Gemini Omni Flash 1.2 Video Extend

Continue a finished Gemini Omni Flash 1.2 video. Pass the task_id of the completed clip, describe what happens next, and choose how many seconds to add (3 to 10). The result is the whole video: the original clip followed by the new part, with sound. You can add reference images, characters and voices to steer the new part, and you can extend an extension again. Try it in the browser: Gemini Omni Flash 1.2 API playground.

Model

google/gemini-omni-flash-1.2-video-extend

Parameters

Parameter	Type	Required	Default	Description
`task_id`	string	Yes	-	Task ID of the completed video to extend. It must be a `google/gemini-omni-flash-1.2-video` generation or an earlier `google/gemini-omni-flash-1.2-video-extend` result, made at `"360p"` or `"720p"`.
`prompt`	string	Yes	-	What happens next: how the action, camera, scene and sound continue. Use `@ImageN`/`@CharacterN` to point at references.
`duration`	integer	Yes	-	Seconds to add. Any whole number from `3` to `10`. This is the length of the new part, not of the whole video.
`seed`	integer	No	Random	Seed for reproducible results, `0` to `2147483647`.
`reference_image_urls`	string[]	No	-	Publicly reachable image URLs that keep objects and scenes consistent in the new part. Max 3.
`reference_characters`	array	No	-	Character references for the new part. Max 2 character items. See Character References.
`voice`	string or string[]	No	-	Google voice preset ID, or an array of up to 3 IDs. See available voices.
`allow_audio_filtered`	boolean	No	`false`	When `true`, the generation runs without audio instead of failing when the audio track is filtered.
`nsfw_check`	boolean	No	`false`	Check the prompt and input images for NSFW content before generating. Off unless set to `true`

The new part keeps the source video’s shape and resolution, so there is no aspect_ratio or resolution field.

Billing

You pay per second of new video only, at the source video’s resolution. Extending a 360p clip by 5 seconds is billed as 5 seconds at the 360p rate, whatever the length of the original. See current rates on the pricing page.

Limits

Limit	Value
New part	3 to 10 seconds
Source resolution	`"360p"` or `"720p"`
Reference images	3
Character references	2
Voices	3

Example — Add 5 Seconds

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "google/gemini-omni-flash-1.2-video-extend",
    "input": {
      "task_id": "YOUR_COMPLETED_TASK_ID",
      "prompt": "The camera keeps pulling back as the crowd starts to cheer.",
      "duration": 5
    }
  }'

Example — New Part With a Reference Image and a Voice

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "google/gemini-omni-flash-1.2-video-extend",
    "input": {
      "task_id": "YOUR_COMPLETED_TASK_ID",
      "prompt": "The @Image1 poster is now hanging on the wall and a narrator says: \"Welcome home.\"",
      "duration": 4,
      "reference_image_urls": [
        "https://example.com/poster.png"
      ],
      "voice": "kore"
    }
  }'

Prompt References

Token	Refers to
`@Image1`, `@Image2`	Items from `reference_image_urls` only
`@Character1`, `@Character2`	Items from `reference_characters` only

Rejected Combinations

Input	Why rejected
`task_id` of a video from another model, or of an Omni Flash 1.2 edit	Only Omni Flash 1.2 generations and extensions can be extended.
Source video made at `"1080p"` or `"4k"`	Only 360p and 720p videos can be extended.
Source video made with `reference_characters`	Videos made with character references cannot be extended.
Source task still processing, or failed	The source video must be completed.
`duration` below 3 or above 10	The new part is 3 to 10 seconds.
More than 3 `reference_image_urls`	Reference image limit.
More than 2 character items	Character item limit.
More than 3 voices	Voice limit.

Response

{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}

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