The phrase “AV over IP” is thrown around a lot. But what does it really mean in commercial AV installations today? Put simply, AV over IP is about sending uncompressed audio and video information over standard IP mediums. Put a little bit more complexly, it can also mean encoding the sources and streaming the content with some compression to mitigate bitrate over IP mediums. But ultimately, it means providing extension and switching of video and audio sources over standard IP.
That means inputs and outputs anywhere and everywhere, in a formerly confined signal path world. “Sources can be ‘any’ and ‘many,’ including desktop PC outputs, video cameras, media players, satellite/cable boxes, etc.,” explained Samuel Recine, director of sales for the Americas and Asia Pacific at Matrox Graphics. “And destinations can be ‘any’ and ‘many,’ including receiver boxes connected directly to televisions in huddle rooms or public spaces, video wall controllers in control rooms, laptops or PCs decoding and displaying the source streams, or even purely software-based decoding and displaying on handheld devices like smartphones or tablets.”
“The beauty of IP is there are many ways to achieve the goal.” That’s how Paul Harris, CEO of Aurora Multimedia put it. Finally, the AV industry has found the next best method to distribute audio and video, and it actually works for us. “IP offers a standardized infrastructure, but until recently, the methods of delivery over the infrastructure could not accommodate the full range of customer requirements,” he said. Now though, the application will determine the allowable image quality, bandwidth, and latency. “For low bandwidth, H.265 answers the call, but with a penalty of latency and image quality due to high levels of compression. If more bandwidth is available, there are low-latency, visually lossless compressions like JPEG 2000, TICO, and a few others to delivery higher quality images at a lower latency. When bandwidth is not an issue and having no latency with no compression is important (broadcast, videoconferencing, etc.), this can now be achieved on a 10G network topology.”
But it’s not just about connecting some CatX cables and calling it done. You still need to look out for technologies that use CatX cables to transmit AV information, but via proprietary hardware and/or proprietary switching (like HDBaseT, for example.) These has limits where real-deal AV over IP “is effectively limitless in its ability to be multicast and sent over LAN, WAN, Internet, wireless and so forth,” emphasized Matrox’s Recine.
Even if it can go anywhere, it has to pack its bags. When standard IP mediums and standard IP protocol transmission are used, audiovisual information can travel as freely as computer data, with all of the same management tools, permissions for stream access, and security protocols. But, Recine notes, “Most vendors using standard IP mediums apply some form of compression to the source audiovisual information so that the use of data networks can be properly leveraged. This includes being able to send audiovisual sources using wireless transmission over Wi-Fi routers to things like smartphones and tablets.”
But AV over IP packs light, so it travels faster. If you’re not hung up on compression, and you’re willing to trade in the unbridled bandwidth of a dedicated signal, then please enjoy the freedom offered by the “virtual signal paths” provided by AV over IP solutions, which remove distance limitations and allow full HD video capabilities with minimal latency. “Unlike traditional distribution methods, AV over IP solutions have the ability to deliver dynamic and real-time content, creating more engagement and lower cost of ownership for customers,” enthused Chris Bundy, Core Brands Marketing Manager, Control Brands, adding that this provides a certain amount of future proofing. “IP is the optimal means of signal distribution in a commercial environment, and ultimately where all AV distribution is headed.”
So it depends on whether you’re willing to put up with compression or not. You can use video-specific infrastructures like HDBaseT or HDMI, which are designed to handle these high bandwidths and do not compress video. Or you can go the distance with lower-latency AV over IP, and in that case, said Rob Carter, technology manager for DigitalMedia at Crestron, “Understanding which compression technologies are used and their relative tradeoffs is critical to a successful design.” The two main compression technologies in the Pro AV space are H.264 and JPEG 2000. Both can result in a high-quality image, but H.264 optimizes for bandwidth while JPEG 2000 optimizes for latency (i.e., processing delay time).
