Long Video

Long Video creates a connected 4–180 second video from one prompt. Choose HappyHorse or Seedance as the generation provider and track the asynchronous task through the standard task endpoint or a callback.

Model

Model	Description
`long-video`	Long-form prompt-to-video generation with optional global image references

When provider is set to seedance, Long Video uses Seedance 2.0 as the underlying generation model.

Pricing

Completed tasks are billed by requested duration, resolution, and provider.

Provider	Resolution	Credits per second
HappyHorse	720p	27.5
HappyHorse	1080p	47.2
Seedance	480p	21.6
Seedance	720p	45.6
Seedance	1080p	114

Credits are pre-charged when the task is created and fully refunded if generation fails.

Create a task

POST https://api.aivideoapi.ai/v1/videos/generations

Request body

Field	Type	Required	Description
`model`	string	Yes	Must be `long-video`
`input`	object	Yes	Generation parameters
`callback_url`	string	No	Receives the standard task completion or failure callback

Input parameters

Field	Type	Required	Description
`prompt`	string	Yes	Video description, 1–2500 characters
`duration`	integer	Yes	Output duration from 4 to 180 seconds
`provider`	string	No	`happyhorse` (default) or `seedance`
`resolution`	string	No	Default `720p`; HappyHorse supports 720p/1080p, Seedance supports 480p/720p/1080p
`aspect_ratio`	string	No	Default `16:9`; supports `16:9`, `9:16`, `1:1`, `4:3`, `3:4`
`continuity_mode`	string	No	`consistent` (default) or `seamless`
`style`	string	No	Optional style direction, up to 500 characters
`image_urls`	string[]	No	Up to five global reference images; only valid in `consistent` mode
`native_audio_continuity`	boolean	No	Seedance only; default `false`
`seed`	integer	No	Random seed from 0 to 2147483647; default `42`

Example

curl -X POST https://api.aivideoapi.ai/v1/videos/generations \
  -H "Authorization: Bearer sk-your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "long-video",
    "callback_url": "https://your-server.com/webhook",
    "input": {
      "prompt": "A traveler follows a river from the mountains to a coastal city",
      "duration": 60,
      "provider": "seedance",
      "resolution": "720p",
      "aspect_ratio": "16:9",
      "continuity_mode": "consistent",
      "image_urls": ["https://example.com/character.jpg"],
      "native_audio_continuity": true
    }
  }'

Response

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "8b6a5162-5c91-4a42-8e80-4c8ef5486f24"
  }
}

Query the task

curl https://api.aivideoapi.ai/v1/tasks/{taskId} \
  -H "Authorization: Bearer sk-your-api-key"

The task moves from pending to processing, then to completed or failed. A completed task returns the final video in output.urls.

Error Codes

When a request fails, the API returns a JSON error response:

{
  "error": {
    "code": "insufficient_credits",
    "message": "Your credit balance is too low. Please top up.",
    "type": "billing_error"
  }
}

Error Reference

HTTP Status	Code	Type	Description
400	`invalid_request`	invalid_request_error	Missing or invalid parameters
401	`invalid_api_key`	authentication_error	API key is invalid, disabled, or deleted
402	`insufficient_credits`	billing_error	Credit balance too low, please top up
403	`ip_not_allowed`	permission_error	Request IP not in the key's allowlist
404	`model_not_found`	invalid_request_error	Model does not exist or is inactive
404	`task_not_found`	invalid_request_error	Task ID does not exist
429	`rate_limit_exceeded`	rate_limit_error	Too many requests, please slow down
429	`spend_limit_exceeded`	billing_error	Key spend limit reached (hourly/daily/total)
500	`internal_error`	api_error	Unexpected server error
503	`upstream_error`	upstream_error	Upstream AI provider returned an error

Common Scenarios

invalid_request (400)

Returned when required fields are missing or invalid.

{
  "error": {
    "code": "invalid_request",
    "message": "'model' is required.",
    "type": "invalid_request_error"
  }
}

insufficient_credits (402)

Your balance is too low. Check your balance with GET /v1/credits and top up in Dashboard > Billing.

invalid_api_key (401)

Possible causes:

The key does not start with sk-
The key has been disabled or deleted
The user account has been banned

upstream_error (503)

The upstream AI provider returned an error. This may happen when:

The input contains sensitive or prohibited content
The provider is temporarily unavailable
The request parameters are not supported by the provider

Credits are automatically refunded when a task fails due to upstream errors.