# Prepare an MP4 for video outpainting.
Check the file before the prompt.

> This release accepts a regular MP4 up to 5 seconds and 4 MB. Trim and export the source first; changing the filename does not change its container or size.

Source: https://videooutpainting.com/prepare-mp4-for-video-outpainting · Updated: 2026-10-09 · Publisher: Video Outpainting (independent; not affiliated with Lightricks)

## What MP4 can I upload for video outpainting here?

Use one regular MP4 with one video track, up to 5 seconds and 4 MB. Trim a single shot and export it with the intended visible orientation. The server checks file size and container metadata before a paid generation can be submitted. Those checks do not prove that every codec will decode at the provider, and source audio will not appear in the downloaded result.

## Prepare the source in your editor

1. **Choose one short shot** Extract the section you actually need to reframe. Keep the original file and choose a continuous shot you can compare with the result.
2. **Export an ordinary MP4** Use an H.264 MP4 export when available. Bake the intended orientation into the image dimensions instead of depending only on a rotation tag. Renaming a MOV file to .mp4 is not an export.
3. **Check duration, size and playback** Keep the exported source within 5 seconds and 4 MB. If the file is too large, reduce bitrate or dimensions in the editor, export again and confirm that it plays correctly.
4. **Sign in and inspect the upload** Open the [outpainting workspace](https://wan3prime.com/video-outpainting). The original preview displays the parsed dimensions. Choose a different supported output shape and review the fixed quote before submitting.

## Interpret an upload problem before retrying

| Problem | What it means here | Next action |
| --- | --- | --- |
| File exceeds the size limit | The upload is refused before provider staging | Trim or re-export at a lower bitrate |
| Unsupported or unreadable container | The server could not validate a regular MP4 | Export a new MP4; do not rename the extension |
| Video is too long | The source exceeds the short-clip limit | Extract the relevant shot |
| Already the requested shape | This workflow expects a different output aspect ratio | Choose the other supported shape or use a conventional editor |
| Sign-in is required | The source must be tied to your processing account | Sign in on Wan3Prime before uploading |

## Source preparation does not improve the original recording

A smaller file can fit the limit, but compression can remove detail. Preview the export before uploading, especially on small labels, foliage and fast-moving edges. Outpainting should not be treated as a replacement for a clear source.

The upload metadata parser accepts encoded dimensions from 64 to 4096 pixels. This is a validation boundary, not a recommendation to submit the smallest possible frame. It does not offer arbitrary crop placement, multiple video tracks or custom output dimensions.

The source is staged at an unlisted provider URL to run the job. Anyone with that URL may access it until it expires. Completed results are stored privately and downloaded through the owner’s account. Read the [privacy policy](https://videooutpainting.com/privacy-policy) before submitting confidential footage.

## MP4 preparation questions

### Can I upload MOV, WebM or a video link?

This workspace accepts an uploaded MP4. It does not provide a remote-link import or claim MOV and WebM support. Export a supported file first.

### Does a refused local upload cost 70 credits?

A file rejected during upload is not a submitted generation job. The 70-credit debit happens when a validated generation is created; inspect the quote before that step.

### Will trimming or compressing preserve my sound in the output?

No. The processing preset returns a silent MP4. Save your authorized source audio separately if you plan to reattach it later.

### Will my upload remain available after changing accounts?

A staged source belongs to the account that uploaded it. Changing accounts clears the source from the current workspace, and another account cannot submit its signed upload token.

## Limits checked for this release

The limits above come from this workspace’s upload and generation validation, checked October 8, 2026. The [fal LTX 2.3 outpaint API](https://fal.ai/models/fal-ai/ltx-2.3-quality/outpaint/api) documents the underlying model; provider options are broader than the options offered here.

Next choose [portrait output](https://videooutpainting.com/video-outpainting-landscape-to-portrait) or [landscape output](https://videooutpainting.com/video-outpainting-portrait-to-landscape), and read [outpainting limitations](https://videooutpainting.com/video-outpainting-limitations) before processing.

## Check the evidence behind these examples

Inspect the [source videos, returned files and full-frame test extracts](https://videooutpainting.com/video-outpainting-test-methodology). The public methodology identifies the preset, individual jobs, publisher and observations so you can review the evidence directly.