What is CPV?
CPV (or Cost Per View) is programmatic bidding method to buy video impressions, meaning the advertiser will only pay for video impressions (VAST or VPAID) when the impression is actually viewed. Compared this to Cost Per Mille (CPM) where the advertiser pays for impressions regardless if they are viewed or not.
CPV is not supported by every Demand Side Platform or Supply Side Platform. Where there is no support for CPV it is usually provided via reporting as the actual Cost Per View, sometimes represented as CPV or eCPV (effective Cost Per View)