One play of a screen ad can reach many people, so a programmatic digital out-of-home (DOOH) opportunity can count as more than one impression, or as less than one. OpenRTB 2.6-202211 added a DOOH object, a Qty object and DOOH implementation notes, so a bid request can say how many impressions a spot represents.
What does the DOOH object change?
A bid request that carries a DOOH object must not also contain a site or app object. The object describes the screen placement: an exchange-provided id, a name, the venue type, the publisher, a domain, keywords and the content shown there. If no venue taxonomy is named, the OpenOOH Venue Taxonomy is assumed.
Screens differ from phones in ways the implementation notes spell out. Most sit on private networks, so a DSP cannot geolocate by IP address, and the request carries publisher-reported latitude and longitude instead. DOOH devices are identified as device type 8.
Moving screens such as taxi tops and bus panels commonly report near-real-time GPS positions. Panels come from many vendors, and the notes say there is no recognized global standard for identifying a DOOH device.
Why can one screen play be many impressions?
A web impression is one user viewing one page. A screen play is seen by everyone nearby, and IAB Tech Lab notes the resulting number can be greater or less than 1 because it comes from statistical modeling. Fractions such as 0.32 impressions per ad display are common.
The IAB page adds that screen size and direction change both the size of the possible audience and the chance that it sees the ad. The implementation notes add that the rates can follow hourly-adjusted projections or real-time sensor data.
The Qty object carries the estimate. Its multiplier field is the quantity of billable events deemed to have occurred if the item is bought, and the spec’s own example is a DOOH opportunity considered to be 14.2 impressions.
How do the multiplier and source type keep pricing honest?
A multiplier is only as good as whoever measured it. The Qty object therefore has a sourcetype field, and AdCOM defines its values:
| Value | Meaning |
|---|---|
| 0 | Unknown |
| 1 | Measurement vendor provided |
| 2 | Publisher provided |
| 3 | Exchange provided |
The OpenRTB spec marks multiplier as required and sourcetype as recommended. When the source is a measurement vendor, the object must also name that vendor’s domain. Check that sellers send all of it.
Price is quoted as a CPM per impression, not per play. The implementation notes work an example: a $2.50 CPM bid on an auction for 30.3 impressions costs (2.50 / 1000) x 30.3, or $0.07575. The AUCTION_MULTIPLIER macro in the billing notice reports the quantity won, which should never exceed the multiplier in the request. The notes also warn that buyer and seller systems can truncate decimals differently, so align rounding at the account level.
What else is different about buying screens?
Timing is looser than on the web. Panels can lose connectivity, so some owners take bids ahead of display. The implementation notes say the accepted lead time from bid confirmation to display can be 1 to 2 hours.
The notes recommend separate events: the win notice (nurl) is not a guarantee that impressions will occur, while the billing notice (burl) fires when the creative has rendered and the impressions are billable. The imp.dt field gives the estimated fulfillment time.
Creative approval is manual. The same notes say large networks usually pre-approve every ad by human review, which can take working days, and many networks prohibit changes after approval.
What does this mean for a buyer?
Treat the multiplier as a priced input. Before a DOOH flight, ask the seller who measured it, whether it changes by time of day, and when the billing notice fires. Vectravia’s Omni Buy bids on DOOH with the OpenRTB DOOH object and the Qty impression multiplier, and plans DOOH beside six other channels from one budget. The digital out-of-home channel page lists the standards involved.