> ## Documentation Index
> Fetch the complete documentation index at: https://docs.anyfast.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# HappyHorse 1.1 I2V

> Animate a first-frame image with synchronized audio using HappyHorse 1.1 I2V.

HappyHorse 1.1 I2V turns one first-frame image into a 24 fps MP4 video with synchronized audio. The prompt describes the movement and camera behavior that follow the input frame.

`I2V` means **image-to-video**. This model accepts exactly one image with `type: "first_frame"`.

## Key capabilities

* **First-frame image-to-video** - Animate a single input image
* **Synchronized audio** - Generate audio with the video
* **Resolution** - `720P` or `1080P`
* **Duration** - An integer from 3 to 15 seconds
* **Aspect ratio preservation** - Output approximately follows the input image ratio

## Input image requirements

* Formats: JPEG, JPG, PNG, or WEBP
* Input: public HTTP/HTTPS URL or Base64 data URL
* Dimensions: width and height must both be at least 300 pixels
* Aspect ratio: from 1:2.5 to 2.5:1
* File size: up to 20 MB

## Quick example

```bash cURL theme={null}
curl https://www.anyfast.ai/v1/video/generations \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{
    "model": "happyhorse-1.1-i2v",
    "input": {
      "prompt": "The cat runs across the grass as the camera follows smoothly.",
      "media": [
        {
          "type": "first_frame",
          "url": "https://example.com/cat.png"
        }
      ]
    },
    "parameters": {
      "resolution": "720P",
      "duration": 5,
      "watermark": false
    }
  }'
```

<Note>
  HappyHorse 1.1 I2V does not accept a `ratio` setting. The output uses the first-frame image's aspect ratio as its baseline and may be adjusted slightly for video encoding.
</Note>

## Parameters

| Parameter               | Type    | Required | Description                                                                                     |
| ----------------------- | ------- | -------- | ----------------------------------------------------------------------------------------------- |
| `model`                 | string  | Yes      | Must be `happyhorse-1.1-i2v`                                                                    |
| `input.prompt`          | string  | No       | Motion and camera description. Maximum 5,000 non-Chinese characters or 2,500 Chinese characters |
| `input.media`           | array   | Yes      | Must contain exactly one first-frame image                                                      |
| `input.media[0].type`   | string  | Yes      | Must be `first_frame`                                                                           |
| `input.media[0].url`    | string  | Yes      | Public image URL or Base64 data URL                                                             |
| `parameters.resolution` | string  | No       | `720P` or `1080P`. Default: `1080P`                                                             |
| `parameters.duration`   | integer | No       | Video duration from 3 to 15 seconds. Default: `5`                                               |
| `parameters.watermark`  | boolean | No       | Whether to add the HappyHorse watermark. Default: `true`                                        |
| `parameters.seed`       | integer | No       | Random seed in `[0, 2147483647]`                                                                |

<CardGroup cols={2}>
  <Card title="API Reference" icon="code" href="/api-reference/model-api/alibaba/happyhorse-1.1-i2v">
    View the request and response schema.
  </Card>

  <Card title="Task Query" icon="magnifying-glass" href="/guides/model-api/alibaba/happyhorse-task-query">
    Poll task status and retrieve the result URL.
  </Card>
</CardGroup>

## Official reference

See the [Alibaba Cloud Model Studio HappyHorse image-to-video API reference](https://help.aliyun.com/en/model-studio/happyhorse-image-to-video-api-reference).

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