Recover overwritten or interrupted video on a card or dashcam

Overwritten from the start

Loop recording in dashcams and CCTV writes new clips over the oldest ones. When newer recordings overwrote the beginning of a video but its index survived, Frame Witness rebuilds the frames still on the device into a playable video, with its sound when it survived in the same piece, labelled as a partial reconstruction. The overwritten part cannot come back.

Cut by a power loss

An MP4 or MOV records its index at the end. If the camera lost power, the index was never written and the file does not open. With a complete video from the same camera and settings, Frame Witness rebuilds a new index around the original media bytes; the video track is rebuilt, the audio is not, and the result is labelled as a derived file, never the original.

Fragmented, not overwritten

A clip that plays for a few seconds and stops was often stored in pieces. Frame Witness follows MP4, MOV, 3GP, AVI, MKV and WebM pieces through their own index. On generated test images with 16 videos cut into pieces, version 1.0.10 recovered 13 identical with the pieces in order and 12 with the pieces shuffled (from 6 and 4 in the version before). These are generated images, not camera cards.

What cannot come back

• Overwritten data. Bytes that new files replaced are gone for every program.
• Full and overwrite formats. A full format in Windows writes zeros over the volume; an overwrite format or a wipe does the same with other patterns.
• SSD TRIM. A drive that receives TRIM usually erases freed blocks itself.
• Encryption without the key. A BitLocker volume, or a phone with file-based encryption, cannot be read without its key.

Frequently asked questions

Can overwritten dashcam footage be recovered?

The overwritten part cannot. Frames that remain on the card can be rebuilt into a labelled partial video when the clip's index survived.

Is a rebuilt video the original file?

No. Frame Witness labels it as a reconstruction or a derived file; its SHA-256 identifies the rebuilt bytes, not the original recording.

Try it on your own source

Download Frame Witness for Windows (version 1.0.14, Authenticode-signed by Aurelio Avila, SHA-256 fa22d6c7f97da0b4e5efa889e5abb9e4d98815a9b76ac0087424944b21bad6c2). The free account gives a quick scan of the first 8 GiB, up to 100 results, previews and saving files up to 1 MiB each; full scans and larger files need a licence, with current prices on the pricing page.

Related

• Dashcam and CCTV video recovery
• MP4, MOV and 3GP: how Frame Witness recovers them
• Recover a fragmented MP4 from a formatted SD card