Video playback method

A video playback method, comprising:

• providing an original video, wherein the original video is obtained by using a camera module to shoot a scene;
• providing, by a user, a playback time length to determine a time length of a synthesis video, wherein the time length of the synthesis video is less than a time length of the original video;
• extracting at least one object path from the original video;
• adjusting the at least one object path selectively to synthesize the at least one object path to the synthesis video;
• calculating a suggested time length according to crowdedness of the at least one object path at different pixels in a scene;
• providing the suggested time length to a user to assist the user in deciding the playback time length;
• generating a crowdedness map according to the original video to describe crowdedness values of the at least one object path at different pixels;
• calculating with an equation
• F
• n
• =
• ⌈
• C
• m
• C
• th
• ⌉
• ,
• wherein Fn indicates a suggested number of frames, Cm indicates an associated value of the crowdedness values, and Cth indicates a threshold value;
• and
• calculating with an equation
• T
• p
• =
• ⌈
• F
• n
• R
• f
• ⌉
• ,
• wherein Tp indicates the suggested time length, and Rf indicates a frame rate of the synthesis video,
• wherein the associated value Cm is an average value of the crowdedness values of all pixels in the crowdedness map, and the threshold value Cth is greater than 0 and less than the associated value Cm;
• or the associated value Cm is an average value of a range which is top 10% to top 50% of the crowdedness values of the crowdedness map.