# Kling 4.0 Reference to Video API

> Genererer 3–30 sekundda videoid, mat geahčči gitta 10 referánsačáhcego, 5 referánsavideo ja 7 elemeantta

Ráhkada video čállin `prompt` ja referánsačáhcegoid, referánsavideoid ja persovdna- dahje dávvir-elemeanttaid vuođul, mat čujuhuvvojit promptas @Image1, @Video1 dahje @Element1. Guhkodat lea 3 rájes 30 sekundii (standárda 5), ja boahtos lea 720p dahje 1080p ja govvaráddjeauto auto, 16:9, 9:16, 1:1 dahje 21:9. Geavat `multi_prompt` shot-spesifihkka promp שאל?

- 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/se/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 | Ráhkadanrávvagat mat deavdet gáibádusa addit juogo `prompt` dahje `multi_prompt`. Čujuhit addojuvvon sisa-addiide geavat @Image1, @Video1, @Element1 jna. |
| `multi_prompt` |  | array of object {prompt, duration} \| null | no |  | ≥ 1 items | Čuohpahusguovdasaš ráhkadanrávvagat, mas juohke bivdda meroštallá ovtta čuohpahusa, man bistin lea oassin video olles guhkkodagas. |
| `multi_prompt[].prompt` |  | string | yes |  | 1 – 512 characters | Dálá čuohpahasa teakstaravvagat. |
| `multi_prompt[].duration` |  | integer | no | `5` | 1 – 30 | Ovttaskas čuohpahusa bistin, mihtiduvvon sekunddain. |
| `duration` |  | integer | no | `5` | 3 – 30 | Video guhkkodat sekunddain, 3 gitta 30 rádjái. |
| `start_image_url` | `image` | string (image URL) \| null | no |  |  | Eaktodáhtolaš vuosttaš rámma govva, mii lohkkojuvvo mielde govvačujuhusaid rádjái. Fiilla eanemus sturrodat lea 30.0 MB; govdodat ja allodat ferteba goappašagat leat unnimusat 300 px, ja govvagorri gaskal 0.40 ja 2.50. |
| `image_urls` | `images` | array of image URL \| null | no |  | ≤ 10 items | Govvačujuhusat maidda čujuhuvvo @Image1, @Image2 jna. bokte, eanemusat 10 govva. Juohke fiilla sturrodat lea eanemusat 30.0 MB, goappašiid mihtuid fertejit leat unnimusat 300 px, ja govvagorri gaskal 0.40 ja 2.50. |
| `video_urls` | `videos` | array of video URL \| null | no |  | ≤ 5 items | Eanemusat 5 čujuhusvideo, maidda čujuhuvvo @Video1, @Video2 jna. bokte; juohkehačča bistin lea 3–30 sekunda (eanemusat 30.05 sekunda), ja daid oktasaš bistin ovttas elemeantavideoguimmiin ii oaččo leat badjel 30 sekunda. Juohke fiilla sturrodat ferte leat eanemusat 300 MB, ja govdodat ja allodat goappašagat gaskal 700 px ja 4553 px. Govvagorri ferte leat gaskal 0.40 ja 2.50, ja rámmadávjodat gaskal 23.9 ja 60.05 FPS. |
| `elements` |  | array of object {frontal_image_url, reference_image_urls, video_url, voice_id} \| null | no |  | ≤ 7 items | Čoakkáldat mas leat eanemusat 7 figuvrra dahje áđa, main eanemusat 3 sáhttet sisttisdoallat `voice_id` ja eanemusat 3 sáhttet geavahit video. Čujut dáidda elemeanttaide @Element1, @Element2 jna. bokte. |
| `elements[].frontal_image_url` |  | string (image URL) \| null | no |  |  | Ovddabeale govva mii čájeha elemeantta váldooinnosa. Fiilla eanemus sturrodat lea 30.0 MB; goappašiid mihtuid fertejit leat unnimusat 300 px, ja govvagorri ferte leat gaskal 0.40 ja 2.50. |
| `elements[].reference_image_urls` |  | array of image URL \| null | no |  | ≤ 3 items | Lassigovat mat čájehit elemeantta iešguđet čiehkaid, 1 gitta 3 oinnosa. Juohke fiilla sturrodat sáhttá leat eanemusat 30.0 MB, goappašiid mihtuid fertejit leat unnimusat 300 px, ja govvagorri ferte leat gaskal 0.40 ja 2.50. |
| `elements[].video_url` |  | string (video URL) \| null | no |  |  | Elemeantta videoovdanbuktin govaid sajis, man bistin lea 3–30 sekunda (eanemusat 30.05 sekunda). Fiila ii oaččo leat stuorát go 300 MB; sihke govdodat ja allodat ferteba leat 700–4553 px. Dorjojuvvon govvagorit leat 0.40–2.50, ja rámmadávjodagat 23.9–60.05 FPS. |
| `elements[].voice_id` |  | string \| null | no |  |  | Elemeantii meroštallojuvvon jietna. |
| `resolution` |  | enum (string) | no | `1080p` | `720p`, `1080p` | Boađusa resolušuvdna. |
| `aspect_ratio` |  | enum (string) | no | `16:9` | `auto`, `16:9`, `9:16`, `1:1`, `21:9` | Video govvagorri, mii válljejuvvo njuolga dahje mearriduvvo čujuhusaid vuođul válljemiin '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} | Modealla ráhkadan video. |

## 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