What to do right now
- Copy the original file to another disk and work only on copies.
- Prepare a short normal clip recorded on the same device with the same resolution, frame rate and codec.
- Add both files to damaged file repair to rebuild the index.
How to repair it
Keep the original
Copy the interrupted file from the card to another disk on the PC. Leave the original on the card and do not record anything new to it.
Confirm it was interrupted
If the file size matches the recording time but it will not play or shows zero length, it was most likely interrupted. FileFix Ultimate's structure check reports a missing moov box. A very small file means hardly any data was written.
Prepare a reference clip
You need a normal clip from the same device with the same settings: resolution, frame rate, codec and stabilisation. If you have none, record about ten seconds with the same settings to another card or the PC.
Run the repair
In damaged file repair, select the interrupted video and choose the reference clip. Based on the reference's setup, the frame positions are found again, a new index is built and the result is saved as a new MP4 or MOV file.
Check the result
Play the repaired file. The last few seconds may be missing or the sound may be slightly out of sync. The result is shown honestly with its validation status.
Why a reference clip from the same device is needed
The moov box of an MP4 or MOV holds the codec settings and the position and size of every frame. Many cameras write this box at the end of the file when recording stops normally. When recording is interrupted, it is missing entirely.
Codec settings differ by device and recording mode, so they have to come from a normal clip shot on the same device with the same settings. Frame positions are found again by reading the video data from the start. A reference with different settings gives broken pictures or a failed repair.
How truncated files differ
Files cut off during copying, or missing their end after recovery, often have the index at the front but not enough data. A truncated MP4 like this is fixed by shortening the index so it plays up to the data that remains. The guide on repairing corrupted video explains this further.
When repair will not work
- No reference clip from the same device and settings is available.
- Recording stopped right after it started, so almost no video data was written.
- The file was fragmented on the card and mixed with other video data.
- The device records in a proprietary or encrypted format.
How FileFix Ultimate helps
- From version 1.0.4, rebuilds MP4 and MOV files without a moov index using a reference clip.
- From version 1.0.4, fixes truncated MP4 files up to the playable part.
- The result is always a new file; the original is never modified.
- A structure check first reports a missing index, missing media data or truncation.
FileFix Ultimate is free, works offline and never writes to the drive you are recovering from. Check the signature before you run it.
Frequently asked questions
My video will not play because the battery died while recording.
The recording did not end normally, so the index is missing. Rebuilding it with a normal clip from the same device often makes it playable.
Can any video be the reference?
No. It must come from the same device with the same resolution, frame rate and codec. Different settings make the repair fail.
I get a moov atom not found error.
That means the index (the moov box) is missing. It is the typical error of an interrupted recording and can be repaired with a reference clip.
Does the repair change the original?
No. The repaired result is saved as a new file and the original stays as it is.