Seedance 2.5 vs 2.0: what changed in duration and references
Seedance 2.5 raises the clip to 30 seconds and references to 50 in BytePlus's docs. The 2.0 vs 2.5 table and how Sume's own limits differ, read 2026-09-29.
Seedance 2.5 changes three limits from 2.0 in BytePlus's own tutorial: 30 seconds per request instead of 15, up to 50 references instead of 15, and audio-only references. On Sume, seedance-2.5 takes 4 to 30 seconds and seedance-2 takes 4 to 15.
How do the two versions differ on paper?
The ModelArk tutorial compares them directly. Sume's figures come from its video docs and API code.
| Limit | Seedance 2.0 | Seedance 2.5 |
|---|---|---|
| Duration per request (BytePlus) | 15 s | 30 s |
| References (BytePlus) | 15 (9 images, 3 videos, 3 audio) | 50 (30 images, 10 videos, 10 audio) |
| Total reference audio or video (BytePlus) | 15 s | 30 s |
| Audio-only reference (BytePlus) | Needs an image or video | Supported |
| Duration on Sume | 4 to 15 s | 4 to 30 s |
| Resolutions on Sume | 480p, 720p, 1080p | 480p, 720p, 1080p |
Does Sume expose all 50 references?
No. Sume's API accepts at most 12 input_references per request for seedance-2.5, image, video and audio combined. The 50 is BytePlus's figure for its own API; see Seedance 2.5 reference limits.
Does the price change between versions?
Sume prices both from the same video-token formula with different per-token rates, so the same clip length costs different amounts. Compare them in Seedance 2.5 price per second and Seedance video token pricing.
When should I stay on 2.0?
If your clips are 15 seconds or shorter and you use at most a handful of references, the extra headroom is not needed. Both models accept the same aspect ratios on Sume: 21:9, 16:9, 4:3, 1:1, 3:4 and 9:16.
Sources
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Written by Sume