Opinion: videowall processors vs controllers

The distinction between these two functions sometimes gets lost, but is worth remembering, says Tim Griffin, founder and CTO of Userful.

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Historically, there has been an explicit distinction between a videowall processor and a videowall controller, and the role each plays within a videowall system. Nowadays it seems that the line between these two components has been blurred to the point that they are being used interchangeably. Technology advancements have made it possible for the processor and controller functions to be integrated within the same device, but it is still helpful to understand and discuss these two functions separately.

Videowall processors (or video processors) are advanced signal routers that that take several inputs and create or composite them together into a single image, which can then be output to a grid of synchronised displays (aka a videowall). Videowall controllers, on the other hand, enable the output to multiple displays and allow those displays to be controlled and coordinated in interesting ways: for example, providing additional control over the content, layout and configuration of the videowall. Thought of simplistically, the processor processes the video content, and the controller controls the displays in the videowall. For the most advanced use cases you need both sets of functionality.

Processor approaches

To better understand the difference between them, let’s look at the approaches to videowall processors out there. First, there are some fixed solutions that use proprietary hardware, with one input and a fixed number of outputs. These ‘black boxes’ usually come pre-configured for a specific use case, and though reliable and easy to set up, have limited future expansion possibilities.

Then there is the video card approach, which uses a standard PC with added specialised video cards. This approach gives more flexibility, but can still be limiting when it comes to expansion, and of course the number of PCI slots in the PC may restrict the number of cards (and thus inputs and outputs) that the system can support.

Finally, there is the network-based approach – or AV-over-IP – that leverages the Ethernet infrastructure and standard PCs to both create and capture the content, process it, and deliver it to the videowall displays. The number of inputs and outputs it is only limited by the network’s bandwidth and the power of the PC. This approach offers more scalability and flexibility than the other two approaches.

Control considerations

It is also worth thinking about the level of control you will need coming from the ‘controller’ side of your videowall solution. The ‘black box’ approach generally comes with very limited control capabilities, typically just scaling the one source onto the fixed number of outputs (these are often called tile matrix scalers); whereas the software-based solutions are able to provide a richer set of control features. You will definitely want a full videowall controller for more complex applications (control rooms, live events, high-end digital signage). Be aware that if you choose the ‘PC with extra video cards’ approach, you will likely find yourself in trouble when attempting to add controller features, as it is often the case that controller software is very specific about the supported hardware, which can be very limiting.

Videowall controllers enable users to adjust the content layout, switch which content is playing where on the videowall, and even perform the more advanced task of sectioning the videowall into zones (or windows) with multiple content simultaneously. Some videowall controllers even offer interactive capabilities to videowalls: from supporting interactive content, such as desktop environments and web browsers, to having added control of the videowalls from external devices, like smartphones and tablets.

A great feature of some software-based solutions, including Userful, is the capability of interconnecting with a wide range of external devices, via APIs, to provide a more engaging and interactive experience to the audience. APIs are now ushering videowalls into the phenomenon of the Internet Of Things. For example, a set of external sensors, such as presence or face detection, can be ‘connected’ to a videowall controller so that when somebody walks by, or stands in front of the videowall, they automatically trigger a change in the content or layout displayed.

The added flexibility of software-based videowall controller solutions allows them to be up to date with the rapid pace of technological change, without having to incur another big investment. Ultimately, this contributes significantly to videowalls’ return on investment.

What is the Difference Between Video Matrix Switcher and Videowall Processor?

The video matrix switcher can switch multiple signals from the input channel to any one of the output channels that are independent of each other, and can switch a variety of high-resolution video signals to various display terminals, such as NTSC standard and PAL standard. The videowall processor is a high-tech device that divides a complete image signal into several blocks and distributes them to several video display units. It is a large-screen dynamic image display screen composed of multiple ordinary video units, which can support the simultaneous connection of multiple video devices.

1. Video matrix switcher and videowall processor work differently

A video matrix switcher is a device that switches and outputs multiple video input signals to multiple display devices. Generally speaking, the number of input terminals is greater than the number of output terminals. For example, if we want to monitor the signals transmitted by 100 cameras on 10 monitors at the same time, we can use the video matrix switcher to switch. The video matrix switcher can be divided into HDMI matrix, DVI matrix, VGA matrix, AV matrix according to the signal format. Videowall processor divides a complete image signal into several blocks and distributes them to several video display units (such as rear projection unit) to compose a large-screen dynamic image display screen with multiple ordinary video units while multiple signal formats can also be processed simultaneously.

2. Display mode of video matrix switcher and videowall processor

The video matrix switcher can only display the transmitted video signal on the monitor intact, but the number of displayed windows can be adjusted according to the needs. However the videowall processor provides a variety of display modes, which can realize window roaming, signals overlapping, zoom, picture-out-picture tiling, picture-in-picture, window perspective and other functions, and preset multiple modes, as well as pre-layout modes.

3. Image processing of video matrix switcher and videowall processor

Strictly speaking, a video matrix switcher can only be regarded as a signal transmission device, which plays the role of transmitting signals. Although the signal quality delivered by different types of video matrix switcher is different, these are caused by hardware configuration limitations. Videowall processor plays more of a role in controlling and processing signals. It can not only divide signals, but also adjust images, such as color correction, high-definition digital signal processing, image docking and fine-tuning, etc.

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