Advertisers only pay for “true” views, meaning when a video played for more than 30 seconds (or if the whole video has been played if it is shorter than 30 seconds), or if a user has interacted with the ad. There are two formats:
InStream ads, which are pre- or mid-roll ad spots that the user can skip after 5 seconds.
Video Discovery ads, which appear within pages a user is browsing (similar videos, YouTube search results etc.).