How to capture still image from a live video programatically

Question

When i try to take a screenshot of my desktop I found the area of the Windows Media Player window was empty, nothing in it, I google for it for a while and found that most of video players user Overlay surfaces for performance, and overlay surfaces can not be caputured, so some ideas come out said to disable the DDraw accelaration so that you can grap an still image from a live video, but when the player was launched, it's already use the hardware accelaration, even i disable hardware accelaration, it will not take effect until i relaunch the player, my question is: how to capture a image from a live video without diasble the ddraw accelaration? or how to make the settings(disable hardware accelaration) work work without relaunch the video player?

• I won't play the vedio with my program, i just want to take a still image while it is played by a 3rd party player such as Windows Media Player or Real player etc...
• I want to do this programatically, say by C/C++ and DirectX, so I don't want to use any exsisting software or tools
• No matter which player in use, my program should capture it, I know some tool can do this like CapTrue and tencent qq, so i think it is possible to do so.

Answer 1

AFAIK, this is an intentional "feature" in WMP, for protection. If you need to have WMP, then you need a decent screengrabber. Unfortunately, the ones I know like hypersnap are not free.

If you only want a screengrab of a frame, VLC is your friend, like @zdd said.

Answer 2

A workaround can be to use vlc to play your file. It gives a screenshot option in it directly.