seedance-2-5
seedance-2.5 Video Generation
- Async API; returns task_id for polling
- Text-to-video / multimodal reference / edit / extend / first–last frame
- Up to 30s per job; up to 30 images + 10 videos + 10 audios as references
- Resolution 480p / 720p only; mp4 or mov output
POST
Main changes vs 2.0: max duration 15s → 30s; references 9 images + 3 videos + 3 audios → 30 images + 10 videos + 10 audios; audio-only reference supported; mov output added.
Note: resolution is 480p / 720p only (2.0’s 1080p / 4k are not available on 2.5).
Note: resolution is 480p / 720p only (2.0’s 1080p / 4k are not available on 2.5).
Authentication
string
required
Bearer token auth. Get a key from the API Key page.
Request parameters
string
required
Fixed value:
seedance-2.5boolean
default:"false"
Whether to run content moderation before submitting the video task.Response when flagged:
true: useomni-moderation-latestto review prompts and input imagesfalseor omitted: do not send a moderation request, adding no moderation cost or latency (default)
- Text:
prompt,negative_prompt - Images:
image_urls,image_with_roles[].url,first_frame_image,last_frame_image - Image-type private
asset://assets: resolve and review their original public URL - Base64 images: review them after conversion to a public URL
video_urls, audio_urls, and video/audio private assets are not reviewed, because the moderation model does not support video or audio.Supported model IDs: seedance-2.0, seedance-2.0-fast, seedance-2.0-mini, seedance-2.0-face, seedance-2.0-fast-face, seedance-2-0 (legacy), and seedance-2.5.The moderation call itself is not billed to the user submitting the video request.Example:string
required
Prompt. Reference media with
@图片1 / @视频1 / @音频1 (1-based index matching array order). English aliases in prompts may also be used depending on model behavior; keep indices aligned with arrays.Example: "Use @视频1 for first-person framing throughout, @音频1 as BGM, first frame is @图片1"string
default:"720p"
Resolution — only:
480p720p(default)
1080p / 2k / 4k return a sync 400.string
default:"adaptive"
Aspect ratio (field name
aspect_ratio is also accepted).Values: 16:9, 4:3, 1:1, 3:4, 9:16, 21:9, adaptive (default)integer
default:"5"
Duration in seconds:
4~30-1: model picks duration (pre-charge at the 30s cap; settle to actual length after completion)
boolean
default:"true"
Whether to generate audio (alias field name:
audio).true: with audio (default)false: silent video
boolean
default:"false"
Add an “AI generated” watermark. Default
false.integer
Random seed. Different seeds usually yield different results for the same request; the same seed is similar but not guaranteed identical.
string
default:"mp4"
Output container:
mp4(default)mov: higher color precision — recommended for edit / extend workflows
array<string>
Reference image URLs, all treated as
reference_image.Supports:- Public URL:
https://example.com/pic.jpg - Private asset:
asset://cm9xxxxxxxx
image_with_roles.array<object>
Images with explicit roles.Example:
If
video_urls / audio_urls are present, first_frame / last_frame are auto-converted to reference_image (multimodal reference job).array<string>
Reference videos (
reference_video).Input: video URL or asset ID (asset://...).See Reference video specs.array<string>
Reference audio URLs (
reference_audio). Public URLs or asset://....Max 10; total duration ≤ 30s (each clip 2~30s).2.5 supports audio-only reference (no image/video required).
boolean
default:"false"
When
true, the successful result also includes the last-frame image for chaining.array<object>
Tool list for enhancements such as web search.Example:
Media limits
Reference video specs
- Input: video URL or asset ID (
asset://...) - Container:
mp4,mov— codecs in the table below - Resolution:
480p,720p - Duration: each clip [2, 30] s; up to 10 reference videos; total duration of all videos ≤ 30s
- Per-video dimensions:
- Aspect ratio (width/height): [0.4, 2.5]
- Side length (px): [300, 6000]
- Total pixels: [640×640=409600, 3326×2494=8295044], i.e. width × height must fall in [409600, 8295044]
- Size: each video ≤ 200 MB
- Frame rate (FPS): [24, 60]
Supported codecs
Task types and constraints
The service infers task type from references and prompt intent. The last three types hard-constrainsize / duration; violations fail asynchronously after the job starts (e.g. InvalidParameter.TaskTypeConstraint):
Asset library
You can pass public URLs as references, or upload into the library first and useasset://. Prefer the library when:
- Real human faces must use the library — raw URLs are blocked by content moderation; only approved library assets can be used
- Assets are reused often — upload once, skip repeated moderation on later jobs, faster submits
- URLs are signed temporary links — the platform stores a durable copy on ingest so later use does not depend on the original URL staying alive
- Library assets are synced to all available channels so multi-channel routing can use them wherever the job lands
asset:// IDs work in both 2.0 and 2.5 generation requests. Full submit fields: also see Private avatar assets.
Upload assets
The response includes a local task
id. Poll with Get task status (GET /v1/tasks/{id}). After approval, list assets to obtain the asset:// ID.
Media limits (validated at submit)
Violations return 400 immediately (which asset index and which rule), without starting moderation or consuming moderation quota:
Error example:
For 30s video assets, submit with
If the platform cannot probe the media (e.g. network blip), it may pass through and leave the decision to moderation.
"model": "seedance-2.5" (2.0 cannot use assets longer than 15s).If the platform cannot probe the media (e.g. network blip), it may pass through and leave the decision to moderation.
Use in generation requests
Reference approved assets withasset:// in image_urls / image_with_roles / video_urls / audio_urls:
Management APIs (quick reference)
Asset APIs are free of charge (auth + rate limits only); they do not create billing records.
FAQ
Q: How long does moderation take?Images usually seconds; video and real-person assets may take minutes. Poll the task
id until a terminal status.
Q: Moderation failed with no clear reason?Some failures omit a detailed reason (often a transient fetch failure). The platform already retries once; if it still fails, change the URL (ensure it is publicly downloadable) and resubmit. Q: Same asset for both 2.0 and 2.5 — upload twice?
No. Upload once;
asset:// works for both generations. Cross-channel / cross-model sync is handled by the platform.
Q: Can I pass a real-person face as a raw URL?Real-person assets must go through the library first.
Billing
- Billed by seconds × resolution tier.
- With reference video input: billable seconds = total input video duration (≤30s) + output duration, at the input-reference rate tier.
duration = -1(auto): pre-charge at the 30s cap; settle to actual output after completion.- Omit
duration: generate and bill 5 seconds. - Failed jobs or content moderation blocks: full refund (charge only on successful output).
Request examples
Text-to-video (30s)
Multimodal reference (image + video + audio)
Video edit
First–last frame
Private asset
Web search
Common errors
Response (submit)
integer
Status code;
200 on successarray
Submit response with
status / task_idCompleted task (GET /v1/tasks/{task_id})
After submit, poll with Get task status. When status is completed, the payload looks like this.
Completed response example
Completed fields
Notes
- Failed tasks (
status=failed):costis always0(pre-charge fully refunded); reason indata.error.message usagemay be missing for a few seconds after completion (settlement lag); query again shortly