Kling motion control: 3 s minimum on Kling, 1 s field on Sume

Keep your motion reference at 3 seconds or longer. Kling's guide says the supported duration for uploaded action videos is 3 to 30 seconds (read 2026-10-07), while Sume's duration_seconds field accepts any number from 1 to 30. The Sume field is only the reservation basis, so a value of 1 will pass validation even when the vendor rule would not.

The Sume docs do not say what happens when a clip shorter than 3 seconds reaches the provider. That gap is the reason to follow the stricter vendor number.

Two ranges that look the same but are not

One range describes what the model can use. The other describes what Sume's gateway will admit and price. They overlap for most clips and diverge at the short end.

What the field does and does not do

duration_seconds declares the length of your motion video so Sume can reserve the price: ceil of the value times $0.126 times 1.25. Sume never forwards it to the provider, because the provider has no duration setting. The length of the motion video sets the length of the output.

That means a wrong value does not change the clip, only the reservation. A 1-second declaration reserves $0.1575, a 3-second one $0.4725, and a 30-second one $4.725. Declare what you measured, not what you hope to pay.

Planning around the floor

Measure first. If your clip lives on Sume, POST /v1/video-inspect returns probe facts such as the duration, so you can fill the field from data instead of from memory.

• Under 3 seconds: loop or extend the move in an editor so the reference reaches at least 3 seconds, then declare 3 or the measured length.
• Fast or complex action: Kling warns the result can come back shorter than the reference, so check the output length before you build a timeline around it.
• Over 30 seconds: split the performance and join the clips afterward (Timeline can join them).

What happens to the money

Sume reserves at admit, captures at completion, and refunds on failure. The docs do not describe a partial adjustment when the output ends up shorter than the declared length, so budget for the declared amount. For a 3-second reference at $0.4725, that is a small cost to test one move before you commit a long clip.