# Kling 2.1 Master Image-to-Video

> Animate a still photo into a short, cinematic video with fluid, film-grade motion driven by a text prompt at the premium master tier.

## Overview

- **Endpoint**: `https://queue.modelrunner.run/kuaishou/kling-video/v2.1-master/image-to-video`
- **Model ID**: `kuaishou/kling-video/v2.1-master/image-to-video`
- **Category**: image-to-video
- **Kind**: inference
- **Tags**: kling, kling-video, kuaishou, image-to-video, video-generation

## Pricing

- **Price**: $0.28 per output second

## Request Lifecycle

This model runs on the ModelRunner **asynchronous queue API** — a single POST does not return the output. Every call requires an `Authorization: Key $MODEL_RUNNER_KEY` header. Run three steps:

1. **Submit** — `POST https://queue.modelrunner.run/kuaishou/kling-video/v2.1-master/image-to-video` with a JSON body. The response carries request handles only (no output yet):

```json
{
  "status": "IN_QUEUE",
  "request_id": "<21-char id>",
  "status_url": "https://queue.modelrunner.run/kuaishou/kling-video/v2.1-master/image-to-video/requests/<request_id>/status",
  "response_url": "https://queue.modelrunner.run/kuaishou/kling-video/v2.1-master/image-to-video/requests/<request_id>",
  "cancel_url": "https://queue.modelrunner.run/kuaishou/kling-video/v2.1-master/image-to-video/requests/<request_id>/cancel"
}
```

2. **Poll status** — `GET <status_url>` until `status` is `COMPLETED`. Possible values are `IN_QUEUE`, `IN_PROGRESS`, `COMPLETED`, `FAILED`, `CANCELLED`. A `FAILED` request responds with HTTP 400 and an `error` field.

3. **Read result** — `GET <response_url>`. Returns the finished request, including the generated `output`:

```json
{ "id": "<request_id>", "status": "COMPLETED", "output": ..., "input": ... }
```

The JavaScript and Python SDKs below perform steps 2–3 for you. In any language without an SDK (Swift, Go, Kotlin, etc.) you must implement the polling loop and the final result fetch yourself — see the cURL example for the full flow.

### Input Schema

- **`prompt`** (`string`, _required_):
  Text description of the motion/action to animate in the video.

- **`duration`** (`duration`, _optional_):
  Length of the generated video in seconds.
  - Default: `"5"`
  - Options: `"5"`, `"10"`

- **`cfg_scale`** (`number`, _optional_):
  How strongly the video follows the prompt. Higher values increase prompt adherence; lower values allow more creative motion.
  - Default: `0.5`
  - Range: `0` to `1`

- **`image_url`** (`string`, _required_):
  The source frame the video animates from. Use a JPEG image (min 300x300px, aspect ratio roughly 0.4-2.5).

- **`negative_prompt`** (`string`, _optional_):
  Describe content to avoid in the generated video.
  - Default: `"blur, distort, and low quality"`

### Output Schema

_No `Output` schema properties are available._

## Default Example

**Input**

```json
{
  "prompt": "The astronaut turns slowly to scan the horizon as wind-blown red dust streams past, the low sun casting long shadows across the dune, subtle cinematic camera push-in",
  "duration": "5",
  "cfg_scale": 0.5,
  "image_url": "https://media.modelrunner.ai/Kq9jtJtJ4GKFKfOVR6tXc.jpeg",
  "negative_prompt": "blur, distort, and low quality"
}
```

**Output**

```json
"https://media.modelrunner.ai/qPoEEjPUO9vE4EHlbI26n.mp4"
```
## Usage Examples

### cURL

The queue API is asynchronous: submit the request, poll `status_url` until it is `COMPLETED`, then read the result from `response_url`. Requires `jq`.

```bash
# 1. Submit the request (returns request handles, not the output)
SUBMIT=$(curl --silent --request POST \
  --url https://queue.modelrunner.run/kuaishou/kling-video/v2.1-master/image-to-video \
  --header "Authorization: Key $MODEL_RUNNER_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "prompt": "The astronaut turns slowly to scan the horizon as wind-blown red dust streams past, the low sun casting long shadows across the dune, subtle cinematic camera push-in",
  "duration": "5",
  "cfg_scale": 0.5,
  "image_url": "https://media.modelrunner.ai/Kq9jtJtJ4GKFKfOVR6tXc.jpeg",
  "negative_prompt": "blur, distort, and low quality"
}')

STATUS_URL=$(echo "$SUBMIT" | jq -r '.status_url')
RESPONSE_URL=$(echo "$SUBMIT" | jq -r '.response_url')

# 2. Poll until the request leaves the queue / in-progress state
while true; do
  STATUS=$(curl --silent --url "$STATUS_URL" \
    --header "Authorization: Key $MODEL_RUNNER_KEY" | jq -r '.status')
  echo "Status: $STATUS"
  case "$STATUS" in
    COMPLETED) break ;;
    FAILED|CANCELLED) echo "Request $STATUS"; exit 1 ;;
  esac
  sleep 1
done

# 3. Read the finished request, including the generated output
curl --silent --url "$RESPONSE_URL" \
  --header "Authorization: Key $MODEL_RUNNER_KEY"
```

### JavaScript

```javascript
import { modelrunner } from "@modelrunner/client";

const result = await modelrunner.subscribe("kuaishou/kling-video/v2.1-master/image-to-video", {
  input: {
  "prompt": "The astronaut turns slowly to scan the horizon as wind-blown red dust streams past, the low sun casting long shadows across the dune, subtle cinematic camera push-in",
  "duration": "5",
  "cfg_scale": 0.5,
  "image_url": "https://media.modelrunner.ai/Kq9jtJtJ4GKFKfOVR6tXc.jpeg",
  "negative_prompt": "blur, distort, and low quality"
}
});

console.log(result.data);
```

### Python

```python
import asyncio
import modelrunner_ai

async def main():
    response = await modelrunner_ai.submit_async(
        "kuaishou/kling-video/v2.1-master/image-to-video",
        arguments={
  "prompt": "The astronaut turns slowly to scan the horizon as wind-blown red dust streams past, the low sun casting long shadows across the dune, subtle cinematic camera push-in",
  "duration": "5",
  "cfg_scale": 0.5,
  "image_url": "https://media.modelrunner.ai/Kq9jtJtJ4GKFKfOVR6tXc.jpeg",
  "negative_prompt": "blur, distort, and low quality"
}
    )
    result = await response.get()
    print(result["output"])

asyncio.run(main())
```

## Additional Resources

- [Playground](https://modelrunner.ai/models/kuaishou/kling-video/v2.1-master/image-to-video)
- [OpenAPI Schema](https://modelrunner.ai/models/kuaishou/kling-video/v2.1-master/image-to-video/openapi.json)
- [LLM Instructions](https://modelrunner.ai/models/kuaishou/kling-video/v2.1-master/image-to-video/llms.txt)