Video Thumbnails on Fedora XFCE

tl;dr version: it seems that the gstreamer-ffmpeg package is required for Thunar (or tumblerd, specifically) to render thumbnails of video files on the XFCE desktop for Fedora 16. This package is provided by RPM Fusion yum repository (rpmfusion-free-updates specifically).

It seems to be pretty hard to find this information online. None of my Fedora XFCE systems were able to render thumbnails of videos, and this caused me some headaches with removable drives (when I'd be done with the drive and want to unmount it, I wouldn't be able to because "the device is still busy"... and lsof /media/Cyro would show that tumblerd was the culprit... it was trying to render thumbnails of any video files I may have seen while browsing in Thunar and wasn't having much luck with it).

The usual set of packages that provide all the video codecs for me didn't do the job (vlc, smplayer, gstreamer-plugins-{good,bad,ugly}), I even tried installing ffmpegthumbnailer and no luck. Finally I installed gstreamer-ffmpeg, and after doing a killall thumblerd and then visiting a folder full of videos in Thunar, it finally worked and started making thumbnails.