# Kling 4.0 Reference to Video API

> Menghasilkan video berdurasi 3-30 detik yang mempertahankan tampilan hingga 10 gambar referensi, 5 video referensi, dan 7 elemen

Membuat video dari `prompt` teks serta gambar referensi, video referensi, dan elemen karakter atau objek, yang dirujuk dalam prompt sebagai @Image1, @Video1, atau @Element1. Durasi berkisar antara 3 hingga 30 detik (default 5), dengan output pada 720p atau 1080p dan rasio aspek auto, 16:9, 9:16, 1:1, atau 21:9. Gunakan `multi_prompt` untuk prompt per pengambilan gambar; dalam hal ini, durasi total adalah jumlah durasi setiap pengambilan gambar. Batasnya adalah 10 gambar, 5 video masing-masing berdurasi 3-30s, dan 7 elemen, yang hingga 3 di antaranya dapat membawa suara.

- Model id: `kling/v4/reference-to-video`
- Made by: Kling
- Category: Reference to Video
- Output: video
- Price per second of your output video: from $0.157 / second of output video (cheapest run $0.157 (157 API credits))
- Run: `POST https://api.doitong.com/v1/run/kling/v4/reference-to-video`
- Quote: `POST https://api.doitong.com/v1/quote/kling/v4/reference-to-video`
- Docs page: https://doitong.com/id/developers/models/kling/v4/reference-to-video

## Pricing

Price: **from $0.157 / second of output video** (the lowest tier; the quote prices your exact input). Price per second of your output video: the input files are measured before the run (length, resolution, frame rate). The quote measures the same files and is exactly what the run charges.

Price by tier:

