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

LTX-2.5 is Lightricks' open-source audio-video model. This endpoint generates synchronized video and audio from a text prompt in a single pass, in a speed-optimized mode built for rapid iteration and previews.
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Table of contents

About

Text 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

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/text-to-video/fast", {
  input: {
    prompt: "Through-the-veil shot of a bride's face during an Indian wedding ceremony, camera positioned behind the sheer red dupatta fabric, the embroidered pattern creating a textured overlay on her face, her eyes lined with kohl looking down at henna-covered hands, marigold garlands in soft background bokeh, 85mm f/1.2 focused through the fabric layer, warm tungsten and candlelight, Mira Nair Monsoon Wedding intimacy"
  },
  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("lightricks/ltx-2.5/text-to-video/fast", {
  input: {
    prompt: "Through-the-veil shot of a bride's face during an Indian wedding ceremony, camera positioned behind the sheer red dupatta fabric, the embroidered pattern creating a textured overlay on her face, her eyes lined with kohl looking down at henna-covered hands, marigold garlands in soft background bokeh, 85mm f/1.2 focused through the fabric layer, warm tungsten and candlelight, Mira Nair Monsoon Wedding intimacy"
  },
  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/text-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/text-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);

Read more about file handling in our file upload guide.

5. Schema#

Input#

prompt string* required

The prompt to use for the generated video

duration DurationEnum

The duration of the generated video in seconds. Set to 'auto' to let the model choose the duration automatically. Default value: "auto"

Possible enum values: 6, 8, 10, 12, 14, 16, 18, 20, auto

resolution ResolutionEnum

The resolution of the generated video. Default value: "1080p"

Possible enum values: 720p, 1080p, 1440p, 2160p

aspect_ratio AspectRatioEnum

The aspect ratio of the generated video Default value: "16:9"

Possible enum values: 16:9, 9:16

fps FramesperSecondEnum

The frames per second of the generated video. Default value: "25"

Possible enum values: 24, 25, 48, 50

generate_audio boolean

Whether to generate audio for the generated video Default value: true

camera_motion Enum

Optional camera motion applied to the generated video.

Possible enum values: dolly_in, dolly_out, dolly_left, dolly_right, jib_up, jib_down, static, focus_shift

{
  "prompt": "Through-the-veil shot of a bride's face during an Indian wedding ceremony, camera positioned behind the sheer red dupatta fabric, the embroidered pattern creating a textured overlay on her face, her eyes lined with kohl looking down at henna-covered hands, marigold garlands in soft background bokeh, 85mm f/1.2 focused through the fabric layer, warm tungsten and candlelight, Mira Nair Monsoon Wedding intimacy",
  "duration": "auto",
  "resolution": "1080p",
  "aspect_ratio": "16:9",
  "fps": 25,
  "generate_audio": true
}

Output#

video VideoFile* required

The generated video file

{
  "video": {
    "file_name": "7ufClzCcdMD-up1rau1jF_6xx4WLgg.mp4",
    "content_type": "video/mp4",
    "url": "https://v3b.fal.media/files/b/0a90dde7/7ufClzCcdMD-up1rau1jF_6xx4WLgg.mp4"
  }
}

Other types#

LTXV23AudioToVideoRequest#

audio_url string* required

URL of the audio file to generate a video from. Duration must be between 2 and 20 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

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

LTXV23ImageToVideoResponse#

video VideoFile* required

The generated video file

LTXV25ImageToVideoFastRequest#

image_url string* required

The URL of the start image to use for the generated video.

end_image_url string

The URL of the end image to use for the generated video. When provided, generates a transition video between start and end frames.

prompt string* required

The prompt to use for the generated video

duration DurationEnum

The duration of the generated video in seconds. Set to 'auto' to let the model choose the duration automatically. Default value: "auto"

Possible enum values: 6, 8, 10, 12, 14, 16, 18, 20, auto

resolution ResolutionEnum

The resolution of the generated video. Default value: "1080p"

Possible enum values: 720p, 1080p, 1440p, 2160p

aspect_ratio AspectRatioEnum

The aspect ratio of the generated video. If 'auto', the aspect ratio will be determined automatically based on the input image. Default value: "auto"

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

fps FramesperSecondEnum

The frames per second of the generated video. Default value: "25"

Possible enum values: 24, 25, 48, 50

generate_audio boolean

Whether to generate audio for the generated video Default value: true

camera_motion Enum

Optional camera motion applied to the generated video.

Possible enum values: dolly_in, dolly_out, dolly_left, dolly_right, jib_up, jib_down, static, focus_shift

LTXV23TextToVideoResponse#

video VideoFile* required

The generated video file

LTXV25TextToVideoRequest#

prompt string* required

The prompt to use for the generated video

duration DurationEnum

The duration of the generated video in seconds. Set to 'auto' to let the model choose the duration automatically. Default value: "auto"

Possible enum values: 6, 8, 10, auto

resolution ResolutionEnum

The resolution of the generated video. Default value: "1080p"

Possible enum values: 720p, 1080p

aspect_ratio AspectRatioEnum

The aspect ratio of the generated video Default value: "16:9"

Possible enum values: 16:9, 9:16

fps FramesperSecondEnum

The frames per second of the generated video. Default value: "25"

Possible enum values: 24, 25, 50

generate_audio boolean

Whether to generate audio for the generated video Default value: true

camera_motion Enum

Optional camera motion applied to the generated video.

Possible enum values: dolly_in, dolly_out, dolly_left, dolly_right, jib_up, jib_down, static, focus_shift

LTXV23AudioToVideoResponse#

video VideoFile* required

The generated video file

LTXV25ImageToVideoRequest#

image_url string* required

The URL of the start image to use for the generated video.

end_image_url string

The URL of the end image to use for the generated video. When provided, generates a transition video between start and end frames.

prompt string* required

The prompt to use for the generated video

duration DurationEnum

The duration of the generated video in seconds. Set to 'auto' to let the model choose the duration automatically. Default value: "auto"

Possible enum values: 6, 8, 10, auto

resolution ResolutionEnum

The resolution of the generated video. Default value: "1080p"

Possible enum values: 720p, 1080p

aspect_ratio AspectRatioEnum

The aspect ratio of the generated video. If 'auto', the aspect ratio will be determined automatically based on the input image. Default value: "auto"

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

fps FramesperSecondEnum

The frames per second of the generated video. Default value: "25"

Possible enum values: 24, 25, 50

generate_audio boolean

Whether to generate audio for the generated video Default value: true

camera_motion Enum

Optional camera motion applied to the generated video.

Possible enum values: dolly_in, dolly_out, dolly_left, dolly_right, jib_up, jib_down, static, focus_shift

LTXV23ImageToVideoFastResponse#

video VideoFile* required

The generated video file

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