Frequently Asked Questions
Last Updated: June 2026
This FAQ explains how LUFS Optimizer works, what files it supports, how loudness processing helps MP4 videos, and what creators should know before uploading a file.
What is LUFS?
LUFS stands for Loudness Units relative to Full Scale. It measures perceived loudness over time instead of only measuring the highest peak in the audio. LUFS is useful because it better reflects how loud a video feels to a listener.
What does LUFS Optimizer do?
LUFS Optimizer helps make MP4 video audio louder, cleaner, and more consistent. It uses loudness targeting and true peak protection so creators can prepare videos for YouTube, TikTok, Instagram, podcasts, DJ mixes, and other online platforms.
Is LUFS Optimizer free?
Yes. LUFS Optimizer is currently free to use. You can upload an MP4, choose a preset, process the file, and download the optimized version without creating an account.
Do I need to create an account?
No. Registration is not currently required. The tool is designed to be simple and fast for creators who need to process a finished MP4 file.
What file types are supported?
LUFS Optimizer currently supports MP4 video files only. Non-MP4 files are rejected, and fake MP4 files are also rejected when they fail validation.
What is the maximum upload size?
The maximum file size is 500 MB. Files larger than 500 MB are blocked and should be compressed or shortened before uploading.
What is the maximum video length?
Videos must be 60 minutes or shorter. This limit helps keep processing reliable and prevents extremely long jobs from overloading the server.
Will LUFS Optimizer reduce video quality?
The tool focuses on audio processing while preserving video quality whenever possible. The goal is to improve the loudness and consistency of the audio without changing the visual quality of the video.
Can LUFS Optimizer make my MP4 louder?
In many cases, yes. If the original audio has room to be improved, LUFS Optimizer can increase perceived loudness and make the file sound more consistent. If the source audio is already badly distorted or clipped, no tool can fully repair that damage.
What is true peak protection?
True peak protection helps reduce the risk of clipping after encoding, uploading, or playback. This matters because platforms may re-encode your MP4 after upload.
Can I use this for YouTube?
Yes. Many creators prepare YouTube videos around practical loudness targets before uploading. See Best LUFS for YouTube for more details.
Can I use this for TikTok or Instagram Reels?
Yes. Short-form videos are often watched on phones, so clear and consistent audio is important. See Best LUFS for TikTok and Best LUFS for Instagram Reels.
Can I use this for podcast clips?
Yes. LUFS Optimizer can help speech-heavy MP4 podcast clips sound more consistent, especially when they are posted to YouTube, TikTok, Instagram, or social media.
Can I use this for DJ mixes?
Yes. DJ mix videos can benefit from controlled loudness optimization, but it is important not to over-process already mastered music. See Best LUFS for DJ Mixes.
How long are files stored?
Uploaded and processed files are temporary. Files older than approximately 24 hours are automatically removed from the server.
Why was my file rejected?
Your file may have been rejected because it was not a valid MP4, was larger than 500 MB, was longer than 60 minutes, or failed media validation.
Who do I contact for support?
You can contact support at support@lufsoptimizer.com or visit the Contact page.