How to design an audio and video distribution infrastructure

Understand the methods that can be used to get audio and video signals where they need to go, helps determine the design of the AV infrastructure. s. Kyles Davis, Content Strategist at Harman Pro, explains in this article what are the ways to distribute AV signals: Proprietary AV hardware, a LAN and the existing enterprise network.

AV distribution is essentially the method used to carry audio and video signals from the source to the destination. Processing may stop halfway through, But the route you take to get there is distribution, AV infrastructure.

Just like a country's transport infrastructure, AV infrastructure is the complex set of paths used to connect everything. Those pathways can merge, dividing up and even offering multiple ways to get to the same place. and, as well as the transport infrastructure, determining the best method to carry AV signals is a highly political issue, Everyone seems to have an opinion about it.

Generally speaking, There are three main ways to distribute AV signals: Proprietary AV hardware, An isolated local area network (LAN) and the existing enterprise network.

These methods are not mutually exclusive. Rarely is a single distribution method chosen for the entire AV infrastructure, Nor will a single method be chosen for the transport infrastructure of an entire country. Understand the three main methods for getting audio and video signals where they need to go, will help determine the best method for designing the AV infrastructure.

Proprietary AV Hardware

The traditional method has its roots in analog AV distribution, where signals are sent over wire (Usually made of copper) From source to destination.

If multiple sources needed to be connected to multiple destinations, The solution required a matrix switch of some kind, A device with multiple inputs and multiple outputs that can be switched between them. This approach has extended to the digital realm, with standard and fiber category digital signals and cabling entering the solution.

However, Many of the rules are the same, and an AV device built specifically for this task is still required. For the video, and some integrated audio solutions, This means a digital media selector (Digital Media Switcher), such as the AMX Enova DGX series.

For some integrated audio solutions, This functionality could be combined with processing within a digital signal processor (Dsp), such as the BSS Soundweb London series. If there are more input signals than output signals, You can choose to use the local input and output ports of an audio mixer or audio card. Either way, the distribution method in all these cases is to use AV technology instead of standard network technology.

Distribution over IP in a separate network

Although with digital signs, the lines are somewhat blurry, the method I'm specifically referring to involves the use of standard IP network equipment.

With dedicated IP solutions, there's no need for a purpose-built AV device. Instead, Network selectors can be used (Network Switches), Routers, Etc. to create the AV infrastructure.

The way these solutions work, From a topology perspective, varies depending on Networked AV technology. In some cases, The distribution must be totally 'home run', meaning that distribution should only be done through a single switch with all AV devices connected to it. In other cases, Can traverse multiple switches in any standard network topology.

With the Harman Blu Link protocol, audio is distributed in a ring topology, without any switches or routers involved.

The way the distribution is implemented on the hardware also varies. Sometimes, network distribution is integrated into another AV device, with a designated networked AV port on the device (Harman's networked DSPs and amplifiers distribute audio in this way).

In other cases, a device may be specifically designed to put AV signals into the network (such as AMX SVSI encoders ) or take them off the grid (Decoders).

However, in these applications, the infrastructure remains a separate network from any existing IT network that can be used for Internet access, For example.

There are a number of reasons for this. In some cases, The requirement is a technical necessity. For example, Martin's LED video solutions use Martin's P3 protocol that leverages the Gigabit Ethernet standard, but uses a proprietary layer protocol 2 that allows for rapid distribution of video on standardized equipment. To achieve this without facing traffic problems, The protocol is not compatible with existing enterprise networks.

Another reason why a solution might require a separate network would be to avoid problems with the existing network. These can be limitations to available bandwidth or other issues with equipment already present. It could also be due to some discomfort on the part of the IT department to sharing the same network (Or it could be a bit of both).

Different AV Distribution Technologies Have Different Requirements and Limitations, and in some cases, you can choose to set up a network separate from your existing IT network, using both existing or new category wiring, depending on the installation.

Existing IT network

In some facilities, It is possible to distribute audio and video signals over a network that is already operational. This provides maximum range to the distribution of the VA, because there is not only an infrastructure in place thanks to which you can send the audio or video signal to any place where you want to send it today, rather, the connectivity is already present to send the signal wherever it wants to be sent in the future.

Of course, to make distribution over the existing network possible, Network requirements must be respected. Bandwidth can be particularly problematic, Especially for video distribution.

When using an existing network, even when running a virtual LAN (VLAN) to isolate network signals, You need to make sure that the network switch can handle the total bandwidth, both AV distribution and normal network traffic.

Making sure that the bandwidth of the video signal represents less than the maximum bandwidth of a gigabit switch is not enough. All video streams on the switch must be taken into account, as well as normal traffic. Network Technologies, such as multicast and IGMP snooping, They can help prevent the entire network from flooding, but you also have to consider normal IT traffic. That's why it's important to get feedback and buy-in from the IT department for a successful and manageable deployment.

The AV distribution method used will largely depend on the application in question. Physical Limitations, of the environment and even decisions from the management, influence the method to be chosen.

For example, you might have a conference room solution that connects local AV sources to a nearby display. Since there is a great deal of distance to consider, an AV selector can be used (I mean, Traditional Distribution).

While there are technologies that allow traditional distribution to be used over long distances, It's especially cost-effective when sources and outlets are close by. IP-based distribution can also be used, using a separate IT network. Which option you choose depends on the features you want.

Dedicated AV Selectors, like the AMX N7142 , They offer built-in capabilities that can be interesting, as a DSP, Amplification & Control.

For this example, we have chosen to use traditional switching for AV distribution in the room. However, If you want to display digital signage on the screen, When the space is not in use, Networked AV is a common choice for digital signage distribution as it has the advantage of being able to endlessly scale a solution, as long as the network can handle the traffic.

If networked AV is used for digital signage, a set-top box can be added to the conference room solution to bring digital signage over the already existing IT network.

Now we have a hybrid system. The digital signage video is sent over the existing computer network to the set-top box. The set-top box is connected to the AV selector and uses traditional AV distribution to transition from the set-top box to the display. In this case, multiple distribution methods are being used in the same application, leveraging the benefits of each for a more comprehensive overall application.

We could extend this scenario and include a whole host of new parameters that could make audio and video connect in different ways. But even though the design can become complex, have a good understanding of the basics, including the three main distribution options, It goes a long way in simplifying the options and making the task less intimidating.

s. Kyles Davis

Content Strategist Harman Professional Solutions (Distributor in Spain and Portugal AVIT Vision)
 

 

 

Other articles on AVIT Vision, Harman Group, Harman