When clicking an icon/thumbnail of a video clip in the medialibrary, we could perhaps temporarily swap the icon/thumbnail by a preview of the video (without sound). This would complement the "full preview on double-click" feature to make it easier to choose a clip, without requiring the user to interrupt his workflow.

We need to check if that is indeed possible with gtk cells.

Of course, this feature would need to be ultra robust, decoupled and guaranteed not to be able to take down the UI or the rest of the app. It must also not cause performance/resources problems.