As of present, Kaltura has one of the few working examples of an HTML5 video player with subtitle annotations (and its being tested on Wikimedia Commons).

Of course, if subtitles and subtitle hyperlinks can be implemented in the Kaltura player, then what about full-blown YouTube-like annotations (including notes, speech bubbles, spotlights and video pauses) which are already available in YouTube’s Flash player?

What would it take for Kaltura or another company to use a combination of CCS3 or canvas with a dynamic, easy image map-plotting mechanism? And the case of uploader-arranged playback manipulations (such as pauses or replays), what can be used?

Other possibilities can ensue, such as the transposition of internal or external media into timeline rather than needing to manually edit other external content into the video itself.

I’m pretty certain that such could and should happen with future iterations of HTML5 players like Kaltura’s.