AUSTIN, TX: The number of digital ads served that include video has almost doubled since 2013, but marketers are still not taking full advantage of the opportunity, a new report has found.

According to ad measurement company Sizmek, digital ads including video increased from 9% in the first half of 2013 to 15% in the first half of 2015.

However, while this shows that video is gaining importance in marketing strategies, the report also said that out of 4,000 advertisers that served in-stream video ads or rich media ads over the period, only 18% used both.

It said there is opportunity for video in rich media advertising because nearly 11% of ads served in 2015 were rich media, but less than 5% of those rich media ads included video.

Andy Kahl, research director at Sizmek, said video has now become an "exceptionally important" medium for brands and marketers have more choices than ever, although they still have plenty of opportunity to reach new audiences.

"This study shows that although there has been swift adoption of the medium, most marketers are still learning how to effectively execute a digital advertising strategy that comprises multiple types of video," he said.

"There is still a lot of opportunity for marketers to reach new and existing audiences with content outside the realm of a repurposed television spot."

Turning to video growth rates around the world since 2013, the report found EMEA registered the highest rate at 160%, although North America recorded the most growth in 2015 at 52%, followed by APAC, at just under 50%.

Meanwhile, looking at industry sectors, the report found the Consumer Packaged Goods (CPG) vertical leveraged video ads the most, at 22%, followed by Entertainment (20%) and Auto (10%).

Data sourced from Sizmek; additional content by Warc staff