# Kling Video · O3 · 4k · Reference to Video API

> Video basado en referencias en 4K con prompts de varias tomas, fotogramas inicial y final, elementos y audio nativo opcional

Construye un video a partir de un `prompt` de hasta 2500 caracteres o de `multi_prompt` para varias tomas, pero no de ambos. Guíalo con `start_image_url`, `end_image_url`, imágenes de referencia `image_urls` y `elements`, citados en el prompt como @Image1 o @Element1, hasta 7 en total. La duración es de 3 a 15 segundos, la relación de aspecto es 16:9, 9:16 o 1:1, y `generate_audio` añade sonido.

- Model id: `kling-video/o3/4k/reference-to-video`
- Made by: Kling
- Category: Reference to Video
- Output: video
- Price: $0.42 / second (5 s ≈ $2.10) (cheapest run $2.10 (2100 API credits))
- Run: `POST https://api.doitong.ru/v1/run/kling-video/o3/4k/reference-to-video`
- Quote: `POST https://api.doitong.ru/v1/quote/kling-video/o3/4k/reference-to-video`
- Docs page: https://doitong.com/es/developers/models/kling-video/o3/4k/reference-to-video

## Pricing

Price: **$0.42 / second (5 s ≈ $2.10)**. Billed per second of output (`duration`, default 15).

The full example input below costs $2.10 = 2100 API credits (5 s × 420 API credits).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.ru/v1/quote/kling-video/o3/4k/reference-to-video` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

Send either the canonical name or the native field name (not both). Canonical names are the same across models.

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `enable_safety_checker` |  | boolean | no | `true` |  | Las comprobaciones de seguridad solo se pueden desactivar con autorización de la cuenta; las solicitudes sin autorización siempre se someten a comprobación. |
| `prompt` |  | string \| null | no |  | ≤ 2500 characters | Instrucciones de texto utilizadas para generar el video. Proporciona exactamente uno de prompt o multi_prompt. |
| `multi_prompt` |  | array of object {prompt, duration} \| null | no |  |  | Lista de prompts utilizada para generar un video con varias tomas. |
| `multi_prompt[].prompt` |  | string | yes |  |  | Instrucciones de texto para la toma actual. |
| `multi_prompt[].duration` |  | enum (string) | no | `5` | `1`, `2`, `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15` | Duración de la toma actual, medida en segundos. |
| `start_image_url` | `image` | string (image URL) \| null | no |  |  | Imagen utilizada para el fotograma inicial del video. El tamaño del archivo no debe superar 50 MB; el ancho y la altura deben ser de al menos 300px cada uno, con una proporción de entre 0.40 y 2.50. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Imagen que proporciona el fotograma final del video, limitada a 50 MB. El ancho y la altura deben ser de al menos 300 px cada uno, con una proporción de 0.40 a 2.50. |
| `image_urls` | `images` | array of image URL \| null | no |  |  | Imágenes que proporcionan referencias de estilo o apariencia, a las que se hace referencia en el prompt mediante @Image1, @Image2 y así sucesivamente. Los elementos y las imágenes de referencia no pueden superar conjuntamente 7 entradas. Cada archivo debe tener como máximo 50 MB, con un ancho y una altura de al menos 300px y una proporción de entre 0.40 y 2.50. |
| `elements` |  | array of object {frontal_image_url, reference_image_urls, video_url, voice_id} \| null | no |  |  | Personajes u objetos que se deben incluir, a los que se hace referencia en el prompt mediante @Element1 y @Element2. |
| `elements[].frontal_image_url` |  | string (image URL) \| null | no |  |  | Imagen frontal que muestra la vista principal del elemento. El tamaño del archivo no debe superar 50 MB; el ancho y la altura deben ser de al menos 300px cada uno, con una proporción de entre 0.40 y 2.50. |
| `elements[].reference_image_urls` |  | array of image URL \| null | no |  |  | Proporciona entre 1–3 imágenes de referencia adicionales que muestren distintos ángulos. Cada imagen debe tener una proporción de entre 0.40 y 2.50, medir al menos 300px en ambas dimensiones y no superar 50.0MB. |
| `elements[].video_url` |  | string (video URL) \| null | no |  |  | URL que apunta al video de un elemento; solo un elemento por solicitud puede incluir un video. El archivo debe tener como máximo 200 MB, con un ancho y una altura de entre 720px y 2160px. La duración debe estar entre 3 segundos y 10.05 segundos, y los FPS entre 24.0 y 60.0. |
| `elements[].voice_id` |  | string \| null | no |  |  | Voice ID asignado al elemento. Las referencias a ese elemento utilizan su voz asignada. |
| `generate_audio` |  | boolean | no | `false` |  | Controla si se genera audio nativo junto con el video. |
| `duration` |  | enum (string) | no | `5` | `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15` | Duración del video, de 3 a 15 segundos. |
| `shot_type` |  | enum (string) | no | `customize` | `customize`, `intelligent` | Elige cómo la generación de varias tomas planifica sus tomas; al seleccionar 'intelligent', se delega la estructura de las tomas al modelo. |
| `aspect_ratio` |  | enum (string) | no | `16:9` | `16:9`, `9:16`, `1:1` | Proporción entre el ancho y la altura de los fotogramas del video generado. |

