Display-based video walls: building features
One of the main issues that must be solved when building a video wall is how will the distribution and management of video signals be carried out? Do I need to use a video wall controller or video server to create a video wall? In order to answer this question, you need to determine the method of building a video wall, the requirements for the characteristics and functionality of the video wall.
The simplest option is to use the controllers built into the displays. By connecting the display in a chain, you can build a video wall for solving simple tasks, namely, displaying a signal from a single source. This usually is enough for the objectives of advertising and the creation of a Bulletin Board. The resolution of the wall is equal to the resolution of the incoming signal. This option is the cheapest, as it does not require additional equipment.
External controllers and switches.
Often for presentations, you need to work with several signal sources, displaying them on the screen either alternately or simultaneously. This can be a speaker's laptop, several video cameras showing the audience from different angles, or other sources of video content that will be used during the presentation. In this case, you need a device that can connect and combine all these signals. The simplest solution here is a matrix switch. Typically, this device has the same number of inputs and outputs (usually HDMI) and can be configured 2x2, 4x4, 8x8, 9x9, 16x16, 32x32. The last two options are often based on a modular architecture. Modular switches have several advantages in addition to higher port capacity compared to fixed devices:
• using linear I / o cards, you can flexibly dial any ports: VGA, HDMI, DVI, SDI, HDBaseT
• improved fault tolerance: if one port fails, only the faulty line card can be replaced. There is a backup for power supplies and the ability to install additional fans to cool the device.
Using a matrix switch, you can output one signal to all the displays of the video wall, forming a large image, or use only part of it for a large image, and the rest for secondary information. This is usually used in video surveillance systems. For example, if you have a 3x3 video wall, a 2x2 wall segment displays a large signal from the camera that the operator is currently working with, and other displays display images from other cameras in multi – window mode. In the same scenario, you can organize presentations and video conferences when the main part of the wall is broadcasting the main content, and other Windows display additional information or images of other participants in the video conference.
Please note that when creating systems for presentations and video conferences, we recommend using seamless matrix switches (seamless). In this case, this means that there will be no black screen when switching from one signal source to another. Such pauses of 3-5 seconds are insignificant if it is a broadcast of commercials in the store, but they will be extremely annoying during presentations and especially video conferences, if there is a discussion with a frequent change of speaker. All these problems can be avoided by a seamless matrix switch with a built-in scaler. Switching between different signal sources will look like changing a scene in a movie.
Areas of application: video surveillance Systems, dispatching and situation centers, advertising, information boards, creating large screens in conference rooms, video Walls based on IP networks.
If you need to create a system of displays distributed across one or more rooms, you will inevitably face the problem of distance. A standard HDMI cable imposes a distance limit of about 15 meters for FullHD. In addition, it is very inconvenient to lay. Of course, you can use various extenders and signal amplifiers, or using an optical HDMI cable to get around these points, but this leads to a sharp increase in the budget, and adding devices to the system also reduces fault tolerance in General.
In this case, the best solution is based on the customer's IP network. As a rule, the local network is already on the site, which reduces the initial cost of creating the infrastructure. The solution itself is quite simple. It uses receivers and transmitters that convert the signal and transmit it to the network, as well as a network switch with IGMP snooping support. All management is done via the web interface.
The number of receivers is equal to the number of displays, and the number of transmitters is equal to the number of signal sources. Switching is performed via a Gigabit switch. At the same time, you can freely add displays and signal sources to the system. The number of displays can be quite large.
This solution is ideal for large systems covering hundreds of square meters, such as hotels, airports, railway and bus stations, shopping and exhibition centers.
Solutions for dispatch centers and situation centers
When creating video walls, the solutions offered for dispatching and situation centers stand out. A special feature of these objects is the need for high image quality, working with large video streams and multi-layered images. Matrix switches and video controllers can not provide such functionality as "picture in picture", "drag and drop", multi-layered and free arrangement of Windows on the video wall. This functionality is provided by video servers-powerful workstations with high performance in video processing and a large set of ports. Such devices are often designed for a specific task to get the optimal configuration.