I changed the visualization option in a working Movie Player from GOOM to one of the options using libvisual. Now the program automatically freezes whenever it is opened, the preferences menu cannot be reached, and must be Force Quit-ed to close.
I have a feeling it won't work again until the visualization setting is reset. However, "sudo apt-get purge totem" followed by "apt-get install totem" does not work! The viewer window is still black and the program freezes when it is opened.
Additional context: I initially was looking at the visualization menu because I wanted to install projectm http://projectm.sourceforge.net/ (Milkdrop for Linux) and did "sudo apt-get install libvisual-projectm". However, it did not appear in the menu, and I selected one of the existing included libvisual plugins instead. So the projectm problem is probably an unrelated bug.