LTX-2.5 is Lightricks' open-source audio-video model. This endpoint generates video timed to a supplied audio clip in a speed-optimized mode — useful for music-driven content, dialogue-led shorts, and ads keyed to a track.

lightricks/ltx-2.5/audio-to-video/fast

Learn more about LTX 2.5

Inference

Commercial use

Partner

Schema

LLMs

Playground API Examples

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lightricks/ltx-2.5/audio-to-video/fast

Schema

LLMs

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Ltx 2.5 Fast Audio to Video API Docs | fal

lightricks/ltx-2.5/audio-to-video/fast

Learn more about LTX 2.5

Inference

Commercial use

Partner

Schema

LLMs

Playground API Examples

1. Calling the API

2. Authentication

API Key

3. Queue

4. Files

5. Schema

About

Audio To Video Fast

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

Migrate to @fal-ai/client

The @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.

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("lightricks/ltx-2.5/audio-to-video/fast", {
  input: {
    audio_url: "https://v3b.fal.media/files/b/0a90dfe7/3a-DUXzO79XWIYwUDfHZX_output.mp3"
  },
  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 an environment where you cannot set environment variables, you can configure the API key manually on the client.

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

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

Protect your API 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.

3. Queue#

Long-running requests

For long-running requests, such as training jobs or models with slower inference times, it is recommended to check the Queue status and rely on Webhooks instead of blocking while waiting for the result.

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("lightricks/ltx-2.5/audio-to-video/fast", {
  input: {
    audio_url: "https://v3b.fal.media/files/b/0a90dfe7/3a-DUXzO79XWIYwUDfHZX_output.mp3"
  },
  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("lightricks/ltx-2.5/audio-to-video/fast", {
  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("lightricks/ltx-2.5/audio-to-video/fast", {
  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);

Auto uploads

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.

5. Schema#

Input#

audio_url string* required

URL of the audio file to generate a video from. Duration must be between 2 and 20 seconds; pro models support a maximum of 10 seconds. Must be publicly accessible or base64 data URI.

image_url string

URL of an image to use as the first frame of the video. If not provided, prompt is required.

prompt string

Text description of how the video should be generated. Required if image_url is not provided. When image_url is provided, this describes how the image should be animated.

guidance_scale float

Guidance scale for video generation. Higher values make the output more closely follow the prompt. Defaults to 5 for text-to-video, or 9 when providing an image.

aspect_ratio AspectRatioEnum

The aspect ratio of the generated video. If 'auto', the aspect ratio will be determined automatically based on the input image, or defaults to 16:9 if no image is provided. Default value: "auto"

Possible enum values: auto, 16:9, 9:16

{
  "audio_url": "https://v3b.fal.media/files/b/0a90dfe7/3a-DUXzO79XWIYwUDfHZX_output.mp3",
  "image_url": "https://v3b.fal.media/files/b/0a90dfd2/G1zBOgd-17yqZ-2S5TN4j_M3nzt3Sp.png",
  "prompt": "A woman whispering to the microphone",
  "aspect_ratio": "auto"
}

Output#

video VideoFile* required

The generated video file

{
  "video": {
    "file_name": "qqP0ClY8E3d83X8y0zLse_shyIe9XU.mp4",
    "url": "https://v3b.fal.media/files/b/0a90dfec/qqP0ClY8E3d83X8y0zLse_shyIe9XU.mp4",
    "content_type": "video/mp4"
  }
}

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

Related Models

Loading API documentation…

1. Calling the API

2. Authentication

API Key

3. Queue

4. Files

5. Schema

About

Audio To Video Fast

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

Migrate to @fal-ai/client

The @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.

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("lightricks/ltx-2.5/audio-to-video/fast", {
  input: {
    audio_url: "https://v3b.fal.media/files/b/0a90dfe7/3a-DUXzO79XWIYwUDfHZX_output.mp3"
  },
  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 an environment where you cannot set environment variables, you can configure the API key manually on the client.

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

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

Protect your API Key

3. Queue#

Long-running requests

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("lightricks/ltx-2.5/audio-to-video/fast", {
  input: {
    audio_url: "https://v3b.fal.media/files/b/0a90dfe7/3a-DUXzO79XWIYwUDfHZX_output.mp3"
  },
  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("lightricks/ltx-2.5/audio-to-video/fast", {
  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("lightricks/ltx-2.5/audio-to-video/fast", {
  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)#

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);

Auto uploads

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.

5. Schema#

Input#

audio_url string* required

URL of the audio file to generate a video from. Duration must be between 2 and 20 seconds; pro models support a maximum of 10 seconds. Must be publicly accessible or base64 data URI.

image_url string

URL of an image to use as the first frame of the video. If not provided, prompt is required.

prompt string

Text description of how the video should be generated. Required if image_url is not provided. When image_url is provided, this describes how the image should be animated.

guidance_scale float

Guidance scale for video generation. Higher values make the output more closely follow the prompt. Defaults to 5 for text-to-video, or 9 when providing an image.

aspect_ratio AspectRatioEnum

The aspect ratio of the generated video. If 'auto', the aspect ratio will be determined automatically based on the input image, or defaults to 16:9 if no image is provided. Default value: "auto"

Possible enum values: auto, 16:9, 9:16

{
  "audio_url": "https://v3b.fal.media/files/b/0a90dfe7/3a-DUXzO79XWIYwUDfHZX_output.mp3",
  "image_url": "https://v3b.fal.media/files/b/0a90dfd2/G1zBOgd-17yqZ-2S5TN4j_M3nzt3Sp.png",
  "prompt": "A woman whispering to the microphone",
  "aspect_ratio": "auto"
}

Output#

video VideoFile* required

The generated video file

{
  "video": {
    "file_name": "qqP0ClY8E3d83X8y0zLse_shyIe9XU.mp4",
    "url": "https://v3b.fal.media/files/b/0a90dfec/qqP0ClY8E3d83X8y0zLse_shyIe9XU.mp4",
    "content_type": "video/mp4"
  }
}

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

lightricks/ltx-2.5/audio-to-video/fast

lightricks/ltx-2.5/audio-to-video/fast

Table of contents

1. Calling the API

2. Authentication

3. Queue

4. Files

5. Schema

About

1. Calling the API#

Install the client#

Migrate to @fal-ai/client

Setup your API Key#

Submit a request#

2. Authentication#

API Key#

Protect your API Key

3. Queue#

Long-running requests

Submit a request#

Fetch request status#

Get the result#

4. Files#

Data URI (base64)#

Hosted files (URL)#

Uploading files#

Auto uploads

5. Schema#

Input#

Output#

Other types#

VideoFile#

Related Models

Table of contents

1. Calling the API

2. Authentication

3. Queue

4. Files

5. Schema

About

1. Calling the API#

Install the client#

Migrate to @fal-ai/client

Setup your API Key#

Submit a request#

2. Authentication#

API Key#

Protect your API Key

3. Queue#

Long-running requests

Submit a request#

Fetch request status#

Get the result#

4. Files#

Data URI (base64)#

Hosted files (URL)#

Uploading files#

Auto uploads

5. Schema#

Input#

Output#

Other types#

VideoFile#

Related Models