Although YouTube is the clear leader in video sharing and viewing, Facebook is gaining ground as an outlet for big companies to market their products via online videos, a report published on Monday by y Ampere Analysis says. London-based Ampere predicts a new advertising "arms race" between the two rivals, neck and neck in terms of audience sizes with around 1.4 billion to 1.3 billion monthly active users, respectively for Facebook and YouTube. That means consumers will likely see more ads, but also enjoy a richer range of video programming as a result, it said.

Ampere surveyed 10,000 consumers in Europe and North America and found that 15% have watched videos on Facebook in the past month. Among people who watch video on Facebook, one-sixth of them (16.67 percent) have not watched anything YouTube in the past month.

In addition, Facebook?s video viewers are all logged in, registered users, which means the company potentially has far more data on them - data that advertisers can take advantage in order to offer targetted, interest-based ads.

Facebook still doesn?t offer pre-roll ads, and also charges advertisers for a video view if just three seconds of the ad are shown, which is less than YouTube requires. On the other hand, Ampere found that advertising rates were comparable between the two platforms, which suggests advertisers really value Facebook?s audience.

The Internet will overtake TV advertising in 12 key markets, representing 28 percent of global ad spending by 2017, separate research by media-buying firm ZenithOptimedia said on Monday.

Online video is now growing faster than any other digital category or subcategory, rising 33 percent in 2014, and is forecast to grow 29 percent a year through 2017, Zenith said.