The video market
Last year, online video advertising revenue accounted for just over £1 billion, 29% of total display. When broken down by device, video took an even larger share at 36% of total display revenue, £693 million. This is unsurprising given the growth opportunity from mobile, having overtaken desktop as first screen last year. Mobile can attribute its growth largely to increased 4G connectivity, faster internet speeds and easier smartphone accessibility. This has fuelled the video market, growing from a mere £18 million in 2008 to a whopping £1 billion in 2016. 
Audience video consumption
Consumer habits are changing and moving online; UK adults spend almost 1 hour a day watching digital videos according to eMarketer. Amongst millennials, a highly sought-after demographic, the time spent watching digital video is even higher and has some important implications. For instance, 4 in 5 millennials find video helpful during initial research for a purchase decision. Advertisers must be where their customers are and if they are missing out on video, they are missing out on a sizeable market opportunity.
What video formats are being adopted by advertisers?
A few of the more popular online video ad formats are:
These linear video ads tend to be available in pre-roll, mid-roll and post-roll on video publishers that have in-stream inventory such as premium publishers like the Daily Mail and of course You Tube and Facebook.
Show the video within a standard banner size and placement. When the user interacts with the video ad it may expand into the page, overlaying the content on the web page.
- Outstream or native video
Video ads that appear within the main body of editorial content. As the user scrolls down the page, the video autoplays. These video ads are contextually relevant and can form rich ad experiences.
Video advertising is the future, and by 2020 online video is expected to account for 82% of all consumer internet traffic.  The medium creates another way to connect and engage with audiences, particularly as part of the upper funnel targeting strategy. The combination of harnessing data, creativity and plugging it through programmatic pipes can ensure the right users are reached in the right context at scale to provide a relevant and seamless user experience.
 The IAB