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alibaba/happy-horse/reference-to-video

Generate 1080p video with synchronized native audio from a text prompt and references. Aspect ratios: 16:9, 9:16, 1:1, 4:3, 3:4. Duration: 3–15s.
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Table of contents

About

Generate a video from 1-9 reference images using the Happy Horse reference-to-video model

Reference subjects from the supplied images using character1, character2, ... character9 in the prompt — order matches the order of image_urls. Each image's shortest side must be at least 400 px (720P or higher recommended), up to 10 MB (JPEG, JPG, PNG, or WEBP).

1. Calling the API#

Install the client#

The client provides a convenient way to interact with the model API.

npm install --save @fal-ai/client

Setup your API Key#

Set FAL_KEY as an environment variable in your runtime.

export FAL_KEY="YOUR_API_KEY"

Submit a request#

The client API handles the API submit protocol. It will handle the request status updates and return the result when the request is completed.

import { fal } from "@fal-ai/client";

const result = await fal.subscribe("alibaba/happy-horse/reference-to-video", {
  input: {
    prompt: "A dance battle between character1 and character2, cinematic lighting, smooth camera movement.",
    image_urls: ["https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20250925/wpimhv/rap.png"]
  },
  logs: true,
  onQueueUpdate: (update) => {
    if (update.status === "IN_PROGRESS") {
      update.logs.map((log) => log.message).forEach(console.log);
    }
  },
});
console.log(result.data);
console.log(result.requestId);

2. Authentication#

The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.

API Key#

In case your app is running in an environment where you cannot set environment variables, you can set the API Key manually as a client configuration.
import { fal } from "@fal-ai/client";

fal.config({
  credentials: "YOUR_FAL_KEY"
});

3. Queue#

Submit a request#

The client API provides a convenient way to submit requests to the model.

import { fal } from "@fal-ai/client";

const { request_id } = await fal.queue.submit("alibaba/happy-horse/reference-to-video", {
  input: {
    prompt: "A dance battle between character1 and character2, cinematic lighting, smooth camera movement.",
    image_urls: ["https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20250925/wpimhv/rap.png"]
  },
  webhookUrl: "https://optional.webhook.url/for/results",
});

Fetch request status#

You can fetch the status of a request to check if it is completed or still in progress.

import { fal } from "@fal-ai/client";

const status = await fal.queue.status("alibaba/happy-horse/reference-to-video", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
  logs: true,
});

Get the result#

Once the request is completed, you can fetch the result. See the Output Schema for the expected result format.

import { fal } from "@fal-ai/client";

const result = await fal.queue.result("alibaba/happy-horse/reference-to-video", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);

4. Files#

Some attributes in the API accept file URLs as input. Whenever that's the case you can pass your own URL or a Base64 data URI.

Data URI (base64)#

You can pass a Base64 data URI as a file input. The API will handle the file decoding for you. Keep in mind that for large files, this alternative although convenient can impact the request performance.

Hosted files (URL)#

You can also pass your own URLs as long as they are publicly accessible. Be aware that some hosts might block cross-site requests, rate-limit, or consider the request as a bot.

Uploading files#

We provide a convenient file storage that allows you to upload files and use them in your requests. You can upload files using the client API and use the returned URL in your requests.

import { fal } from "@fal-ai/client";

const file = new File(["Hello, World!"], "hello.txt", { type: "text/plain" });
const url = await fal.storage.upload(file);

Read more about file handling in our file upload guide.

5. Schema#

Input#

prompt string* required

Text prompt describing the desired video. Reference subjects from your images using character1, character2, ... up to character9 (the order matches the order of image_urls). Max 2500 characters.

image_urls list<string>* required

Reference images for subject consistency (1-9 images). Formats: JPEG, JPG, PNG, WEBP. Shortest side must be at least 400 px (720P or higher recommended). Max 10 MB each.

aspect_ratio AspectRatioEnum

Aspect ratio of the generated video. Default value: "16:9"

Possible enum values: 16:9, 9:16, 1:1, 4:3, 3:4

resolution ResolutionEnum

Output video resolution tier. Default value: "1080p"

Possible enum values: 720p, 1080p

duration DurationEnum

Output video duration in seconds (3-15). Default value: "5"

Possible enum values: 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15

seed integer

Random seed for reproducibility (0-2147483647).

enable_safety_checker boolean

Enable content moderation for input and output. Default value: true

{
  "prompt": "A dance battle between character1 and character2, cinematic lighting, smooth camera movement.",
  "image_urls": [
    "https://help-static-aliyun-doc.aliyuncs.com/file-manage-files/zh-CN/20250925/wpimhv/rap.png"
  ],
  "aspect_ratio": "16:9",
  "resolution": "1080p",
  "duration": 5,
  "enable_safety_checker": true
}

Output#

video VideoFile* required

The generated video file.

seed integer* required

The seed used for generation.

{
  "video": {
    "url": "",
    "content_type": "image/png",
    "file_name": "z9RV14K95DvU.png",
    "file_size": 4404019
  }
}

Other types#

VideoFile#

url string* required

The URL where the file can be downloaded from.

content_type string

The mime type of the file.

file_name string

The name of the file. It will be auto-generated if not provided.

file_size integer

The size of the file in bytes.

width integer

The width of the video

height integer

The height of the video

fps float

The FPS of the video

duration float

The duration of the video

num_frames integer

The number of frames in the video

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