Adsense publisher who uses video units feature (YouTube content and video ads on your pages) will not be able to use this feature anymore. Google Adsense is retiring this feature at the end of April because video units hasn’t had made impact as Google had hoped for.
If you opted into image ads, this change won’t affect the video ads that appear in your AdSense for content ad units. Adsense is retiring only the specific video units, not the video ads appear in content ad units.
After 2009 April end, any video units (Leaderboard or Skyscraper video units) on your pages will direct users to YouTube.com and other video unit sizes will show standard embedded YouTube players. If you are publisher make sure you remove the video units from your page and replace it with content ad units.