"I'm suffering from Windows exhaustion and am considering a switch to Linux, but I do a lot of video processing and I would like to know if this is possible in Linux and just how much is possible. Thanks for any help."
A lot is possible, actually. There are several good linux video packages around. Do a bit of googling and you will find them. My suggestion: choose a major distro, install every single package there is in the install cd's so you don't have to deal with dependencies very much in the begining. Please notice that you are migrating from one OS to another, and a learning curve wlll be there; waiting for you. Be patient. Linux is worth.
This sticky thread is a list of apps for linux. Take a look. Its in a brazilian linux website, in portuguese, but its quite easy to understand, the list is self-explanatory.