Can VLC repair a corrupted video? What works and what does not

By the FixMP4 engineering team · Updated October 9, 2026 · Tested on real H.264, HEVC and AAC recordings

VLC can repair one specific kind of damage: a broken or missing index in AVI files, using its "Damaged or incomplete AVI file: Always fix" setting. It can also play many partially damaged files that other players refuse. VLC cannot repair an MP4 or MOV whose index (moov atom) is missing, which is the usual result of a recording cut off by a dead battery or crash: VLC will either refuse the file or play nothing. For that case you need an index rebuild, which you can try for free with the FixMP4 repair tool.

What VLC can do

How to use VLC's AVI repair

1. Open VLC and go to Tools, Preferences (on a Mac: VLC, Settings).
2. Click Input / Codecs.
3. Find Damaged or incomplete AVI file and choose Always fix.
4. Save, then open the AVI again. VLC rebuilds the index in memory each time it plays the file.

This fixes playback in VLC only; the file on disk is unchanged. To get a permanently fixed copy, use Media, Convert / Save, choose a profile (for example H.264 + MP3 (MP4)), and convert. Note that converting re-encodes the video, which takes time and costs some quality.

Why VLC cannot fix a missing moov atom

An MP4 or MOV stores the description of its content, codec settings, frame sizes, positions and timing, in the moov atom. Players, including VLC, read it first. A recorder writes it when recording stops, so a recording cut off by a dead battery, crash or full card has no moov atom at all. Without it, VLC does not know what codec the data uses or where frames begin, so there is nothing to play or convert. Renaming the file to .avi or .mkv does not help, because the data is not AVI or MKV. See fix "moov atom not found" for the full explanation.

The fix for MP4 and MOV: rebuild the index

1. Record a short reference clip on the same device with the same settings (resolution, frame rate, codec, colour profile). For iPhone Voice Memos and other AAC audio you can usually skip this.
2. Open the repair tool and add the broken file and the reference.
3. FixMP4 scans the raw frames, takes codec parameters from the reference, and writes a new index. It shows a free preview of your repaired file.
4. Export with a subscription. Then the repaired file plays in VLC and everywhere else.

Nothing is re-encoded, so unlike VLC's convert, quality is identical to the original. Nothing is uploaded either.

Other useful VLC tricks

• Codec information: Tools, Codec Information shows the codec, resolution and frame rate of a working file, exactly the settings a reference must match.
• Playing HEVC on Windows: VLC decodes HEVC without the Microsoft extension, which solves many "file not supported" problems; see "file is not supported".
• Extracting audio: Media, Convert/Save with an audio profile pulls the soundtrack out of a playable but glitchy video.
• Increasing file caching (Preferences, Show all, Input/Codecs, file caching) can help with files on slow network drives, not with corruption.

When VLC plays it but your editor does not

If VLC plays the file but Premiere, Final Cut or DaVinci Resolve refuses it, the file is probably fine but uses a variable frame rate, an unusual profile, or a codec the editor lacks. Transcode it to an editing-friendly format (with HandBrake or Shutter Encoder) rather than repairing it.

A quick decision guide

• The file is AVI and will not play or seek: turn on VLC's Always fix.
• The file plays in VLC but nowhere else: it is a codec support issue; keep using VLC or transcode a copy.
• The file is MP4, MOV or M4A, will not open in VLC, and the recording was cut off: rebuild the index with a reference.
• The file is 0 bytes: no player or repair tool can help; try data recovery on the original card.
• The file plays for a while and then stops in every player: the recording or copy ended there; check whether the original device still holds a longer version.

Following this order saves time, because the cheapest checks come first and only genuinely damaged MP4 files need a repair tool.

Common mistakes

• Enabling "Always fix" and expecting it to repair MP4 files; it only applies to AVI.
• Converting a glitchy MP4 in VLC and losing quality when the original would have played fine after an index rebuild.
• Deleting the original after a conversion that silently stopped early.

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