Replace the background in an AI video: Ray3.2 or an Omni edit on Sume?

Luma's Ray3.2 announcement lists an enhanced reframe capability that covers aspect ratio changes, frame extension and background replacement while keeping the original lighting. Sume's catalog lists no Luma id, so on Sume the background swap is a prompt edit with gemini-omni-flash-1.1: you send the source clip as video_url and describe the change.

Both facts were read on 2026-10-07, Luma's from its Ray3.2 post and Sume's from the Video Router docs.

What each route states

Luma's post was published on June 9, 2026 and lists 1080p output and clips of up to 20 seconds. It does not give a price. Sume's Omni edit mode has hard rules that are easy to trip on.

The Sume request

Edit mode takes prompt and video_url. video_url is the edit source, so it cannot be sent together with image_url, end_image_url or reference_*_urls; if you want a clip to condition a new generation, use reference_video_urls instead.

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: omni-bg-001" \
  -d '{
    "model": "gemini-omni-flash-1.1",
    "prompt": "Replace the office background with a sunlit greenhouse. Keep the person and the lighting on them the same.",
    "video_url": "https://example.com/clip.mp4",
    "resolution": "720p",
    "mode": "async"
  }'

Writing the prompt so the subject survives

• Say what stays: the person, their clothing, the camera move.
• Name the new background in concrete nouns and one light direction.
• Do not ask for a different aspect ratio in the same job; crop afterwards.
• Edit a short test clip first, then the full one, since the output follows the source.

If you specifically need Ray3.2

Luma sells Ray3.2 through its own API for enterprise integrations. That path is outside Sume. If your brief says "Ray3.2 HDR with EXR", you will not get it from an Omni edit, which returns a normal video file. If the brief says "swap the background and keep the shot", the Omni route is the one Sume documents.

Checking that the edit kept the shot

Edits fail in quiet ways: the subject's face drifts, the light on the person changes, or the camera move is replaced by a new one. Compare the first, middle and last frames of the source and the result side by side before you accept an edit. If the subject drifts, shorten the instruction rather than lengthening it, and name only the element that should change.

Because Sume's Omni edit takes its output length from the source clip, a long source costs more than a short one. Cut your test to a few seconds, perfect the prompt there, then run the full clip.

• Frame 0: does the subject match the source?
• Midpoint: is the background change stable under motion?
• Last frame: has the lighting on the subject stayed put?

What Luma's post does not say

Luma's page gives no price and no per-feature limits for reframe, so a cost comparison would be invented. What it does state is a set of capabilities and an API for enterprise integrations. If you need those capabilities, the right step is to read Luma's API terms directly; the Sume side of this comparison only covers what Omni's documented edit mode does.