I created a YouTube video and I want to block out a corner of the video after I uploaded it. Is it possible to block out a portion of the video and make the annotation permanent?
To make the annotation present for the whole video simply make the annotation span the whole videos length. Though do remember that annotation can be disabled, so this blocking method is not very effective. In fact a lot of people have them disabled by default, so they won't even know that an attempt to hide something was tried.
Edit: Since you mentioned privacy as one of your tags, I will assume this is to block something sensitive out. Using an annotation would be a terrible way to block out sensitive information, as I stated above.