DarkCrystal HD Capture SDK Duo DarkCrystal HD Capture SDK Duo is a 1080p HD capture card which allows capture video from 2 HD sources and 2 SD sources simultaneously. It can be used for the most mission-critical applications while saving the precious PCI-E slot for other crucial needs. Moreover, it comes with a software development kit which has included the often used applications that helps developers or system Integrators to complete their tasks easily. Allows web broadcasters to provide more HD video content. With the help of SDK, the online TV broadcasters can stream the crystal-like video quality in most bandwidth-efficient way. Text or image overlay can also be done in few clicks.