Advertising executives admit the tide of ads is changing and online video ads taking the lead, new research has found.

Seventy-five percent of ad agency executives say that online video ads are more effective than traditional TV ads compared with just 17 percent who say they are less effective. That sentiment is shared when comparing online video ads with social media and search advertising ads as well. Ad executives also feel that online video ads are also more effective than direct response and display ads, a new eMarketer report found.

"The popularity of digital video viewing is helping drive the expansion of the online video ad market," the eMarketer report said. "Ad execs may be responding to U.S. consumers’ seemingly endless demand for online video."

Overall, research estimates that video views among Internet users grew by 23 percent this year.

As a result, research predicts spending on digital video advertisements to grow by more than 40 percent this year. That growth will bring spending on digital advertising to $4.1 billion this year. Most executive believe the largest growth will come in online and mobile video during the rest of this year, with mobile display and social media ads seeing growth as well. Direct response and television ads, on the other hand, are expected to see a drop in spending until the end of the year.

"Ad buyers are faced with an increasingly complicated equation when it comes to online video ads, and they need to consider which sites to purchase ads on, what format the ads will take and how to measure their effectiveness," eMarketer said.