David wants to know if a streaming movie in Netflix would have to download all over again each time he'd rewind to rewatch a scene. Leo says that it depends, but if he's just rewinding to see a scene that he just saw, it won't have to redownload that. Netflix does cache the movie as it plays, but if he wants to go to completely different part of the video, it will probably have to download that part again.
If David wants to jump right to the end of something, it won't need to download the entire video for him to do that. Most video players including Netflix will just start downloading from the point that he selects.