DFMirage

DFMirage is "cutting edge" video driver mirroring technology for the Windows NT OS family. It is a driver for a virtual video device managed at the DDML level of the graphics system that exactly mirrors the drawing operations of one or more physical display devices. A detailed explanation of how a mirroring video driver works may be found in the Windows DDK. Display mirroring technology is widely employed by remote desktop applications such as: NetMeeting, PC Anywhere, VNC, Webex, etc. Mirroring is a technically superior method when compared to primitive screen grabbing, because it allows the capture of only the minimally updated regions and retrieves the data directly, bypassing the intermediate copy. Using the DFMirage video hook driver solves the problem of reliably and efficiently detecting modified areas on the screen. This driver may be used transparently with office, CAD and other types of business and utility applications. An example is the open-source TightVNC application which uses the DFMirage driver with great success.