Google Ad Manager

The client can set some parameters at a per-session level, provided as URL-parameters to the initial session request.

Query Parameter	Description
sz(required)	Client video screen size; these are set from URL parameters player_width, player_height or alternatively from sz=PLAYER_WIDTHxPLAYER_HEIGHT
ppid	Publisher provided ID
idtype	Device type
rdid	Resetable Device ID
is_lat	Limited ad tracking flag
msid	Application ID
an	Application name
paln	PAL nonce

Full description of variables:

https://support.google.com/admanager/answer/1068325?hl=en