37 Seedance 2.5 clips of 7 seconds: $149.65 at 720p on Sume

Thirty-seven Seedance 2.5 clips of 7 seconds each cost $149.65 at 720p on Sume: 7 s x $0.5778 per second = $4.0446 per clip, and 37 x $4.0446 = $149.6502. The same batch costs $69.59 at 480p and $368.18 at 1080p. Seven seconds is inside the model's 4-30 second range, so the price is linear in length with no rounding up to a longer clip.

The arithmetic

Sume bills the provider list price times 1.25, and the catalog publishes the result per output second. Seedance 2.5 is priced linearly inside its valid duration range, so a 7-second clip is just seven times the per-second number. Multiply by the clip count and you have the batch total. No extras are included here: the figures use default options.

The whole batch is 259 output seconds (37 x 7). At 720p that is 259 x $0.5778 = $149.6502, which matches the clip-by-clip total. Doing it both ways is a cheap way to catch a typo before you submit.

What a fixed budget buys

If you have exactly $100 for the run, divide by the per-clip price. At 720p, $100 / $4.0446 = 24 full clips (24 x $4.0446 = $97.0704), leaving $2.9296 unspent. At 480p, $100 / $1.880739 = 53 clips. At 1080p, $100 / $9.95085 = 10 clips.

Because the price is per output second, shortening every clip by one second saves 37 x $0.5778 = $21.38 at 720p. Lengthening by one second costs the same amount. That is usually a cheaper lever than dropping a resolution tier.

Why the invoice can differ by cents

The catalog describes how a job is held: the estimate is stored in USD micros and rounded up to cents for the balance check, the job is captured on completion, and failed or pre-generation canceled jobs are refunded before capture. With 37 jobs the balance hold can sit a few cents above the exact list math. It is a hold, not a higher price.

The catalog also exposes applied_* estimate fields that add an agent fee of 550 basis points. This post uses the base per-second prices, which is what a direct API call to the video endpoint is priced from; check the applied fields if you run the same work through an agent.

A second scenario

Add a realistic retake rate. If 20 percent of the 37 clips need a second pass, that is 8 more clips (37 x 0.2 = 7.4, rounded up) at $4.0446 each, or $32.3568. The batch then costs $149.6502 + $32.3568 = $182.007, about $182.01. Budget for the retakes up front, not after the first invoice, and decide whether the redo runs at 480p to keep the extra spend near $15.

Submitting the batch

Each clip is its own job. Send each with an Idempotency-Key so a retry cannot create a duplicate, then poll the job endpoints for results. Queue and concurrency behavior is described in the generation admission page, and a full queue returns queue_full rather than silently dropping work.

Pick the resolution after you see one clip. A single 7-second 480p test costs $1.88, and if the motion is right you can rerun the winning prompt at 720p for $4.04 instead of paying for 37 high-resolution misses.

• Duration range: 4-30 s for seedance-2.5
• Resolutions: 480p, 720p, 1080p
• Billing: provider list x 1.25

Reproduce the numbers

Open https://api.sume.com/v1/catalog, which needs no key, and find the entry for the product. Each model_pricing row carries price, unit, pricing_basis and the estimated, minimum and maximum cents. Multiply the unit price by your quantity and round only at the end. The catalog also has applied_* fields that include an agent fee of 550 basis points; the figures in this post use the base prices.