Looping product banner: same photo as first and last frame

To make a looping product banner, send the same photo twice in frame_images to POST /v1/videos on seedance-2, once as first_frame and once as last_frame. The model animates between two identical frames, so the clip ends where it began and repeats without a visible jump. The catalog lists both frame types for the model.

Why this works

seedance-2 lists first_frame and last_frame in supported_frame_images. When you pin both, the model has to leave the packshot and come back to it. Anything that moves, such as steam, light or a slow rotation, returns to the start pose at the end of the clip.

A loop is a good fit for a hero banner or an in-feed unit, where a short clip repeats. Pick a short duration. A 4 to 6 second clip is easier to keep clean than a long one.

The request

Use the same URL for both frames. The prompt asks for a motion that can return, such as a slow breathing zoom, drifting light or a gentle sway.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: banner-loop-sku-77" \
  -d '{
    "model": "seedance-2",
    "prompt": "Soft light drifts across the product, steam curls up, then settles",
    "duration": 5,
    "aspect_ratio": "16:9",
    "frame_images": [
      {"type": "image_url", "image_url": {"url": "https://example.com/p77.jpg"}, "frame_type": "first_frame"},
      {"type": "image_url", "image_url": {"url": "https://example.com/p77.jpg"}, "frame_type": "last_frame"}
    ]
  }'

What to check

Play the clip on repeat before you publish. A loop fails in the middle if the model drifts away from the product, and it fails at the seam if the audio does not match. If the model generates audio, decide whether the loop should be silent.

The catalog tells you which models accept which frame types, so read supported_frame_images before you switch models. A model that lists only first_frame cannot close a loop this way.

Make it fit the slot

Banners are rarely 16:9. If the slot is a different shape, request the closest supported aspect ratio and crop in the page, or use a Timeline render with cover, contain or blur to fit a canvas.