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kling v4
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Generate videos with Kling 4.0 Reference to Video
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("fal-ai/kling-video/v4/reference-to-video", {
input: {},
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("fal-ai/kling-video/v4/reference-to-video", {
input: {},
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("fal-ai/kling-video/v4/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("fal-ai/kling-video/v4/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 stringText prompt. Reference inputs as @Image1, @Video1, @Element1, etc. Either prompt or multi_prompt must be provided.
Per-shot prompts for multi-shot generation. The video duration is the sum of the shot durations.
duration integerVideo duration in seconds (3-30). Default value: 5
start_image_url stringOptional image to use as the first frame. Counts toward the image reference limit.
Reference images, referenced as @Image1, @Image2, ... (max 10).
Reference videos (3-30s each, 30s combined with element videos), referenced as @Video1, @Video2, ... (max 5).
Characters/objects, referenced as @Element1, @Element2, ... (max 7). Up to 3 elements may carry a voice_id and up to 3 may be video elements.
resolution ResolutionEnumOutput resolution. Default value: "1080p"
Possible enum values: 720p, 1080p
aspect_ratio AspectRatioEnumAspect ratio of the generated video. 'auto' adapts it to the references. Default value: "16:9"
Possible enum values: auto, 16:9, 9:16, 1:1, 21:9
{
"prompt": "@Element1 and @Element2 are having dinner at the table in @Image1",
"multi_prompt": null,
"duration": 5,
"image_urls": null,
"video_urls": null,
"elements": null,
"resolution": "1080p",
"aspect_ratio": "16:9"
}The generated video.
{
"video": {
"content_type": "video/mp4",
"file_name": "output.mp4",
"file_size": 3020124,
"url": "https://v3b.fal.media/files/b/0aac4497/-fHk6MiMZhLy2FncCbyM7_clip_reference.mp4"
}
}frontal_image_url stringThe frontal image of the element (main view).
Additional views of the element from different angles (1-3).
video_url stringA video of the element, used instead of images (3-30s).
voice_id stringVoice bound to this element. Create one with https://fal.ai/models/fal-ai/kling-video/create-voice
prompt string* requiredThe prompt for this shot.
duration integerShot duration in seconds. Default value: 5
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.