I tried to capture Media Player or Real Player, Why do I grab only a blank, black screenshot?
The problem is usually due to graphics hardware acceleration being used to display the image. The newer media players from Microsoft and RealNetworks are good about trying to use any graphics hardware acceleration that is available on the system. Most video capture programs used to capture video from a video camera use “hardware overlay” by default for their video preview. Note that this kind of problem affects all screen capture programs, and even the image put in the clipboard by the PrintScreen key.