[Note that when I have deployed this to the web, the video itself is not playing smoothly. It seems that after a few tries, it does stream  properly. I will figure this one out, but thought I might as well get this up anyway. It almost seems as if the timeline markers are interfering wtih the video playback. :-( ]

I have been exploring the interaction of ink playback with video.

An interesting challenge is to have annotataton that doesn't get "stuck" on the screen.

Silverlight's media element has timeline markers, which you can synchronize with events.

The way I have leveraged the timeline markers is that I have an ink data file with 5 separate collections; the last of these has no strokes in it so that it clears the canvas. In Javascript I created 5 timeline markers and tied four of them to the name of a particular collection. Each time a marker is hit, I play the associated collection. Below is a link to the persisted ink file so that you can see it's structure.

Note that I have been hoping to let users annotate videos of their own choosing by entering a URL for a YouTube or other video. Unfortunately, Silverlight does not [currently?] support the format which is used by YouTube and Yahoo ("flv" format, aka Flash) and I can't find a good source of WMV content. You can read more about this here in my blog post. 

Next steps will to let you ink videos, pausing, clearing and continuing and then save your annotations as well.