Videowalls are sexy! Any individual who has ever witnessed a single image stretched across multiple display screens will agree. Videowall technologies are growing in popularity and most modern-day retail spaces have at least one videowall to show off to the public.
There are many ways to display a single image across multiple screens but in order to get true videowall functionality, a video processor needs to manage the various inputs and content displayed simultaneously on the larger display area. To AV professionals without deep expertise in videowall technology, the idea of a videowall is a huge mountain of information which most choose to avoid. It seems like too intricate a system to even start understanding. But in reality, videowall basics are pretty straightforward. Essentially there are only two components to a basic videowall: the display hardware and the video source content to be shown. In order to create a videowall, the hardware element requires multiple relevant display screens, with ultra-narrow bezels, installed in a specific array. The most common configuration is a four screen set-up in a ‘2x2’ arrangement. This indicates an extended display area with a width of two screens and a height of two screens. Other basic configurations include 3x3, 4x4, or even bigger arrays. However, the bigger the video wall, the more pixelated the image will appear. These type of arrays are typically used in large scale venues with greater than normal viewing distances, meaning that the viewer is not very close to the display surface and pixelation detail will not be noticeable.
When designing a basic videowall displaying a single image, it is important to keep the height and the width of the display area in equal proportions to ensure that any image displayed maintains the correct aspect ratio. The ‘aspect ratio’ is an undefined value pertaining to the shape (ratio of width to height) of any display. There are various different aspect ratio standards globally but the most common is 16:9, used for HD video and also the standard in which LCD screens are manufactured. Should a single-image video wall design include more screens in width than in height, or vice versa, it will result in video images appearing out of shape.
In order to display one image across multiple screens, a simple set-up is required. This can be done without the use of a videowall processor if the correct screens are used. Almost all display screens manufactured for videowalls (with ultra-narrow bezels) have a software feature built into the standard menu structure that allows the configurator to set up image sharing or tiling. This feature allocates identities to each screen forming part of the combined set-up as well as its location within the overall configuration. One complete video image is then distributed to each screen either through a ‘daisy chain’ set-up or ‘star’ formation distribution system. Each individual screen will only display the section of the incoming image, based on its identity in the tiling set-up. The user however will experience an impressive giant image displayed across multiple screens – processor free.
Not all videowalls are this basic. More often than not, large display areas are created with custom aspect ratios to service numerous users or viewers simultaneously. In layman’s terms, many operators would view one massive videowall but each individual will only be focusing on a selection relevant to their own contribution. They will be able to view other areas of the wall should an event in another window require their attention. The specific window could then be enlarged across the entire wall, or duplicated in multiple windows for all users to view. In a solution such as this one, it is important to display multiple different sources on the same videowall. For this functionality, a videowall processor is required to manage the incoming signals as well as the extended display area. Custom solutions will require systems to be uniquely pre-configured in order to complement a client’s needs. Many videowall configurations will thus be different from each other.
The videowall processor itself has subcomponents, the most important being the chassis and processing power. Different size frames are chosen to accommodate system requirements. Frame selection is based on processing capacity and slot availability which is to be populated with input and output cards. Many frames can be selected with dual power-supply units and dual hard drives for redundancy in mission critical solutions where unplanned downtime could have catastrophic results. These redundancy components are hot-swappable and can be replaced without interrupting system operation. The next two components are the input and output cards, which are required to capture the source video and supply the correct graphics to the display screens. A range of input cards are available to capture various video formats such as HDMI, 3G-SDI and compressed video streams from TCP/IP systems. Output cards are mostly standard but capable of transmitting both digital and analogue signals to the videowall.
The final component is the wall control software. The videowall software empowers the user to create multiple windows, each displaying an individual source, anywhere and in any size on the entire video wall display area, independent from one another. Videowalls can be used for many custom requirements – from digital signage applications and retail spaces to information centres. The software component is also designed to allow input signal manipulation and it is possible to rotate, flip and custom-crop input signals to display an attractive out-of-the-ordinary display solution intended to catch the eye. Albeit not necessary, external touch-panel control systems are popular to control videowall functionality. Bigger touch panels allow for sufficient real estate to display a graphical layout of the videowall itself and the available input sources and provides a user-friendly dashboard from where the entire videowall layout can be controlled without having to access the configuration software.
A final, but very important part of the videowall installation is the use of a professional manufacturer for the mounting frame. The architecture of videowalls is symmetrical, with multiple square components and careful design and precision installation practice is essential for a pristine appearance. The screens need to be mounted against each other with a micro ventilation space between each screen bezel. The display surface of each screen should be perfectly aligned with the adjacent screens in the wall to provide a flush overall finish. If any of these elements stray from the symphony of exact displays, it will accentuate the imperfection and make the entire videowall appear untidy.
In a nutshell, videowalls are simple. The processor is the palette. The video wall is the canvas. The configurator is the artist.
