.3GP file signature
A 3GPP multimedia file file begins with the bytes 66 74 79 70 33 67 (ftyp3g in ASCII) at offset 4 (0x4). The signature is the same whatever the file is named, which is why a renamed or extensionless 3GP file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 4 | 66 74 79 70 33 67 | ftyp3g |
MIME type: video/3gpp · usual extensions: .3gp
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.3gp
file file.3gpWindows (PowerShell):
Format-Hex -Path file.3gp -Count 32This signature sits at offset 4, so look there rather than at the first bytes: xxd -s 4 -l 16 file.3gp.
If the bytes do not match
A file named .3gp whose first bytes are something else is not a 3GP file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the 3GP guide explains what a genuine file should contain.