HealVideo

How to fix “moov atom not found”

“moov atom not found” is the error FFmpeg, VLC and many editors show when a video file has lost its index. The video itself is usually still there, so the file can often be rebuilt.

What the error means

MP4 and MOV files are made of boxes, also called atoms. The mdat box holds the video and sound. The moov box is the index: frame sizes, timing, and the settings a decoder needs to read the picture.

Cameras write the moov box last. When recording stops suddenly, there is an mdat full of video and no moov. Players give up, and you see “moov atom not found” or “invalid data found when processing input”.

How HealVideo rebuilds it

HealVideo looks through the raw video data for the frames themselves, puts them back in order, and writes a new file with a fresh index. To read the frames it needs the decoder settings that were in the lost index. It gets them from a camera profile (settings saved for a known camera), or from one working clip recorded on the same camera in the same mode.

Every result is test-played by decoding its first 30 seconds. If only part of the video could be saved, HealVideo says so instead of calling it fixed.

Steps

  1. Install HealVideo and drop in the file that shows the error.
  2. HealVideo confirms the index is missing and checks whether it knows your camera.
  3. If it doesn’t, add a clip from the same camera that plays. Same resolution and frame rate works best.
  4. Start the repair. You get a new file; the broken one is left exactly as it was.

What can be repaired

Recording cut short, index still there
HealVideo copies everything that is still readable into a new file that plays.
Index missing (“moov atom not found”), H.265 video
HealVideo finds the frames in the raw data and builds a new file. It needs a camera profile or one working clip from the same camera.
Index missing, H.264 video
Needs the free tool untrunc installed next to HealVideo, plus one working clip from the same camera.
Videos deleted from an exFAT memory card
HealVideo reads an image of the card and puts each video’s scattered pieces back in order.

Repaired files from the frame finder have video but no sound yet. Damage inside the picture itself (glitches in a file whose structure is fine) is not something HealVideo can undo.

Related guides

Updated 2026-10-13. HealVideo is an early preview (version 0.1). Found a mistake? Tell us on GitHub.