Seedance reference video: 0.6x rate, but 15 s of input assumed

A Seedance request with a reference video is billed at 0.6 times the normal token price, but Sume's estimator adds 15 seconds of input footage to the tokens it counts. For a short output that makes the clip dearer, not cheaper: a 5 s clip at 720p with a reference video costs 2.4 times the same clip without one.

The formula

The estimator in Sume's pricing package works like this. Tokens = (width x height x seconds x 24 fps) / 1024. With a reference video, seconds = output seconds + 15, and the cost is multiplied by 6/10. At 720p 16:9 (1280 x 720) one second is 1280 x 720 x 24 / 1024 = 21,600 tokens. The seedance-2 list rate is $0.014 per 1,000 tokens, and Sume sells at list x 1.25.

Examples

Worked examples for seedance-2 at 720p, 16:9. Check your own row in GET /v1/videos/models before you budget.

Where the premium shrinks

The ratio is (output + 15) x 0.6 / output. At 5 s that is 20 x 0.6 / 5 = 2.4. At 10 s it is 25 x 0.6 / 10 = 1.5. The longer your output, the smaller the premium; break-even is 0.6 x (s + 15) = s, so s = 22.5 s. Only seedance-2.5, which allows up to 30 s, can reach that: at 25 s the ratio is 40 x 0.6 / 25 = 0.96.

What is assumed

The 15 s figure is an assumption in the estimator for when the input duration is not known. Treat these numbers as the estimate that sets your reserve, and verify the final charge in usage.cost on a real job.

Runway's version of the same idea

For contrast, Runway's pricing page lists Seedance2_5 at 20, 30 and 68 credits per second for 480p, 720p and 1080p, plus an input charge (credit value $0.01, read 2026-10-05). The page as read does not state the input rate, so a direct comparison is not possible from public numbers.