Low-bandwidth H.264 streams play nicely in most network environments, allowing many streams per link and the ability to interoperate on corporate networks. For instance, most web-based video uses H.264 compression. It’s also commonly used by streaming cameras and mobile devices, and H.264 streaming solutions in the Pro AV market can frequently interoperate with these devices. The cost is in latency, which can easily add up to half a second of delay in the video stream. This make H.264 great for long-haul applications and overflow rooms, but not appropriate for in-room extension where mouse and keyboard lag can becomes jarring.
JPEG 2000 solutions are much higher bandwidth, practically saturating a 1Gb Ethernet link. As a result they generally require dedicated network cabling per run, similar to standard uncompressed technologies like HDMI and HDBaseT. The upside to JPEG 2000 is that it is lower latency than H.264, resulting in less video delay. However, the latency is still higher than uncompressed solutions, so extra care must be taken to ensure a positive user experience for the in-room applications.
Latency is additive, so ensure you take into account delays introduced by other devices like display scalers and video conferencing systems. Also keep audio/video synchronization in mind: humans are very sensitive to video delays with respect to audio, and if you are using a separate audio distribution system even small amounts of video latency can quickly become problematic.
If you’re talking about audio, check your definitions.“There is an important difference between Audio over IP (AoIP) and Audio over Ethernet (AoE), and people all too often use synonymously,” explained Amanda Roe, global public relations and research manager at Biamp. She provided a helpful primer on the distinctions. AoIP is a technology category for moving compressed audio over the Internet, most commonly used by broadcasters and services like Spotify and Pandora. It is not practical for professional AV needs, because its use of dedicated codecs for data compression and a subsequent requirement for multiple global hops increase latency significantly. Meanwhile, AoE is a technology category for moving uncompressed audio across an Ethernet network. Latency here is not an issue, as AoE generally resides within a LAN. AoE Bonus: “Because networked AV signals are packets just like other network traffic they are not as susceptible to interference on the line caused by the proximity of power or other high-frequency cables,” Roe added, “and they can be sent anywhere in a building where there is network connectivity without the need to install special cabling or switching hardware.”
With so many variations, what questions should be asked before selecting AV over IP technology? “Before selecting products, it’s best to understand the scale, scope and expected performance levels from the end user,” asserted Joe da Silva, director of product marketing for Extron. “By knowing these details early on, resellers and consultants will be better equipped to understand if they should select a product for use within a room or group of rooms, or if it will be used across the entire enterprise. Understanding the bandwidth requirements, desired image quality, and acceptable latency based on the application, all come together to define what product or group of products will help them achieve their system design goals.”
Then you can into the nitty gritty. Erik Indresovde, director of AV products at Black Box listed several considerations for product selection: How is administration and management handled? Does it come with a system for remote management? How easy is it to install? Does it require networking specialists or is there an easy way to set it up? Is it a solution meant to be used on a local area network or to send video over the Internet? What is the latency? Will I notice any difference from a conventional direct connection system? Is the solution 4K compatible? What type of audio, video, and peripheral signals are supported (e.g., HDMI, analog audio, RS-232, USB)? Does the system have video wall support?
Now you can consider yourself prepared for the future. “The Internet is not the hula-hoop of today—it’s not going away, and it isn’t shrinking,” observed Mark Armon, product manager for tvONE. “More and more users are becoming proficient in certain aspects of IT and therefore expectations of AV gear are increased to encompass things like interoperability, collaboration and instant access. The idea of ‘going to a specific conference room’ is in question. Why can’t we do the meeting right here? Why can’t I share my screen? Why can’t I connect? AV devices already live in IT racks and closets. The writing is on the wall, get on the network or get out of the IT rack. Obviously there is a gap between what a network can handle vs what AV needs. But this is temporary. In 10 years, the ‘smartphone generation’ will expect a level of connectivity, that is difficult to imagine in today’s world, but it is inevitable.”
