AV Over IP: A Better Mousetrap?

The transition to digital AV has created some amazing products and technologies. But it has also complicated matters. Now, instead of using big cables and racks of switchers to transport video and computer display signals, we have digital display interfaces that are supposed to configure the right resolution, check to see if copy protection is required, and piggy−back control signals, power, and even Ethernet traffic.

What’s also changed is that the tail wags the dog now. By that, we mean that the world of consumer electronics largely dictates what we’ll be using in the world of commercial AV products. A good example? The High Definition Multimedia Interface (HDMI), which launched in 2002 and is now installed in over a billion devices worldwide.

HDMI, which was only designed to carry a signal from a DVD or Blu−ray player to a television, is now at the core of large, complex AV matrix switching products that include category wire extenders. There are even ways to convert the transition−minimized differential signaling (TMDS) format used by HDMI to packets for transmission over structured wire and optical fiber.

But is it wise in this day and age of “everything over IP” to bet the farm on a proprietary display/audio format that requires frequent updating, and in fact is in danger of being outrun by ultra−high resolution displays that will be fed with 10−bit and 12−bit high frame rate video content? Would it not be a smarter move to configure AV and control signals to travel over fast public and private IP networks, internal and external?

First of all, can it be done? The answer is an emphatic “yes!” and it’s already being done by telecom companies and cable, satellite, and terrestrial broadcast TV networks. A combination of lower prices on telecom and Internet switching gear, combined with lower−cost structured wire and inexpensive optical fiber with quick−crimp connectors is stimulating the installation of 1 Gigabit and 10 Gigabit networks.

Next, how is it done? By employing the universal language of codecs, like AVC H.264 and the new High Efficiency Video Codec (HEVC) H.265. Both codecs can compress video signals down to much smaller sizes, resulting in manageable streaming rates to accommodate the available network bandwidth. And if the latency introduced by these codecs is an issue, then a “zero” compression codec (JPEG2000) can be put to work to transmit full−bandwidth HD and even UHD video.

These compressed and non−compressed video and audio streams travel as packets, “wrapped” in a virtual envelope with Internet Protocol addressing to get them where they need to be. Watching and hearing an AV stream is as simple as dialing up its IP address, and the system has a huge capacity for expansion.

Now, we can do away with costly and complex proprietary matrix switches and employ garden−variety network switches to do the job. The only requirement is that these switches support Layer 3 of the Open Systems Interconnection (OSI) model. That means that any Layer 3 switch can be used to build or upgrade an AV−over−IP network, and connections to displays and other equipment require nothing more than a network interface card.

Okay, what about displays and other products that don’t use interface cards, but rely on standard display interfaces like HDMI, DisplayPort, and even DVI? Simple: You add a compact, inexpensive outboard network interface box or card to convert the signal from AV−over−IP to the correct display format. Need to update or change an interface? Simply swap out the box or card.

Now, all of your AV interconnects run through conventional network switches (which can be purchased from numerous companies) and you’re using just two types of wiring – category cable (preferably category 6 for faster speeds) and/or optical fiber – to connect everything in your network. You don’t need to worry about bandwidth limitations as long as your switch is fast enough and your cables are rated correctly. That’s future−proof reassurance.

Granted, you’ll need to bone up on some network and IP knowledge and terminology to design and implement an AV−over−IP system. But that will be time well spent, seeing as how the worlds of AV and IP gear are crossing paths much more frequently. And in installations where a company or institutional IT department has influence and/or control, AV−over−IP uses concepts that are very much in their comfort zone.

And let’s be pragmatic about this. The rest of the world has moved or is moving to the AV−over−IP model. Packetizing signals offers tremendous flexibility in multiplexing signals from a source to multiple destinations: You can multiplex video, audio, control, Ethernet traffic, and high−speed data traffic all in the same cable. Leave the standards and format wars to someone else for a change.

AV−over−IP: It’s here. Are you ready?


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