Ep 2: VAST: what a video ad tag actually is

When your player asks for an ad, what actually comes back?

VAST is an XML template telling a video player what to play and report.

The player on news.example hits a mid-roll and calls its ad server. The reply comes in two shapes. A Wrapper says, ask this other server. An InLine holds the ad itself. An Impression link to ping when it starts. A Duration, say fifteen seconds. And Media Files, the video in several sizes. Then tracking events. Start, first quartile, midpoint, third quartile, complete. The player fires each one, so the buyer knows it ran. Every Wrapper adds a round trip. After more than five, the player may give up, report error three oh two, and play nothing.

Today, paste a video tag into a VAST tester and count the Wrappers.

Next: ad pods, why CTV can’t auction one slot at a time.