29.07.19

Audio networks: Pitched battle?

Audio networks

If two or more products provide the same service, can it be assumed that they are locked in competition? Steve Montgomery seeks the answer with regards to the options available for audio over IP in the shape of Dante, AVB, Milan and more. Additional reporting from Hurrairah bin Sohail.

Standards, formats and protocols have always been one of the tech industry’s favourite points of competition. A peek at the past throws up many examples, with VHS versus Betamax and Blu-ray versus HD-DVD being notable battles. Jump to the present and we find ourselves with a similar situation in the world of audio.

Audio has been distributed in packetised form over networks for many years. The two predominant formats, AVB and Dante, have provided integrators with the benefits of simplified wiring, transmission flexibility and convenience which comes with distributing audio content over local area networks. But are the two locked in cutthroat competition to the death or is the battle not as intense?

Of the two, Dante is currently more common and more widely supported by the industry. There are many technical differences between the two, but both seek to improve the reliability of transmitting media over data networks and foster compatibility between equipment from different vendors.

Joe Andrulis, executive vice president of corporate development at Biamp, explains: “AVB and Dante are both protocols for transmitting audio and now video over an IP network, so it is fair to say they are pursuing similar goals. I don’t know if I’d pitch one against the other but it is reasonable to compare them. They were born at different times with different initial priorities, although those seem to be converging now. One of the major distinctions lies in their licensing: Dante is a commercial offering while AVB is an industry-driven initiative.”

It is generally the responsibility of system designers and system integrators to select the solution most suited to their individual project. Andrulis continues: “To a degree, the customer must investigate the advantages and disadvantages of each system and make a choice for any given system. Someone transmitting media over a data network has to choose one or the other protocol and buy equipment that supports the selected protocol.

“Dante got off to an early lead that it still maintains today through its wonderful handling of network audio. AVB provided earlier support for both network audio and video and seems to slowly be gaining traction and more and more network switches support the protocols AVB depends on. Audinate has recently announced Dante support for network video so that gap with AVB may be closing.

“As far as integrators are concerned, they like protocols and equipment that makes it easier to economically and reliably deliver the systems their customers demand. That same can be said of equipment vendors like Biamp. We don’t advocate for specific protocols as much as we consider them tools to deliver needed capabilities. We select those that best meet customer and market demands.”

This means that manufacturers need to design products that are capable of operating with both networking technologies.

Andrulis says: “We try to avoid betting on outcomes of things that are out of our control like protocol adoption and instead stay closely attuned to buyer preferences. We’ll support the protocols our customers desire, including multiple protocols, if necessary. Today, we offer AVB, Dante, and AES67 options. We don’t want customers who want to buy Biamp products to feel they can’t because we don’t support the protocol on which they have standardised and built their customer solutions around.”

The recently introduced Dante AV Module supports one video channel and eight bi-directional channels of uncompressed Dante audio. It is suited to product manufacturers creating 1Gb video-over-IP products and includes Dante control, transport and synchronisation and is built using an architecture that is completely codec-agnostic, allowing manufacturers to use the codec of their choice. It was developed in response to market demand for integrated audio and video over IP technology.

Lee Ellison, CEO of Audinate, says: “Customers want us to bring the ‘V’ to AV. The Dante AV Module and the Dante AV Product Design Suite will enable manufacturers to quickly launch integrated audio and video products into market, with all of the benefits Dante has to offer.

With Dante AV, we’re taking everything we’ve learned from years in networked audio to the video world, and delivering on our vision of a truly integrated, easy to use and interoperable AV experience.”

The Dante AV Product Design Suite includes a JPEG2000 codec supporting 4K60 4:4:4 video for visually lossless results with low latency over a 1Gb network.

Dante AV Product Design Suite also implements HDCP (Highbandwidth Digital Content Protection) to prevent copying of digital audio and video content as it travels across connections.

The general adoption of these new technologies is likely to be affected by new AV-related developments. Particularly with Dante. Mark Murphy, a director of system integrator Vanguardia, believes: “Dante will be dominant for the near future, but others will catch up. Audio over IP will become the default solution. It is hard to predict how the introduction of Dante AV and its ability to carry video will dramatically change AVB adoption.”

Whilst AVB is regarded by many as a technically superior network technology, it is not a complete application solution. AVB devices have lacked application layer interoperability because there were no rules to enable implementation for features including stream formats, media clock sources, redundancy, and software control of the network.

