Seedance 2.5 vendor features Sume does not document: a buyer checklist
Localized editing, 50 references, MOV output, 10+ languages: which Seedance 2.5 claims from BytePlus and Volcano Engine map to Sume docs, and which do not.
BytePlus and Volcano Engine advertise Seedance 2.5 with 4 to 30 second clips, up to 50 references, localized video editing, clip extension, MOV output and more than ten languages. On Sume's Video Router, the docs read on 2026-10-04 document the duration range, three resolutions and reference fields with lower caps than 50. They do not document localized editing, extension or an output format switch for seedance-2.5, so do not plan on them.
Claim by claim
A checklist helps you separate what the vendor offers on its own platform from what you can call through Sume. "Not documented" means the docs and request schema I read do not mention it; it does not prove the model cannot do it behind the scenes.
| Vendor claim | Source | Sume docs |
|---|---|---|
| 4 to 30 second videos | BytePlus, Volcano Engine | documented: 4 to 30 s |
| 480p, 720p, 1080p at 24 FPS | BytePlus | three resolutions documented; frame rate not stated in the Sume docs read |
| Up to 50 references (30/10/10) | BytePlus | lower caps in the Video Router docs: up to 10 images and 3 videos of at most 3 s for reference-to-video |
| Localized in-video editing | BytePlus, Volcano Engine | not documented for seedance-2.5 |
| Extend a clip forward or backward | BytePlus | not documented for seedance-2.5 |
| MP4 or MOV output | BytePlus | docs example downloads video.mp4; no format field |
| 10+ languages | BytePlus, Volcano Engine | not a Sume field; prompt in the language you need |
Where the vendor claims are written
The duration, frame rate, resolutions, editing, languages and output formats are on BytePlus's product page (BytePlus: Dreamina Seedance 2.5). Extension and the 30, 10 and 10 reference split are on its explainer (BytePlus: What is Seedance 2.5). Volcano Engine's activity page lists the 50 references, local editing and the language count (Volcano Engine: Seedance 2.5).
What to do when you need an unlisted feature
For a trim, use video trim at $0.02 per job. For a longer sequence, join clips on Timeline 1.0 rather than hoping for an extension field. For an edit of an existing clip, the Video Router documents video_url only for models that list it, such as Gemini Omni Flash 1.1, so check capabilities per model.
Ask for the feature through Sume support rather than guessing at a hidden parameter.
Check the live catalog
The Video Router docs tell you to read capabilities from GET /v1/video-router/models rather than assuming one envelope. Run it before you commit a project to a feature that depends on a vendor claim.
curl https://api.sume.com/v1/video-router/models/seedance-2.5 \
-H "Authorization: Bearer $SUME_API_KEY"Sources
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Written by Sume