# Kling Video 4K Video to Video > Kling's Native 4K is a video generation model that directly outputs professional-grade 4K video in one step, eliminating the need for post-production upscaling ## Overview - **Endpoint**: `https://fal.run/fal-ai/kling-video/o3/4k/video-to-video/reference` - **Model ID**: `fal-ai/kling-video/o3/4k/video-to-video/reference` - **Category**: video-to-video - **Kind**: inference **Tags**: utility, editing ## Pricing For every second of video you generated, you will be charged **$0.42** regardless of whether audio is on or off. For example, a **5s** video will cost **$2.10**. For more details, see [fal.ai pricing](https://fal.ai/pricing). ## API Information This model can be used via our HTTP API or more conveniently via our client libraries. See the input and output schema below, as well as the usage examples. ### Input Schema The API accepts the following input parameters: - **`prompt`** (`string`, _required_): Text prompt for video generation. Reference video as @Video1. - Examples: "Integrate @Element1 in the scene. Style video should be following watercolor style of @Image1" - **`video_url`** (`string`, _required_): Reference video URL. Only .mp4/.mov formats, 3-15s duration, 720-3840px resolution, max 200MB. - Examples: "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/video_reference.mp4" - **`image_urls`** (`list`, _optional_): Reference images for style/appearance. Reference in prompt as @Image1, @Image2, etc. Maximum 4 total (elements + reference images) when using video. - Array of string - Examples: ["https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/image_url1.jpg","https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/image_url2.jpg"] - **`keep_audio`** (`boolean`, _optional_): Whether to keep the original audio from the reference video. Default value: `true` - Default: `true` - Examples: false - **`elements`** (`list`, _optional_): Elements (characters/objects) to include. Reference in prompt as @Element1, @Element2. - Array of KlingV3ImageElementInput - Examples: [{"frontal_image_url":"https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/element1_front.png","reference_image_urls":["https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/element1_reference1.png"]}] - **`shot_type`** (`string`, _optional_): The type of multi-shot video generation. Default value: `"customize"` - Default: `"customize"` - **`aspect_ratio`** (`AspectRatioEnum`, _optional_): Aspect ratio. Default value: `"auto"` - Default: `"auto"` - Options: `"auto"`, `"16:9"`, `"9:16"`, `"1:1"` - Examples: "auto" - **`duration`** (`Enum`, _optional_): Video duration in seconds (3-15s for reference video). - Options: `"3"`, `"4"`, `"5"`, `"6"`, `"7"`, `"8"`, `"9"`, `"10"`, `"11"`, `"12"`, `"13"`, `"14"`, `"15"` - Examples: "5" **Required Parameters Example**: ```json { "prompt": "Integrate @Element1 in the scene. Style video should be following watercolor style of @Image1", "video_url": "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/video_reference.mp4" } ``` **Full Example**: ```json { "prompt": "Integrate @Element1 in the scene. Style video should be following watercolor style of @Image1", "video_url": "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/video_reference.mp4", "image_urls": [ "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/image_url1.jpg", "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/image_url2.jpg" ], "keep_audio": false, "elements": [ { "frontal_image_url": "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/element1_front.png", "reference_image_urls": [ "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/element1_reference1.png" ] } ], "shot_type": "customize", "aspect_ratio": "auto", "duration": "5" } ``` ### Output Schema The API returns the following output format: - **`video`** (`File`, _required_): The generated video. - Examples: {"content_type":"video/mp4","file_size":15809901,"file_name":"output.mp4","url":"https://storage.googleapis.com/falserverless/example_outputs/kling-o3/pro-v2v-reference/output.mp4"} **Example Response**: ```json { "video": { "content_type": "video/mp4", "file_size": 15809901, "file_name": "output.mp4", "url": "https://storage.googleapis.com/falserverless/example_outputs/kling-o3/pro-v2v-reference/output.mp4" } } ``` ## Usage Examples ### cURL ```bash curl --request POST \ --url https://fal.run/fal-ai/kling-video/o3/4k/video-to-video/reference \ --header "Authorization: Key $FAL_KEY" \ --header "Content-Type: application/json" \ --data '{ "prompt": "Integrate @Element1 in the scene. Style video should be following watercolor style of @Image1", "video_url": "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/video_reference.mp4" }' ``` ### Python Ensure you have the Python client installed: ```bash pip install fal-client ``` Then use the API client to make requests: ```python import fal_client def on_queue_update(update): if isinstance(update, fal_client.InProgress): for log in update.logs: print(log["message"]) result = fal_client.subscribe( "fal-ai/kling-video/o3/4k/video-to-video/reference", arguments={ "prompt": "Integrate @Element1 in the scene. Style video should be following watercolor style of @Image1", "video_url": "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/video_reference.mp4" }, with_logs=True, on_queue_update=on_queue_update, ) print(result) ``` ### JavaScript Ensure you have the JavaScript client installed: ```bash npm install --save @fal-ai/client ``` Then use the API client to make requests: ```javascript import { fal } from "@fal-ai/client"; const result = await fal.subscribe("fal-ai/kling-video/o3/4k/video-to-video/reference", { input: { prompt: "Integrate @Element1 in the scene. Style video should be following watercolor style of @Image1", video_url: "https://storage.googleapis.com/falserverless/example_inputs/kling-o3/pro-v2v-reference/video_reference.mp4" }, logs: true, onQueueUpdate: (update) => { if (update.status === "IN_PROGRESS") { update.logs.map((log) => log.message).forEach(console.log); } }, }); console.log(result.data); console.log(result.requestId); ``` ## Additional Resources ### Documentation - [Model Playground](https://fal.ai/models/fal-ai/kling-video/o3/4k/video-to-video/reference) - [API Documentation](https://fal.ai/models/fal-ai/kling-video/o3/4k/video-to-video/reference/api) - [OpenAPI Schema](https://fal.ai/api/openapi/queue/openapi.json?endpoint_id=fal-ai/kling-video/o3/4k/video-to-video/reference) ### fal.ai Platform - [Platform Documentation](https://fal.ai/docs/documentation) - [Python Client](https://fal.ai/docs/api-reference/client-libraries/python) - [JavaScript Client](https://fal.ai/docs/api-reference/client-libraries/javascript) ### Other agent-readable surfaces This file covers one model. To find anything else: - [Platform overview](https://fal.ai/llms.txt): Entry points and representative endpoint IDs - [Documentation index](https://fal.ai/docs/llms.txt): Every documentation page - [Full documentation text](https://fal.ai/docs/llms-full.txt): The whole documentation inlined - Any other model: `https://fal.ai/models//llms.txt`