Repair a corrupted MP4 video

Typical symptoms of a corrupted MP4

• The file has a normal-looking size but no player opens it.
• It shows 0:00, no thumbnail, or a duration much shorter than the recording.
• VLC, QuickTime, Windows Media Player and your editor all reject the same file.
• FFmpeg or ffprobe reports moov atom not found or Invalid data found when processing input.
• It was the last clip recorded before a crash, a power cut, a battery removal or a full memory card.

What usually causes it

An MP4 is a container. The large mdat part holds the compressed video and audio; the moov part is the index with track descriptions, timing and the position of every frame. Cameras and phones write the media continuously and the index when recording stops. Anything that prevents a clean stop leaves media without an index:

• battery drained or removed, or the device crashed or overheated;
• memory card removed, full or failing during recording;
• drone crash or power loss on landing;
• a recording app killed by the system.

A second group of problems comes from copying: a transfer, download or upload that stopped early produces a truncated MP4. If the original still exists, copying it again is the real fix.

Before attempting repair

1. Re-copy from the source if the original is still on the camera, phone or card, and check whether the new copy plays.
2. Try VLC to rule out a codec problem: many phones and cameras record HEVC, which some players cannot decode. See video won’t play.
3. Keep the original untouched. Work on a copy and avoid tools that modify files in place.
4. Record a reference clip with the same device and settings if you still have the device.

Why common fixes don’t work on interrupted recordings

Tools that do rebuild the index, such as the open-source untrunc, work by learning the structure from a healthy file of the same device. FrameRescue uses the same principle, plus its own structural analysis and checks, in a browser without installing anything.

How FrameRescue repairs a corrupted MP4

1. You upload the damaged MP4, and optionally a healthy clip from the same device. Large uploads can be paused and resumed.
2. FrameRescue analyzes the structure, identifies the streams and rebuilds the index around the media that survived.
3. The candidate result is decoded and checked. A file is not presented as repaired just because a new container was written.
4. When a repaired file is ready, you unlock one download for €5.00. If no repair is ready, you pay nothing.

Corrupted MP4 questions

Can VLC repair a corrupted MP4?

VLC’s built-in repair option is for AVI files. VLC can sometimes play a damaged MP4 that other players reject, which is useful for checking, but it cannot rebuild a missing MP4 index.

Can FFmpeg fix a corrupted MP4?

FFmpeg can remux a file whose index is intact, and that solves some playback problems. When the index is missing, FFmpeg cannot find the streams and stops with errors such as “moov atom not found”, so structural repair is needed first.

Is it safe to repair an MP4 online?

Upload only to a service you trust, and keep your own copy of the original. FrameRescue uses HTTPS, resumable uploads and checks the result before offering it; you do not need an account.

Do I need a sample or reference file?

Not always, but a short healthy clip recorded with the same device and settings improves the chances, especially for audio and for less common cameras.

What if only part of the video comes back?

Repair can only use the data that exists. If the end of the recording was never written, the repaired video stops where the data stops.

Related repair guides

• Fix “moov atom not found”

  What the missing movie index means and why copy or faststart commands don’t rebuild it.

• Repair a truncated MP4

  Recording interrupted or copy cut off? How to tell, and when a reference-based repair is needed.

• Video won’t play? Find the cause

  Codec, player, incomplete copy or damaged file: quick checks for MP4 and MOV videos that won’t open.

• Phone died while recording

  Does the video save? Where to look on iPhone, Android and cameras, and how to repair the unfinished file.