Publishers who have yet to adopt the new protocol pose an even thornier challenge for SSPs. At PubMatic, an inventory quality team receives reports on the publishers with the highest volume of in-stream placements and spot-checks whether they are complying with the new standards, which can be effective at weeding out offenders, according to Kyle Dozeman, chief revenue officer, Americas at PubMatic.

To help enforce compliance, The Trade Desk employs a media quality team that aims to find publishers out of compliance with the IAB standards and notify the SSPs that work with them, according to three SSPs. The Trade Desk declined to comment on its process for verifying publisher compliance.

Currently, the primary hurdle is getting publishers to send the new specifications in the bidstream at all. Once they do, the next challenge will be to create a system to determine whether they are correctly labeling their inventory.

It is unlikely that any ad-tech firm will regularly audit compliance, meaning that publishers might be in the position of grading their own homework, according to sources. Verification firms could provide the service, though they would need to introduce a tailored solution to do so.

“They wouldn’t ever say it’s an SSP’s responsibility to make sure the taxonomy is being used correctly,” one SSP executive told Adweek.

This article was updated to clarify that the IAB Tech Lab created the new video specifications.