Seedance 2.0 Fast I2V

Faster variant of Dreamina Seedance 2.0 image-to-video. Accepts the same multimodal inputs as Seedance 2.0 I2V—text prompt plus optional reference images and audio—with lower latency. Resolution limited to 480p/720p.

POST /seedance-2.0-fast-i2v/async

Seedance 2.0 Fast I2V

cURL

curl --request POST \
  --url https://api.modellix.ai/api/v1/bytedance/seedance-2.0-fast-i2v/async \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "<string>"
}
'

200

{
  "code": 0,
  "message": "success",
  "data": {
    "status": "pending",
    "task_id": "task-abc123",
    "model_id": "model-123",
    "get_result": {
      "method": "GET",
      "url": "https://api.modellix.ai/api/v1/tasks/task-abc123"
    }
  }
}

Authorizations

Authorization · string · header · required

API Key authentication. Format: Bearer YOUR_API_KEY.

Body

application/json

Seedance 2.0 Fast image-to-video request. Same fields as Seedance 2.0 I2V but resolution limited to 480p/720p.

prompt · string · required

Text describing the video to generate. Reference optional inputs with placeholders such as [Image 1] or [Audio 1] when applicable.

Required string length: 1 - 2000

first_frame_image · string

Optional. URL or Base64 of the starting frame. Do not use together with reference_images in the same request.

Minimum string length: 1

Example:

"https://example.com/first.jpg"

last_frame_image · string

Optional. URL or Base64 of the ending frame. Do not use together with reference_images in the same request.

Minimum string length: 1

Example:

"https://example.com/last.jpg"

reference_images · string[]

Optional. Up to 9 reference images for style or subject guidance. Do not use together with first_frame_image or last_frame_image.

Required array length: 1 - 9 elements

Image URL or Base64 data.

Minimum string length: 1

audio_urls · string[]

Optional. Up to 3 reference audio URLs (e.g., for rhythm or voice style).

Required array length: 1 - 3 elements

Audio URL (e.g., https://example.com/audio.mp3)

Minimum string length: 1

ratio · enum<string> · default: 1:1

Aspect ratio of the generated video.

Available options: 21:9, 16:9, 4:3, 1:1, 3:4, 9:16

resolution · enum<string> · default: 720p

Output resolution of the video. Fast variant does not support 1080p.

Available options: 480p, 720p

duration · enum<integer> · default: 5

Video duration in seconds (4-15 seconds).

Available options: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

seed · integer · default: -1

Random seed for reproducible generation. Use -1 for random.

Required range: -1 <= x <= 4294967295

camera_fixed · boolean · default: false

Whether to keep the camera fixed during generation.

generate_audio · boolean · default: true

Whether to generate audio for the video.

execution_expires_after · integer · default: 172800

Task expiration time in seconds.

Required range: 3600 <= x <= 259200

return_last_frame · boolean · default: false

Whether to return the last frame of the generated video.

Response

200 - application/json

Task submitted successfully

code · integer · required

Response code, 0 indicates success

Example:

0

message · string · required

Response message

Example:

"success"

data · object · required

Detailed data about the submitted asynchronous task.

Show child attributes