Debate surrounding the long-term future of networking has been dominated by the Audio/Video Bridging (AVB) project for a couple of years now. The standardisation-promoting activities of the AVnu Alliance and the popularity of Audinate’s Dante technology – perceived by many as a pathway towards AVB implementation – have done much to ensure that AVB’s profile remains high.
But on the basis of a robust showing at IBC 2012, another approach to the networking problem could soon be rivalling AVB for column inches: Ravenna, which utilises standard IP to deliver real-time distribution of audio and other media. Of the 21 manufacturers who have signed up to the initiative, no fewer than 19 – including such heavy-hitters as Merging Technologies, Genelec and Lawo – could be found at IBC, with many indicating their affiliation by the display of identical stand flags.
The announcement on day one that IP codec manufacturer Qbit had also agreed to implement the technology further underlined the feeling of momentum behind Ravenna, which was developed by Germany-based, Lawo-sponsored company ALC NetworX.
Welcoming PSNEurope to the Ravenna stand on the edge of Hall 8 at Amsterdam’s RAI centre, ALC NetworX senior product manager Andreas Hildebrand (pictured) agreed that a ‘tipping point’ appeared to be in prospect, remarking: “We have worked long and hard to communicate the benefits of this technology, and it is evident to me that the message is now getting across.”Road to routabilityIf that has proven challenging at times, it is hardly surprising with so many approaches to audio-over-IP competing for pro-audio users’ attention. But in its ability to operate without licensing purely on existing, Layer 3-based networks, Hildebrand believes that Ravenna has a strong offering.
“Ravenna streams can traverse subnet boundaries and, under certain conditions, can even use WAN connections. Since only standardised protocols and mechanisms are employed, Ravenna can operate on existing network infrastructures utilising available equipment capabilities,” explains Hildebrand.
This contrasts with Layer 2-based AVB’s requirement for dedicated switches – an issue that could limit its relevance to complex existing broadcast networks. But with broadcast not perceived to be among the core applications for AVB, it may be that the notion of a rivalry between the two technologies is erroneous anyway.
While he is careful not to dismiss possible adoption in other sectors including live, Hildebrand is emphatic that ALC NetworX does “not consider AVB as a competing technology at all. While AVB has other strengths which have a better match in other pro-audio use cases, we see the need for both Layer 2 and Layer 3 technologies for professional media distribution applications.”
Perhaps more than any of its other features – among them low latency, flexible payload format definition, scalability and fully synchronised operation – it is the technology’s licensing-free status that Hildebrand regards as its greatest single selling point. “Manufacturers do not have to buy any black-box IP or pay any licensing fee to ALC NetworX to implement Ravenna into their devices – all protocol ingredients are fully published and freely available,” he clarifies.Regional variations?
But while there is a firm rebuttal to any suggestion of competition with AVB, Hildebrand acknowledges that another lingering perception – that which paints Ravenna as a primarily European phenomenon with only minimal support in the US – does need to be addressed, however mistaken it might be.
“Although the majority of Ravenna partners are actually based in Europe, most of them are engaged in worldwide business. Through the worldwide deployment of Ravenna-enabled devices, we actually experience a growing interest from other continents,” says Hildebrand.
The adoption of Ravenna by US-based broadcast audio specialist Telos Alliance is likely to be particularly significant here. Telos publicised its Ravenna partnership at NAB 2012, where Axia – Telos’s studio audio division – also introduced a new generation of Ravenna-supporting IP audio interfaces, xNodes.
And that’s not all...
“While the xNodes are fully Ravenna-compatible, through close co-operation with the Axia development team we even found a way [to achieve] interoperability between thousands of deployed legacy Livewire and new Ravenna devices – truly a major milestone.”
Additionally, Axia is one of the proponents of the AES X192 task group, which was established by CobraNet pioneer Kevin Gross (of AVA Networks) in 2010 to develop audio-over-IP interoperability standards. Hildebrand is confident that the resulting documents will be applicable to Ravenna – a development that would further enhance the technology’s market credibility.
Miguel Sancho, technical director of AEQ, pinpoints the resonance between the two, noting that AEQ joined the Ravenna project “with the objective to work through this partnership in the preparation and implementation of AES X192. Our commitment is to provide users with IP interconnection of audio equipment in professional and broadcast environments with the additional commitment of trying to facilitate the interconnection via IP to existing equipment, manufactured prior to AES X192 being a standard.” Signing up to Ravenna, adds Sancho, is “our way of contributing to the implementation of AES X192”.
Meanwhile, August’s news that the AES and the EBU are to collaborate on a new common packet-based network standard for linear PCM audio – dubbed ‘Next Generation AES/EBU Interface Based on IP Technology’ – suggests that the entire audio-over-IP initiative is moving into an important new phase.Sorry, no soothsaying
In any case, as Merging Technologies CEO Claude Cellier, observes, Ravenna-based networks are already a reality.
“Some of our users are already deploying Ravenna networks with over 96 channels (equivalent bandwidth to 384 channels running at 48kHz) for some prestige recordings, and all it takes is a simple [sub] Euro 300 managed switch to route those signals between all the I/O nodes,” notes Cellier, adding that Ravenna is “turning out to be a no-brainer to deploy over new or existing networks” provided that basic configuration rules are applied.
With AVB arguably suffering at present from questions about the availability of sufficient quantities of compliant product, the notion that there might soon be one overriding approach to networking able to command near-universal support holds less currency than it did 18 or even 12 months ago.
Hildebrand concurs with PSNEurope’s suggestion that there will probably continue to be a multiplicity of different solutions – “there are, and always will be, application areas where you can potentially apply one or the other technology” – but believes that Ravenna’s case is now clearly drawn.
As for where exactly his preferred technology will stand in a couple of years’ time: “Well, with Ravenna we can do a lot, but I have to report that soothsaying is not on the feature list...”ravenna.alcnetworx.com