Seedance 2.5: the 30-second model, and how to run it

Seedance 2.5 is ByteDance's long-form video model. On VdoBloom it is the only model that renders a single 30-second take — double the 15-second ceiling of Seedance 2, Kling V3 Turbo, Kling 3.0 and MiniMax H3. If a shot needs to run past 15 seconds without a cut, this is the model that does it, and there is no second option in the roster.

The trade is resolution. Seedance 2.5 renders at 480p or 720p and has no 1080p or 4K tier at all. Its sibling Seedance 2 reaches 4K but stops at 15 seconds, so inside a single model family you are choosing between length and pixels. No setting combination gives you both in one job.

You can reach it three ways, and the choice is really about what you are starting from. In Text to Video you write the prompt yourself — Seedance 2.5 accepts up to 30,000 characters — and pick the model from the list. In Image to Video you upload a photo and the model animates it. In Seedance Effects you skip prompt writing entirely and apply a curated preset to your uploads. The model, the 30-second ceiling and the credit rate are identical in all three; what changes is who writes the prompt and whether a photo is involved.

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What this tool does

  • Seedance 2.5 generates up to 30 seconds in one job — double the 15-second ceiling of Seedance 2, Kling V3 Turbo, Kling 3.0 and MiniMax H3.
  • Duration is selectable at every whole second from 4 to 30 — 27 discrete options, not a fixed set of 5/10/15 presets.
  • Seedance 2.5 renders at 480p or 720p only. It has no 1080p option and no 4K option; within the Seedance family only Seedance 2 reaches 4K.
  • Seedance 2.5 is selectable in three places on VdoBloom: Text to Video, Image to Video and Seedance Effects. The model, the duration range and the credit rate are the same in all three.
  • The Seedance Effects tab exposes four models — Seedance 2, Seedance 2 Fast, Seedance 2 Mini and Seedance 2.5 — and opens on Seedance 2, so selecting 2.5 there is an explicit switch.
  • Who writes the prompt depends on the tab. Text to Video and Image to Video take a prompt you write, up to 30,000 characters on Seedance 2.5 against 20,000 on Seedance 2. On Seedance Effects the prompt belongs to the effect and stays server-side.
  • Audio is generated natively and the audio flag is on by default, with no separate audio surcharge in the credit price.
  • Pricing is linear per second: 9.2 credits per second at 480p and 20.0 at 720p. A 4-second draft is 37 or 80 credits; a full 30 seconds is 276 or 600.
  • Attach a photo as the first frame in Image to Video and the aspect ratio is forced to "adaptive" — the output follows your source photo's shape. In Text to Video, with no image attached, the ratio you pick is the ratio you get.
  • A new VdoBloom account starts with 10 free credits, which does not cover any Seedance 2.5 render — the cheapest possible job on this model is 37 credits.

How it works

  1. 1.Pick the tab that matches what you are starting from

    Text to Video at /dashboard/video-creation/text-to-video/ if you are starting from a written idea. Image to Video at /dashboard/video-creation/image-to-video/ if you are starting from a photo. Seedance Effects at /dashboard/video-creation/seedance-effects/ if you would rather apply a curated preset than write anything. Seedance 2.5 appears in the model list in all three.

  2. 2.Select Seedance 2.5 explicitly

    No tab opens on it — Text to Video starts on Runway Gen-3 and Seedance Effects starts on Seedance 2. Selecting 2.5 changes two controls at once: the duration grid expands to every second from 4 to 30, and the resolution list narrows to 480p and 720p. If you had 1080p or 4K selected on Seedance 2, it resets to 480p.

  3. 3.Supply the prompt, or let an effect supply it

    In Text to Video and Image to Video the prompt box is yours, and 2.5 accepts up to 30,000 characters — enough to describe camera, performance and sound beats across a full 30 seconds. On Seedance Effects there is no prompt box: you pick a curated effect, upload the photos it asks for, and its stored prompt runs. That catalogue is admin-managed and changes over time, so browse what is live rather than looking for a specific name.

  4. 4.Set duration and resolution — they are the entire bill

    Cost is linear, so the two dials multiply out with no surprises: 9.2 credits per second at 480p, 20.0 at 720p. Ten seconds costs 92 or 200; thirty costs 276 or 600. Test a long idea at 480p before committing 600 credits to the 720p version of it.

