Seedance 2.5 on eroq — 4 to 30 second clips, seeds, first/last frame

Seedance 2.5 is the long-form engine of the eroq video roster. Where most engines stop at 10 or 12 seconds, it renders anything from 4 to 30 seconds in one pass, at up to 1080p, with two controls the others mostly lack — a reproducibility seed and first/last-frame interpolation. It sits on the Creator plan and up, and it is SFW only, because its provider moderates upstream. This guide covers what it does, what it costs per length, and how to write for it.

What Seedance 2.5 does

The spec, in one list:

• Length: 4 to 30 seconds, chosen per clip. Your plan caps the ceiling (below).
• Resolution: up to 1080p, in 16:9, 9:16 or 1:1.
• Seed: a number that pins the render. Same prompt, same settings, same seed — same clip.
• First and last frame: give it a start image and an end image and it interpolates the motion between them.
• Image-to-video: a reference photo or a Character as the starting frame.
• Content: SFW only. Mature fiction goes to Motion One, the roster's uncensored engine.

Every other engine on the roster gives up at least one line of that list — length, resolution, the seed or the end frame. The longer clip is the headline, but the seed and the end frame are what make it usable for planned production rather than slot-machine rendering.

Plan access and the length cap

Seedance 2.5 is unlocked on Creator ($49 a month, 6,000 credits) and everything above it. Hobby and free accounts can't run it; Hobby gets Seedance 1.0 Lite and Hailuo 02, and Motion One is on every account.

The plan also caps how long any clip can be, and this is where Seedance 2.5 and the plans meet:

• Creator: clips up to 20 seconds.
• Studio, Team, Agency: clips up to 30 seconds — the engine's full range.

So a 30-second single-shot render is a Studio-and-up feature, not just an engine feature. Creator gets 20 of the 30, which is already more than any other engine on the roster offers. Annual billing takes 20% off, and there is a 50% discount on the first month if you subscribe within three hours of signing up. Details on /pricing.

Credits per length

The anchors: 180 credits for 5 seconds, 340 credits for 10 seconds. At the entry pack (1 credit ≈ 1¢) that is roughly $1.80 and $3.40. Notice that the second five seconds cost 160 credits, less than the first five — the meter flattens as the clip gets longer.

A few reference points from those numbers:

• A Creator month (6,000 credits) is about 33 five-second clips, or 17 ten-second ones, if you spend it all on Seedance 2.5.
• Failed generations refund themselves automatically, so an upstream error costs nothing.
• Credits never expire and monthly plan credits roll over, so an unused September doesn't vanish in October.

Compared with Seedance 1.0 Pro (140 credits per 5 seconds, 3–12 s), 2.5 costs more per second and buys length, the end-frame control and the same 1080p ceiling. The full trade-off is on /compare/seedance-2-5-vs-seedance-1-pro.

How to prompt it

The engine likes one flowing paragraph: subject, motion, camera, light, mood, in that order, 30–80 words. Write the prompt as a shot description, not a keyword list.

Two things change once clips get longer than 10 seconds.

Give the clip a second beat. A 5-second prompt describes one action. A 20-second prompt needs a "then" — she reaches the top of the stairs, then the beam sweeps out. Without a second beat, long renders drift.

Pick the camera move from the rack, then repeat it in words. The Video tool offers 17 moves (Push-in, Tracking, Orbit, Crane up, FPV drone and so on) and also detects directions written in the prompt, so "slow push-in" in the text is read too. For a long clip, one move is usually enough; two is the maximum before it looks like an edit.

The Director's rack — film type, era, tempo, gear, lens, aperture, palette, lighting — is folded into the prompt server-side, so you can leave the look to the rack and keep the prose about what happens. If a draft is rough, Enhance rewrites it into a director-grade prompt for free; it is a good way to learn the register.

Working with the seed

The seed is the variable you hold still. Once a render is close, keep the seed and change one thing — the lens, the palette, one word of motion — and the next render changes on that axis only. Without a seed, every render is a fresh draw and you can't tell whether your edit helped.

Working with first and last frame

First/last-frame interpolation is the control that turns Seedance 2.5 into a tool for planned shots. Render (or upload) the opening frame, render the closing frame — two images — and let the engine move between them. It suits anything with a known destination: a product turning to reveal its label, a character crossing a room, a landscape shifting from dusk to night. With a Character's reference photos as the start frame, the same face carries through the clip.

Example prompts

A 12-second, 16:9 shot with a second beat:

A lighthouse keeper in a yellow oilskin climbs the spiral stairs of a stone lighthouse at dusk, lantern swinging in her hand, rain streaking the windows as she reaches the lamp room and the great lens begins to turn. Slow push-in following her up the stairs, then a wide as the beam sweeps out over a black sea. Warm practicals against a nostalgic blue twilight, calm and resolute.

Settings: 12 s, 16:9, 1080p, seed set once the first take lands. Rack: Film type Arthouse, Lighting Practicals, Palette Nostalgic blue.

An 8-second first/last-frame shot for a product:

A ceramic teapot on a linen tablecloth turns slowly through a quarter rotation as morning window light slides across its glaze, steam rising from the spout. Static camera, macro lens, soft cross lighting, pastel dawn palette, dreamy and unhurried.

Settings: 8 s, 1:1, first frame = the teapot facing left, last frame = the teapot facing camera, both rendered in the Image tool from the same reference photos.

Where it sits in the roster

Use Seedance 2.5 when the shot is longer than 10 seconds, when you need to land on a specific end frame, or when you are iterating with a seed toward a precise result. For a 5-second portrait where faces and fluid motion matter most, Kling 2.5 Turbo is the usual pick — /compare/seedance-vs-kling lays out the difference. For clips with sound, Veo 3 Fast is the only engine that renders one. For mature fiction, Motion One is the uncensored engine and works on every account. The engine page at /models/seedance-2-5 keeps the current spec.

FAQ

How long can a Seedance 2.5 clip be?

The engine renders 4 to 30 seconds. Your plan sets the ceiling — 20 seconds on Creator, 30 seconds on Studio, Team and Agency.

How many credits does a Seedance 2.5 clip cost?

180 credits for 5 seconds and 340 for 10 seconds, about $1.80 and $3.40 at the entry pack. Failed renders are refunded automatically.

Can I use Seedance 2.5 for mature content?

No. Seedance 2.5 is SFW only because its provider moderates upstream. Motion One is eroq's uncensored video engine, within the acceptable-use policy, and it is on every plan including free.

Open the Video tool and pick Seedance 2.5 from the engine list — /studio/video.