Totem never works right in my experience. My latest problem is that totem will not display some video Thumbnails. I fixed the problem by installing ffmpegthumbnailer and using this to generate thumbnails. But unfortunately it appears to have only fixed the problem within Nautilus. Shotwell, it seems, is still relying on Totem for its thumbnails because all the same videos that Totem wouldn't show Thumbnails for, Shotwell still won't either--even though Nautilus is now showing thumbnails for them because of ffmpegthumbnailer.
How do I get Shotwell to use ffmpegthumbnailer instead of Totem for video thumbnails?