  5. 5.Check the displayed cost, then generate

    The credit cost recomputes from model plus duration plus resolution before you spend anything, and it is the same figure whichever tab you are in. Credits are deducted up front and refunded automatically if the job fails. Audio is generated by default, so the returned clip arrives with sound unless you strip it in an editor.

Frequently asked questions

What is Seedance 2.5?

Seedance 2.5 is ByteDance's long-form video model, offered on VdoBloom as bytedance/seedance-2-5. Its defining property is duration: it renders any whole-second length from 4 to 30 seconds in a single generation, where the rest of VdoBloom's roster stops at 15. It generates native audio by default and outputs at 480p or 720p.

Can I select Seedance 2.5 in Text to Video?

Yes. Open /dashboard/video-creation/text-to-video/, type your prompt, and Seedance 2.5 is in the model list under the Seedance family alongside Seedance 2, Seedance 2 Fast, Seedance 2 Mini and Seedance 1.5 Pro. Picking it swaps the duration grid to every second from 4 to 30 and the resolution list to 480p and 720p. With no image attached, the aspect ratio you choose is the one used. The same model is also selectable in Image to Video and on the Seedance Effects tab.

Can Seedance 2.5 output 1080p or 4K?

No. Seedance 2.5's resolution list is 480p and 720p, and there is no higher tier at any price. If you need 1080p or 4K from this family, use Seedance 2, which offers 480p, 720p, 1080p and 4K but caps duration at 15 seconds.

How long can a Seedance 2.5 video be?

Four to thirty seconds, selectable at every whole second — 27 options. Thirty seconds is the server-enforced maximum. That makes it the longest single generation available on VdoBloom; the next longest options, including Kling V3 Turbo, Kling 3.0, MiniMax H3 and Seedance 2 itself, stop at 15 seconds.

Do I write my own prompt for Seedance 2.5?

In Text to Video and Image to Video, yes — the prompt box is yours and Seedance 2.5 accepts up to 30,000 characters, against 20,000 for Seedance 2. On the Seedance Effects tab, no: each effect carries its own prompt server-side and your inputs are the photos plus the duration, resolution, aspect ratio and audio settings. Choose the tab by whether you want to write the brief or apply one.

Does Seedance 2.5 work from a photo as well as a prompt?

Both. In Text to Video it works from the prompt alone. In Image to Video you upload a photo, which by default becomes the clip's first frame — and on Seedance 2.5 that specific path forces the aspect ratio to "adaptive", so the output inherits your photo's shape. Crop before you upload. Seedance Effects takes photos too, but attaches them as reference images, so the ratio you choose there is honoured.

Does Seedance 2.5 generate sound?

Yes, natively, and the audio flag defaults to on. Unlike Seedance 1.5 Pro — where switching audio on doubles the per-second rate — Seedance 2.5's price does not change with audio. The 9.2 and 20.0 credits-per-second rates already include it.

Can I try Seedance 2.5 on the 10 free signup credits?

No. The cheapest Seedance 2.5 render is 37 credits, for 4 seconds at 480p, which is nearly four times a new account's 10-credit starting balance. If you want to spend free credits on a video first, pick a model priced for it — a Runway Gen-3 720p 5-second clip is 10 credits — then move to Seedance 2.5 once you have topped up.

Related tools

Seedance 2.5 vs Seedance 2: duration against resolution

Seedance 2.5 runs 30s but caps at 720p; Seedance 2 stops at 15s and reaches 4K. 15s at 720p costs 300 vs 244 credits. The full maths.

Seedance 2.5 price: the full credit table, per second and per clip

Seedance 2.5 costs 9.2 credits/sec at 480p and 20 at 720p. Cheapest render is 37 credits (4s, 480p); a full 30s at 720p is 600 credits.

Seedance 2.5 image to video: your photo decides the aspect ratio

In VdoBloom's Image to Video tab Seedance 2.5 forces adaptive aspect ratio, so output matches your photo's shape. Crop to 9:16 before uploading.

Kling vs Seedance: length, resolution and cost per second

Kling tops out at 15s; Seedance 2.5 runs to 30s. Kling 3.0 4K is 26.8 credits/sec vs Seedance 2 4K at 414 credits for 5 seconds.

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