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Meeting of minds: Where broadcast & AV collide

Just because similar types of equipment are used in different areas of technology does not make them the same. But, as Kevin Hilton discovers, more technologies now common in broadcasting are being adopted by the AV and installations market.

The broadcast and AV sectors are two markets divided by common technologies. Traditionally the most obvious similarities are in audio – microphones, headphones/headsets and loudspeakers – although broadcasting has very different requirements in the performance of these from those used for commercial installations, presentations and live sound. More audio crossover occurred during the pandemic, when broadcast-style mics were used in video conferencing, but the long-term and more significant influence from radio and TV on the installation market is more likely to be in communication links, interconnectivity and networking.

Audio over IP (AoIP) is increasingly the tech of choice as the backbone for network communications in both broadcasting and AV. Audinate’s Dante audio over Ethernet system, introduced in 2006, is possibly the most widely recognised and used AoIP format today, both for installations and broadcasting. Its roots were in live performance and installation work but the protocol was rapidly adopted by broadcast manufacturers for a wide variety of products, including mixing consoles, audio monitoring units, intercom and commentary systems.

Dante now straddles AV and broadcasting, as demonstrated by its presence this year at both the NAB (National Association of Broadcasters) Show and ISE 2022. Joshua Rush, chief marketing officer of Audinate, comments that it is “a very natural fit” for the company and its technology to be at both shows, partly because broadcasting is something that is no longer confined to television and radio. “Now so many businesses, schools and religious organisations have essentially become broadcasters of content — whether that’s internal communications, promotional messaging, education material or religious content — it was inevitable that broadcast ideas, practices and technologies would find their way into the AV realm,” he says.

Rush adds that secure, reliable networking is a “must-have” in broadcasting because the content can be of very high value, which means the consequences of “going dark” are “significant”. The same is now true in commercial and business AV, with conferences often more akin to a broadcast programme than merely a video call. In these situations the audio has to be of good quality so the participants can understand what is being said both and the overall corporate message.

“AoIP and networking are obviously driving huge advances in pro audio right now but we also think that video over IP will become a major issue for pro audio professionals,” Rush comments. “If you can run audio and video over the same network with the all of the connectivity, interoperability, performance and ease-of-use advantages offered by a system like Dante, then you enable the audio professional to do more, more easily. With video and audio on the same network, the audio professional can do sound on a concert and also offer the live web feeds that post-pandemic event producers are looking for.”

From the start, Rush explains, Dante was designed as a plug and play system that would be easy to use and could get wide-spread adoption. This found particular traction in the installation market, but also appealed to broadcasters and manufacturers of broadcast equipment. There was, however, still a requirement for more sophisticated networking features and functionality, which led, in 2010, to the appearance of RAVENNA as a competitor to Dante.

Conceived by Philipp Lawo, chief executive of audio console and video networking manufacturer Lawo, RAVENNA was developed under the auspices of ALC NetworX in conjunction with third party partners. Senior product manager Andreas Hildebrand explains that RAVENNA was initially aimed at “more complex projects” in broadcasting that were taking place at the time. “It’s horses for course,” he says. “RAVENNA is more complicated to set up but we are now seeing some AV installers with more demanding requirements that are along the lines of what we see in broadcasting.”

Dante has been the predominant AoIP system in pro AV. Among the major differences between it and RAVENNA is that the former was based on the first version of the method to synchronise devices on AoIP networks. The precision time protocol (PTP), developed by the IEEE (Institute of Electrical and Electronics Engineers) and launched in 2002, was designed to deliver timing for local computer networks that was more precise than existing NTP (network time protocol) technology and which could be applied in circumstances where GPS (global positioning system) was not viable on technical or financial grounds. PTP is based on the leader/follower principle, where a main device acts as the clock source for multiple devices on a network.

At the time Dante was developed, Audinate did not have an option in which version of PTP it used and so implemented v1. Because devices running on PTPv1, which are able to be carried through low cost, off-the-shelf switches, can be both leaders and followers, an external clock is not always necessary. By the time RAVENNA was under development, an updated PTP version had appeared (v2 in 2008). PTPv2 provided additional features with improved timing accuracy, plus transparent and boundary clock switches. (A transparent clock can gauge and adjust for variable latency as PTP packets pass through switches or routers; a boundary clock is similar to an edge point and implements a refreshed PTP time.)

Andreas Hildebrand comments that PTPv2 “can provide higher accuracy in more demanding  applications”. It is also used for AES67, the AoIP interoperability standard, published in 2013 after RAVENNA was introduced. “RAVENNA allows users to create profiles and AES67 can be another RAVENNA profile,” Hildebrand explains, “which makes it effectively natively compatible with AES67.” (Audinate has since added PTPv2 compatibility to ensure conformance with AES67.)

