I was doing some research into video codecs on Linux today and stumbled on an awesome video on xiph.org entitled "A Digital Media Primer for Geeks" .
It's a 30 minute video of "Monty" Montgomery talking through the basics about audio and video with an emphasis on the digital kinds. There is also a matching wiki page with transcripts and references for digging deeper.
I learned quite a bit by watching it, even though it barely scratches the surface. The parent page states that more videos are coming (this video was released in September, 2010) and I know that I'm looking forward to more!