This is a common question, but there is no screen capture program for Spout. One solution that people have had success with is to install NDI Tools and try the “Scan converter” application to capture the window you want. Test with the NDI “Video Monitor” application. If that works, you can then use Spout to NDI to convert the NDI stream to Spout. The freeframe plugins will work with Resolume or you can use the “NDI to Spout” utility for other programs.