I am running an EC2 instance of Windows Server 2008 and need to capture video output of some running programs. My problem is that when I end the remote desktop session, the video is no longer sent in a way that allows for it to be captured by a running screen-capture process. Is there any way to force Windows to send video in a way that can be captured by software even if no RDP session is active?
There is a way, but you will have to use a different remote desktop than RDP. When a remote desktop connection is disconnected, the display that the programs use ceases to exist. Programs can still update, but there's no display for the OS to use to render the output. Therefore, there's nothing for a capture program to capture. The solution to this problem is to either (1) never log out of your RDP session or (2) use the console which always has a defined display. It's a similar problem to what this user is experiencing, although his program requires the use of the console. I don't know what screen capture program you are using.
In any case, since it's not possible to connect to the console via RDP on Server 2008, you will need to use a different remote desktop tool such as VNC. I tested with RealVNC on Server 2008 R2 and RealVNC Viewer on Windows 7 Pro and was able to successfully connect to the Server 2008 console. You might want to try those programs and see if you have success with your screen capture.
If you are performing automated testing, as the user in the question linked above was doing, you can set some VNC clients to "view only" and then use psexec to start your testing process. A simple batch file may be able to easily start your testing on one or more servers.