Seedance 2.5 extend video beyond 30 seconds: what each round costs

To go past 30 seconds with Seedance 2.5 on Sume you pay for one 30-second job per round: a 60-second video is two rounds and a 90-second video is three. At 720p that is $34.68 and $52.02 before the Timeline join.

ByteDance's launch post says Seedance 2.5 makes up to 30 seconds per generation and supports multi-round extensions. Sume's seedance-2.5 accepts 4 to 30 seconds per request, so each round is its own job.

What does each extra round cost?

Every round is billed as its own job, reserved at submit. The table multiplies one 30-second, 16:9 round by the number of rounds and adds the join.

What does the join add?

Timeline 1.0 charges $0.10 per output minute, rounded up: $0.10 for a 60-second cut and $0.20 for a 90-second one. See the Timeline docs.

How do I carry the scene from one round to the next?

Pull a still near the end of round one and send it as first_frame in frame_images for round two; the still step is unbilled. Get the last frame of a video has the request, and the general extension guide covers the other routes.

Write the second prompt as a continuation: name the same subject, setting and light as round one, then say what changes. A still carries the look of the last moment but not the motion, so describe the movement you want to continue, for example the camera keeps pushing in. Keep the same resolution and aspect ratio in every round so the clips cut together without a visible size change, and keep the same model value so the look stays consistent across rounds.

If a round drifts, discard it and rerun from the same still rather than chaining onward from a weak ending; a bad final frame carries into every round after it.

Do I have to run full 30-second rounds?

No. Anything from 4 to 30 seconds is allowed, so the last round can be short. Price it before you run with the cost estimate guide.

Where does the money go if a round is bad?

Each round is reserved when you submit it, at the provider list rate times 1.25, and rounds are separate jobs. That is a reason to review round one before you spend on round two, and to keep review passes at 480p while the prompt is still moving. Only the final pass needs the resolution you plan to publish.

The 60- and 90-second rows above assume every round is a full 30 seconds and lands on the first try. If you expect two attempts per round, double the row; the Timeline join is charged once, on the finished cut.