01

The RIFF structure

The file starts with RIFF and WEBP signatures. Extended files use VP8X to advertise alpha, animation, EXIF, XMP or ICC features.

Key points
  • VP8: lossy pixels
  • VP8L: lossless pixels
  • ANIM/ANMF: animation
  • EXIF/XMP/ICCP: metadata and color
02

What can go wrong

Removing a chunk without fixing the container length or VP8X feature bits produces an inconsistent file. Odd-length chunks also require a padding byte.

What this does not prove

A metadata result describes the fields and structures that the supported parser could read. It does not, by itself, prove authenticity, intent, authorship or the truth of the visible scene.

Sources