Many innovations for radio and television have been to improve how audio signals are processed and distributed to and round facilities before going into the transmission chain. Others have focused more on improving the listening and viewing experience. Increasingly these two requirements are coming closer together under the growing umbrella of IP (internet protocol) and IT, which are creating new infrastructures to accommodate new ways of producing programmes and coverage of events, such as remote production.
IP will undoubtedly have a major and lasting impact on broadcast technology in general. The expectation among most manufacturers and engineers is that it will ultimately replace SDI (serial digital interface) as the dominant video transport format. There are similar expectations in audio, which, in an unusual switch around of the status quo, has been leading its visual counterpart in embracing and adopting the technology.
Audio over IP (AoIP) has been increasing its presence over the past 10 years; after starting in radio it is now becoming a major consideration for television. But, as with many emerging technologies, although AoIP is increasingly an ongoing subject of discussion and a major focus at exhibitions and various ‘plug-fests’, staged to demonstrate interconnectivity between different types of equipment, the rate of implementation does not reflect that profile.
“There’s still a level of uncertainty about AoIP but it is moving up people’s requirements,” comments Chris Collings, director of distribution company Aspen Media.
Representing a variety of manufacturers that have incorporated AoIP into products, including connectivity and bridging specialist DirectOut, which recently signed up to Audinate’s Dante format in addition to RAVENNA, Aspen Media has supplied equipment to a number of recent broadcast centre installations, unfortunately all covered by non-disclosure agreements.
A current trend appears to be, Collings observes, for broadcasters and facilities to create ‘AoIP islands’ for specific operations. “We’re seeing isolated systems based on, for example, RAVENNA,” he says. “This gives the user all the benefits of networks and PTP [Precision Time Protocol].” Among the facility operators to do this is BBC Studioworks, which has created self-contained RAVENNA networks for recording and post-production at its Elstree and TV Centre studios.”
As might be expected, developers of the main AoIP systems are confident that interest in the technology is growing, with this being reflected in increasing numbers of broadcasters beginning to specify it. “The trend is the shift to AoIP, which has been underway for a while, but we are seeing it pick up momentum and make its way through the entire broadcast workflow,” comments Joshua Rush, SVP of marketing and product development at Audinate. “We’re seeing more requests for proposals from broadcasters that are requiring manufacturers or integrators to outline their support for AoIP.”
Rush concedes that “many broadcasters” will not be in a position to replace all equipment in favour of AoIP at the same time but follow a more piecemeal or staggered route. “We tend to see broadcasters start with upgrading portions of their workflow or facility, which requires them to ‘manage the seams’ with legacy analogue and digital gear,” he says. “It’s not uncommon for a broadcaster to upgrade an OB truck to AoIP but need to interface to a studio that is analogue or MADI.”
Dante and RAVENNA, along with AVB (audio video bridge), LiveWire+ from Telos Alliance and Wheatstone’s WheatNet-IP, are the main AoIP protocols that broadcasters are considering today. As these systems are already established it is highly unlikely that a single standard will emerge, meaning that any choice makes an installation locked into one technology and incompatible with anything else.
The Audio Engineering Society’s interoperability standard, AES67, is helping to ease this problem by creating an interchange hub that the different formats can be connected to and form wider networks. Despite this, there are concerns that full AoIP adoption could still be hampered by the conflict of technologies. “I’m not sure AoIP will become a general requirement before more properly standardised equipment, such as AES67 and AES70 [the open control architecture for networks] becomes available,” says Thomas Lund, senior technologist with loudspeaker monitor manufacturer Genelec. “Dante is too proprietary to be dependable in the long run and most broadcasters are aware of that. Older formats such as analogue, SDI and MADI have survived for decades and still ensure a decent low-latency performance.”
RAVENNA was conceived by Philipp Lawo, chief executive of the console manufacturer that bears his surname. The company has embraced IP for both audio and video, providing equipment to facilities and production organisations such as Dorna Sports, which works on TV coverage of the MotoGP series. Lawo’s SVP of business development for broadcast infrastructure, Erling Hedkvist, comments that these are still “early days” in the implementation of IP for broadcast but this does not mean it is unviable.
Hedkvist observes that the initial problem of a lack of standards is now being addressed, particularly with the recent ratification of SMPTE ST2110 for Professional Media Over Managed IP Networks. This is a “suite” of standards primarily for video but it does incorporate AES67, albeit rebranded as ST2110-30. Hedkvist says the challenge now is to establish best practices because early adopters are “taking the brunt of the learning curve”. He adds that broadcasters are being pragmatic about AoIP, implementing it for solid financial or technical reasons - or both - rather than because it’s cool.
Gustavo Robles, sales director of AEQ, which produces mixing consoles, codecs and routers, agrees that AoIP is a trend but says the level of implementation depends on where broadcasters are in the world. “Some areas are 100 per cent looking for AoIP solutions,” he comments. “Other countries - and customers, led by their budgets - are in a middle position looking for IP but with integration of analogue or digital. In the third category are markets and customers that are still one step behind and asking for digital without IP.”
Among the broadcasters AEQ has worked with that went for the fuller option is Rádio Renascença in Portugal. Since last year the media group, which operates commercial stations RFM, Mega Hits FM and Rádio Sim, has been running on a Dante distribution network at its broadcast centre in Lisbon. The installation is based around a central technical control centre, which houses the audio engines for the on-air consoles, with the matrix connected to all other equipment over four redundant Dante Gigabit Ethernet networks. Multichannel MADI connections also work alongside AoIP.
