Seedance 2.5 has a 4-second minimum: the shortest clip is $1.0747

The shortest Seedance 2.5 clip on Sume is 4 seconds, and it costs $1.0747 at 480p, $2.3112 at 720p and $5.6862 at 1080p. The docs list seedance-2.5 at 4 to 30 seconds, and the three Seedance 2 ids share the 4-second floor with a 15-second ceiling (Video generation).

Send an integer from 4 up. A 2 or 3 second brief is not a Seedance request; use a model whose catalog range starts lower, such as wan-3.0 (2 to 30 s) or gemini-omni-flash-1.1 (3 to 10 s).

Cost of the 4-second floor

Planning around it

A 4-second minimum matters when you cut to beats shorter than that. Two practical routes:

• Generate 4 s and trim the excess with the video trim tool, which is a separate $0.02 job on a media.sume.com source on a media.sume.com source.
• Start at 5 or 6 s and treat the extra second as handle for the edit.
• For true 2 to 3 s stings, pick a model whose range allows them and skip the trim.

Request

The smallest valid Seedance 2.5 call:

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: hook-004" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "Macro shot of coffee pouring into a glass",
    "duration": 4,
    "resolution": "480p",
    "aspect_ratio": "9:16"
  }'

Reservation

The hold at submit for that call is $1.0747. If the balance is short, the call returns 402 insufficient_credits before any work starts.

What 5 seconds costs

One more second is a linear step. A 5-second Seedance 2.5 clip at 9:16 is $1.3434 at 480p, $2.889 at 720p and $7.1078 at 1080p, so the 4-second floor and a 5-second handle differ by about a quarter of the 4-second price.