Google has expanded its AdSense advertising programme for video, moving the initiative from a YouTube-only trial to a beta programme available on all Google Content Network sites.

AdSense for video allows advertisers to purchase transparent InVideo ads or small text ads which rotate along the bottom of videos. The ads are then placed on videos embedded in pages by site publishers.

The programme was launched last year as a small trial limited to YouTube. The expanded beta will push the service to a number of other video sites, including GodTube, Blip.tv and Bobvila.com.

"We have two major goals: to make it easier for publishers to monetise video online, and for advertisers to learn how to reach the video community," product manager Shamim Samadi and product marketing manager Ryan Hayward said in a blog entry.

Publishers wanting to qualify for the beta programme will need to be based in the US and to publish their pages in English. The beta will also be limited to sites that serve more than one million video streams a month.

Google promised to expand the programme to other locations and smaller sites "in the near future".