# Kling 4.0 Reference to Video API

> Hutengeneza video za sekunde 3-30 zinazohifadhi mwonekano wa hadi picha 10 za marejeleo, video 5 za marejeleo na vipengele 7

Huunda video kutoka kwa `prompt` ya maandishi pamoja na picha za marejeleo, video za marejeleo na vipengele vya wahusika au vitu, ambavyo vinatajwa kwenye kidokezo kama @Image1, @Video1 au @Element1. Muda ni kuanzia sekunde 3 hadi 30 (chaguomsingi ni 5), huku tokeo likiwa na mwonekano wa 720p au 1080p na uwiano wa pande auto, 16:9, 9:16, 1:1 au 21:9. Tumia `multi_prompt` kwa vidokezo vya kila picha, ambapo urefu wa jumla ni jumla ya muda wa picha hizo. Vikomo ni picha 10, video 5 za sekunde 3-30 kila moja, na vipengele 7, ambapo hadi 3 vinaweza kuwa na sauti.

- 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/sw/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 | Maagizo ya uzalishaji yanayotimiza sharti la kutoa `prompt` au `multi_prompt`. Ili kurejelea maingizo yaliyotolewa, tumia @Image1, @Video1, @Element1, na kuendelea. |
| `multi_prompt` |  | array of object {prompt, duration} \| null | no |  | ≥ 1 items | Maagizo ya uzalishaji ya picha kwa picha, ambapo kila kidokezo hufafanua picha moja na muda wake huchangia urefu wa jumla wa video. |
| `multi_prompt[].prompt` |  | string | yes |  | 1 – 512 characters | Maagizo ya maandishi ya picha ya sasa. |
| `multi_prompt[].duration` |  | integer | no | `5` | 1 – 30 | Muda wa picha moja, unaopimwa kwa sekunde. |
| `duration` |  | integer | no | `5` | 3 – 30 | Urefu wa video kwa sekunde, kutoka 3 hadi 30. |
| `start_image_url` | `image` | string (image URL) \| null | no |  |  | Picha ya hiari ya fremu ya kwanza inayohesabiwa katika kikomo cha picha za marejeleo. Ukubwa wa juu wa faili ni 30.0 MB; upana na urefu lazima kila kimoja kifikie 300 px, na uwiano wa pande uwe kati ya 0.40 na 2.50. |
| `image_urls` | `images` | array of image URL \| null | no |  | ≤ 10 items | Marejeleo ya picha yanayorejelewa kwa kutumia @Image1, @Image2, na kuendelea, yakiwa na picha zisizozidi 10. Kila faili ina kikomo cha 30.0 MB, inahitaji angalau 300 px katika vipimo vyote viwili, na lazima iwe na uwiano wa pande kati ya 0.40 na 2.50. |
| `video_urls` | `videos` | array of video URL \| null | no |  | ≤ 5 items | Hadi video 5 za marejeleo, zinazorejelewa kwa kutumia @Video1, @Video2, na kuendelea; kila moja ina urefu wa sekunde 3–30 (sekunde 30.05 kwa kiwango cha juu), na muda wake wa pamoja pamoja na video za vipengele hauwezi kuzidi sekunde 30. Kila faili lazima isiwe kubwa kuliko 300 MB, huku upana na urefu kila kimoja kikiwa kati ya 700 px na 4553 px. Uwiano wa pande lazima uwe kati ya 0.40 na 2.50, na kasi ya fremu kati ya 23.9 na 60.05 FPS. |
| `elements` |  | array of object {frontal_image_url, reference_image_urls, video_url, voice_id} \| null | no |  | ≤ 7 items | Mkusanyiko wa hadi wahusika au vitu 7, ambapo visivyozidi 3 vinaweza kujumuisha `voice_id` na visivyozidi 3 vinaweza kutumia video. Rejelea vipengele hivi kama @Element1, @Element2, na kuendelea. |
| `elements[].frontal_image_url` |  | string (image URL) \| null | no |  |  | Picha ya mbele inayoonyesha mwonekano mkuu wa kipengele. Ukubwa wa juu wa faili ni 30.0 MB; vipimo vyote viwili lazima viwe angalau 300 px, na uwiano wa pande lazima uwe kati ya 0.40 na 2.50. |
| `elements[].reference_image_urls` |  | array of image URL \| null | no |  | ≤ 3 items | Picha za ziada zinazoonyesha pembe tofauti za kipengele, zikiwa na mitazamo 1 hadi 3. Kila faili inaweza kuwa na ukubwa wa juu wa 30.0 MB, lazima iwe na angalau 300 px katika vipimo vyote viwili, na lazima iwe na uwiano wa pande kati ya 0.40 na 2.50. |
| `elements[].video_url` |  | string (video URL) \| null | no |  |  | Uwakilishi wa video wa kipengele badala ya picha, wenye urefu wa sekunde 3–30 (sekunde 30.05 kwa kiwango cha juu). Faili lazima isizidi 300 MB; upana na urefu vyote viwili lazima viwe ndani ya 700–4553 px. Uwiano unaoauniwa wa pande ni 0.40–2.50, kwa kasi za fremu za 23.9–60.05 FPS. |
| `elements[].voice_id` |  | string \| null | no |  |  | Sauti iliyotolewa kwa kipengele. |
| `resolution` |  | enum (string) | no | `1080p` | `720p`, `1080p` | Mwonekano wa tokeo. |
| `aspect_ratio` |  | enum (string) | no | `16:9` | `auto`, `16:9`, `9:16`, `1:1`, `21:9` | Uwiano wa video, unaochaguliwa wazi au kutolewa kutoka kwenye marejeleo kwa kuchagua '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 iliyozalishwa na modeli. |

## 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