Frequently asked questions
Is it really free? Any watermark or signup?
Yes. There is no account, no payment, no watermark and no trial limit. The tool runs on your own computer, so there is no server cost for us to pass on to you.
Is there a file-size limit?
The tool itself imposes none. The corrupted file is never loaded into memory as a whole; it is read in small slices, so multi-gigabyte recordings work. The practical limits are the free disk space for the repaired copy and, in browsers without direct-to-disk saving (Firefox, Safari), what the browser can download. For very large files use Chrome or Edge on a desktop.
Which video formats and codecs are supported?
Two kinds of files. MP4, MOV and M4V files with H.264 (AVC) or H.265 (HEVC) video and optional AAC-LC audio, which covers most phones, action cameras, drones and dashcams; these need a healthy reference video. And AVI files with any codec (Motion-JPEG, MPEG-4/Xvid/DivX, H.264, DV and more) with any audio, from older cameras, camcorders, dashcams and DVR recorders; these usually need no reference. MKV, WMV, MTS/M2TS and professional formats are not supported. In MP4/MOV, audio other than AAC-LC is left out of the repaired file.
Does the tool change my original file?
No. Your corrupted file is only read, never modified. The repaired video is created as a new file. Keep the original until you have confirmed the result plays correctly.
Why does my repaired video have no sound?
Sound is kept when it is AAC-LC audio, which is what nearly all phones and cameras record, and when the reference video has the same audio format. If the reference has a different audio type (for example PCM, AC-3 or HE-AAC) or no audio at all, the tool repairs the video only and tells you why in the log.
Does it work offline?
Yes. After the first visit your browser keeps a copy of the tool, so it keeps working without a connection. This also shows that nothing is sent anywhere.
How long does a repair take?
Small files take seconds. For multi-gigabyte recordings the time depends mostly on your disk speed, usually a few minutes. The progress bar shows how far along the scan is.
Can I repair several videos at once?
One video at a time. When a repair finishes, use "Repair another video" to start the next. Each repair is independent, so you can reuse the same reference file for several corrupted files from the same camera.
Is the repaired video lower quality?
No. The picture and sound data is copied unchanged; only the header and index are rebuilt. Nothing is re-encoded.
Why is the repaired file saved as MP4 (or AVI)?
MP4 and MOV recordings are repaired into an MP4 file, which plays almost everywhere. AVI files are repaired into AVI.
Does it work on a phone or tablet?
It runs in modern mobile browsers, but phones have little memory and no direct-to-disk saving, so use a computer for anything beyond small files.
Which files are not supported?
MKV, WMV, MTS/M2TS and professional formats such as ProRes, MXF and RAW video. Fragmented MP4 streams are not supported either.
What should I do if the repaired video does not play?
Try a different reference clip recorded in exactly the same mode, make sure the original file is complete, and open the result in VLC. If it still fails, copy the Technical log under the tool and email it to us together with the camera or app name.