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).
The client provides a convenient way to interact with the model API.
npm install --save @fal-ai/clientThe @fal-ai/serverless-client package has been deprecated in favor of @fal-ai/client. Install the new package and update your imports — see client setup.
Set FAL_KEY as an environment variable in your runtime.
export FAL_KEY="YOUR_API_KEY"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);The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.
import { fal } from "@fal-ai/client";
fal.config({
credentials: "YOUR_FAL_KEY"
});When running code on the client-side (e.g. in a browser, mobile app or GUI applications), make sure to not expose your FAL_KEY. Instead, use a server-side proxy to make requests to the API. For more information, check out our server-side integration guide.
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",
});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,
});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);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.
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.
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.
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);The client will auto-upload the file for you if you pass a binary object (e.g. File, Data).
Read more about file handling in our file upload guide.
prompt string* requiredText 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.
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 AspectRatioEnumAspect ratio of the generated video. Default value: "16:9"
Possible enum values: 16:9, 9:16, 1:1, 4:3, 3:4
resolution ResolutionEnumOutput video resolution tier. Default value: "1080p"
Possible enum values: 720p, 1080p
duration DurationEnumOutput 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 integerRandom seed for reproducibility (0-2147483647).
enable_safety_checker booleanEnable content moderation for input and output. Disabling it requires account authorization; unauthorized requests are always checked. 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
}The generated video file.
seed integer* requiredThe seed used for generation.
{
"video": {
"url": "",
"content_type": "image/png",
"file_name": "z9RV14K95DvU.png",
"file_size": 4404019
}
}url string* requiredThe URL where the file can be downloaded from.
content_type stringThe mime type of the file.
file_name stringThe name of the file. It will be auto-generated if not provided.
file_size integerThe size of the file in bytes.
width integerThe width of the video
height integerThe height of the video
fps floatThe FPS of the video
duration floatThe duration of the video
num_frames integerThe number of frames in the video