Outstream video

Instream ads need video content to run in. Outstream creates video ad inventory where there is none: a player appears within an article, in a feed or as an interstitial ad, plays the ad, and often collapses when done. It lets text-heavy publishers sell video, and advertisers reach people beyond video sites.

Outstream is typically muted by default, auto-plays when in view and pauses when scrolled away. Because viewers did not choose to watch video, attention and completion rates are generally lower than for instream video, and pricing reflects that. IAB Tech Lab updated its definitions in 2023: OpenRTB's "plcmt" field distinguishes instream, accompanying content, interstitial and no-content/standalone placements, largely to stop outstream from being sold as instream.

Mislabelling outstream as instream, so it attracts instream prices, was a widespread transparency problem, and some schemes also stuffed outstream players in hidden or tiny positions (see hidden ads). Buyers should check the declared placement type and verify viewability and video completion rate.

Think of it like this

Outstream is like a TV screen placed on a shop shelf that starts playing an advert as you walk past, even though you came in to buy groceries, not to watch TV.

An example

A news site in Argentina places a muted outstream player after the third paragraph of articles; it achieves 60% viewability and a 35% completion rate, versus 85% for its instream pre-roll.