Why changing a video’s metadata is not enough

Plenty of tools promise to make a video unique by rewriting its metadata. The file does change, and so does its cryptographic hash. Yet the image and the sound stay exactly the same: for a platform as for a fan, it’s the same content. Here’s why.

What metadata contains

Metadata is information attached to the file, alongside the picture and the sound. It typically includes:

• the creation date and time;
• the camera or phone model;
• the encoder and software used, including an image generation tool;
• sometimes the GPS coordinates of where it was shot;
• for photos, the shooting settings (EXIF).

Why platforms don’t use it

Metadata is too easy to edit to serve as evidence. More importantly, most platforms strip much of it on upload, to protect users’ privacy and make files lighter. What’s left to recognise content is the pixels and the sound. That’s what the perceptual fingerprint is computed from.

The test that proves it

Take a video and change its date, its device and its name. Then compute the perceptual fingerprint of both files: it’s identical, bit for bit. The pixels haven’t moved, so nothing the platform measures has changed.

Wiping metadata is still worthwhile

Cleaning metadata doesn’t make a file unique, but it’s a good habit for other reasons:

• privacy, because a GPS position can reveal a home address;
• confidentiality, so a file doesn’t reveal your device or your editing software;

Klypsed removes personal metadata from every variant (GPS position, device, software), then writes it fresh. But it’s the last step, not the main one.

What to do instead

To get a genuinely different version, you have to alter the image and the sound themselves: a slight crop, a mirror, speed, pitch, light and grain. These changes stay subtle for a fan and show up in the fingerprint. Our comparison of methods sums up what each approach really changes, and our step-by-step guide walks through the method.