It may happen to you that you were watching a video and suddenly the screensaver runs due to idle time period runs out and the screensaver gets started, in such a case you might not want to disable the screensaver. But it really annoys when it run in between when you are watching a video or movie.
Cyber-D Antiscreensaver allows you to specify the windows in which you may be watching a video or movie and it prevents the screensaver from running until that window is opened and focussed.
Here is how you can disable screensaver from running when specific windows are opened with this program.
Click the add button on the application interface and then type the window title as shown in the image below.
Click ok and you are done, now this little program will prevent starting of screensaver in between when you are watching a movie.