Used with Video tracks, video clips let you animate the use of video files. 
         
         NoteYou can create Video tracks in both the Action and Edit timelines. 
            
         To create a video clip:
         
         
            - Drag a video file from the Asset browser or Scene browser into the Action Track list. 
- Drag the Video track containing the video clip into the Viewer window. 
               You can use the video as a background or video plane if you drag the track into empty space, or you can drop it on a model
                  to use it as a video texture. 
                NoteIf you are creating an Video track on the Edit timeline, you may need to expand the timeline to see anything other than the
                     first Shot track.