So far what I've been developing has worked in Chrome and, using fallbacks, IE8.

What I don't get is this: Safari just won't start loading <video> or <audio> content.

Safari 6 won't load, and neither will iOS 5's Safari:

My code calls .load() on the elements at the appropriate time (at least for Chrome), so what gives?

Here is the video declaration:

<video width="800" height="600" class="faces" id="facesVideo">
  <source src="video/grid.mp4" type="video/mp4" />
  <source src="video/grid.ogv" type="video/ogg" />
</video>

The audio is declared dynamically, but has the same problem.

Do I need to wait for some DOM event that Chrome doesn't need before calling .load()?

What does it take to get Safari to start buffering until the elements can fire canplaythrough?