- 720p: $0.157 / second of output video
- 1080p: $0.235 / second of output video

The full example input below costs $1.175 = 1175 API credits (5 s output video × $0.235 (1080p)).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/kling/v4/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 |
|---|---|---|---|---|---|---|
| `prompt` |  | string \| null | no |  | ≤ 2500 characters | Instruksi pembuatan yang memenuhi persyaratan untuk menyediakan `prompt` atau `multi_prompt`. Untuk merujuk input yang disediakan, gunakan @Image1, @Video1, @Element1, dan seterusnya. |
| `multi_prompt` |  | array of object {prompt, duration} \| null | no |  | ≥ 1 items | Instruksi pembuatan per shot, dengan setiap prompt menentukan satu shot yang durasinya berkontribusi pada total durasi video. |
| `multi_prompt[].prompt` |  | string | yes |  | 1 – 512 characters | Instruksi teks untuk shot saat ini. |
| `multi_prompt[].duration` |  | integer | no | `5` | 1 – 30 | Durasi satu shot, diukur dalam detik. |
| `duration` |  | integer | no | `5` | 3 – 30 | Durasi video dalam detik, dari 3 hingga 30. |
| `start_image_url` | `image` | string (image URL) \| null | no |  |  | Gambar bingkai pertama opsional yang dihitung dalam batas gambar referensi. Ukuran file maksimum 30.0 MB; lebar dan tinggi masing-masing harus mencapai 300 px, dengan rasio aspek antara 0.40 dan 2.50. |
| `image_urls` | `images` | array of image URL \| null | no |  | ≤ 10 items | Referensi gambar yang dirujuk menggunakan @Image1, @Image2, dan seterusnya, dengan maksimal 10 gambar. Setiap file dibatasi hingga 30.0 MB, memerlukan minimal 300 px pada kedua dimensi, dan harus memiliki rasio aspek antara 0.40 dan 2.50. |
| `video_urls` | `videos` | array of video URL \| null | no |  | ≤ 5 items | Hingga 5 video referensi, dirujuk menggunakan @Video1, @Video2, dan seterusnya; masing-masing berdurasi 3–30 detik (maksimal 30.05 detik), dan total durasinya bersama video elemen tidak boleh melebihi 30 detik. Setiap file tidak boleh lebih besar dari 300 MB, dengan lebar dan tinggi masing-masing antara 700 px dan 4553 px. Rasio aspek harus berada antara 0.40 dan 2.50, dan laju bingkai antara 23.9 dan 60.05 FPS. |
| `elements` |  | array of object {frontal_image_url, reference_image_urls, video_url, voice_id} \| null | no |  | ≤ 7 items | Koleksi hingga 7 karakter atau objek, yang maksimal 3 di antaranya boleh menyertakan `voice_id` dan maksimal 3 boleh menggunakan video. Rujuk elemen-elemen ini sebagai @Element1, @Element2, dan seterusnya. |
| `elements[].frontal_image_url` |  | string (image URL) \| null | no |  |  | Gambar tampak depan yang menunjukkan tampilan utama elemen. Ukuran file maksimum 30.0 MB; kedua dimensi harus minimal 300 px, dan rasio aspek harus antara 0.40 dan 2.50. |
| `elements[].reference_image_urls` |  | array of image URL \| null | no |  | ≤ 3 items | Gambar tambahan yang menampilkan sudut berbeda dari elemen, dengan 1 hingga 3 tampilan. Setiap file maksimal 30.0 MB, harus berukuran minimal 300 px pada kedua dimensi, dan memiliki rasio aspek antara 0.40 dan 2.50. |
| `elements[].video_url` |  | string (video URL) \| null | no |  |  | Representasi video elemen sebagai pengganti gambar, berdurasi 3–30 detik (maksimal 30.05 detik). File tidak boleh melebihi 300 MB; lebar dan tinggi harus berada dalam rentang 700–4553 px. Rasio aspek yang didukung adalah 0.40–2.50, dengan laju bingkai 23.9–60.05 FPS. |
| `elements[].voice_id` |  | string \| null | no |  |  | Suara yang ditetapkan ke elemen. |
| `resolution` |  | enum (string) | no | `1080p` | `720p`, `1080p` | Resolusi output. |
| `aspect_ratio` |  | enum (string) | no | `16:9` | `auto`, `16:9`, `9:16`, `1:1`, `21:9` | Proporsi video, dipilih secara eksplisit atau diturunkan dari referensi dengan memilih 'auto'. |

File parameters (`image`, `images`, `videos`) 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.com/v1/run/kling/v4/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.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.com/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/v4/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.com/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/v4/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.com/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/v4/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/v4/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": 1175,
    "usd": "1.175",
    "charged": 1175,
    "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.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `video` | object {url, content_type, file_name, file_size} | Video yang dihasilkan model. |

## Related models

- [Kling 4.0 Text to Video](https://doitong.com/developers/models/kling/v4/text-to-video.md) (`kling/v4/text-to-video`): from $0.157 / second of output video
- [Seedance 2.0 Fast Reference to Video](https://doitong.com/developers/models/bytedance/seedance-2.0/fast/reference-to-video.md) (`bytedance/seedance-2.0/fast/reference-to-video`): from $0.113 / second
- [Seedance 2.0 Reference to Video](https://doitong.com/developers/models/bytedance/seedance-2.0/reference-to-video.md) (`bytedance/seedance-2.0/reference-to-video`): from $0.141 / second
- [Wan 3.0 Reference to Video](https://doitong.com/developers/models/alibaba/wan-3.0/reference-to-video.md) (`alibaba/wan-3.0/reference-to-video`): from $0.05 / second
- [Kling O1 Reference Image to Video \[Pro\]](https://doitong.com/developers/models/kling-video/o1/reference-to-video.md) (`kling-video/o1/reference-to-video`): $0.112 / second
- [Kling O1 Reference Image to Video \[Standard\]](https://doitong.com/developers/models/kling-video/o1/standard/reference-to-video.md) (`kling-video/o1/standard/reference-to-video`): $0.084 / 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/v4/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/v4/reference-to-video
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/kling/v4/reference-to-video