Kling 3.0 starts at 3 seconds; Sume's kling-3 starts at 4

A 3 second clip works on Kling's own product but not on the kling-3 id on Sume: Kling's comparison page lists Kling 3.0 at 3-15 seconds, while the Sume catalog gives kling-3 ('Kling Video v3 Pro') a 4-15 second range. Send duration: 3 and Sume answers HTTP 400 with unsupported_capability and a message of the form 'kling-3 does not support duration 3', plus the list of accepted values. Send 4 and it runs.

Kling's figures come from Kling 4.0 vs 3.0 on kling.ai, read on 2026-10-03. The Sume side comes from the catalog in the Video Router docs and Video generation docs. Sume does not clamp or round a duration for you on a pinned id; it rejects it, so nothing is billed for a request that cannot run.

Where the two ranges differ

The mismatch is small but it bites the shortest hook clips, which are the ones people most often generate at 3 seconds. The table shows the same field on each side.

Kling 4.0 is a separate case: the same Kling page lists 3-30 seconds for it, but Kling 4.0 is not an id in the Sume catalog today, so there is nothing to call. A pinned request for it fails on the model id before duration is even checked.

What to do for a 3 second slot

You have three honest options. Round up to 4 seconds on kling-3 and trim the extra second afterwards with the video trim tool, which cuts an existing clip to an exact length. Or pin a model whose floor is lower: wan-3.0 starts at 2 seconds and gemini-omni-flash-1.1 at 3. Or keep Kling and plan the edit around a 4 second beat.

Trimming costs nothing in generation terms, but you pay for the 4 seconds you generated, at list price times 1.25 like every Video Router model. If the slot is a fixed 3 seconds in a template, the cheaper path is usually a model that accepts 3 natively, because the extra second is wasted spend multiplied by every variant you run.

Read the range instead of hard-coding it

Do not copy the numbers from this page into code. GET /v1/videos/models returns supported_durations for every id, and the Video Router catalog returns the same envelope under capabilities.duration_seconds. Build the request from that list, and a model whose range changes later will not break your job.

The same habit protects you from vendor marketing pages, which describe the vendor's product rather than the id behind a third-party router. When a vendor page and the Sume catalog disagree, the catalog is what your request is checked against.