Seedance 2 vs 2.5 for 4 seconds: 480p, 720p, 1080p cost

At 4 seconds and 9:16, Seedance 2.5 costs $1.07471 at 480p, $2.3112 at 720p and $5.6862 at 1080p on Sume; Seedance 2 costs $0.70308, $1.5120 and $3.4020.

Both are priced by video tokens, so the cost follows pixels times seconds. The ceilings differ: Seedance 2 stops at 15 seconds and Seedance 2.5 reaches 30 (video docs, read 2026-10-06).

Which one is cheaper at this length?

Computed per job from the Sume rate card:

What else differs?

Both accept first and last frames and image, video and audio references, and both can generate audio.

• Seedance 2.5: 4 to 30 seconds at 480p/720p/1080p.
• Seedance 2: 4 to 15 seconds, also 1080p.
• Aspect ratios follow supported_aspect_ratios in the model list.

curl -X POST "https://api.sume.com/v1/videos" \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: clip-seedance-2.5-4s-001" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "A product on a desk, slow push-in, natural light",
    "duration": 4,
    "resolution": "720p",
    "aspect_ratio": "9:16"
  }'