Seedance 2.5 shortest clip: 4 s, $1.07 at 480p; trim to 3 s for $0.02

Seedance 2.5 does not accept a duration below 4 seconds, so a 3-second shot has to be generated as 4 seconds. On Sume that costs $1.07 at 480p, $2.31 at 720p and $5.69 at 1080p. If you need exactly 3 seconds, cut the result with Sume's video trim, which costs $0.02 per job, so the 480p total is 4 x $0.268677 + $0.02 = $1.094708, shown as $1.09.

The floor on each row

The 4-second floor is specific to the Seedance family. Wan 3.0 goes down to 2 seconds and Gemini Omni Flash 1.1 down to 3, while H3 and H3 Max start at 5.

Trimming to 3 seconds

The video trim API cuts a [start, end) range from one Sume-hosted clip into a new MP4. It needs video_url, start, and one of end or duration, and its public rate is $0.02 per job. The source does not change, so you keep the 4-second original.

The trim is a second job, polled through GET /v1/jobs/:id/status. Send an Idempotency-Key on the trim so a retry does not queue a second one.

curl -X POST https://api.sume.com/v1/video-trim \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: trim-3s-001" \
  -d '{"video_url": "https://media.sume.com/artifacts/artf_demo/clip.mp4", "start": 0, "duration": 3}'

When not to bother

If the 3-second shot is an ad hook or a loop, Wan 3.0 is simpler: a 3-second job at 480p is 3 x $0.0625 = $0.1875, shown as $0.19, with no trim. Pick Seedance 2.5 for the look, not for the short clip.

Why not just pay for 4 seconds

Often you can. A 4-second hook is a perfectly good length, and trimming adds a second job and a second wait. Trim only when the cut is part of the design, for example when 3 seconds must match a beat.

Remember that a tighter cut changes what you paid for: you are billed for the generated 4 seconds whether or not you keep them all. The extra second is the premium for choosing Seedance 2.5 over a row with a lower floor.