Adwords advertisers can now target even your websites for click-to-play video ads - they were earlier limited to sites using square and rectangle ad formats.
To enable video ads in your site, you must accept images ads (it should say text_image in your Adsense code)
Will this mean more income for you ? Sandra Tsui says that if a click-to-play video ad appears in one of your ad units, this means that it has won the auction against other ads and will generate the maximum earnings for you.
To check if an advertiser has targeted your webpage for a Video ad, use the Google Adsense Sandbox. More details here.
Google Video Ads - Sample ads in all available sizes.