Video repair tools compared: upload services, desktop apps and in-browser repair

By the FixMP4 engineering team · October 7, 2026 · 6 min read

Search for "repair corrupted video" and you will find dozens of tools. They fall into three groups: online services that require an upload, desktop programs you install, and tools that run in your browser without uploading. Under the hood they all try to do the same thing, rebuild a broken or missing index around the surviving frames, but the experience, the privacy and the cost are very different. This guide compares the approaches honestly, including where ours falls short.

What every repair tool actually does

Whatever the marketing says, a repair tool for MP4 and MOV files does some combination of:

1. Reading the box structure to find what is missing (index, header, end of file).
2. Reusing a surviving index when one exists.
3. Rebuilding a missing index by scanning the media data, usually with the help of a reference file from the same device, because the codec settings were stored in the lost index.
4. Writing a new file around the original frames.

No tool can bring back frames that were never written or that were overwritten. Be sceptical of anything promising to fix "any" file.

Option 1: online upload services

You upload the broken file to a website, the server repairs it, and you download the result.

Pros: nothing to install; works from any device.

Cons:

• Upload time. A 4 GB 4K video can take a long time to upload on a typical home connection, and many services cap file size.
• Privacy. Your footage sits on a third party's server. That may not be acceptable for family videos, client work or anything under NDA.
• Pricing. Some services charge per file or show results only after payment.

Option 2: desktop software

You install a program on Windows or macOS and repair files locally.

Pros: no upload; can handle large files; often supports more formats, including some professional codecs.

Cons:

• Installation and trust. You give a program full access to your computer.
• Price. Commercial desktop repair tools commonly cost tens of dollars per year, sometimes more, and some only reveal whether the repair worked after you pay.
• Platform. Many are Windows-only or Mac-only.

The open-source command-line tool Untrunc is a well-known free option in this category. It is powerful and free, but it requires using a terminal and, in many cases, compiling it yourself.

Option 3: in-browser repair

The repair runs inside your web browser using JavaScript or WebAssembly. The file is read from your disk by the browser and never uploaded.

Pros:

• Private by design: the file never leaves your device.
• No upload wait and no server-side file size limit.
• Nothing to install, works on Windows, macOS, Linux and ChromeOS.

Cons:

• Limited by the browser's memory, so extremely large files can be slow on low-end devices.
• Professional codecs and unusual formats are less likely to be supported.

FixMP4 belongs to this group.

How to avoid paying for a repair that does not work

The most common complaint about video repair tools is paying first and finding out afterwards that the file still does not play. Protect yourself:

1. Insist on a preview of your own file, not a demo. If a tool cannot show a playable part of your repaired video before payment, assume it may not work.
2. Check what is supported: codecs (H.264, HEVC, ProRes...), containers (MP4, MOV, M4A), and whether a reference file is required.
3. Prefer cancel-anytime subscriptions or clear one-time prices, and read the refund policy before buying.
4. Keep the original file untouched, so you can try another tool if needed.

Where FixMP4 fits

• Runs in your browser, no upload.
• Free diagnosis and a free 15-second repaired preview of your own file.
• $9/month or $29/year, cancel anytime in one click; no per-file fees.
• Supports H.264 and HEVC video with AAC audio in MP4, MOV and M4A, including iPhone Voice Memos.
• Does not support yet: ProRes, AV1, VP9, MPEG-4 Part 2, PCM/ALAC/Opus audio, fragmented MP4 and encrypted files.

If your file is in the unsupported list, use a desktop tool that explicitly supports your codec, or Untrunc if you are comfortable with the command line.

Quick decision guide

Try it on your own file with the FixMP4 repair tool; the preview is free.

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