Rather than blindly embedding everything, video metadata is first requested through the URL metadata lookup service.
This slightly protects you from automatically connecting to third party servers and also vastly improves page loading performance in tandem with caching on the server.
A similar implementation will eventually make its way to the audio bbcode and will also be worked in the img bbcode somehow.
This will then eventually make it possible to embed audio and video in markdown the same way you'd embed an image.
flash