1.7.7. - video snapshot

Is there the possibility to see a snapshot of an uploaded video in the library list?

Unfortunately no. (20 characters)

Massimo_Rosciano brings up a good question though. You can get a preview of the video in the layout designer, it just looks like the feature was never carried over to the media library.

Also Massimo_Rosciano, in 1.8, still in Alpha as of right now, you do have the option to enable previews on videos in the media library.