> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unifically.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Gemini Omni Flash 1.2 Video Extend

> Add 3 to 10 seconds to a finished Gemini Omni 1.2 Flash video. See supported inputs, parameters, billing, response fields, and API examples.

Continue a finished [Gemini Omni Flash 1.2](https://docs.unifically.com/models/video/google/gemini-omni-flash-1.2-video.md) 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](https://unifically.com/models/gemini-omni-flash-1.2).

## Model

```text theme={null}
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](https://docs.unifically.com/models/video/google/gemini-omni-flash-1.2-video.md#character-references). |
| `voice` | string or string\[] | No | - | Google voice preset ID, or an array of up to 3 IDs. See [available voices](https://docs.unifically.com/api-reference/resources.md#get-google-veo-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](https://unifically.com/pricing).

## 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

```bash theme={null}
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

```bash theme={null}
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

```json theme={null}
{
  "code": 200,
  "success": true,
  "data": {
    "task_id": "abc123def456",
    "status": "processing"
  }
}
```

> [!NOTE]
>
> **Volume discounts** are available for almost all models. Reach out at [contact@unifically.com](mailto:contact@unifically.com) to discuss custom pricing.


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