In video editing, it is sometimes necessary to add frames to the video to achieve the effect of slow playback. The optical flow method that comes with PR is simple, convenient and easy to use.

However, when the screen is switched, the screen will tear. At this time, because the optical flow method calculates the intermediate frame by comparing the two frames before and after and by algorithm operation. However, the gap between the two frames is too big when the lens is switched, and the algorithm can't be calculated. At this time, the picture will tear. Find some distorted pictures and cut them out. Then use frame sampling, or frame mixing processing, so that there will be no picture tearing. In addition, the optical flow method is not suitable for videos with fast picture changes. The effect is very poor, you can try other frame repair methods.