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

> ## Agent Instructions
> fal has two developer products. Model APIs run hosted models through an API key. fal Serverless deploys your own Python apps and models on fal GPUs.
> To call a hosted model, start with the [Quick Start](https://fal.ai/docs/documentation/quickstart.md) and the [Model APIs overview](https://fal.ai/docs/documentation/model-apis/overview.md).
> To deploy your own model with fal Serverless, start with these pages:
> - [Introduction to Serverless](https://fal.ai/docs/documentation/serverless/index.md): What fal Serverless is and the three ways to deploy on it.
> - [Installation & Setup](https://fal.ai/docs/documentation/development/getting-started/installation.md): Install the fal CLI with `pip install fal` and authenticate.
> - [Quick Start](https://fal.ai/docs/documentation/development/getting-started/quick-start.md): Build a Hello World app, test it with `fal run`, and ship it with `fal deploy`.
> - [App Lifecycle](https://fal.ai/docs/documentation/development/app-lifecycle.md): How a `fal.App` goes from code to running runners.
> - [Define Your Endpoints](https://fal.ai/docs/documentation/development/endpoints-overview.md): Structure the API endpoints that your app exposes.
> - [Deploy to Production](https://fal.ai/docs/documentation/deployment/deploy-to-production.md): Persistent URLs, authentication modes, and automatic scaling.
> - [Machine Types](https://fal.ai/docs/documentation/deployment/machine-types.md): Available GPU and CPU machine types and how to choose one.
> - [Pricing](https://fal.ai/docs/documentation/serverless/pricing.md): Per-second billing and the runner states that are billed.
> - [Scaling Parameter Reference](https://fal.ai/docs/documentation/deployment/scale-your-application.md): Parameters that control runners, concurrency, and scale to zero.
> - [Optimizing Cold Starts](https://fal.ai/docs/documentation/serverless/optimizations/optimize-cold-starts.md): Causes of cold starts and ways to make them shorter.
> - [Examples](https://fal.ai/docs/examples/index.md): Complete Serverless apps for image, video, audio, 3D, realtime, and multi-GPU workloads.
> - [Migrating to fal](https://fal.ai/docs/documentation/development/migrating-to-fal.md): Guides to move an existing Docker server or an app from another platform to fal.
> fal Serverless deploys need access that the fal team approves for each account. Request access at https://fal.ai/dashboard/serverless-get-started.

# Kling Video O3 Standard Reference To Video API

> API reference for Kling Video O3 Standard Reference To Video. Transform images, elements, and text into consistent, high-quality video scenes, ensuring stable character identity, object details, and e

**Endpoint:** `POST https://fal.run/fal-ai/kling-video/o3/standard/reference-to-video`
**Endpoint ID:** `fal-ai/kling-video/o3/standard/reference-to-video`

<Card title="Try it in the Playground" icon="play" href="https://fal.ai/models/fal-ai/kling-video/o3/standard/reference-to-video/playground">
  Run this model interactively with your own prompts.
</Card>

## Quick Start

<CodeGroup>
  ```python title="Python" theme={null}
  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/standard/reference-to-video",
      arguments={},
      with_logs=True,
      on_queue_update=on_queue_update,
  )
  print(result)
  ```

  ```javascript title="JavaScript" theme={null}
  import { fal } from "@fal-ai/client";

  const result = await fal.subscribe("fal-ai/kling-video/o3/standard/reference-to-video", {
    input: {},
    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);
  ```

  ```bash title="cURL" theme={null}
  curl --request POST \
    --url https://fal.run/fal-ai/kling-video/o3/standard/reference-to-video \
    --header "Authorization: Key $FAL_KEY" \
    --header "Content-Type: application/json" \
    --data '{}'
  ```
</CodeGroup>

