“Video walls are large displays composed of multiple smaller screens, tightly arranged to create a coherent viewing surface. They require video display controllers to drive the screens to show multiple images or video and also to stretch images and video across multiple screens, including all screens. Video display controller inputs include cameras, recorders, computers, or media players. The video controller software manages the decoding, cropping or scaling and arrangement of these sources on the graphics outputs to achieve the desired display across the video wall, including contiguous image display across multiple screens. Modern graphics cards are powerful, with multi-channel outputs for driving displays, and so video display controller hardware is relatively straightforward and standard components can be used. However the key to optimum video display wall controller system performance, power, ease of use and integration flexibility all lies in the software. When used in video surveillance applications (for CCTV control rooms), a key parameter is video decode density. This is the number of IP video streams at a specific resolution which can be decoded simultaneously. Highly optimised software, like VIEWSPAN Nexus, will derive the absolute maximum performance from any standard hardware, with option VIEWSPAN hardware ranges available for specific types of application, from large high-density video walls to single-screen digital signage applications.”