Television is now catching up with radio in terms of adopting AoIP. Stephen Brownsill, audio products manager with TSL Products, comments that the TV sector “is beginning to recognise the advantages - and ultimately the necessity - to convert to both AoIP and video over IP operations.”
TSL Products’ PAM1-IP and PAM2-IP audio monitoring units are able to accommodate SMTPE ST2110 streams and the Ember+ open control protocol, in addition to SDI, AES and analogue connections.
Brownsill acknowledges that because a great deal of audio is still carried over older transport technologies, broadcasters and facilities are now facing a similar choice as when, in the 1990s, digital audio and video began to emerge: “It is just a matter of time before anyone wishing to perpetuate a plant with AV signals flowing over coax and twisted pair cables will find themselves operating a museum, with little or no support from vendors. The recent ratification of SMPTE standards and practices for IP AV signal transport, along with ‘all IP interconnected facility’ demos at the NAB and IBC shows, are beginning to have a positive effect in terms of sparking interest in making the jump to IP.”
As well as what it offers as an overall networking technology, AoIP is also making an impact on the design and operation of specific equipment crucial to broadcasting, most notably mixing consoles and intercom. Wheatstone and Telos subsidiary Axia have been producing IP mixers for 12 and 15 years respectively, primarily for radio. They have now been joined by Calrec Audio, which, at the recent NAB Show, introduced the Type-R desk, its first native, all IP product. Unlike the company’s live TV boards, this is not based on Calrec’s proprietary Hydra2 router and I/O interfaces. Instead it is modular with a “simple” 2U core and integrated I/Os, which connect to an AES67 network.
The Type-R takes Calrec back into the radio market, which the company’s director of product management, Henry Goodman, sees as being ahead of TV in the take up of AoIP implementation. “IP is still a challenge for people moving on with their existing infrastructures, especially in TV,” he says. “The OB side is not so hard because it is relatively easy to build a new truck and make a conscious decision about how far to take it into IP. Multi-studio complexes are more challenging as they can be refurbished only one studio at a time. And when you’ve got a new studio it’s an island of IP that has to be interfaced with everything else around it.”
Ian Staddon, VP of sales at Digico, agrees that conversion of formats is a major issue in the transition to AoIP, which he views as becoming a general requirement. “The older technologies are still being used and need to be converted into an AoIP format,” he says. “But that is purely for transportation and not processing. The fact that there are multiple AoIP formats means it is a challenge to make the transition. Consequently a lot of broadcasters are still relying on the old standards for elements of their infrastructure.”
IP also began to make its presence felt on intercom in the early 2000s. Trilogy Communications, now a subsidiary of Clear-Com, was the pioneer in this field with its Mercury system. Today AoIP is not only part of big matrix-based communications systems from the big three manufacturers - Clear-Com, Riedel Communications and RTS - but has made possible a new breed of matrixless devices from smaller companies. These include Sonifex, Telos and Glensound, which produces the Beatrice range.
Glensound managing director, Gavin Davis, comments that “AoIP is finally happening properly”. The small-scale UK manufacturer is now producing commentary units, interfaces and headphone amplifiers, as well as intercom, all based on Dante/AES67. On the comms side, Davis said the company saw a market for small, easy-to-use talkback units for small radio stations, OB trucks and theatres.
The OB sector in particular has recognised that AoIP-based systems offer more flexibility, something that appeals to production clients. Most OB operators have taken this route, including NEP Visions, which now uses RTS AoIP-based systems in all its UK vehicles. These run on the manufacturer’s OMNEO platform, featuring Dante for media transport. NEP head of sound Paul Fournier says this has simplified installation, with everything now on CAT5 or fibre cables, as well as allowing panels to be set-up for specific users and productions.
Not all areas of broadcast and pro audio lend themselves as readily to AoIP as intercom. The microphone sector sees the potential, with US wireless specialist Wisycom integrating IP into the chain from antenna management to frequency control, coordination and monitoring. Another leading maker of wireless systems, Sennheiser, is a little more circumspect. Tobias von Allwörden, portfolio manager for broadcast, likens the transition to AoIP to the change from analogue to digital radio mics: “This is a process that will not be completed in a few months but will continue for quite some time. The benefits of technology that is purely IP/digitally-based are obvious. There will be a time of co-existence but, ultimately, users will not see a technological advantage in keeping traditional technologies alive.”
The most noticeable change in broadcast operations that IP in general is making possible is remote production. This has been on the increase for the last few years, particularly in the US small-scale TV station sector, but this year sees the concept starting to come into its own. During the Winter Olympics in South Korea, several major broadcasters, including the BBC and NBC, used remote connections to control equipment and processes, such as audio mixing, from their bases back at home.
“Remote production is steadily gaining traction,” comments Henry Goodman at Calrec. “It’s becoming more prevalent for each major sporting event and is getting better all the time.”
AEQ’s Gustavo Robles also sees the rise of this technique, but adds that it does complicate matters for the sound department: “We should offer the same level of audio quality but having transmit and receive lines in the middle, which we didn’t have in the past, might limit the quality of service. Delay is also critical and we have put a lot of effort into algorithms to ensure good quality at low bandwidths with low delay.”
Such benefits aren’t always obvious to the viewer at home, of course. But discrepancies in lip-synching will keep one of the bulwarks of TV broadcasting - the angry complaint - going for some time.
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