Seedance 2.5 with a reference video: the reserve by clip length

When a Seedance 2.5 request includes a reference video, Sume's rate card assumes 15 seconds of input video, adds those tokens to the output tokens, and prices the total at 0.6x. At 720p 16:9 that makes a 5-second clip about $6.93 instead of $2.89 and a 10-second clip about $8.67 instead of $5.78. Above 25 seconds the reference makes the estimate lower than the plain price, because the 0.6 factor outweighs the added 15 seconds.

The rule in the rate card

From Sume's pricing code: billable tokens are computed for (output seconds + 15 assumed input seconds), then the total is multiplied by 6/10. The base rate is fal's $0.0214 per 1,000 tokens at 720p, and Sume bills list x 1.25. This is the estimate used when the request is accepted; it is not a promise about the final settled amount, so read the job's usage after it finishes.

Sume's video docs say it bills provider list x 1.25 on every video model.

What to do with it

For short clips, a reference video is the expensive input: a 5-second clip with one costs more than two plain 5-second clips. If you only need a still as a starting point, use a frame image and keep the plain rate from the 720p price table. Sume lists reference video support for Seedance 2.5 in its Video Router docs.