Standardizing AoIP is Enabling Interoperability

LOS ANGELES—Broadcast mixing console manufacturers began implementing Audio-over-Internet Protocol transports over a decade ago, but with no standards in place, one brand was typically unable to network with another. That is now changing, and with the advanced capabilities and broader implementation of newer protocols, plus the publication of the AES67-2013 standard late last year, true interoperability could soon be a reality.

Of course, there has been a standardized digital audio transport available since 1991: AES10, otherwise known as MADI. Patrick Warrington, technical director for U.K.-based Calrec Audio says that MADI continues to serve the industry well, but the industry can expect to see AoIP interconnections providing a more flexible and elegant replacement in the near future. “AoIP offers greater capacity, flexibility, and multicast possibilities, all on an infrastructure shared with other services,” he said.

Wheatstone’s new Dimension 3 console offers the company’s network access to audio in all major formats: HD/SDI, AES, MADI, AoIP, analog or TDM. At the 2014 NAB Show, Calrec announced the development of an Audinate Dante interface for its proprietary Hydra2 digital audio network; that card will be launched at the IBC Show in September. Supporting Dante, probably the most widely adopted digital media networking technology currently, will further expand the pool of products with which Calrec can interoperate. The company also announced the adoption of ALC NetworX’s Ravenna IP-based audio and media networking technology at the most recent NAB Show.

“ALC NetworX’s involvement in drafting AES67 means Ravenna interfaces will be directly compatible with other AES67- compatible equipment,” Warrington said. “Ravenna, with its open technology approach and scalable performance capabilities, is a perfect way to implement a powerful and flexible gateway between Hydra2’s unsurpassed performance and AES67’s broader connectivity.”

Solid State Logic selected Dante as its third party protocol of choice, but only in its Network I/O range of products. “It was important that any protocol could be deployed on our clients’ existing standard network infrastructure and share the infrastructure with standard network traffic,” said Dan Duffell, head of marketing for the Oxford, U.K.-based developer of professional audio consoles.

Audinate’s involvement and commitment to potential future standards including AVB and AES67 also encouraged SSL to implement that particular protocol, Duffell added. Audinate has announced that it will provide a Dante firmware upgrade to AES67 by the end of this year.

But as Duffell also pointed out, “The availability of over 350 [Dante-enabled] products from 150 manufacturers means interoperable systems can be built today. For our customers, the ability to build systems from many devices that can all ‘talk’ to each other allows them to pick products for specific tasks based on the merit of that unit alone, not based on a previous purchasing decision.”

Andreas Hilmer, director of marketing for Lawo in Rastatt, Germany, said the company supports Ravenna because open protocols help guarantee broadcasters’ long-term investments. “With a proprietary solution our customers would be depending on a specific supplier or licensor,” he said.

As an established standard, AES67 will enable Lawo to provide customers with solutions that are open for integration with third-party products and for future developments, said Hilmer. “We also think that the standardization by the AES will further increase the acceptance of audioover- IP solutions and make it without a doubt the audio transport format of the future, just like AES3 and AES10/MADI are today.”

At the 2014 NAB Show, SSL demonstrated AoIP networking via its new network I/O broadcast audio interface range. “AES67 is really a subset of all the proprietary protocols out there,” commented Phil Owens, head of eastern U.S. sales for Wheatstone Corp. in New Bern, N.C. That includes the proprietary Wheatnet-IP, which supports AES67 in the latest product release, as well as Ravenna, Livewire, Dante, and other protocols.

“As such it provides for the inclusion of non-Wheatstone devices in our system environment. This open-ended capability may prove to be useful, depending on the number of manufacturers that choose to support it.”

However, said Owens, “It will probably be quite a while before building a system using the ‘a la carte’ approach—one from company A, one from company B—will be able to compete with a fully integrated system from one manufacturer.”

Indeed, there appear to be some technical stumbling blocks to a more rapid and widespread adoption of AES67. “In our view, plugging in an RJ-45 [cable] should be to AoIP as plugging in an XLR is to AES3,” said John Davis, technical support manager for Logitek Electronic Systems in Houston. But, he noted, “Even after the question of whether AES67 will violate one company’s patent is resolved, it doesn’t go far enough.”

Lawo’s mc256 audio console offers Ravenna AoIP networking. AES67 falls short in a few areas, according to Davis. “In order for AoIP systems to truly be interoperable they must do three things: rate-lock the machines, announce the names and addresses of the streams, and provide for some kind of machine control,” he said. “AES67 is a good start in that it provides for a common timing method to rate-lock everything on the network, but it does not announce the streams or provide a common control protocol.”

Owens from Wheatstone, too, observed that AES67 does not provide discovery or control. That said, “We chose to implement AES67 compatibility for users that wanted to bring in audio from AES67-enabled devices,” he said.

When Wheatstone-IP was launched in 2008 it offered capabilities beyond any third-party schemes, said Owens. “Wheatnet-IP allows for audio transport, device discovery, and device control over the network,” he said. “It allows us to integrate the extensive features of our various devices into one environment with full control and configurability through one interface. With Wheatnet-IP, users interact with the system as a whole, rather than just individual devices.”

When Logitek introduced JetNet, which uses proprietary methods of timing, control, and stream annunciation, there were no third-party protocols with those features available that weren’t patented, according to Davis. “Therefore we came up with our own method of ratelocking the units together, sending control information, and telling the machines the names and addresses of the streams while following the RTP over UDP standards.”

But Logitek will soon plunge into the interoperability pool, having licensed the Livewire protocol, Davis reported. “We plan to have our products able to communicate using both JetNet and Livewire on the same network within the next few months. We also have the capability to add other protocols as necessary.”

AES standards are by no means static and are often be subject to later revision. “We believe that the format will evolve over time to include compatibility with other standards that address the control and discovery issues, and we’’ll be involved with that as well,” said Owens. “It may be that one day someone will produce a really cool device that speaks AES67. When that day comes we’ll be ready for it.”

Steve Harvey began writing for Pro Sound News and Surround Professional in 2000 and is currently senior content producer for Mix and a contributor to TV Tech. He has worked in the pro audio industry—as a touring musician, in live production, installed sound, and equipment sales and marketing—since November 1980.