Tim Boot, Avnu Alliance Pro AV segment chair, Meyer Sound, says: “It is a little like having all of the structural building blocks and technical requirements for easy multiway communication – but not speaking the same language.

Many alternative solutions available today have been knitted together using proprietary networking solutions, requiring extensive design, installation and support work from industry professionals and creating risky propositions that are not guaranteed for long-term viability. As the network has evolved and continues to scale, so has the opportunity for the industry. The network should not be a competitive market on its own or a bottleneck for innovation.”

Enter Milan. Henning Kaltheuner, head of market intelligence and strategic business development at d&b audiotechnik, says: “Milan is based on open IEEE standard AVB technology, which has been known for some years but for certain reasons never became widespread in the AV industry. A key obstacle for AVB was that it does not have a defined, truly end-to-end interoperable way to implement it. So far there were no agreed rules for stream formats, media clocking, redundancy and network control which could guarantee an ecosystem of interoperable products shared by the AV industry. While AVB is a superior network technology that offers very easy and fail safe connectivity, deterministic stream behaviour, data and media coexisting safely in one LAN with enhanced time precision, Milan adds the specification for implementing AVB in a truly interoperable way.”

Boot adds: “When it comes to networked audio platforms, the professional media industry has two major requirements. At the most basic level, it requires guaranteed delivery of high quality audio, not subject to dropouts or latency. However, the industry needs to solve this with a long-term, stable and viable platform. When making decisions on networking infrastructure, end users need to be confident that they’ve chosen an enduring standard and a network that can support them as their media and data needs scale; today, tomorrow, and even years from now.”

By implementing AVB, audio, video and data can coexist on one network, with one cable connection and without causing interference between the data packets. Another new feature in AVB Ethernet is that timing is built into the network itself. AVB networks are self-contained synchronised structures. The timing is baked into the network hardware, so it is far more precise than any software-based synchronisation such as PTP.

Streams in AVB systems use the network time together with the stream reservation mechanism to predetermine their arrival time at the receiver and media clocking is independent from the network time which enables multiple media clock domains to coexist on a single network.

Regarding the benefits Milan brings to the table, Kaltheuner says: “Milan networks don’t require deep network configurations, the bandwidth for media streams is automatically reserved by AVB switches without the need for any deep switch configuration. While the handling is close to plug-and-play the achievable reliability of transport is outstanding. In a Milan network no other data flow can influence the media streams, whether in timing or in reliability. For users this is a new experience of network handling. The Milan initiative aims to transform the simplicity of analogue connectivity into highly flexible converged network systems.”

Milan-ready products have been announced by several leading product manufacturers. At ISE this year, Avnu Alliance members d&b audiotechnik and Adamson announced new products, implementing the Milan specifications. Luminex has also recently announced its Avnu-certified GigaCore switch. At the same time, L-Acoustics announced the publication of an open source, free-to-use AVDECC Library that is now fully Milan compatible with the recently published Milan Discovery, Connection and Control Specification for Listeners and Talkers.

The open source library offers a set of tools for controlling AVB and Milan devices using the AVDECC (IEEE1722.1) protocol and to meet Avnu Milan specifications. These libraries can be implemented on Windows, Linux and macOS using standard development tools. Unit tests and sample programs are also available. The open source tools are available today on GitHub.

As we go into the future, there is enormous potential to distribute all forms of data, including audio, video and information over the same channel, highly effectively.

However, it needs effort by industry participants. Boot summarises: “Manufacturers need to begin by utilising the network as a foundation for their value proposition and make it a priority in all channels within the business; both external and internal. Manufacturers must also work with other companies, openly sharing information on networked products and working together on open standards to help ensure greater network interoperability. The network should simply be easy, reliable and future-proof. It must be open for creativity to enable the creation of valuable products and today it is seeing a convergence of audio, video and control on the same network. One that is scaled across applications and markets.”

Kaltheuner says: “Practically, Milan makes system design and commissioning easier and faster, systems are becoming more fail-safe, especially against unwanted interaction by noneducated users. Milan can be implemented in rather small devices at very low cost. It scales very well into applications that so far were hard to cover with network structures. The key requirements for price sensitivity and easy handling can very well be met by Milan."