## Related

* [Kling O3 Image to Video \[Pro\]](/docs/model-api-reference/video-generation-api/kling-o3-image-to-video) — Video Generation
* [Kling O3 Reference to Video \[Pro\]](/docs/model-api-reference/video-generation-api/kling-o3-reference-to-video) — Video Generation
* [Kling O3 Edit Video \[Pro\]](/docs/model-api-reference/video-generation-api/kling-o3-edit-video) — Video Generation
* [Kling O3 Text to Video \[Pro\]](/docs/model-api-reference/video-generation-api/kling-o3-text-to-video) — Video Generation
* [Kling O3 Reference Video to Video \[Pro\]](/docs/model-api-reference/video-generation-api/kling-o3-reference-video-to-video) — Video Generation

## Capabilities

* Text prompt input
* Duration control
* Aspect ratio control

## API Reference

### Input Schema

<ParamField body="prompt" type="string">
  Text prompt for video generation. Either prompt or multi\_prompt must be provided, but not both.
</ParamField>

<ParamField body="multi_prompt" type="list<KlingV3MultiPromptElement>">
  List of prompts for multi-shot video generation.
</ParamField>

<ParamField body="start_image_url" type="string">
  Image to use as the first frame of the video.
</ParamField>

<ParamField body="end_image_url" type="string">
  Image to use as the last frame of the video.
</ParamField>

<ParamField body="image_urls" type="list<string>">
  Reference images for style/appearance. Reference in prompt as @Image1, @Image2, etc. Maximum 4 total (elements + reference images) when using video.
</ParamField>

<ParamField body="elements" type="list<KlingV3ComboElementInput>">
  Elements (characters/objects) to include. Reference in prompt as @Element1, @Element2.
</ParamField>

<ParamField body="generate_audio" type="boolean" default="false">
  Whether to generate native audio for the video.
</ParamField>

<ParamField body="duration" type="DurationEnum" default="5">
  Video duration in seconds (3-15s). Default value: `"5"`

  Possible values: `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15`
</ParamField>

<ParamField body="shot_type" type="string" default="customize">
  The type of multi-shot video generation. Default value: `"customize"`
</ParamField>

<ParamField body="aspect_ratio" type="AspectRatioEnum" default="16:9">
  The aspect ratio of the generated video frame. Default value: `"16:9"`

  Possible values: `16:9`, `9:16`, `1:1`
</ParamField>

### Output Schema

<ParamField body="video" type="File" required>
  The generated video.
</ParamField>

## Input Example

```json theme={null}
{
  "prompt": "@Element1 and @Element2 is having dinner at this table on @Image1",
  "multi_prompt": null,
  "start_image_url": "https://v3b.fal.media/files/b/0a8d1b63/EcYdmuNB1LTFjtn3Ryjrf_6ROoQV4u.png",
  "image_urls": [
    "https://v3b.fal.media/files/b/0a8d1b63/EcYdmuNB1LTFjtn3Ryjrf_6ROoQV4u.png"
  ],
  "elements": [
    {
      "frontal_image_url": "https://v3b.fal.media/files/b/0a8d1b64/-ddhNV-utVpHj_1uGfuY-_i6viYke3.png",
      "reference_image_urls": [
        "https://v3b.fal.media/files/b/0a8d1b5e/Gl1qUHJeTG63vAGtQmGM-_S3kPW32v.png"
      ]
    },
    {
      "frontal_image_url": "https://v3b.fal.media/files/b/0a8d1b66/cWe8LC84I_OF6ee9ZtnsO_nY9Hw5UB.png",
      "reference_image_urls": [
        "https://v3b.fal.media/files/b/0a8d1b60/Dt21s8LElZdSccIGDC7ec_Nuaraa9P.png"
      ]
    }
  ],
  "generate_audio": false,
  "duration": "8",
  "shot_type": "customize",
  "aspect_ratio": "16:9"
}
```

## Output Example

```json theme={null}
{
  "video": {
    "content_type": "video/mp4",
    "file_name": "output.mp4",
    "file_size": 3192162,
    "url": "https://v3b.fal.media/files/b/0a8d200d/ejCxI5DalzOPlP4yf6uP3_output.mp4"
  }
}
```

## Limitations

* `aspect_ratio` restricted to: `16:9`, `9:16`, `1:1`