What is AdSense for video?

adsense for video, a new thing for many bloggers. what it really is?
this question is frequently click your mind when you listen adsense for video.
Publishers can earn revenue with video content using relevant, non-intrusive ad placements from Google's extensive advertiser network. Video content will display both InVideo overlay and text overlay ads.
Now question is that what is Invideo overly and text video overly ads? so here is brief explanation.

InVideo overlay ads are Flash-based ads. These ads will be targeted to publishers' content based on the relevance of advertisers' campaigns to your content. Advertisers may choose to include a companion video ad which opens when a user clicks on the overlay, pausing the content and playing a video ad within the video player. InVideo ads will compete in the Google auction. publishers get revenue and will be paid on a cost-per-thousand impressions basis.

These ads are placement-targeted to your site and appear within your video streams. When placement-targeted, they are paid on a cost-per-thousand impressions basis. Text overlay ads are drawn from the campaigns of AdWords advertisers and may be contextually targeted to signals in your video and your site. When contextually targeted, text overlay ads are paid on a cost-per-click basis.