I noticed that some recent video uploads allow frames throughout the video to be previewed at the bottom of the screen with the slider while the video is playing normally. I have not been able to find out exactly what this feature is called.
Is this a feature that can be enabled by the viewer on any given video, or is it inherent to the upload itself? Could I add it to videos I have already uploaded? I think it would be more useful for longer videos where the viewer might want to watch a particular segment.