> ## 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. # Kling O1 Video > Generate videos with Kling O1 Generate high-quality AI videos using Kling O1. Supports text-to-video, raw reference images, persistent subject/object elements (image only), start/end frames, video transform, and video reference. Same shape as Omni 3.0 but does not support `multi_shots`, `native_audio`, or video-type elements. Max duration 10s. ## Model ``` kuaishou/kling-o1-video ``` ## Parameters | Parameter | Type | Required | Default | Description | | ------------------- | ----------------- | -------- | ------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `video_mode` | string | No | - | Input mode. Allowed: `"elements"`, `"start_end_frame"`, `"transform"`, `"video_reference"`. Omit for text-to-video | | `prompt` | string | **Yes** | - | Text prompt | | `mode` | string | No | `"pro"` | `"std"` (720p) or `"pro"` (1080p) | | `duration` | integer | No | `5` | Video length in seconds (3–10) | | `aspect_ratio` | string | No | - | `"1:1"`, `"9:16"`, `"16:9"`, or `"auto"`. Must be `"auto"` when `video_url` is set; rejected otherwise. Omit to let the server choose (`"auto"` if `video_url`, else `"16:9"`) | | `image_urls` | string\[] | No | - | Raw reference image URLs uploaded per request (max 7). No description, no reuse. Use `@Image1`, `@Image2` in `prompt` | | `start_image_index` | integer | No | - | 1-based index into `image_urls` marking which reference image anchors the first frame. No end-frame equivalent | | `elements` | ElementInput30\[] | No | - | Persistent subject/object assets (image only on O1). Auto-created on Kling and auto-deleted if submit fails. Use `@Element1`, `@Element2` in `prompt`. Coexists with `image_urls` | | `start_frame_url` | string | No | - | First frame image URL (`start_end_frame` mode) | | `end_frame_url` | string | No | - | Last frame image URL (`start_end_frame` mode) | | `video_url` | string | No | - | Source video URL (`transform` / `video_reference` modes) | ## Modes | Mode | Required inputs | Optional inputs | Notes | | ------------------------- | ---------------------------------------- | --------------------------- | -------------------------------------------------------------------------------------------- | | *omitted* (text-to-video) | `prompt` | — | Rejects every input field including `elements`, `image_urls`, `start_frame_url`, `video_url` | | `elements` | At least one of `image_urls`, `elements` | — | Combined `image_urls` + `elements` cap of **7**. `video_url` rejected | | `start_end_frame` | `start_frame_url` | `end_frame_url`, `elements` | — | | `transform` | `video_url` | `image_urls`, `elements` | Combined `image_urls` + `elements` cap of **4**. `aspect_ratio` must be `"auto"` | | `video_reference` | `video_url` | `image_urls`, `elements` | Combined `image_urls` + `elements` cap of **4**. `aspect_ratio` must be `"auto"` | **Text-to-video with elements** — set `video_mode: "elements"` and pass only the `elements` array (no `image_urls` required). The omit-`video_mode` path is strictly for pure text-to-video with **zero** inputs; any reference (image or element) requires `elements` mode. ## Reference images vs elements * **`image_urls`** — raw images uploaded per request. Single-use, no description, no reuse across tasks. Cap 7. Reference in `prompt` as `@Image1`, `@Image2`, … * **`elements`** — persistent subject/object assets stored on the Kling account. Auto-created from your input on submit and auto-deleted if the submit fails. Reference in `prompt` as `@Element1`, `@Element2`, … Both can be used together; they share the per-mode combined cap. ## Elements O1 supports IMAGE elements only — passing an element with `type: "video"` returns 400. ```json theme={null} "elements": [ {"description": "Woman in red jacket", "type": "image", "image_urls": ["front.jpg", "side.jpg"]} ] ``` Each element accepts: | Parameter | Type | Default | Description | | ------------- | --------- | --------- | ------------------------------------------------ | | `description` | string | `""` | Short description of the element (max 100 chars) | | `type` | string | `"image"` | Must be `"image"` on O1 | | `image_urls` | string\[] | - | Source image URLs for the element (max 4) | ## Example - Text-to-Video ```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": "kuaishou/kling-o1-video", "input": { "prompt": "A cinematic drone shot over a misty forest at dawn", "duration": 10, "mode": "pro" } }' ``` ## Example - Reference Images ```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": "kuaishou/kling-o1-video", "input": { "video_mode": "elements", "prompt": "Create a video featuring @Image1 and @Image2", "image_urls": ["https://example.com/ref1.jpg", "https://example.com/ref2.jpg"], "duration": 10, "mode": "pro" } }' ``` ## Example - With Elements ```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": "kuaishou/kling-o1-video", "input": { "video_mode": "elements", "prompt": "@Element1 walks through a park at sunset", "elements": [ {"description": "Woman in red jacket", "type": "image", "image_urls": ["https://example.com/front.jpg"]} ], "duration": 10, "mode": "pro" } }' ``` ## Example - Start/End Frame ```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": "kuaishou/kling-o1-video", "input": { "prompt": "Smooth transition between scenes", "video_mode": "start_end_frame", "start_frame_url": "https://example.com/start.jpg", "end_frame_url": "https://example.com/end.jpg", "duration": 10, "mode": "pro" } }' ``` ## Response ```json theme={null} { "code": 200, "success": true, "data": { "task_id": "abc123def456", "status": "processing" } } ```