Andr&eacute; Boekhorst

The Live Video Annotation plugin allows you to add timed footnotes to a YouTube video while you are watching the video. Visitors can see these notes later while watching the video. It’s really easy to use and the interface is designed as if you were chatting away.
It can be used for:
<ul>
<li>Add notes to video lectures.</li>
<li>Give translations to a video.</li>
<li>Add bookmarks to a video.</li>
<li>Easily add links to external resources mentioned in a video.</li>
<li>Create your own Pop-Up Video.</li>
<li>Whatever you can think of.</li>
</ul>
More Information on <a href="http://www.andreboekhorst.nl/wordpress/live-video-annotation-plugin/" title="Andre Boekhorst WordPress Amsterdam" rel="nofollow ugc">the authors website</a>.

Live Video Annotation

The Live Video Annotation plugin allows you to add timed footnotes to a YouTube video. Visitors can see these notes later while watching the video.

Moe Loubani

If you’ve ever wanted to draw on an image or add a caption or text to your image then this is the plugin for you. Best of all it allows you to add your caption, save it, display it, then go back and edit it in different layers and objects laid on top of your image.
It extracts the text from the annotations and displays them as selectable and stylable text just below.
You can hold shift as you draw rectangles to make them perfect squares, same with the ellipse tool and circles.

Image Annotator

This is a plugin that uses the HTML5 canvas and FabricJS to allow you to add shapes and text on top of images and display those images.

Live Video Annotation vs Image Annotator