The new algorithm works by creating a "dictionary" to explain what it sees as it processes a video. Then, at every moment, it asks itself, "Can I explain what's happening now with my dictionary?" If the answer is no, that's an indication something new and exciting is happening in the video, so the algorithm makes note of that. The algorithm doesn't need to see the whole video before it starts putting together its highlight reel. That, along with coding techniques Zhao and Xing used, helps the algorithm work faster.