# Kling O1 Reference Image to Video [Pro] API

> Pro reference-to-video that keeps characters and objects consistent, 3 to 10 seconds, no input video

Generates a clip from a required `prompt` of up to 2500 characters. Refer to supplied `elements` as @Element1 and to `image_urls` as @Image1; at most 7 elements and reference images may be combined. Duration is 3 to 10 seconds (default 5) and aspect ratio is 16:9, 9:16 or 1:1.

- Model id: `kling-video/o1/reference-to-video`
- Made by: Kling
- Category: Reference to Video
- Output: video
- Price: $0.112 / second (5 s ≈ $0.56) (cheapest run $0.56 (560 API credits))
- Run: `POST https://api.doitong.com/v1/run/kling-video/o1/reference-to-video`
- Quote: `POST https://api.doitong.com/v1/quote/kling-video/o1/reference-to-video`
- Docs page: https://doitong.com/developers/models/kling-video/o1/reference-to-video

## Pricing

Price: **$0.112 / second (5 s ≈ $0.56)**. Billed per second of output (`duration`, default 10).

The full example input below costs $0.56 = 560 API credits (5 s × 112 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.com/v1/quote/kling-video/o1/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` |  | Safety checks can be disabled only with account authorization; requests without authorization always undergo checking. |
| `prompt` |  | string | yes |  | ≤ 2500 characters | Ordered references use @Element1, @Element2, and so on for elements, and @Image1, @Image2, and so on for images. |
| `image_urls` | `images` | array of image URL \| null | no |  |  | Extra images that guide style or appearance, addressed in the prompt using @Image1, @Image2, and so on. Elements, reference images, and the starting image together cannot exceed 7 entries. Each file is limited to 50 MB, with width and height each at least 300 px and an aspect ratio from 0.40 to 2.50. |
| `elements` |  | array of object {frontal_image_url, reference_image_urls} \| null | no |  |  | Characters or objects to appear in the video, addressed in the prompt using @Element1, @Element2, and so on. Elements, reference images, and the starting image together cannot exceed 7 entries. |
| `elements[].frontal_image_url` |  | string (image URL) | yes |  |  | Front-facing image providing the element's main view, limited to 50 MB. Width and height must each be at least 300 px, with an aspect ratio from 0.40 to 2.50. The timeout is 20 seconds. |
| `elements[].reference_image_urls` |  | array of image URL | no |  |  | Supply 1–3 additional reference images showing different angles. Each image must have an aspect ratio between 0.40 and 2.50, measure at least 300px in both dimensions, and be no larger than 50.0MB. |
| `duration` |  | enum (string) | no | `5` | `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10` | Video length measured in seconds. |
| `aspect_ratio` |  | enum (string) | no | `16:9` | `16:9`, `9:16`, `1:1` | Width-to-height ratio for frames in the generated video. |

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

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-video/o1/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-video/o1/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-video/o1/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-video/o1/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/o1/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": 560,
    "usd": "0.56",
    "charged": 560,
    "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 produced by the model. |

## Related models

- [Kling O1 First Frame Last Frame to Video \[Pro\]](https://doitong.com/developers/models/kling-video/o1/image-to-video.md) (`kling-video/o1/image-to-video`): $0.112 / second
- [Kling O1 First Frame Last Frame to Video \[Standard\]](https://doitong.com/developers/models/kling-video/o1/standard/image-to-video.md) (`kling-video/o1/standard/image-to-video`): $0.084 / 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 O1 Edit Video \[Pro\]](https://doitong.com/developers/models/kling-video/o1/video-to-video/edit.md) (`kling-video/o1/video-to-video/edit`): $0.168 / second of input video
- [Kling O1 Edit Video \[Standard\]](https://doitong.com/developers/models/kling-video/o1/standard/video-to-video/edit.md) (`kling-video/o1/standard/video-to-video/edit`): $0.126 / second of input video
- [Kling O1 Reference Video to Video \[Pro\]](https://doitong.com/developers/models/kling-video/o1/video-to-video/reference.md) (`kling-video/o1/video-to-video/reference`): $0.168 / second
- [Kling O1 Reference Video to Video \[Standard\]](https://doitong.com/developers/models/kling-video/o1/standard/video-to-video/reference.md) (`kling-video/o1/standard/video-to-video/reference`): $0.126 / second
- [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

## Links

- HTML page: https://doitong.com/developers/models/kling-video/o1/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/o1/reference-to-video
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/kling-video/o1/reference-to-video