Tool
Check a file signature
An extension is just a name. The first bytes reveal what is really inside.
The short answer
After a recovery, the extension is often a guess.
Carving tools assign file names and extensions from assumptions. This tool reads the first 64 bytes of your file and compares the signature it finds with the extension. Everything runs locally in your browser. There is no upload, no server request and no storage. Only the first bytes are read, not the whole file.
01 / Check
Choose a file
02 / Interpret
What the result means — and what it does not
If the signature matches the extension, the start of the file is sound. That is a necessary but not a sufficient condition: a file can begin correctly and still break off in the middle. Proving otherwise requires reading the container and decoding the streams.
If it does not match, rename the file to the detected format and try opening it again. That is often the entire fix, for instance when a carver stored a MOV file as MP4.
If nothing is recognised, either the start is damaged, the format is not covered here, or the file contains no media data.
This tool looks only at the start of the file. It cannot establish whether a video is readable across its full duration. That is exactly what the multi-stage verification inside the application is for.
Common questions
Is my file uploaded?
No. The file is read through your browser's FileReader interface and never leaves your machine. There is no network request in this tool.
Which formats are detected?
Those relevant to media recovery: JPEG, PNG, HEIF, GIF, MP4, MOV, MXF, Matroska, WAV, RF64, AIFF, MP3, FLAC, AVI, Canon CR2 and CR3, plus TIFF-based RAW formats such as ARW, NEF, DNG and ORF.
Can I check very large video files?
Yes. Only the first 64 bytes are read, regardless of file size. The result is therefore instant even for a file of several gigabytes.
Start correct, rest unclear?
This is how the application checks a file across its entire length.