When a video campaign is being planned is difficult to compare different platforms, as each uses different metrics and there aren't standards on video ads. Only on programmatic, the metrics are well defined.
Youtube is also an exception on this list, as Google's website offers the option to buy pre-rolls (of 15 seconds), and bumper ads of 6 seconds, on a CPM basis; formats non-skipable. And when advertisers do buy CPM on Youtube, the programmatic metrics should be used.
What counts as a video view?
On Programmatic, a view is when the video is completed 100%. On Youtube, a view (called TrueView) is when a viewer watches for 30 seconds of the video (or the duration if it’s shorter than 30 seconds). On Facebook, and Instagram, a view is counted on 3 seconds of auto-play. In Snapchat a view is counted when the video starts.
How big is the audience?
On programmatic, as it covers all publishers (like Bloomberg, CNN, BBC, Disney, Twitch, etc and small publishers like video games or apps), and many formats like outstream, pre-roll, mid and post-roll, normally all the users on the internet are covered. Youtube has 1.5 billion logged users per month this year, Facebook 2 billion, Snapchat 255 million (less than Twitter with 328 million).
Where does the video play?
On programmatic, advertisers can target ads on different devices, contexts, audiences, websites, skippable inventory and non-skipable inventory. The video inventory can be outstream or in-stream (on instream advertisers can also select pre-roll, mid-roll and post-roll. There is also Video Multiple Ad Playlist (VMAP), used by publishers to create commercial breaks, similar to linear broadcast TV, and is mostly used in long-form content. On VMAP you can select the ad pod position: Intro/First or Outro/Last.
On Youtube the video ads can be pre-roll, mid-roll or post-roll. The ads with 15 seconds can be non-skippable (if bought via a cpm deal), but these type of ads are normally only accessible to big budgets. The TrueView ads are skippable and normally the most common. Youtube ads are mainly displayed on Youtube.com, however, there are Youtube partners also with TrueView ads in programmatic, via Doubleclick Ad Exchange. The TrueView ads are skipable after 5 seconds. Youtube has a format called Bumper ads, displayed mainly on small screens (mobile phones), that last up to 6 seconds, and are non-skipable.
On Snapchat, Instagram and Facebook, the video ads appear mainly mixed with user generated content, in feed or between stories. Mainly they are mid-roll ads but there are also pre-roll and post-roll ads.