Video

Seedance 2.5

ByteDance's Seedance 2.5 on POST /v1/videos, with the same request and job shape as every other video model (see Video generation). This page covers what is specific to Seedance 2.5: the five ways to call it, task_type for calls with a reference video, which hosts support what, and the errors you can hit.

Use bytedance/seedance-2.5 to let VideoRouter pick the cheapest host that can serve your exact request, or bytedance/seedance-2.5/<host> (for example bytedance/seedance-2.5/fal) to try one host first. A named host is a preference: if it fails, the call falls over to the others unless you send "provider": {"allow_fallbacks": false}.

First-frame, first-and-last-frame and reference inputs can't be mixed in one call. Duration is duration_secs from 4 to 30 seconds; resolution is 480p, 720p or 1080p; aspect_ratio accepts 21:9 as well as the usual ratios (a 21:9 request is only routed to hosts that can render it, see Video generation). Draft mode is covered below.

How many reference files a call can carry depends on the host that serves it (up to 30 images, 10 videos and 10 audio clips on the largest). VideoRouter only routes the call to hosts that can take everything you sent, and returns a 400 if none can.

Reference videos: task_type

When a call includes input_video_references, Seedance has to decide what the job is: a new video guided by your clip (reference), an edit of the clip, or an extension of it. task_type chooses.

Default: if you send input_video_references and don't send task_type, the call runs as reference, a new video that uses your clip as a guide. Sending "auto" explicitly lets the prompt decide instead (not recommended, and you may get unexpected results); send "edit" / "extend" to change the clip. Calls without a reference video (images or audio only) have no task to pick and ignore it.

Which hosts support what

Pinning a task_type routes the call only to hosts that can honor it. If none of the hosts available for your model can, the call returns 400 task_type_not_supported. Support for reference videos on Seedance 2.5:

Because reference is the default, a Seedance 2.5 call with a reference video and no task_type is only routed to hosts that can pin it. If you name a host that can't (for example bytedance/seedance-2.5/replicate), the call runs there as auto rather than being moved to a different host.

Examples

A new scene that uses a clip as the character reference (the default), at 21:9:

curl https://videorouter.sh/api/v1/videos \
  -H "Authorization: Bearer llmr_sk_live_..." -H "Content-Type: application/json" \
  -d '{"model": "bytedance/seedance-2.5",
       "prompt": "@Video1 is the character, identity reference only. Late night in a small basement bathroom, he measures the sink with a cloth tape, whispering to himself. Slow handheld push-in.",
       "duration_secs": 30, "aspect_ratio": "21:9", "resolution": "1080p",
       "input_references": [{"type": "image_url", "image_url": {"url": "https://example.com/bathroom.png"}}],
       "input_video_references": [{"type": "video_url", "video_url": {"url": "https://example.com/character.mp4"}}]}'

Edit a clip (no duration or ratio):

curl https://videorouter.sh/api/v1/videos \
  -H "Authorization: Bearer llmr_sk_live_..." -H "Content-Type: application/json" \
  -d '{"model": "bytedance/seedance-2.5",
       "prompt": "@Video1 is the reference. Replace the man with the character in @Image1.",
       "task_type": "edit",
       "input_references": [{"type": "image_url", "image_url": {"url": "https://example.com/hero.jpg"}}],
       "input_video_references": [{"type": "video_url", "video_url": {"url": "https://example.com/clip.mp4"}}]}'

Extend a clip:

curl https://videorouter.sh/api/v1/videos \
  -H "Authorization: Bearer llmr_sk_live_..." -H "Content-Type: application/json" \
  -d '{"model": "bytedance/seedance-2.5",
       "prompt": "Extend @Video1: continue the shot, he slowly lifts his head and looks into the camera.",
       "task_type": "extend", "duration_secs": 12,
       "input_video_references": [{"type": "video_url", "video_url": {"url": "https://example.com/clip.mp4"}}]}'

Draft mode

Iterate cheaply, pay for 1080p once. Send "draft": true and Seedance 2.5 renders a 480p preview at roughly a quarter of the 1080p price. Re-roll as many drafts as you like; when one is right, send its id as draft_id and the same take is re-rendered at 1080p — same prompt, references, seed and audio setting, so the final keeps the exact composition and motion you approved.

# 1. 480p draft
curl https://videorouter.sh/api/v1/videos \
  -H "Authorization: Bearer llmr_sk_live_..." -H "Content-Type: application/json" \
  -d '{"model": "bytedance/seedance-2.5/atlas-cloud", "prompt": "A red balloon drifts up against a blue sky",
       "duration_secs": 5, "draft": true}'
# -> {"id": "atlascloud:abc...", "draft": true, "draft_expires_at": 1791659164, ...}

# 2. poll GET /v1/videos/{id} until "completed", watch the 480p preview, then:
curl https://videorouter.sh/api/v1/videos \
  -H "Authorization: Bearer llmr_sk_live_..." -H "Content-Type: application/json" \
  -d '{"draft_id": "atlascloud:abc..."}'
# -> a NEW job id (with "from_draft"); poll it for the 1080p video

• Billing: the draft bills as a normal 480p render and the final as a normal 1080p render (each at the host's real cost + the platform fee). Drafting pays off when you would otherwise generate several 1080p takes to find a good one — a single draft + final costs a little more than rendering 1080p directly.
• Window: a draft can be finalized within 7 days (draft_expires_at), once, and only after it has completed. A failed final can be retried.
• Final request: carries only draft_id — no prompt, images, duration or resolution (they're fixed by the draft).
• Host pinning: a draft only exists on the host that rendered it, so the final always runs there and never fails over. Drafts route only to hosts that support draft mode; text-to-video and image-to-video only (no reference/edit inputs).

Errors and failed jobs

“Seedance read this prompt as a video edit”

If you send a fixed duration_secs / aspect_ratio with task_type: "auto" and the prompt reads as an edit, Seedance rejects the job, sometimes only after a few minutes. Either resend with "task_type": "reference" (and reword the prompt so the clip is only a reference), or with "task_type": "edit" and without those two fields. A failed job is not charged.

“The output audio may be related to copyright restrictions”

Seedance sometimes rejects a finished render because of the audio it generated. It is not tied to your request, the job is not charged, and resubmitting usually succeeds.

Billing

Seedance 2.5 is billed per second of output at the host's real cost plus the platform fee. On most hosts the seconds of your reference video count as well (edit: clip plus output), so a longer reference clip costs more. The price estimate shows this; the final charge is the host's actual cost, and failed jobs are not charged. See Video generation: billing and Pricing & billing.