Here are some thought about the main categories when listing FLOSS projects related to video.
We can either categorize them by their type (GUI/CLI/ softwares libraries for developers), or by their features in the workflow (Editing, compositing, modeling, …). But with the latter we could have software (like Blender) overlapping too much (even with photography).
Apart from sofware, and as @dav suggest, we can also list entry points in the libre video nebula, list libre video organizations (powering most of the global video infrastructure BTW), and also principles such as http://ethiccinema.org/.