You may start seeing video-based advertisements in your Facebook news feed soon -- as the social network begins to sell video advert space to vendors.

According to the Wall Street Journal, sources "familiar with the matter" say that the social networking giant will begin selling video-based advertisements this week as it taps into revenue usually spent by firms on broadcasting and television adverts.

Facebook's news feed -- on browsers and mobile -- will be the destination of these ads on Thursday, and the social network is expected to announce the change today. According to the publication's sources, the adverts will play -- without sound -- automatically within their news feeds whether an individual clicks on them or not. It is unknown how long the adverts will be, although some outlets have suggested a cap of 15 seconds.

However, the ads won't come cheap, as earlier reports have suggested that the advertisements could cost firms between $1 million and $2 million for a day-long run.

In a confidential sales pitch guide recently obtained by TechCrunch -- although not necessarily related to this particular advert test -- the social networking giant instructed adtech partners in how to sell video ads on site. The 32-page document, titled "Facebook For Business: Video On Facebook," reveals how the tech giant wants to sway revenue away from television and broadcast advertisements, and lure firms towards "engaging digital real estate," touting Facebook's extensive reach and the scale of user-input personal data which could be used to personalise and target advertisements.

It is unknown how many companies have signed up for the new advertising push, or whether some marketers may be waiting to see if there is user backlash before signing up.

Last week, some Facebook users said they had witnessed videos appearing in their news feeds as the technology was tested by Facebook engineers. Although it is believed that the video rollout was due to launch in summer, the project was delayed due to engineering problems, slow loading and the belief they may alienate or annoy users.

Update 12.41GMT: A Facebook spokeswoman told ZDNet that rather than "launching or selling anything," the social network will be testing these types of advertisements with one partner for one day, on Thursday. In a blog post, Facebook states: