Grok Imagine Video Extend - Unifically

Extend a previously generated video using xAI’s Grok Imagine model via HTTP streaming. Provide the task_id of a completed video generation and choose between preset mode or custom mode.

Extend only works on videos generated with Grok Imagine Video (xai/grok-imagine-video, the speed-optimized 1.5 build). Task IDs from Grok Imagine Video 1.5 (xai/grok-imagine-1.5-video) are not supported — that model is API-level and separate.

Model

xai/grok-imagine-video-extend

Modes

There are two mutually exclusive modes:

Mode	How to activate	Behaviour
Preset	Provide `video_preset`	The preset controls the video style. `prompt`, `extend_at`, and `extend_duration` are ignored
Custom	Omit `video_preset`	You control timing and prompt. `prompt`, `extend_at`, and `extend_duration` are required

Parameters

Parameter	Type	Required	Description
`task_id`	string	Yes	Task ID of a completed video generation
`video_preset`	string	No	`"spicy"` or `"normal"`. Enables preset mode
`prompt`	string	No	Text prompt to guide the extension. Required in custom mode
`extend_at`	float	No	Second in the source video to start the extension from. Required in custom mode
`extend_duration`	int	No	Length of the extension: `6` or `10` seconds. Required in custom mode

Example Requests

Preset Mode

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "xai/grok-imagine-video-extend",
    "input": {
      "task_id": "abc123def456",
      "video_preset": "spicy"
    }
  }'

Custom Mode

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "xai/grok-imagine-video-extend",
    "input": {
      "task_id": "abc123def456",
      "prompt": "The camera continues panning right to reveal a mountain range",
      "extend_at": 8.5,
      "extend_duration": 10
    }
  }'

Response

{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "xyz789ghi012",
    "status": "processing"
  }
}

Volume discounts are available for almost all models. Reach out at contact@unifically.com to discuss custom pricing.