Best AI video model for seamless loops: the end-frame rows

To make a clip that loops, you need a row that accepts an end frame, because the usual trick is to give the model the same picture (or a matching pose) as the first and last frame. On Sume, the rows that list an end frame are the Seedance family, kling-3, wan-3.0, minimax-h3, minimax-h3-max and gemini-omni-flash-1.1. The rows that do not are grok-imagine-video-1.5, the Veo rows, higgsfield-genjutsu, h3-max-recast and the Tencent text-to-video rows.

Which rows accept an end frame?

An end frame goes in frame_images with frame_type: "last_frame", next to the first_frame entry. The catalog validates frame_type against what each row lists, so an unsupported row answers 400 unsupported_capability instead of dropping the field.

How do I request a loop?

Send the same image URL as both frames, a short duration, and the lowest resolution the row lists. The docs describe the two frame types but do not promise that identical frames produce a seamless join, so treat the first result as a test and look at the seam before you spend more. Audio matters for loops: a row that always makes sound (H3, H3 Max, Omni) will give you a track that does not loop on its own, so plan to detach or replace it.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "wan-3.0",
    "prompt": "Steam drifts up from the cup, camera static, the scene returns to its start",
    "duration": 4,
    "resolution": "480p",
    "aspect_ratio": "16:9",
    "frame_images": [
      {"type": "image_url", "image_url": {"url": "https://example.com/cup.jpg"}, "frame_type": "first_frame"},
      {"type": "image_url", "image_url": {"url": "https://example.com/cup.jpg"}, "frame_type": "last_frame"}
    ]
  }'

When is a loop not worth it?

If the clip must match a brand film exactly, a loop made from model motion is a gamble. A cheaper path is a short clip, then repeat it on a timeline. Pick the row by length: wan-3.0 can make a 2-second loop, while H3 and H3 Max start at 5 seconds.