Among the AV installations RAVENNA has been deployed for is an opera house project that needed to incorporate rights management to enable multiple operators — including a host broadcaster and local sound mixing — to access the same sources without hindering each other. “The ability to assign individual access rights to the various streams across large sites is quite important,” says Hildebrand, who confirms there is “a merging” of pro AV and broadcast.

This, he observes, was happening anyway but was, like so many other things, accelerated during the pandemic. “More companies are becoming broadcasters,” Hildebrand says. “Some conference rooms are now more like broadcast studios and the content produced is more televisual. Pro AV is the bigger market now and there is also the question of network video. Networked audio is now extremely mature but the video side is very different. We’re seeing things coming in like SMPTE ST 2110, which is becoming successful in broadcast. What we need to watch is what happens with standards for video, as well as audio, in pro AV.”

There is the possibility that IP audio and video in the AV sector could be covered by standards already being used in the broadcast sector. Drawn up by SMPTE (Society of Motion Picture and Television Engineers), ST 2110 standardises professional media over managed IP networks, while ST 2022-6, the ratification of which in 2012 is regarded by the broadcast technology community as a key moment in the adoption of IP, specifies the transport of high bit rate media signals over IP networks.

ST 2110 is also being considered as a standard for IP in AV; audio transport is specified by ST 2110-30, which is based on AES67. There is, however, the feeling among some in the sector that ST 2110 is not quite right for AV and a more relevant standard should be developed. The contender for this is IPMX (IP Media Experience), which takes elements of ST 2110, ST 2059 (for synchronising video over IP networks), RTP (real-time transport protocol) and the various parts of NMOS (Networked Media Open Specifications). NMOS was developed by the Advanced Media Workflow Association (AMWA), which, like SMPTE, has primarily concentrated on technologies for broadcasting.

Chris Hollebone, marketing manager for digital audio workstation developer Merging Technologies, comments that IPMX is an open standard with some “slight differences” to what broadcasters have signed up to. At this stage, he adds, it is not clear which way the situation might go. Merging itself, while well established in music recording, broadcast and post-production, has been involved with AV and experiential audio for approximately the last five years. This includes museums, venues and theme parks but Hollebone says the company is also very involved with “total experiences”, such as virtual reality and dome/sphere operations, as seen at Expo 2020 in Dubai, which often employ hybrid networks.

Another broadcast-oriented company that is now looking at the possibilities of its technologies in AV is NewTek, which, since 2019, has been owned by 3D graphics and newsroom automation developer Vizrt. NewTek established itself with the TriCaster portable video production and live transmission system, launched in 2005. In 2015 it introduced the Network Device Interface (NDI), a royalty-free software specification for sending high quality, low latency video over gigabit Ethernet connections.

As Roberto Musso, senior product manager for NDI, comments, this technology became a de facto standard for live video connectivity in broadcasting when camera manufacturers, including Sony and Panasonic, began to support it. 

“During the pandemic there was a big acceleration of this technology because it can run over internet and virtualised environments,” he says. “It can do this because the video is compressed and easier to use over a gigabit connection than something like
ST 2110.”

This set-up does not require synchronisation, which Musso says also became an important feature over the last two years, particularly for live productions in the cloud. 

“It’s not possible to run PTP because there is no hardware there,” he explains. “It then became interesting for audio because NDI can manage multiple audio channels in a single stream, even without video. But while we can run a single stream in a single transmission with multiple channels and that will be synced, NDI is not able to sync different streams like Dante, which supports PTP.”

Virtual production studio with Absen displays

Musso says there is “an interest in NDI audio in the installation world, especially for the possibility to transport multi-channel audio in a single transmission where PTP is not needed.” One of the areas within AV that NewTek/Vizrt is looking at is digital signage, which now relies as much upon sound as it does video. 

“What we realised when we started to look at the display market was [the potential of] digital signage,” he comments. “You can combine video, multichannel audio and metadata. I would say that a big advantage for NDI is the free SDK [software developer kit] and we’re getting something like 2000 downloads per month. We know there is a huge company that produces video servers for events and they use NDI for the video distribution. So I am pretty sure the next step will be audio.”

Small steps are already being taken by technology from broadcast into the AV/installation sector. With the lines between the two continuing to blur, the big leap cannot be too far away. 

This year’s ISE certainly illustrated the overlaps, not just in black boxes on the show floor, but writ large on Absen’s stand (see page 34 for more on this), where it showcased its virtual production studio – proof positive not only of the increasing overlaps between broadcast and AV, but also just how effective immersive digital backdrops are in creating real-world environments where actors, in particular, can react to their almost-real surroundings, unlike the days of greenscreens. 

As Ewan McGregor opines during the filming of the new Obi-Wan Kenobi series for Disney+ in the May edition of Installation stablemate Total Film, when discussing the 90s Star Wars prequels: “I found it very hard to make those films. It was lots and lots of greenscreen and bluescreen… they were just so hard to make.” Those days are over, and as AV and broadcast continue to converge, audiences and programme makers are the ultimate beneficiaries.