Gemini Omni Flash Video

Generate short text-to-video, start-frame, and reference-to-video clips with Google’s Gemini Omni Flash video model.

Model

google/gemini-omni-flash-video

Parameters

Parameter	Type	Required	Default	Description
`prompt`	string	Yes	-	Main video prompt. Use `@ImageN` or `@CharacterN` to point at specific references. Unknown references are left as plain text.
`seed`	integer	No	Random	Seed sent to Gemini Omni Flash. If omitted, a seed is generated automatically and returned when available.
`aspect_ratio`	string	No	`"16:9"`	Output orientation. Allowed: `"16:9"`, `"9:16"`.
`duration`	integer	No	`4`	Clip length in seconds. Allowed: `4`, `6`, `8`, `10`.
`resolution`	string	No	`"720p"`	Output resolution. Allowed: `"720p"`, `"1080p"`, `"4k"`. With `"1080p"` or `"4k"`, the video is upscaled as part of the same task before it completes — no separate upscale task needed. `"720p"` returns the native, non-upscaled output.
`start_image_url`	string	No	-	Publicly reachable image URL used as the first frame. Cannot be combined with `reference_image_urls` or `reference_characters`.
`reference_image_urls`	string[]	No	-	Publicly reachable image reference URLs. Max 7 total expanded image + character image URLs. Cannot be combined with start/end frame fields.
`reference_characters`	array	No	-	Character references. Max 3 character items; expanded character image URLs count toward the total 7 reference limit.
`voice`	string	No	-	Request-level Google Flow voice preset ID. Requires at least one image or character reference. 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.

Start/end frame support is now available for Gemini Omni Flash video generation. For now, only start frame control (start_image_url) is available — end frame support is not yet available on Google’s end, but it’s coming in an upcoming Google update. We’ll keep you posted!

Start-frame mode and reference mode are separate generation modes. Do not combine start_image_url with reference_image_urls or reference_characters.

Character References

Each character must be an object with image_urls. Even one-image characters must use an array.

{
  "image_urls": [
    "https://example.com/character-front.png",
    "https://example.com/character-profile.png"
  ],
  "name": "Ada",
  "description": "warm, sharp, curious"
}

Field	Type	Required	Description
`image_urls`	string[]	Yes*	Publicly reachable character image URLs. Use 1-10 images for a character entity.
`name`	string	No	Display name for the character.
`description`	string	No	Character notes/personality text.

*image_urls must contain at least one URL.

Example — Reference-to-Video

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-video",
    "input": {
      "prompt": "Make @Character1 and @Image1 dance in a neon studio with energetic camera movement.",
      "reference_image_urls": [
        "https://example.com/neon-studio.png"
      ],
      "reference_characters": [
        {
          "image_urls": [
            "https://example.com/dancer.png"
          ],
          "name": "Dancer"
        }
      ],
      "duration": 10,
      "aspect_ratio": "9:16"
    }
  }'

Example — Start Frame

Use start_image_url to anchor the first frame of the generated clip.

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-video",
    "input": {
      "prompt": "Camera slowly pans across the scene as clouds drift overhead",
      "start_image_url": "https://example.com/start.jpg",
      "aspect_ratio": "16:9",
      "duration": 6,
      "resolution": "1080p"
    }
  }'

Prompt References

Token	Refers to
`@Image1`, `@Image2`	Items from `reference_image_urls` only
`@Character1`, `@Character2`	Items from `reference_characters` only. With multiple `image_urls`, the token points to the character item; extra images are identity references

Rejected Combinations

Input	Why rejected
`end_image_url`	End frame support is not yet available on Google’s end. Use Veo 3.1 for first-and-last-frame workflows until Google enables it.
`start_image_url` with `reference_image_urls` or `reference_characters`	Start-frame mode and reference mode are separate generation modes.
More than 7 total expanded image URLs	Gemini Omni Flash generation reference limit.
More than 3 character items	Character item limit.
`image_url` on a character	Use `image_urls` instead, even for one image.
Plain string character entries	Character entries must be objects with `image_urls`.
Empty `image_urls`	A character needs at least one image.
More than 10 `image_urls` on one character	Character entity image limit.

Response

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

​Model

​Parameters

​Character References

​Example — Reference-to-Video

​Example — Start Frame

​Prompt References

​Rejected Combinations

​Response

Model

Parameters

Character References

Example — Reference-to-Video

Example — Start Frame

Prompt References

Rejected Combinations

Response