Technology update


ISE 2018 report: AV over IP – standards starting to emerge


In the convergence of AV and IT, the technology of AV over stan- dard IT networks is crucially im- portant. This year’s ISE showed many manufacturers presenting solutions for the transmission of audio and video signals over standard IP networks. Now all we are missing are the standards that deliver uniformity across the industry.


Further development in AV over IT are promising, not least because if AV signals can be transmitted


over the compa-


ny network, in the traditional model, audiovisual (AV) signals are forwarded in designated networks created for the pur- pose. The equipment in such a network consists mainly of video matrix switchers with a given number of input and out- put (I/O) ports and signal ex- tenders forwarding the signals via high quality CAT cables or optical lines. Extenders send- ing signals in point-to-point configurations are called trans- mitters, while those receiving the signals at the far end are receivers. In AV Over IP setups, audio and video signals are usually sent through standard IT net- works (although it is still, on oc- casions, recommended to build a dedicated, purpose-built network for video distribution) and so the need for separate AV infrastructure can be re- moved. Devices sending signals are typically called encoders (when the transmitter actually encodes the signal), as they convert audio and video signals into data that can be streamed


across a standard Ethernet


network to a receiving decoder device, that converts (decodes) the received data back to audio and video signals.


Advantages


Advantages of this configura- tion include scalability. Eth- ernet networks can have a virtually limitless size, with any number of encoders and decoders work together in one- to-one, one-to-many or ma- ny-to-many AV configurations. It is not unusual for networks to exceed 100m, with all of the same management tools, per- missions for stream access and security protocols as computer data.


In an AV Over IP network a standard


Ethernet switch re-


places the conventional AV matrix switch without the lim- itation of a fixed I/O size. This creates a big advantage for AV Over IP systems which are in this


sense infinitely expand-


able, as long as there are free ports available on the central Ethernet switch used, further devices can be added to the network.


Crestron presented their NVX system at ISE 2018 for 1 GBit networks, a pioneer in this field.


The number of input and out- put ‘ports’ of the virtual ma- trix environment can be freely configured, so it is possible to create systems which have a lot of devices on the output side, while only a very few on the input.


Cost savings are often the de- terminant of which system to use. There is only need for a single cable installation which minimises costs and reduces the complexity of dedicated cable grids for AV signals. AV signals are basically transferred as data packets, just like the usual network traffic, without being affected by interference caused by other nearby cables. Where AV switches might cost thousands of pounds, AV over IP solution can be executed us- ing simple Ethernet switches, cutting costs substantially.


Standards? But


unfortunately, there are


still no uniform standards and the issue of bandwidth remains unsolved. The most appropriate networks for the transmission of 4K HDR signals, at 60 Hz, are 10 Gbit networks, but the reality is that most corporate networks are designed for a 1 Gbit bandwidth.


Standards aside, there are still many challenges to be overcome in achieving user ex- pectations of sending HD and 4K/UHD video while retaining the image quality of an HDMI or HDBaseTTM video solution. In order to do so, the HDMI bandwidth has increased to 18 Gbps with the release of HDMI 2.0.


Neither 1 Gb and 10 Gb Eth- ernet networks have enough bandwidth for 4K/UHD HDR video streams, and so a degree of compression is necessary. Some processing time is need- ed to process the video, which imposes a degree of latency. The end result can either be lossless, without degradation of the image, or it can be lossy but the artefact is more accept- able than even a small level of latency. Audio signals are usu- ally time-coded, to sync with the delay of the video signal. The greater the degree of compression the lower the quality and the greater the la- tency. If the compression is lighter, then more bandwidth is needed, while quality is better and latency remains minimal.


Solutions on show at ISE


What was on offer at this year’s ISE regarding IP signal trans- mission? The HDBaseT Alli- ance, had wanted to develop a standard which worked for 1 GBit to 10 GB networks with HDBaseT over IP. The Alliance announced that they needed to go back to basis and as such presented nothing new. The SDVoE Alliance developed a second “quasi-standard” based on 10 Gbit networks. Numer-


P8 AV News April 2018


Lightware designed and developed the VINX encoder/decoder pair for 1 Gb Ethernet networks, providing 4K@30 Hz and Full HD video signal extension with hardly noticeable latency and proprietary,


take in to account for example without a standards-based ap- proach, products from different manufacturers are currently not compatible with each other. In addition to the ‘quasi-stan- dards,’ some manufacturers presented their own propri- etary solutions for IP signal transmission. Crestron pre- sented their NVX system for 1 GBit networks, a pioneer in this field. Selecting a solution when comprehensive standards are lacking, commits you to a specific manufacturer with all the corresponding advantages and disadvantages. It is also to be expected that for the fore- seeable future hybrid systems which combine IP with HDBa- seT transmission will survive.


Options


Martin Wagner of Macon re- ports


that his organisation’s


consultants see three potential solutions continuing in the ab- sence of a comprehended stan- dard.


1 Gbit systems are relatively easy to implement and are a suitable replacement for ex- isting systems. Today, the big- gest advantage is that 1 Gbit systems can be integrated into existing corporate networks and standard IT components can be used for signal distribution significantly reducing costs. Although higher compression rates are required for audio and video transmission, 1 Gbit systems are often sufficient for


for some of their solutions. Al- though this means losing one of the main advantages of IP technology (utilisation of stan- dard IT network hardware), it is a very powerful solution. The task of finding the opti- mal compression


ratio while


also retaining quality is much easier in case of smaller reso- lutions. Also, with the newest HDMI, DVI or SDI transmission standards it has become easier to compress efficiently as com- pared to analogue signals. With a compression algorithm such as the H.264 standard, the bandwidth needed for 1080p quality transmissions can be performed at 10-20 Mbits/sec, which is less than 1 percent of the bandwidth of the original signal.


ous exhibitors presented work- ing solutions utilising this ap- proach. Most IT standard components are designed for 1 Gbit, rath- er than 10 Gbit networks, and many companies still lack the necessary infrastructure to de- ploy this type of solution. With no substantial commercial base, components such as 10 Gbit switches are so expensive that they don’t really save costs when compared to an HDBaseT infrastructure.


This being so, one of the main arguments


for the IP-based


transmission, lower price, is a bit of a non-starter. A 10 GB sys- tem also significantly limits the flexibility and scalability over a 1 GB solution and requires large bandwidths between switches for in-house distribu- tion. There are other issues to


many applications. 10 Gbit systems based on


SDVoE ‘quasi-standards’ this offers very good transmission options thanks to the higher bandwidth, especially if, for example, 4K HDR with low latencies is being transmitted. Since the development of 4K solutions will not stop (display manufacturers looking to pres- ent 8K displays this year) the future probably lies in this di- rection. However, today SDVoE solutions still offer little cost advantage over HDBaseT infra- structures.


In addition, manufacturers such as EvertzAV or Lightware use IP technologies as a basis. However, they are highly opti- mized in certain parameters and are therefore proprietary solutions. EvertzAV for example use their own switch hardware


Additional reporting With thanks to Macon and Lightware Visual Engineering for their contributions to this piece.


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