sume/auto duration limit: 3 to 10 seconds, and how to go longer
Sume's Video Router docs give sume/auto a 3 to 10 second clip range at 16:9 or 9:16, default 8 seconds at 720p. For 30 seconds, pin seedance-2.5 or join clips.
The Video Router docs put sume/auto clips at 3 to 10 seconds, at 16:9 or 9:16, with defaults of 720p and 8 seconds. If you need a longer clip, send a pinned catalog id instead: seedance-2.5 accepts 4 to 30 seconds and wan-3.0 accepts 2 to 30. Auto has no longer setting, so a longer video means a pinned model or joined clips.
What exactly are the Auto limits?
From the Video Router docs: "Auto create controls default to 720p and 8s, with 3–10s clips at 16:9 or 9:16." The legacy Video 1.0 page adds that duration is an integer number of seconds validated against the Auto serving family. It does not name an error code for a value outside the range, so read the response body when a request is refused.
| Model | Length | Note |
|---|---|---|
| sume/auto | 3 to 10 s | Defaults 720p and 8 s; 16:9 or 9:16 |
| seedance-2.5 | 4 to 30 s | 480p, 720p, 1080p |
| wan-3.0 | 2 to 30 s | Pinned id |
| Other catalog models | up to 15 s | Check supported_durations |
How do I get a longer clip?
Set model to a pinned id on POST /v1/videos and duration inside that model's range. The docs say limits are not uniform, and that the models endpoint reports supported_durations for each id, so read it before you submit. Every other catalog model tops out at 15 seconds. A pinned model also changes what else you can ask for, such as 1080p on seedance-2.5, so re-read its limits rather than copying Auto's defaults across, because a default that is valid for Auto may not be valid for the model you pin.
What if I want the router and a long video?
Generate several Auto clips and join them. Timeline 1.0 is the assembly surface, but the docs give no Auto-specific rule for it, so treat that as a workflow choice, not a documented feature. The one-request route is the pinned model: a 30-second AI video through the API covers it.
How should I write duration in the request?
Send duration as an integer number of seconds, for example 8. The Video 1.0 page also accepts duration_seconds as an alias and says that if both are set, they must agree. Leave both out and Auto uses its 8 second default at 720p, so a request with only a prompt is a valid short clip.
Does the limit apply to every Auto URL?
The Video 1.0 page says its URLs use the same Auto model selection, capability validation and pricing. For 4K, that page says to use POST /v1/videos with sume/auto. The decision guide, with the tradeoffs, is sume/auto or a pinned video model.
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