> ## 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 Video Edit > Edit videos with Google's Gemini Omni Flash video edit model Edit an existing uploaded video with Google's Gemini Omni Flash video edit model. Provide exactly one source video URL in `reference_video_urls`. ## Model ```text theme={null} google/gemini-omni-flash-video-edit ``` ## Parameters | Parameter | Type | Required | Default | Description | | ---------------------- | --------- | -------- | ---------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `reference_video_urls` | string\[] | Yes | - | Publicly reachable source video URL. Must contain exactly one URL. Uploaded source videos must meet the limits below. | | `prompt` | string | Yes | - | Edit instruction. Use `@Video1` to refer to the source video and `@ImageN`/`@CharacterN` for extra references. | | `reference_image_urls` | string\[] | No | - | Publicly reachable image URLs used as edit references. They count toward the total reference limit. | | `reference_characters` | array | No | - | Character references for the edit. Max 3 character items. Each character may include 1-10 `image_urls`. Supports per-character `voice` or `custom_voice`. See [available voices](/api-reference/resources#get-google-veo-voices). | | `seed` | integer | No | Random | Seed sent with the edit request. If omitted, a seed is generated automatically and returned when available. | | `start_frame` | integer | No | `0` | First source frame index included in the edit range. | | `end_frame` | integer | No | Source end | Last source frame index included in the edit range. If omitted, the service uses the detected final frame when available. | | `allow_audio_filtered` | boolean | No | `false` | When `true`, the generation runs without audio instead of failing when the audio track is filtered. | ## Limits | Limit | Value | | ------------------------------------------ | ---------------- | | Video references | 1 | | Character references | 3 | | Total video + image + character references | 7 | | Uploaded source video size | Up to 1 GB | | Uploaded source video length | Up to 30 seconds | ## Character References Each character must be an object with `image_urls`. Even one-image characters must use an array. Gemini Omni Flash edit also supports per-character preset voices and custom tuned voices. ### Preset Voice ```json theme={null} { "image_urls": [ "https://example.com/character.png" ], "name": "Ada", "description": "warm, sharp, curious", "voice": "achernar" } ``` ### Custom Tuned Voice ```json theme={null} { "image_urls": [ "https://example.com/character.png" ], "name": "Ada", "description": "warm, sharp, curious", "custom_voice": { "voice": "achernar", "name": "Ada voice", "voice_performance": "calm, bright, expressive", "sample_dialogue": "Hello, I am Ada.", "speaker": "Ada" } } ``` | 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. Used as the temporary character handle/name. | | `description` | string | No | Character notes/personality text. | | `voice` | string | No | Preset voice for this character. Do not combine with `custom_voice` on the same character. | | `custom_voice` | object | No | Tuned voice config for this character. Use this instead of `voice` when you want to modify a base voice. | | `custom_voice.voice` | string | Yes | Preset voice used as the base voice for tuning. See [available voices](/api-reference/resources#get-google-veo-voices). | | `custom_voice.name` | string | Yes | Display name for the tuned voice. | | `custom_voice.voice_performance` | string | Yes | Direction for the tuned voice delivery, such as tone, energy, accent, pacing, or acting notes. | | `custom_voice.sample_dialogue` | string | Yes | Sample line used for tuning. Max 120 characters. | | `custom_voice.speaker` | string | No | Speaker label for the tuned voice. Defaults to the custom voice `name` when omitted. | \*`image_urls` must contain at least one URL. ## Example ```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-video-edit", "input": { "reference_video_urls": [ "https://example.com/source-video.mp4" ], "prompt": "Make @Video1 look like it was filmed underwater, and replace the main person with @Character1.", "reference_image_urls": [ "https://example.com/underwater-style.png" ], "reference_characters": [ { "image_urls": [ "https://example.com/ada-front.png", "https://example.com/ada-profile.png" ], "name": "Ada", "description": "confident explorer", "voice": "achernar" } ], "seed": 4734, "start_frame": 0, "end_frame": 122 } }' ``` ## Prompt References | Token | Refers to | | ---------------------------- | -------------------------------------- | | `@Video1` | The source video for edit requests | | `@Image1`, `@Image2` | Items from `reference_image_urls` only | | `@Character1`, `@Character2` | Items from `reference_characters` only | ## Rejected Combinations | Input | Why rejected | | ------------------------------------------------- | --------------------------------------------------------------------------------- | | `task_id` | Edit requests must use `reference_video_urls`; source task IDs are not supported. | | Missing or empty `reference_video_urls` | An edit needs exactly one source video URL. | | More than one `reference_video_urls` item | Video edit accepts one source video. | | `end_frame` lower than `start_frame` | Frame range must move forward. | | More than 7 total video + image + character items | Gemini Omni Flash edit reference 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. | | `voice` and `custom_voice` on the same character | Use a preset voice or a tuned voice, not both. | ## Response ```json theme={null} { "code": 200, "success": true, "data": { "task_id": "abc123def456", "status": "pending" } } ```