Prediction and Motion Estimation
The prediction comes in when actually adding the motion estimation to both frames t and t+1.  Consider a video of a ninja cutting a melon in half, but shot at a very short shutter speed, so as to freeze motion in each frame.  The motion estimator notices that the sword is moving between frame t and frame t+1.  (It also moved between frame t-1 and t, and also frame t+1 to t+2).  Frame t gets half the motion from t-1 to t and half the motion from t to t+1.  The latter half is the prediction.  Frame t+1 gets half the motion from t to t+1 and half the motion from t+1 to t+2.  In this way, the video does not appear to shift half a frame later than the audio.