prebid
Prebid Server doesn't transform device size to DPIs on calculating the creative sizes for Interstitial ads
Background
The OpenRTB protocol states that the dimensions for device.w and device.h are "Physical height of the screen in pixels".
However, the dimensions for banner.h & banner.w and format.h & format.w are "... device independent pixels (DIPS)."
Description
Neither Java nor GO servers do the transformation of physical pixels to DIPs if w and h are absent in banner and format objects.
In a result, for modern screens with a high pixel ratio, the array of generated sizes will contain very big values. And the most popular mobile interstitial size, 320x480, will be missed in the request.
Intended Behaviour
Prebid Server should utilize device.pxratio to transform the device's sizes to DIPs when generating the list of available sizes for the interstitial ad.
Discussed at the backlog meeting. Neither Go or Java do the transformation as you noted. This could cause problems if we change this behavior. We can discuss this further at the PMC next week.
Discussed at the PMC. We'll add a request-level config option that will enable this behavior. @YuriyVelichkoPI please propose the request field name.
