of the subject. Hair, glass and thin cables are where a background swap shows. If the edges fail on the cheapest route, move to the next one instead of retrying the same body.