PID is Postscribed ID technology, which is applied to each disc during the manufacture process.

Postscribed ID ™ enables individual serialization and identification of DVD-Video/ROM discs. The disc surface is modified to embed the ID data. Our browser-based client interface reads out the PID information on the discs and forwards it to the authentication server, to manage the rights per disc for DRM download.

The PID is automatically read by the disc drive and does away with the need for cumbersome
serial codes. The authentication of the disc happens invisible to the end user.