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POST
/
seedance-2.0-fast-v2v
/
async
Seedance 2.0 Fast V2V
curl --request POST \
  --url https://api.modellix.ai/api/v1/bytedance/seedance-2.0-fast-v2v/async \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "<string>",
  "video_urls": [
    "<string>"
  ]
}
'
{
  "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"
    }
  }
}

Documentation Index

Fetch the complete documentation index at: https://docs.modellix.ai/llms.txt

Use this file to discover all available pages before exploring further.

Authorizations

Authorization
string
header
required

API Key authentication. Format: Bearer YOUR_API_KEY.

Body

application/json

Seedance 2.0 Fast video-to-video request. Same fields as Seedance 2.0 V2V but resolution limited to 480p/720p.

prompt
string
required

Text describing how to transform or extend the reference video(s). Use placeholders such as [Video 1], [Image 1], or [Audio 1] when referencing optional inputs.

Required string length: 1 - 2000
video_urls
string[]
required

One to three reference video URLs that define the source motion or content to transform.

Required array length: 1 - 3 elements
Minimum string length: 1
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. 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.

Required array length: 1 - 3 elements
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.