Will all existing YouTube 3D videos be enabled in 3D Vision?
The majority of existing YouTube 3D videos are expected to be enabled beginning on May 25, with the remainder to follow. However, videos that include advertising overlays will not be supported at this time. Also, playback of 3D videos that are posted on a YouTube channel page will not be supported at this time, as HTML5 streaming is not yet available on YouTube channels. To view these videos, click on the "Try 3D on the main YouTube video page" button when it appears.