minimax/h3-max/extend-video

H3 Max Extend Video adds a text-guided continuation to an existing video. It supports prompt expansion, adjustable duration and aspect ratio, and output resolutions from 480p to 2K, returning either the full extended video or only the new footage.

Learn more about H3

Inference

Commercial use

Schema

LLMs

Playground API Examples

1. Calling the API

2. Authentication

API Key

3. Queue

4. Files

5. Schema

About

Extend a video with new footage based on a prompt.

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("minimax/h3-max/extend-video", {
  input: {
    video_url: "https://storage.googleapis.com/falserverless/example_inputs/flux-3-red-panda.mp4",
    prompt: "The red panda keeps walking along the log, then looks up at a bird."
  },
  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("minimax/h3-max/extend-video", {
  input: {
    video_url: "https://storage.googleapis.com/falserverless/example_inputs/flux-3-red-panda.mp4",
    prompt: "The red panda keeps walking along the log, then looks up at a bird."
  },
  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("minimax/h3-max/extend-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("minimax/h3-max/extend-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);

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#

video_url string* required

URL of the video to extend. Must be 1.625 s to 60 s long, up to 50 MB, aspect ratio between 0.4 and 2.5.

prompt string* required

What happens next. Describe the continuation, not the source.

enable_prompt_expansion boolean

Automatically enhance the prompt using the source video to help keep the continuation consistent. May increase processing time. Default value: true

duration integer

Seconds of new footage to add after the source. The actual duration may be slightly longer. Default value: 5

resolution ResolutionEnum

Output video resolution. Default value: "768P"

Possible enum values: 480P, 768P, 1080P, 2K

aspect_ratio AspectRatioEnum

Output aspect ratio. 'auto' follows the source video. Other values crop the video to fit the selected ratio. Default value: "auto"

Possible enum values: auto, 21:9, 16:9, 4:3, 1:1, 3:4, 9:16

seed integer

Seed for the continuation. Random when omitted.

output OutputEnum

'extended' returns the whole source video followed by the new footage. 'continuation' returns only the generated continuation. Default value: "extended"

Possible enum values: extended, continuation

enable_safety_checker boolean

Moderate the source video and the prompt. Default value: true

{
  "video_url": "https://storage.googleapis.com/falserverless/example_inputs/flux-3-red-panda.mp4",
  "prompt": "The red panda keeps walking along the log, then looks up at a bird.",
  "enable_prompt_expansion": true,
  "duration": 5,
  "resolution": "768P",
  "aspect_ratio": "auto",
  "output": "extended",
  "enable_safety_checker": true
}

Output#

video File* required

The extended video, or only the continuation per 'output'.

seed integer* required

Seed used for the continuation.

duration float* required

Seconds of returned video.

source Source* required

Source video information: width, height, frame rate, duration, and audio.

expanded_prompt string

The prompt used after expansion, or null when unchanged.

timings Timings

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

Other types#

DubbingSegment#

start float* required

end float* required

text string* required

translated_text string* required

TranscriptSegment#

start float* required

Speech start in source-video seconds.

end float* required

Speech end in source-video seconds.

text string* required

Source text, or final dialogue when auto_translate is false.

EncodedReferenceImage#

id string* required

revision integer* required

image_sha256 string* required

owner_id string* required

audience string* required

fingerprint string* required

url string* required

sha256 string* required

size_bytes integer* required

height integer* required

width integer* required

qwen_grid array

expires_at integer* required

signature string* required

File#

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.

AVCheckpoint#

url string* required

Unguesseable service-issued checkpoint artifact URL.

sha256 string* required

size_bytes integer* required

version integer

Default value: 1

model string

Default value: "minimax-h3"

transformer_family TransformerFamilyEnum

Default value: "fl2va"

Possible enum values: fl2va, ref2va, ref2va-tdm-k10

encoded_reference_images list<EncodedReferenceImage>

loras list<CheckpointLoRA>

resolution ResolutionEnum* required

Possible enum values: 480p, 544p, 640p, 704p, 768p, 1080p, 1440p

checkpoint_id string* required

owner_id string* required

sha256 of the issuing caller's gateway identity.

source_request_id string* required

Issuing request id — audit/provenance lineage only.

issued_at integer* required

expires_at integer* required

audience string

Default value: "minimax-h3/continue-video"

signature string* required

Service HMAC binding the complete descriptor.

H3MaxCameraKeyframe#

time float* required

Normalized video time, from 0 at the start to 1 at the end.

azimuth float* required

Horizontal camera angle around the subject, in degrees.

elevation float* required

Vertical camera angle around the subject, in degrees.

distance float* required

Camera distance from the subject in normalized scene units.

CheckpointLoRA#

locator string* required

Opaque service-owned adapter locator.

sha256 string* required

size_bytes integer* required

scale float* required

transformer_family TransformerFamilyEnum* required

Possible enum values: fl2va, ref2va, ref2va-tdm-k10

transformer_variant string* required

minimax/h3-max/extend-video

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#

DubbingSegment#

TranscriptSegment#

EncodedReferenceImage#

File#

AVCheckpoint#

H3MaxCameraKeyframe#

CheckpointLoRA#

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