Seedance video

Seedance video uses an asynchronous task API. The create call returns a task object, not the finished video file.

POST /v1/videos

Poll and download:

GET /v1/videos/{task_id}
GET /v1/videos/{task_id}/content

Send JSON. Put every field at the top level. Do not wrap these fields in metadata. images and videos accept only public http or https URLs. Base64 and data URIs are not supported. The links must stay available until the task finishes. Check GET /v1/models before calling. A duration or resolution outside the table fails the task.

Models

Model ID	What it does	Duration	Resolution
`seedance-2.0`	Text, image, reference, first and last frame	4–15 seconds	`480p`, `720p`, `1080p`, `4k`
`seedance-2.5`	Same modes, plus edit and extend	4–30 seconds	`480p`, `720p`, `1080p`

Request fields

Field	Required	Description
`model`	Yes	A model ID from the table
`prompt`	Yes	Subject, action, camera, and what must stay unchanged. For references, say “image 1” or “video 1”
`mode`	No	`text2video`, `image2video`, `reference`, `frames2video`. `seedance-2.5` also accepts `video_edit` and `video_extend`
`duration`	No	4–15 seconds for `seedance-2.0`, 4–30 seconds for `seedance-2.5`. `video_edit` and `video_extend` may send `-1` to follow the source video length
`resolution`	No	`480p`, `720p`, `1080p`. Only `seedance-2.0` also accepts `4k`
`aspect_ratio`	No	For example `16:9`, `9:16`, `1:1`, `4:3`, `3:4`, `21:9`
`images`	No	Array of public image URLs. URLs only, not base64
`videos`	No	Array of public video URLs. URLs only, not base64
`face_check`	No	Whether to check faces. Omitted is treated as enabled
`generate_audio`	No	`true` or `false`
`output_format`	No	For example `mp4` or `mov`. Omitted uses the default format

image2video uses the first item in images as the first frame. frames2video uses the first item as the first frame and the second as the last frame. reference may include both images and videos. video_edit and video_extend put the source video in videos.

Text to video

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.0",
    "prompt": "A quiet lake at dawn, mist lifting, camera held still",
    "mode": "text2video",
    "duration": 5,
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "face_check": false
  }'

Image to video

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "The cat in the picture turns its head slightly. Keep the camera still",
    "mode": "image2video",
    "duration": 4,
    "resolution": "480p",
    "aspect_ratio": "16:9",
    "images": [
      "https://example.com/cat.jpg"
    ]
  }'

Reference image or video

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.0",
    "prompt": "The person in image 1 walks with the motion from video 1",
    "mode": "reference",
    "duration": 5,
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "face_check": true,
    "images": [
      "https://example.com/person.jpg"
    ],
    "videos": [
      "https://example.com/motion.mp4"
    ]
  }'

First and last frame

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.0",
    "prompt": "Move naturally from the first frame to the last frame and keep the person consistent",
    "mode": "frames2video",
    "duration": 5,
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "images": [
      "https://example.com/first.jpg",
      "https://example.com/last.jpg"
    ]
  }'

Edit and extend

Only seedance-2.5 supports these modes. duration: -1 follows the source length:

curl https://kaienapi.com/v1/videos \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "Keep the subject and motion, and change the light to dusk",
    "mode": "video_edit",
    "duration": -1,
    "resolution": "720p",
    "videos": [
      "https://example.com/source.mp4"
    ],
    "generate_audio": false,
    "output_format": "mov"
  }'

Use video_extend to extend the clip.

Polling

Save id from the create response. Poll every 3–5 seconds until completed or failed:

curl "https://kaienapi.com/v1/videos/$TASK_ID" \
  -H "Authorization: Bearer <YOUR_API_KEY>"

Read url when the task completes. That URL is the video file. cost in the response is not the account charge; use the console usage record. On failure, read error.message. Download the bytes directly:

curl "https://kaienapi.com/v1/videos/$TASK_ID/content" \
  -H "Authorization: Bearer <YOUR_API_KEY>" \
  --output result.mp4

Prices

The charge is based on output seconds. Prices are CNY per second and follow the API key group, standard or stable.

Model	Resolution	`standard`	`stable`
`seedance-2.0` face check on	480p / 720p / 1080p / 4k	0.462 / 0.696 / 1.735 / 3.535	0.462 / 0.994 / 2.478 / 5.050
`seedance-2.0` face check off	480p / 720p / 1080p / 4k	0.5775 / 0.800 / 2.16875 / 4.41875	0.5775 / 1.2425 / 3.0975 / 6.3125
`seedance-2.5`	480p / 720p / 1080p	0.54 / 1.06 / 2.99	0.67 / 1.51 / 3.74

If the console model page and the bill disagree, the bill is the charge.

Getting started

Images and video

Audio

AI tools

API Reference

Models

Request fields

Text to video

Image to video

Reference image or video

First and last frame

Edit and extend

Polling

Prices

​Models

​Request fields

​Text to video

​Image to video

​Reference image or video

​First and last frame

​Edit and extend

​Polling

​Prices

Models

Request fields

Text to video

Image to video

Reference image or video

First and last frame

Edit and extend

Polling

Prices