What to do right now
- Try a second player first; many “broken” videos are a codec problem.
- Compare the file size with the recording length; a tiny file is incomplete.
- If the recording was interrupted, keep the original and use a specialised rebuild tool.
How to diagnose
Try another player
Open the file in a second player such as VLC. Windows needs the HEVC Video Extensions to play H.265 videos from many phones and cameras; without them you may get sound but no picture.
Check the size and length
A ten-minute recording that is only a few megabytes was not saved completely. A file that plays the first part and then stops was truncated.
Think about how it was created
If the camera or phone switched off while recording, the file's index (the moov box) was probably never written. That is a typical interrupted recording.
Check the structure
When FileFix Ultimate recovers MP4 or MOV files, it checks their structure and reports problems such as a missing moov box, a missing media data box or a truncated file.
Choose the right fix
For codec problems, install the codec or use another player. For interrupted recordings, specialised tools can rebuild the index using a healthy reference video from the same camera. Truncated files can only play the part that exists.
How an MP4 file is built
An MP4 or MOV file is made of boxes. The media data box holds the actual video and audio. The moov box is the index: it describes the tracks, the codec and where every frame is. Many cameras write the moov box at the very end, when recording stops normally.
If recording is interrupted, the media data is on the card but the index is missing, so players cannot interpret it. Because the index depends on the camera's exact settings, rebuilding it needs a reference file recorded with the same device and settings.
Recovered videos
Videos are large and are often stored in several fragments, especially on cards that were nearly full. A recovered video can therefore contain the start of the recording and then data from another file. The structure check helps spot this before you spend time on it.
When it won't work
- FileFix Ultimate does not repair video files; it checks and labels their structure.
- Video data that was never written, or was overwritten, cannot be recovered by any tool.
- Rebuilding an index without a matching reference video rarely works.
How FileFix Ultimate helps
- Recovers deleted MP4 and MOV files from cards, USB sticks and drives.
- Checks the box structure of recovered videos and reports missing index, missing media data or truncation.
- Can use FFmpeg's ffprobe for a deeper check if you have it installed.
- Labels results honestly instead of calling every extracted video recovered.
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
Why does my video play sound but no picture?
Usually a missing codec, often HEVC (H.265). Install the codec or use a player that includes it.
Can I fix an MP4 from a camera whose battery died?
Often, with a tool that rebuilds the moov index from a reference video recorded by the same camera with the same settings. Keep the original file unchanged while you try.
Why does a recovered video show parts of another video?
The file was fragmented on the disk and the recovered data includes pieces of other files. Only the first part is likely to be correct.