File parameters (`image`, `end_image`, `images`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{}
```

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.ru/v1/run/kling-video/o3/4k/reference-to-video?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.ru/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.ru/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/kling-video/o3/4k/reference-to-video?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.ru/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/kling-video/o3/4k/reference-to-video", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.ru/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "kling-video/o3/4k/reference-to-video",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "kling-video/o3/4k/reference-to-video",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 2100,
    "usd": "2.10",
    "charged": 2100,
    "refunded": 0
  },
  "input": {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field"
  },
  "output": {
    "video": {
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp4",
      "content_type": "video/mp4",
      "file_name": "0-output.mp4",
      "file_size": 1843200
    }
  },
  "outputs": [
    {
      "type": "video",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp4",
      "content_type": "video/mp4",
      "file_size": 1843200,
      "width": 1280,
      "height": 720,
      "duration": 5,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.ru/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.ru/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `video` | object {url, content_type, file_name, file_size} | Video producido por el modelo. |

## Related models

- [Kling O3 Text to Video \[Pro\]](https://doitong.com/developers/models/kling-video/o3/pro/text-to-video.md) (`kling-video/o3/pro/text-to-video`): from $0.112 / second
- [Kling O3 Text to Video \[Standard\]](https://doitong.com/developers/models/kling-video/o3/standard/text-to-video.md) (`kling-video/o3/standard/text-to-video`): from $0.084 / second
- [Kling Video · O3 · 4k · Text to Video](https://doitong.com/developers/models/kling-video/o3/4k/text-to-video.md) (`kling-video/o3/4k/text-to-video`): $0.42 / second
- [Kling O3 Image to Video · Pro](https://doitong.com/developers/models/kling-video/o3/pro/image-to-video.md) (`kling-video/o3/pro/image-to-video`): from $0.112 / second
- [Kling O3 Image to Video · Standard](https://doitong.com/developers/models/kling-video/o3/standard/image-to-video.md) (`kling-video/o3/standard/image-to-video`): from $0.084 / second
- [Kling Video · O3 · 4k · Image to Video](https://doitong.com/developers/models/kling-video/o3/4k/image-to-video.md) (`kling-video/o3/4k/image-to-video`): $0.42 / second
- [Kling O3 Reference to Video \[Pro\]](https://doitong.com/developers/models/kling-video/o3/pro/reference-to-video.md) (`kling-video/o3/pro/reference-to-video`): from $0.112 / second
- [Kling O3 Reference to Video \[Standard\]](https://doitong.com/developers/models/kling-video/o3/standard/reference-to-video.md) (`kling-video/o3/standard/reference-to-video`): from $0.084 / second

## Links

- HTML page: https://doitong.com/developers/models/kling-video/o3/4k/reference-to-video
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=kling-video/o3/4k/reference-to-video
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.ru/v1/models/kling-video/o3/4k/reference-to-video